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x86: remove paravirt_enabled()

PATCH Applied Luis R. Rodriguez 4 participants 39 messages Apr 14, 2016 – Apr 3, 2024

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#0 lore raw

v6 cover x86: remove paravirt_enabled()

This v6 series addresses:

- addresses the __init on xen_dom0_set_legacy_features() as Juergen asked, the reason the size impact doesn't changea as per 0-day is 0-day uses x86 tinyconfig but the gains should be there

- I looked for stragglers on Reivewed-by / Acked-by tags, I could not find anything else missing. If I left your tag out it means the patch has changed since your last review and your blessings would be good to have. Seems the only ones missing were Rusty's for lguest stuff and Juergen Acked-by for the patch "x86/paravirt: remove paravirt_enabled()"

- Folds the X86_SUBARCH_INTEL_MID and X86_SUBARCH_CE4100 new uses of the quirks. As such it also adjusts the commit log for the X86_SUBARCH_INTEL_MID patch to account for the vmlinux size impact as per 0-day on tinyconfig.

This has been all tested by 0-day. This series is available on git here:

https://git.kernel.org/cgit/linux/kernel/git/mcgrof/linux-next.git/log/?h=20160413-pv-disabled-v6

Luis R. Rodriguez (16):
x86/boot: enumerate documentation for the x86 hardware_subarch x86/xen: use X86_SUBARCH_XEN for PV guest boots tools/lguest: make lguest launcher use X86_SUBARCH_LGUEST explicitly x86/rtc: replace paravirt rtc check with platform legacy quirk x86, ACPI: move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code x86/init: use a platform legacy quirk for ebda tools/lguest: force disable tboot and apm
apm32: remove paravirt_enabled() use
x86/tboot: remove paravirt_enabled()
x86/cpu/intel: remove not needed paravirt_enabled() for f00f work
around
pnpbios: replace paravirt_enabled() check with legacy device check x86, ACPI: parse ACPI_FADT_LEGACY_DEVICES
x86/init: rename ebda code file
x86/paravirt: remove paravirt_enabled()
x86/init: disable pnpbios for X86_SUBARCH_INTEL_MID x86/init: disable pnpbios and rtc for X86_SUBARCH_CE4100

 arch/x86/Makefile                     |  3 ++-
 arch/x86/include/asm/paravirt.h       | 11 --------
 arch/x86/include/asm/paravirt_types.h |  6 -----
 arch/x86/include/asm/processor.h      |  2 --
 arch/x86/include/asm/x86_init.h       | 50 +++++++++++++++++++++++++++++++++++
 arch/x86/include/uapi/asm/bootparam.h | 41 +++++++++++++++++++++++++++-
 arch/x86/kernel/Makefile              |  6 ++++-
 arch/x86/kernel/acpi/boot.c           |  9 +++++++
 arch/x86/kernel/apm_32.c              |  2 +-
 arch/x86/kernel/cpu/intel.c           |  2 +-
 arch/x86/kernel/{head.c => ebda.c}    |  2 +-
 arch/x86/kernel/head32.c              |  2 ++
 arch/x86/kernel/head64.c              |  1 +
 arch/x86/kernel/kvm.c                 |  8 ------
 arch/x86/kernel/paravirt.c            |  1 -
 arch/x86/kernel/platform-quirks.c     | 35 ++++++++++++++++++++++++
 arch/x86/kernel/rtc.c                 | 18 ++-----------
 arch/x86/kernel/tboot.c               |  6 -----
 arch/x86/lguest/boot.c                |  3 ---
 arch/x86/xen/enlighten.c              | 12 ++++++---
 drivers/pnp/pnpbios/core.c            |  3 ++-
 include/linux/pnp.h                   |  2 ++
 tools/lguest/lguest.c                 | 10 +++++--
 23 files changed, 169 insertions(+), 66 deletions(-)
 rename arch/x86/kernel/{head.c => ebda.c} (98%)
 create mode 100644 arch/x86/kernel/platform-quirks.c
Signature · 1 line
2.7.2
#1 lore raw

PATCH v6 1/16 x86/boot: enumerate documentation for the x86 hardware_subarch

Although hardware_subarch has been in place since the x86 boot protocol 2.07 it hasn't been used much. Enumerate current possible values to avoid misuses and help with semantics later at boot time should this be used further.

These enums should only ever be used by architecture x86 code, and all that code should be well contained and compartamentalized, clarify that as well.

v4: updates documentation further -- be a bit more pedantic about
annotating care and use of these guys.
v5: Use s/SOC/SoC and also anntoate that both domU and dom0 are
both currently supported through the PV boot path.
v6: add big fat warning about how this is for legacy platforms
only, as per Ingo's request

---
 arch/x86/include/uapi/asm/bootparam.h | 41 ++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)
arch/x86/include/uapi/asm/bootparam.h +40 -1
index 329254373479..c18ce67495fa 100644
@@ -157,7 +157,46 @@ struct boot_params {
 	__u8  _pad9[276];				/* 0xeec */
 } __attribute__((packed));
 
-enum {
+/**
+ * enum x86_hardware_subarch - x86 hardware subarchitecture
+ *
+ * The x86 hardware_subarch and hardware_subarch_data were added as of the x86
+ * boot protocol 2.07 to help distinguish and support custom x86 boot
+ * sequences. This enum represents accepted values for the x86
+ * hardware_subarch.  Custom x86 boot sequences (not X86_SUBARCH_PC) do not
+ * have or simply *cannot* make use of natural stubs like BIOS or EFI, the
+ * hardware_subarch can be used on the Linux entry path to revector to a
+ * subarchitecture stub when needed. This subarchitecture stub can be used to
+ * set up Linux boot parameters or for special care to account for nonstandard
+ * handling of page tables.
+ *
+ * These enums should only ever be used by x86 code, and the code that uses
+ * it should be well contained and compartamentalized.
+ *
+ * KVM and Xen HVM do not have a subarch as these are expected to follow
+ * standard x86 boot entries. If there is a genuine need for "hypervisor" type
+ * that should be considered separately in the future. Future guest types
+ * should seriously consider working with standard x86 boot stubs such as
+ * the BIOS or EFI boot stubs.
+ *
+ * WARNING: this enum is only used for legacy hacks, for platform features that
+ *	    are not easily enumerated or discoverable. You should not ever use
+ *	    this for new features.
+ *
+ * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard
+ *	PC mechanisms (PCI, ACPI) and doesn't need a special boot flow.
+ * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest
+ * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path,
+ * 	which start at asm startup_xen() entry point and later jump to the C
+ * 	xen_start_kernel() entry point. Both domU and dom0 type of guests are
+ * 	currently supportd through this PV boot path.
+ * @X86_SUBARCH_INTEL_MID: Used for Intel MID (Mobile Internet Device) platform
+ *	systems which do not have the PCI legacy interfaces.
+ * @X86_SUBARCH_CE4100: Used for Intel CE media processor (CE4100) SoC for
+ * 	for settop boxes and media devices, the use of a subarch for CE4100
+ * 	is more of a hack...
+ */
+enum x86_hardware_subarch {
 	X86_SUBARCH_PC = 0,
 	X86_SUBARCH_LGUEST,
 	X86_SUBARCH_XEN,
Signature · 1 line
2.7.2
#2 lore raw

[tip:x86/boot] x86/boot: Enumerate documentation for the x86 hardware_subarch

x86/boot: Enumerate documentation for the x86 hardware_subarch
Commit-ID:  18c78a96239749fc4aaee84ca1eb5a8e81f2601d
Gitweb:     http://git.kernel.org/tip/18c78a96239749fc4aaee84ca1eb5a8e81f2601d
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:31 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:28:59 +0200

x86/boot: Enumerate documentation for the x86 hardware_subarch

Although hardware_subarch has been in place since the x86 boot protocol 2.07 it hasn't been used much. Enumerate current possible values to avoid misuses and help with semantics later at boot time should this be used further.

These enums should only ever be used by architecture x86 code, and all that code should be well contained and compartamentalized, clarify that as well.

---
 arch/x86/include/uapi/asm/bootparam.h | 41 ++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)
arch/x86/include/uapi/asm/bootparam.h +40 -1
index 3292543..c18ce67 100644
@@ -157,7 +157,46 @@ struct boot_params {
 	__u8  _pad9[276];				/* 0xeec */
 } __attribute__((packed));
 
-enum {
+/**
+ * enum x86_hardware_subarch - x86 hardware subarchitecture
+ *
+ * The x86 hardware_subarch and hardware_subarch_data were added as of the x86
+ * boot protocol 2.07 to help distinguish and support custom x86 boot
+ * sequences. This enum represents accepted values for the x86
+ * hardware_subarch.  Custom x86 boot sequences (not X86_SUBARCH_PC) do not
+ * have or simply *cannot* make use of natural stubs like BIOS or EFI, the
+ * hardware_subarch can be used on the Linux entry path to revector to a
+ * subarchitecture stub when needed. This subarchitecture stub can be used to
+ * set up Linux boot parameters or for special care to account for nonstandard
+ * handling of page tables.
+ *
+ * These enums should only ever be used by x86 code, and the code that uses
+ * it should be well contained and compartamentalized.
+ *
+ * KVM and Xen HVM do not have a subarch as these are expected to follow
+ * standard x86 boot entries. If there is a genuine need for "hypervisor" type
+ * that should be considered separately in the future. Future guest types
+ * should seriously consider working with standard x86 boot stubs such as
+ * the BIOS or EFI boot stubs.
+ *
+ * WARNING: this enum is only used for legacy hacks, for platform features that
+ *	    are not easily enumerated or discoverable. You should not ever use
+ *	    this for new features.
+ *
+ * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard
+ *	PC mechanisms (PCI, ACPI) and doesn't need a special boot flow.
+ * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest
+ * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path,
+ * 	which start at asm startup_xen() entry point and later jump to the C
+ * 	xen_start_kernel() entry point. Both domU and dom0 type of guests are
+ * 	currently supportd through this PV boot path.
+ * @X86_SUBARCH_INTEL_MID: Used for Intel MID (Mobile Internet Device) platform
+ *	systems which do not have the PCI legacy interfaces.
+ * @X86_SUBARCH_CE4100: Used for Intel CE media processor (CE4100) SoC for
+ * 	for settop boxes and media devices, the use of a subarch for CE4100
+ * 	is more of a hack...
+ */
+enum x86_hardware_subarch {
 	X86_SUBARCH_PC = 0,
 	X86_SUBARCH_LGUEST,
 	X86_SUBARCH_XEN,
#3 lore raw

PATCH v6 2/16 x86/xen: use X86_SUBARCH_XEN for PV guest boots

In reply to Luis R. Rodriguez

The use of subarch should have no current effect on Xen PV guests, as such this should have no current functional effects.

---
 arch/x86/xen/enlighten.c | 1 +
 1 file changed, 1 insertion(+)
arch/x86/xen/enlighten.c +1 -0
index 9b8f1eacc110..40487f1ecb4c 100644
@@ -1661,6 +1661,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	boot_params.hdr.ramdisk_image = initrd_start;
 	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
 	boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
+	boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
 
 	if (!xen_initial_domain()) {
 		add_preferred_console("xenboot", 0, NULL);
Signature · 7 lines
2.7.2


_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xen.org/xen-devel
#4 lore raw

[tip:x86/boot] x86/xen: Use X86_SUBARCH_XEN for PV guest boots

x86/xen: Use X86_SUBARCH_XEN for PV guest boots
Commit-ID:  ea1794812410e92c537c839bedeb2d2b2f87c80d
Gitweb:     http://git.kernel.org/tip/ea1794812410e92c537c839bedeb2d2b2f87c80d
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:32 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:28:59 +0200

x86/xen: Use X86_SUBARCH_XEN for PV guest boots

The use of subarch should have no current effect on Xen PV guests, as such this should have no current functional effects.

---
 arch/x86/xen/enlighten.c | 1 +
 1 file changed, 1 insertion(+)
arch/x86/xen/enlighten.c +1 -0
index 880862c..61f4d9f 100644
@@ -1670,6 +1670,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	boot_params.hdr.ramdisk_image = initrd_start;
 	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
 	boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
+	boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
 
 	if (!xen_initial_domain()) {
 		add_preferred_console("xenboot", 0, NULL);
#5 lore raw

PATCH v6 3/16 tools/lguest: make lguest launcher use X86_SUBARCH_LGUEST explicitly

In reply to Luis R. Rodriguez

Be explicit and make use of X86_SUBARCH_LGUEST directly.

---
 tools/lguest/lguest.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
tools/lguest/lguest.c +2 -2
index 80159e6811c2..ff0aa580c6e1 100644
@@ -3351,8 +3351,8 @@ int main(int argc, char *argv[])
 	/* Boot protocol version: 2.07 supports the fields for lguest. */
 	boot->hdr.version = 0x207;
 
-	/* The hardware_subarch value of "1" tells the Guest it's an lguest. */
-	boot->hdr.hardware_subarch = 1;
+	/* X86_SUBARCH_LGUEST tells the Guest it's an lguest. */
+	boot->hdr.hardware_subarch = X86_SUBARCH_LGUEST;
 
 	/* Tell the entry path not to try to reload segment registers. */
 	boot->hdr.loadflags |= KEEP_SEGMENTS;
Signature · 1 line
2.7.2
#6 lore raw

[tip:x86/boot] tools/lguest: Make lguest launcher use X86_SUBARCH_LGUEST explicitly

tools/lguest: Make lguest launcher use X86_SUBARCH_LGUEST explicitly
Commit-ID:  907bb655797427cc6498045d6977e77f8363fff7
Gitweb:     http://git.kernel.org/tip/907bb655797427cc6498045d6977e77f8363fff7
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:33 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:00 +0200

tools/lguest: Make lguest launcher use X86_SUBARCH_LGUEST explicitly

Be explicit and make use of X86_SUBARCH_LGUEST directly.

---
 tools/lguest/lguest.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
tools/lguest/lguest.c +2 -2
index 80159e6..ff0aa580 100644
@@ -3351,8 +3351,8 @@ int main(int argc, char *argv[])
 	/* Boot protocol version: 2.07 supports the fields for lguest. */
 	boot->hdr.version = 0x207;
 
-	/* The hardware_subarch value of "1" tells the Guest it's an lguest. */
-	boot->hdr.hardware_subarch = 1;
+	/* X86_SUBARCH_LGUEST tells the Guest it's an lguest. */
+	boot->hdr.hardware_subarch = X86_SUBARCH_LGUEST;
 
 	/* Tell the entry path not to try to reload segment registers. */
 	boot->hdr.loadflags |= KEEP_SEGMENTS;
#7 lore raw

PATCH v6 4/16 x86/rtc: replace paravirt rtc check with platform legacy quirk

In reply to Luis R. Rodriguez

We have 4 types of x86 platforms that disable RTC:

* Intel MID
* Lguest - uses paravirt
* Xen dom-U - uses paravirt
* x86 on legacy systems annotated with an ACPI legacy flag

We can consolidate all of these into a platform specific legacy quirk set early in boot through i386_start_kernel() and through x86_64_start_reservations(). This deals with the RTC quirks which we can rely on through the hardware subarch, the ACPI check can be dealt with separately.

For Xen things are bit more complex given that the @X86_SUBARCH_XEN x86_hardware_subarch is shared on for Xen which uses the PV path for both domU and dom0. Since the semantics for differentiating between the two are Xen specific we provide a platform helper to help override default legacy features -- x86_platform.set_legacy_features(). Use of this helper is highly discouraged, its only purpose should be to account for the lack of semantics available within your given x86_hardware_subarch.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text    x86_early_init_platform_quirks()
+70     +62    +62          +43

Only 8 bytes overhead total, as the main increase in size is all removed via __init.

v4: split the subarch check from the ACPI check, clarify
on the ACPI change commit log why ordering works
v5: add x86_platform.set_legacy_features() to account for dom0,
add also size impact on vmlinux as per 0-day report
v6: Use __init on xen_dom0_set_legacy_features()

---
 arch/x86/Makefile                     |  1 +
 arch/x86/include/asm/paravirt.h       |  6 ------
 arch/x86/include/asm/paravirt_types.h |  5 -----
 arch/x86/include/asm/processor.h      |  1 -
 arch/x86/include/asm/x86_init.h       | 21 +++++++++++++++++++++
 arch/x86/kernel/Makefile              |  6 +++++-
 arch/x86/kernel/head32.c              |  2 ++
 arch/x86/kernel/head64.c              |  1 +
 arch/x86/kernel/platform-quirks.c     | 21 +++++++++++++++++++++
 arch/x86/kernel/rtc.c                 |  7 ++-----
 arch/x86/lguest/boot.c                |  1 -
 arch/x86/xen/enlighten.c              | 10 +++++++---
 12 files changed, 60 insertions(+), 22 deletions(-)
 create mode 100644 arch/x86/kernel/platform-quirks.c
arch/x86/Makefile +1 -0
index 4086abca0b32..f9ed8a7ce2b6 100644
@@ -209,6 +209,7 @@ endif
 head-y := arch/x86/kernel/head_$(BITS).o
 head-y += arch/x86/kernel/head$(BITS).o
 head-y += arch/x86/kernel/head.o
+head-y += arch/x86/kernel/platform-quirks.o
 
 libs-y  += arch/x86/lib/
 
arch/x86/include/asm/paravirt.h +0 -6
index 601f1b8f9961..6c7a4a192032 100644
@@ -20,12 +20,6 @@ static inline int paravirt_enabled(void)
 	return pv_info.paravirt_enabled;
 }
 
-static inline int paravirt_has_feature(unsigned int feature)
-{
-	WARN_ON_ONCE(!pv_info.paravirt_enabled);
-	return (pv_info.features & feature);
-}
-
 static inline void load_sp0(struct tss_struct *tss,
 			     struct thread_struct *thread)
 {
arch/x86/include/asm/paravirt_types.h +0 -5
index e8c2326478c8..6acc1b26cf40 100644
@@ -70,14 +70,9 @@ struct pv_info {
 #endif
 
 	int paravirt_enabled;
-	unsigned int features;	  /* valid only if paravirt_enabled is set */
 	const char *name;
 };
 
-#define paravirt_has(x) paravirt_has_feature(PV_SUPPORTED_##x)
-/* Supported features */
-#define PV_SUPPORTED_RTC        (1<<0)
-
 struct pv_init_ops {
 	/*
 	 * Patch may replace one of the defined code sequences with
arch/x86/include/asm/processor.h +0 -1
index 9264476f3d57..0c70c7daa6b8 100644
@@ -474,7 +474,6 @@ static inline unsigned long current_top_of_stack(void)
 #else
 #define __cpuid			native_cpuid
 #define paravirt_enabled()	0
-#define paravirt_has(x) 	0
 
 static inline void load_sp0(struct tss_struct *tss,
 			    struct thread_struct *thread)
arch/x86/include/asm/x86_init.h +21 -0
index 1ae89a2721d6..8bb8c1a4615a 100644
@@ -142,6 +142,15 @@ struct x86_cpuinit_ops {
 struct timespec;
 
 /**
+ * struct x86_legacy_features - legacy x86 features
+ *
+ * @rtc: this device has a CMOS real-time clock present
+ */
+struct x86_legacy_features {
+	int rtc;
+};
+
+/**
  * struct x86_platform_ops - platform specific runtime functions
  * @calibrate_tsc:		calibrate TSC
  * @get_wallclock:		get time from HW clock like RTC etc.
@@ -152,6 +161,14 @@ struct timespec;
  * @save_sched_clock_state:	save state for sched_clock() on suspend
  * @restore_sched_clock_state:	restore state for sched_clock() on resume
  * @apic_post_init:		adjust apic if neeeded
+ * @legacy:			legacy features
+ * @set_legacy_features:	override legacy features. Use of this callback
+ * 				is highly discouraged. You should only need
+ * 				this if your hardware platform requires further
+ * 				custom fine tuning far beyong what may be
+ * 				possible in x86_early_init_platform_quirks() by
+ * 				only using the current x86_hardware_subarch
+ * 				semantics.
  */
 struct x86_platform_ops {
 	unsigned long (*calibrate_tsc)(void);
@@ -165,6 +182,8 @@ struct x86_platform_ops {
 	void (*save_sched_clock_state)(void);
 	void (*restore_sched_clock_state)(void);
 	void (*apic_post_init)(void);
+	struct x86_legacy_features legacy;
+	void (*set_legacy_features)(void);
 };
 
 struct pci_dev;
@@ -186,6 +205,8 @@ extern struct x86_cpuinit_ops x86_cpuinit;
 extern struct x86_platform_ops x86_platform;
 extern struct x86_msi_ops x86_msi;
 extern struct x86_io_apic_ops x86_io_apic_ops;
+
+extern void x86_early_init_platform_quirks(void);
 extern void x86_init_noop(void);
 extern void x86_init_uint_noop(unsigned int unused);
 
arch/x86/kernel/Makefile +5 -1
index 89f8ade0bc7c..7a9e44d935de 100644
@@ -2,7 +2,11 @@
 # Makefile for the linux kernel.
 #
 
-extra-y                := head_$(BITS).o head$(BITS).o head.o vmlinux.lds
+extra-y	:= head_$(BITS).o
+extra-y	+= head$(BITS).o
+extra-y	+= head.o
+extra-y	+= platform-quirks.o
+extra-y	+= vmlinux.lds
 
 CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
 
arch/x86/kernel/head32.c +2 -0
index 2911ef3a9f1c..d784bb547a9d 100644
@@ -34,6 +34,8 @@ asmlinkage __visible void __init i386_start_kernel(void)
 	cr4_init_shadow();
 	sanitize_boot_params(&boot_params);
 
+	x86_early_init_platform_quirks();
+
 	/* Call the subarch specific early setup function */
 	switch (boot_params.hdr.hardware_subarch) {
 	case X86_SUBARCH_INTEL_MID:
arch/x86/kernel/head64.c +1 -0
index 1f4422d5c8d0..b72fb0b71dd1 100644
@@ -182,6 +182,7 @@ void __init x86_64_start_reservations(char *real_mode_data)
 	if (!boot_params.hdr.version)
 		copy_bootdata(__va(real_mode_data));
 
+	x86_early_init_platform_quirks();
 	reserve_ebda_region();
 
 	switch (boot_params.hdr.hardware_subarch) {
arch/x86/kernel/platform-quirks.c new file +21 -0
new file mode 100644
index 000000000000..021a5f973ce3
@@ -0,0 +1,21 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+#include <asm/setup.h>
+#include <asm/bios_ebda.h>
+
+void __init x86_early_init_platform_quirks(void)
+{
+	x86_platform.legacy.rtc = 1;
+
+	switch (boot_params.hdr.hardware_subarch) {
+	case X86_SUBARCH_XEN:
+	case X86_SUBARCH_LGUEST:
+	case X86_SUBARCH_INTEL_MID:
+		x86_platform.legacy.rtc = 0;
+		break;
+	}
+
+	if (x86_platform.set_legacy_features)
+		x86_platform.set_legacy_features();
+}
arch/x86/kernel/rtc.c +2 -5
index 4af8d063fb36..62c48da3889d 100644
@@ -14,6 +14,7 @@
 #include <asm/time.h>
 #include <asm/intel-mid.h>
 #include <asm/rtc.h>
+#include <asm/setup.h>
 
 #ifdef CONFIG_X86_32
 /*
@@ -188,10 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-	/* Intel MID platforms don't have ioport rtc */
-	if (intel_mid_identify_cpu())
-		return -ENODEV;
-
 #ifdef CONFIG_ACPI
 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
 		/* This warning can likely go away again in a year or two. */
@@ -200,7 +197,7 @@ static __init int add_rtc_cmos(void)
 	}
 #endif
 
-	if (paravirt_enabled() && !paravirt_has(RTC))
+	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
 	platform_device_register(&rtc_device);
arch/x86/lguest/boot.c +0 -1
index fd57d3ae7e16..f5497ee5fd2f 100644
@@ -1414,7 +1414,6 @@ __init void lguest_init(void)
 	pv_info.kernel_rpl = 1;
 	/* Everyone except Xen runs with this set. */
 	pv_info.shared_kernel_pmd = 1;
-	pv_info.features = 0;
 
 	/*
 	 * We set up all the lguest overrides for sensitive operations.  These
arch/x86/xen/enlighten.c +7 -3
index 40487f1ecb4c..b08489ba5051 100644
@@ -1192,7 +1192,6 @@ static const struct pv_info xen_info __initconst = {
 #ifdef CONFIG_X86_64
 	.extra_user_64bit_cs = FLAT_USER_CS64,
 #endif
-	.features = 0,
 	.name = "Xen",
 };
 
@@ -1505,6 +1504,11 @@ static void __init xen_pvh_early_guest_init(void)
 }
 #endif    /* CONFIG_XEN_PVH */
 
+static void __init xen_dom0_set_legacy_features(void)
+{
+	x86_platform.legacy.rtc = 1;
+}
+
 /* First C function to be called on Xen boot */
 asmlinkage __visible void __init xen_start_kernel(void)
 {
@@ -1525,8 +1529,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 
 	/* Install Xen paravirt ops */
 	pv_info = xen_info;
-	if (xen_initial_domain())
-		pv_info.features |= PV_SUPPORTED_RTC;
 	pv_init_ops = xen_init_ops;
 	if (!xen_pvh_domain()) {
 		pv_cpu_ops = xen_cpu_ops;
@@ -1679,6 +1681,8 @@ asmlinkage __visible void __init xen_start_kernel(void)
 			.u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
 		};
 
+		x86_platform.set_legacy_features =
+				xen_dom0_set_legacy_features;
 		xen_init_vga(info, xen_start_info->console.dom0.info_size);
 		xen_start_info->console.domU.mfn = 0;
 		xen_start_info->console.domU.evtchn = 0;
Signature · 7 lines
2.7.2


_______________________________________________
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[email protected]
http://lists.xen.org/xen-devel
maintainer Reviewed-by on v6 4/16
#8 lore raw

Re: [PATCH v6 04/16] x86/rtc: replace paravirt rtc check with platform legacy quirk

Quoted 31 lines · Luis R. Rodriguez

We have 4 types of x86 platforms that disable RTC:

* Intel MID
* Lguest - uses paravirt
* Xen dom-U - uses paravirt
* x86 on legacy systems annotated with an ACPI legacy flag

We can consolidate all of these into a platform specific legacy quirk set early in boot through i386_start_kernel() and through x86_64_start_reservations(). This deals with the RTC quirks which we can rely on through the hardware subarch, the ACPI check can be dealt with separately.

For Xen things are bit more complex given that the @X86_SUBARCH_XEN x86_hardware_subarch is shared on for Xen which uses the PV path for both domU and dom0. Since the semantics for differentiating between the two are Xen specific we provide a platform helper to help override default legacy features -- x86_platform.set_legacy_features(). Use of this helper is highly discouraged, its only purpose should be to account for the lack of semantics available within your given x86_hardware_subarch.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text    x86_early_init_platform_quirks()
+70     +62    +62          +43

Only 8 bytes overhead total, as the main increase in size is all removed via __init.

Quoted 8 lines

v4: split the subarch check from the ACPI check, clarify
on the ACPI change commit log why ordering works
v5: add x86_platform.set_legacy_features() to account for dom0,
add also size impact on vmlinux as per 0-day report
v6: Use __init on xen_dom0_set_legacy_features()

Juergen

#9 lore raw

[tip:x86/boot] x86/rtc: Replace paravirt rtc check with platform legacy quirk

In reply to Luis R. Rodriguez
x86/rtc: Replace paravirt rtc check with platform legacy quirk
Commit-ID:  8d152e7a5c7537b18b4e9e0eb96f549b016636dc
Gitweb:     http://git.kernel.org/tip/8d152e7a5c7537b18b4e9e0eb96f549b016636dc
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:34 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:01 +0200

x86/rtc: Replace paravirt rtc check with platform legacy quirk

We have 4 types of x86 platforms that disable RTC:

* Intel MID
* Lguest - uses paravirt
* Xen dom-U - uses paravirt
* x86 on legacy systems annotated with an ACPI legacy flag

We can consolidate all of these into a platform specific legacy quirk set early in boot through i386_start_kernel() and through x86_64_start_reservations(). This deals with the RTC quirks which we can rely on through the hardware subarch, the ACPI check can be dealt with separately.

For Xen things are bit more complex given that the @X86_SUBARCH_XEN x86_hardware_subarch is shared on for Xen which uses the PV path for both domU and dom0. Since the semantics for differentiating between the two are Xen specific we provide a platform helper to help override default legacy features -- x86_platform.set_legacy_features(). Use of this helper is highly discouraged, its only purpose should be to account for the lack of semantics available within your given x86_hardware_subarch.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text    x86_early_init_platform_quirks()
+70     +62    +62          +43

Only 8 bytes overhead total, as the main increase in size is all removed via __init.

---
 arch/x86/Makefile                     |  1 +
 arch/x86/include/asm/paravirt.h       |  6 ------
 arch/x86/include/asm/paravirt_types.h |  5 -----
 arch/x86/include/asm/processor.h      |  1 -
 arch/x86/include/asm/x86_init.h       | 21 +++++++++++++++++++++
 arch/x86/kernel/Makefile              |  6 +++++-
 arch/x86/kernel/head32.c              |  2 ++
 arch/x86/kernel/head64.c              |  1 +
 arch/x86/kernel/platform-quirks.c     | 21 +++++++++++++++++++++
 arch/x86/kernel/rtc.c                 |  7 ++-----
 arch/x86/lguest/boot.c                |  1 -
 arch/x86/xen/enlighten.c              | 10 +++++++---
 12 files changed, 60 insertions(+), 22 deletions(-)
arch/x86/Makefile +1 -0
index 4086abc..f9ed8a7 100644
@@ -209,6 +209,7 @@ endif
 head-y := arch/x86/kernel/head_$(BITS).o
 head-y += arch/x86/kernel/head$(BITS).o
 head-y += arch/x86/kernel/head.o
+head-y += arch/x86/kernel/platform-quirks.o
 
 libs-y  += arch/x86/lib/
 
arch/x86/include/asm/paravirt.h +0 -6
index 601f1b8..6c7a4a1 100644
@@ -20,12 +20,6 @@ static inline int paravirt_enabled(void)
 	return pv_info.paravirt_enabled;
 }
 
-static inline int paravirt_has_feature(unsigned int feature)
-{
-	WARN_ON_ONCE(!pv_info.paravirt_enabled);
-	return (pv_info.features & feature);
-}
-
 static inline void load_sp0(struct tss_struct *tss,
 			     struct thread_struct *thread)
 {
arch/x86/include/asm/paravirt_types.h +0 -5
index e8c2326..6acc1b2 100644
@@ -70,14 +70,9 @@ struct pv_info {
 #endif
 
 	int paravirt_enabled;
-	unsigned int features;	  /* valid only if paravirt_enabled is set */
 	const char *name;
 };
 
-#define paravirt_has(x) paravirt_has_feature(PV_SUPPORTED_##x)
-/* Supported features */
-#define PV_SUPPORTED_RTC        (1<<0)
-
 struct pv_init_ops {
 	/*
 	 * Patch may replace one of the defined code sequences with
arch/x86/include/asm/processor.h +0 -1
index 9264476..0c70c7d 100644
@@ -474,7 +474,6 @@ static inline unsigned long current_top_of_stack(void)
 #else
 #define __cpuid			native_cpuid
 #define paravirt_enabled()	0
-#define paravirt_has(x) 	0
 
 static inline void load_sp0(struct tss_struct *tss,
 			    struct thread_struct *thread)
arch/x86/include/asm/x86_init.h +21 -0
index 1ae89a2..8bb8c1a 100644
@@ -142,6 +142,15 @@ struct x86_cpuinit_ops {
 struct timespec;
 
 /**
+ * struct x86_legacy_features - legacy x86 features
+ *
+ * @rtc: this device has a CMOS real-time clock present
+ */
+struct x86_legacy_features {
+	int rtc;
+};
+
+/**
  * struct x86_platform_ops - platform specific runtime functions
  * @calibrate_tsc:		calibrate TSC
  * @get_wallclock:		get time from HW clock like RTC etc.
@@ -152,6 +161,14 @@ struct timespec;
  * @save_sched_clock_state:	save state for sched_clock() on suspend
  * @restore_sched_clock_state:	restore state for sched_clock() on resume
  * @apic_post_init:		adjust apic if neeeded
+ * @legacy:			legacy features
+ * @set_legacy_features:	override legacy features. Use of this callback
+ * 				is highly discouraged. You should only need
+ * 				this if your hardware platform requires further
+ * 				custom fine tuning far beyong what may be
+ * 				possible in x86_early_init_platform_quirks() by
+ * 				only using the current x86_hardware_subarch
+ * 				semantics.
  */
 struct x86_platform_ops {
 	unsigned long (*calibrate_tsc)(void);
@@ -165,6 +182,8 @@ struct x86_platform_ops {
 	void (*save_sched_clock_state)(void);
 	void (*restore_sched_clock_state)(void);
 	void (*apic_post_init)(void);
+	struct x86_legacy_features legacy;
+	void (*set_legacy_features)(void);
 };
 
 struct pci_dev;
@@ -186,6 +205,8 @@ extern struct x86_cpuinit_ops x86_cpuinit;
 extern struct x86_platform_ops x86_platform;
 extern struct x86_msi_ops x86_msi;
 extern struct x86_io_apic_ops x86_io_apic_ops;
+
+extern void x86_early_init_platform_quirks(void);
 extern void x86_init_noop(void);
 extern void x86_init_uint_noop(unsigned int unused);
 
arch/x86/kernel/Makefile +5 -1
index 616ebd2..b81b22e 100644
@@ -2,7 +2,11 @@
 # Makefile for the linux kernel.
 #
 
-extra-y                := head_$(BITS).o head$(BITS).o head.o vmlinux.lds
+extra-y	:= head_$(BITS).o
+extra-y	+= head$(BITS).o
+extra-y	+= head.o
+extra-y	+= platform-quirks.o
+extra-y	+= vmlinux.lds
 
 CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
 
arch/x86/kernel/head32.c +2 -0
index 2911ef3..d784bb5 100644
@@ -34,6 +34,8 @@ asmlinkage __visible void __init i386_start_kernel(void)
 	cr4_init_shadow();
 	sanitize_boot_params(&boot_params);
 
+	x86_early_init_platform_quirks();
+
 	/* Call the subarch specific early setup function */
 	switch (boot_params.hdr.hardware_subarch) {
 	case X86_SUBARCH_INTEL_MID:
arch/x86/kernel/head64.c +1 -0
index 1f4422d..b72fb0b 100644
@@ -182,6 +182,7 @@ void __init x86_64_start_reservations(char *real_mode_data)
 	if (!boot_params.hdr.version)
 		copy_bootdata(__va(real_mode_data));
 
+	x86_early_init_platform_quirks();
 	reserve_ebda_region();
 
 	switch (boot_params.hdr.hardware_subarch) {
arch/x86/kernel/platform-quirks.c new file +21 -0
new file mode 100644
index 0000000..021a5f9
@@ -0,0 +1,21 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+#include <asm/setup.h>
+#include <asm/bios_ebda.h>
+
+void __init x86_early_init_platform_quirks(void)
+{
+	x86_platform.legacy.rtc = 1;
+
+	switch (boot_params.hdr.hardware_subarch) {
+	case X86_SUBARCH_XEN:
+	case X86_SUBARCH_LGUEST:
+	case X86_SUBARCH_INTEL_MID:
+		x86_platform.legacy.rtc = 0;
+		break;
+	}
+
+	if (x86_platform.set_legacy_features)
+		x86_platform.set_legacy_features();
+}
arch/x86/kernel/rtc.c +2 -5
index 4af8d06..62c48da 100644
@@ -14,6 +14,7 @@
 #include <asm/time.h>
 #include <asm/intel-mid.h>
 #include <asm/rtc.h>
+#include <asm/setup.h>
 
 #ifdef CONFIG_X86_32
 /*
@@ -188,10 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-	/* Intel MID platforms don't have ioport rtc */
-	if (intel_mid_identify_cpu())
-		return -ENODEV;
-
 #ifdef CONFIG_ACPI
 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
 		/* This warning can likely go away again in a year or two. */
@@ -200,7 +197,7 @@ static __init int add_rtc_cmos(void)
 	}
 #endif
 
-	if (paravirt_enabled() && !paravirt_has(RTC))
+	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
 	platform_device_register(&rtc_device);
arch/x86/lguest/boot.c +0 -1
index fd57d3a..f5497ee 100644
@@ -1414,7 +1414,6 @@ __init void lguest_init(void)
 	pv_info.kernel_rpl = 1;
 	/* Everyone except Xen runs with this set. */
 	pv_info.shared_kernel_pmd = 1;
-	pv_info.features = 0;
 
 	/*
 	 * We set up all the lguest overrides for sensitive operations.  These
arch/x86/xen/enlighten.c +7 -3
index 61f4d9f..752029d 100644
@@ -1193,7 +1193,6 @@ static const struct pv_info xen_info __initconst = {
 #ifdef CONFIG_X86_64
 	.extra_user_64bit_cs = FLAT_USER_CS64,
 #endif
-	.features = 0,
 	.name = "Xen",
 };
 
@@ -1506,6 +1505,11 @@ static void __init xen_pvh_early_guest_init(void)
 }
 #endif    /* CONFIG_XEN_PVH */
 
+static void __init xen_dom0_set_legacy_features(void)
+{
+	x86_platform.legacy.rtc = 1;
+}
+
 /* First C function to be called on Xen boot */
 asmlinkage __visible void __init xen_start_kernel(void)
 {
@@ -1527,8 +1531,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 
 	/* Install Xen paravirt ops */
 	pv_info = xen_info;
-	if (xen_initial_domain())
-		pv_info.features |= PV_SUPPORTED_RTC;
 	pv_init_ops = xen_init_ops;
 	if (!xen_pvh_domain()) {
 		pv_cpu_ops = xen_cpu_ops;
@@ -1688,6 +1690,8 @@ asmlinkage __visible void __init xen_start_kernel(void)
 			.u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
 		};
 
+		x86_platform.set_legacy_features =
+				xen_dom0_set_legacy_features;
 		xen_init_vga(info, xen_start_info->console.dom0.info_size);
 		xen_start_info->console.domU.mfn = 0;
 		xen_start_info->console.domU.evtchn = 0;
#10 lore raw

[tip: x86/cleanups] x86/rtc: Remove unused intel-mid.h

In reply to Luis R. Rodriguez
The following commit has been merged into the x86/cleanups branch of tip:

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     62fbc013c185896080bc5c7f6dfb26f0746eb217
Gitweb:        https://git.kernel.org/tip/62fbc013c185896080bc5c7f6dfb26f0746eb217
Author:        Andy Shevchenko <[email protected]>
AuthorDate:    Tue, 05 Mar 2024 18:10:24 +02:00
Committer:     Dave Hansen <[email protected]>
CommitterDate: Wed, 03 Apr 2024 08:24:48 -07:00

x86/rtc: Remove unused intel-mid.h

The rtc driver used to be disabled with a direct check for Intel MID platforms. But that direct check was replaced long ago (see second link). Remove the (unused since 2016) include.

[ dhansen: rewrite changelog to include some history ]

---
 arch/x86/kernel/rtc.c | 1 -
 1 file changed, 1 deletion(-)
arch/x86/kernel/rtc.c +0 -1
index 2e70669..51a849a 100644
@@ -10,7 +10,6 @@
 #include <asm/vsyscall.h>
 #include <asm/x86_init.h>
 #include <asm/time.h>
-#include <asm/intel-mid.h>
 #include <asm/setup.h>
 
 #ifdef CONFIG_X86_32
#11 lore raw

PATCH v6 5/16 x86, ACPI: move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code

In reply to Luis R. Rodriguez

This moves the ACPI specific check into the ACPI boot code, it also takes advantage of the x86_platform.legacy.rtc which is checked for already on the RTC initialization code. This lets us remove the nasty #ifdefery and consolidate the checks to use only one toggle to disable the RTC init code.

The works as RTC is initialized by device_initcall(add_rtc_cmos), this will run late in boot on start_kernel() during rest_init(), acpi_parse_fadt() gets called earlier during setup_arch().

---
 arch/x86/kernel/acpi/boot.c | 4 ++++
 arch/x86/kernel/rtc.c       | 8 --------
 2 files changed, 4 insertions(+), 8 deletions(-)
arch/x86/kernel/acpi/boot.c +4 -0
index 8c2f1ef6ca23..8c9c2bdba092 100644
@@ -913,6 +913,10 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+		pr_debug("ACPI: not registering RTC platform device\n");
+		x86_platform.legacy.rtc = 0;
+	}
 
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
arch/x86/kernel/rtc.c +0 -8
index 62c48da3889d..ff4f4180fefd 100644
@@ -189,14 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
-		/* This warning can likely go away again in a year or two. */
-		pr_info("ACPI: not registering RTC platform device\n");
-		return -ENODEV;
-	}
-#endif
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
Signature · 7 lines
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_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xen.org/xen-devel
#12 lore raw

[tip:x86/boot] x86/ACPI: Move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code

x86/ACPI: Move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code
Commit-ID:  088a8ef8207f19aadbade0971af21ad89fdc3815
Gitweb:     http://git.kernel.org/tip/088a8ef8207f19aadbade0971af21ad89fdc3815
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:35 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:01 +0200

x86/ACPI: Move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code

This moves the ACPI specific check into the ACPI boot code, it also takes advantage of the x86_platform.legacy.rtc which is checked for already on the RTC initialization code. This lets us remove the nasty #ifdefery and consolidate the checks to use only one toggle to disable the RTC init code.

The works as RTC is initialized by device_initcall(add_rtc_cmos), this will run late in boot on start_kernel() during rest_init(), acpi_parse_fadt() gets called earlier during setup_arch().

---
 arch/x86/kernel/acpi/boot.c | 4 ++++
 arch/x86/kernel/rtc.c       | 8 --------
 2 files changed, 4 insertions(+), 8 deletions(-)
arch/x86/kernel/acpi/boot.c +4 -0
index 8c2f1ef..8c9c2bd 100644
@@ -913,6 +913,10 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+		pr_debug("ACPI: not registering RTC platform device\n");
+		x86_platform.legacy.rtc = 0;
+	}
 
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
arch/x86/kernel/rtc.c +0 -8
index 62c48da..ff4f418 100644
@@ -189,14 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
-		/* This warning can likely go away again in a year or two. */
-		pr_info("ACPI: not registering RTC platform device\n");
-		return -ENODEV;
-	}
-#endif
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
#13 lore raw

PATCH v6 5/16 x86, ACPI: move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code

In reply to Luis R. Rodriguez

This moves the ACPI specific check into the ACPI boot code, it also takes advantage of the x86_platform.legacy.rtc which is checked for already on the RTC initialization code. This lets us remove the nasty #ifdefery and consolidate the checks to use only one toggle to disable the RTC init code.

The works as RTC is initialized by device_initcall(add_rtc_cmos), this will run late in boot on start_kernel() during rest_init(), acpi_parse_fadt() gets called earlier during setup_arch().

---
 arch/x86/kernel/acpi/boot.c | 4 ++++
 arch/x86/kernel/rtc.c       | 8 --------
 2 files changed, 4 insertions(+), 8 deletions(-)
arch/x86/kernel/acpi/boot.c +4 -0
index 8c2f1ef6ca23..8c9c2bdba092 100644
@@ -913,6 +913,10 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+		pr_debug("ACPI: not registering RTC platform device\n");
+		x86_platform.legacy.rtc = 0;
+	}
 
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
arch/x86/kernel/rtc.c +0 -8
index 62c48da3889d..ff4f4180fefd 100644
@@ -189,14 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
-		/* This warning can likely go away again in a year or two. */
-		pr_info("ACPI: not registering RTC platform device\n");
-		return -ENODEV;
-	}
-#endif
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
Signature · 1 line
2.7.2
#14 lore raw

PATCH v6 5/16 x86, ACPI: move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code

In reply to Luis R. Rodriguez

This moves the ACPI specific check into the ACPI boot code, it also takes advantage of the x86_platform.legacy.rtc which is checked for already on the RTC initialization code. This lets us remove the nasty #ifdefery and consolidate the checks to use only one toggle to disable the RTC init code.

The works as RTC is initialized by device_initcall(add_rtc_cmos), this will run late in boot on start_kernel() during rest_init(), acpi_parse_fadt() gets called earlier during setup_arch().

---
 arch/x86/kernel/acpi/boot.c | 4 ++++
 arch/x86/kernel/rtc.c       | 8 --------
 2 files changed, 4 insertions(+), 8 deletions(-)
arch/x86/kernel/acpi/boot.c +4 -0
index 8c2f1ef6ca23..8c9c2bdba092 100644
@@ -913,6 +913,10 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+		pr_debug("ACPI: not registering RTC platform device\n");
+		x86_platform.legacy.rtc = 0;
+	}
 
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
arch/x86/kernel/rtc.c +0 -8
index 62c48da3889d..ff4f4180fefd 100644
@@ -189,14 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
-		/* This warning can likely go away again in a year or two. */
-		pr_info("ACPI: not registering RTC platform device\n");
-		return -ENODEV;
-	}
-#endif
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
Signature · 1 line
2.7.2
#15 lore raw

PATCH v6 6/16 x86/init: use a platform legacy quirk for ebda

In reply to Luis R. Rodriguez

This replaces the paravirt_enabled() check with a
proper x86 legacy platform quirk.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
+39     +35    +35         +25

That's a 4 byte total overhead, the rest is all cleared out upon init as its all __init text.

v2: document 0-day vmlinux size impact

---
 arch/x86/include/asm/x86_init.h   | 3 +++
 arch/x86/kernel/head.c            | 2 +-
 arch/x86/kernel/platform-quirks.c | 4 ++++
 3 files changed, 8 insertions(+), 1 deletion(-)
arch/x86/include/asm/x86_init.h +3 -0
index 8bb8c1a4615a..89d9d57e145d 100644
@@ -145,9 +145,12 @@ struct timespec;
  * struct x86_legacy_features - legacy x86 features
  *
  * @rtc: this device has a CMOS real-time clock present
+ * @ebda_search: it's safe to search for the EBDA signature in the hardware's
+ * 	low RAM
  */
 struct x86_legacy_features {
 	int rtc;
+	int ebda_search;
 };
 
 /**
arch/x86/kernel/head.c +1 -1
index 992f442ca155..afe65dffee80 100644
@@ -38,7 +38,7 @@ void __init reserve_ebda_region(void)
 	 * that the paravirt case can handle memory setup
 	 * correctly, without our help.
 	 */
-	if (paravirt_enabled())
+	if (!x86_platform.legacy.ebda_search)
 		return;
 
 	/* end of low (conventional) memory */
arch/x86/kernel/platform-quirks.c +4 -0
index 021a5f973ce3..01b159781d96 100644
@@ -7,8 +7,12 @@
 void __init x86_early_init_platform_quirks(void)
 {
 	x86_platform.legacy.rtc = 1;
+	x86_platform.legacy.ebda_search = 0;
 
 	switch (boot_params.hdr.hardware_subarch) {
+	case X86_SUBARCH_PC:
+		x86_platform.legacy.ebda_search = 1;
+		break;
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
 	case X86_SUBARCH_INTEL_MID:
Signature · 7 lines
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#16 lore raw

[tip:x86/boot] x86/init: Use a platform legacy quirk for EBDA

x86/init: Use a platform legacy quirk for EBDA
Commit-ID:  1330e3bc544a1951d81b7f3c7d4cecf77d906f67
Gitweb:     http://git.kernel.org/tip/1330e3bc544a1951d81b7f3c7d4cecf77d906f67
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:36 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:02 +0200

x86/init: Use a platform legacy quirk for EBDA

This replaces the paravirt_enabled() check with a proper x86 legacy platform quirk.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
+39     +35    +35         +25

That's a 4 byte total overhead, the rest is all cleared out upon init as its all __init text.

v2: document 0-day vmlinux size impact

---
 arch/x86/include/asm/x86_init.h   | 3 +++
 arch/x86/kernel/head.c            | 2 +-
 arch/x86/kernel/platform-quirks.c | 4 ++++
 3 files changed, 8 insertions(+), 1 deletion(-)
arch/x86/include/asm/x86_init.h +3 -0
index 8bb8c1a..89d9d57 100644
@@ -145,9 +145,12 @@ struct timespec;
  * struct x86_legacy_features - legacy x86 features
  *
  * @rtc: this device has a CMOS real-time clock present
+ * @ebda_search: it's safe to search for the EBDA signature in the hardware's
+ * 	low RAM
  */
 struct x86_legacy_features {
 	int rtc;
+	int ebda_search;
 };
 
 /**
arch/x86/kernel/head.c +1 -1
index 992f442..afe65df 100644
@@ -38,7 +38,7 @@ void __init reserve_ebda_region(void)
 	 * that the paravirt case can handle memory setup
 	 * correctly, without our help.
 	 */
-	if (paravirt_enabled())
+	if (!x86_platform.legacy.ebda_search)
 		return;
 
 	/* end of low (conventional) memory */
arch/x86/kernel/platform-quirks.c +4 -0
index 021a5f9..01b1597 100644
@@ -7,8 +7,12 @@
 void __init x86_early_init_platform_quirks(void)
 {
 	x86_platform.legacy.rtc = 1;
+	x86_platform.legacy.ebda_search = 0;
 
 	switch (boot_params.hdr.hardware_subarch) {
+	case X86_SUBARCH_PC:
+		x86_platform.legacy.ebda_search = 1;
+		break;
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
 	case X86_SUBARCH_INTEL_MID:
#17 lore raw

PATCH v6 7/16 tools/lguest: force disable tboot and apm

In reply to Luis R. Rodriguez

The paravirt_enabled() check is going away, the area tossed to the kernel on lguest is not zeroed out, so ensure lguest force disables tboot and apm just in case the kernel file being read might have this set for whatever reason.

---
 tools/lguest/lguest.c | 6 ++++++
 1 file changed, 6 insertions(+)
tools/lguest/lguest.c +6 -0
index ff0aa580c6e1..0aa75af6e862 100644
@@ -3357,6 +3357,12 @@ int main(int argc, char *argv[])
 	/* Tell the entry path not to try to reload segment registers. */
 	boot->hdr.loadflags |= KEEP_SEGMENTS;
 
+	/* We don't support tboot */
+	boot->tboot_addr = 0;
+
+	/* Ensure this is 0 to prevent apm from loading */
+	boot->apm_bios_info.version = 0;
+
 	/* We tell the kernel to initialize the Guest. */
 	tell_kernel(start);
 
Signature · 1 line
2.7.2
#18 lore raw

[tip:x86/boot] tools/lguest: Force disable tboot and APM

tools/lguest: Force disable tboot and APM
Commit-ID:  46504590321dc62a11065f8d00e1b12037c37018
Gitweb:     http://git.kernel.org/tip/46504590321dc62a11065f8d00e1b12037c37018
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:37 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:03 +0200

tools/lguest: Force disable tboot and APM

The paravirt_enabled() check is going away, the area tossed to the kernel on lguest is not zeroed out, so ensure lguest force disables tboot and APM just in case the kernel file being read might have this set for whatever reason.

---
 tools/lguest/lguest.c | 6 ++++++
 1 file changed, 6 insertions(+)
tools/lguest/lguest.c +6 -0
index ff0aa580..d9836c5 100644
@@ -3357,6 +3357,12 @@ int main(int argc, char *argv[])
 	/* Tell the entry path not to try to reload segment registers. */
 	boot->hdr.loadflags |= KEEP_SEGMENTS;
 
+	/* We don't support tboot: */
+	boot->tboot_addr = 0;
+
+	/* Ensure this is 0 to prevent APM from loading: */
+	boot->apm_bios_info.version = 0;
+
 	/* We tell the kernel to initialize the Guest. */
 	tell_kernel(start);
 
#19 lore raw

PATCH v6 7/16 tools/lguest: force disable tboot and apm

In reply to Luis R. Rodriguez

The paravirt_enabled() check is going away, the area tossed to the kernel on lguest is not zeroed out, so ensure lguest force disables tboot and apm just in case the kernel file being read might have this set for whatever reason.

---
 tools/lguest/lguest.c | 6 ++++++
 1 file changed, 6 insertions(+)
tools/lguest/lguest.c +6 -0
index ff0aa580c6e1..0aa75af6e862 100644
@@ -3357,6 +3357,12 @@ int main(int argc, char *argv[])
 	/* Tell the entry path not to try to reload segment registers. */
 	boot->hdr.loadflags |= KEEP_SEGMENTS;
 
+	/* We don't support tboot */
+	boot->tboot_addr = 0;
+
+	/* Ensure this is 0 to prevent apm from loading */
+	boot->apm_bios_info.version = 0;
+
 	/* We tell the kernel to initialize the Guest. */
 	tell_kernel(start);
 
Signature · 1 line
2.7.2
#20 lore raw

PATCH v6 8/16 apm32: remove paravirt_enabled() use

In reply to Luis R. Rodriguez

There is already a check for apm_info.bios == 0, the apm_info.bios is set from the boot_params.apm_bios_info. Both Xen and lguest, which are also the only ones that set paravirt_enabled to true, never set the apm_bios.info. The

Xen folks are sure force disable to 0 is not needed because apm_info lives in .bss, we recently forced disabled this on lguest, and on the Xen side just to be sure Boris zeroed out the .bss for PV guests through commit 04b6b4a56884327c1648 ("xen/x86: Zero out .bss for PV guests"). With this care taken into consideration the paravirt_enabled() check is simply not needed anymore.

---
 arch/x86/kernel/apm_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/apm_32.c +1 -1
index 9307f182fe30..c7364bd633e1 100644
@@ -2267,7 +2267,7 @@ static int __init apm_init(void)
 
 	dmi_check_system(apm_dmi_table);
 
-	if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
+	if (apm_info.bios.version == 0 || machine_is_olpc()) {
 		printk(KERN_INFO "apm: BIOS not found.\n");
 		return -ENODEV;
 	}
Signature · 7 lines
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_______________________________________________
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#21 lore raw

[tip:x86/boot] x86/apm32: Remove paravirt_enabled() use

x86/apm32: Remove paravirt_enabled() use
Commit-ID:  8bc55f805697ec2a69c6a576fac8ee36ea9772bb
Gitweb:     http://git.kernel.org/tip/8bc55f805697ec2a69c6a576fac8ee36ea9772bb
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:38 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:03 +0200

x86/apm32: Remove paravirt_enabled() use

There is already a check for apm_info.bios == 0, the apm_info.bios is set from the boot_params.apm_bios_info. Both Xen and lguest, which are also the only ones that set paravirt_enabled to true, never set the apm_bios.info. The

Xen folks are sure force disable to 0 is not needed because apm_info lives in .bss, we recently forced disabled this on lguest, and on the Xen side just to be sure Boris zeroed out the .bss for PV guests through commit 04b6b4a56884327c1648 ("xen/x86: Zero out .bss for PV guests"). With this care taken into consideration the paravirt_enabled() check is simply not needed anymore.

---
 arch/x86/kernel/apm_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/apm_32.c +1 -1
index 9307f18..c7364bd 100644
@@ -2267,7 +2267,7 @@ static int __init apm_init(void)
 
 	dmi_check_system(apm_dmi_table);
 
-	if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
+	if (apm_info.bios.version == 0 || machine_is_olpc()) {
 		printk(KERN_INFO "apm: BIOS not found.\n");
 		return -ENODEV;
 	}
#22 lore raw

PATCH v6 9/16 x86/tboot: remove paravirt_enabled()

In reply to Luis R. Rodriguez

There is already a check for boot_params.tboot_addr prior to paravirt_enabled(). Both Xen and lguest, which are also the only ones that set paravirt_enabled to true, never set the boot_params.tboot_addr. The Xen folks are sure a force disable to 0 is not needed, we recently forced disabled this on lguest. With this in place this check is no longer needed.

Xen folks are sure force disable to 0 is not needed because apm_info lives in .bss, we recently forced disabled this on lguest, and on the Xen side just to be sure Boris zeroed out the .bss for PV guests through commit 04b6b4a56884327c1648 ("xen/x86: Zero out .bss for PV guests"). With this care taken into consideration the paravirt_enabled() check is simply not needed anymore.

---
 arch/x86/kernel/tboot.c | 6 ------
 1 file changed, 6 deletions(-)
arch/x86/kernel/tboot.c +0 -6
index e72a07f20b05..9b0185fbe3eb 100644
@@ -74,12 +74,6 @@ void __init tboot_probe(void)
 		return;
 	}
 
-	/* only a natively booted kernel should be using TXT */
-	if (paravirt_enabled()) {
-		pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
-		return;
-	}
-
 	/* Map and check for tboot UUID. */
 	set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
 	tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
Signature · 7 lines
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_______________________________________________
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#23 lore raw

[tip:x86/boot] x86/tboot: Remove paravirt_enabled() use

x86/tboot: Remove paravirt_enabled() use
Commit-ID:  44ecf0ef907fe45510566d308d670aa5823a4dd5
Gitweb:     http://git.kernel.org/tip/44ecf0ef907fe45510566d308d670aa5823a4dd5
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:39 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:04 +0200

x86/tboot: Remove paravirt_enabled() use

There is already a check for boot_params.tboot_addr prior to paravirt_enabled(). Both Xen and lguest, which are also the only ones that set paravirt_enabled to true, never set the boot_params.tboot_addr. The Xen folks are sure a force disable to 0 is not needed, we recently forced disabled this on lguest. With this in place this check is no longer needed.

Xen folks are sure force disable to 0 is not needed because apm_info lives in .bss, we recently forced disabled this on lguest, and on the Xen side just to be sure Boris zeroed out the .bss for PV guests through commit 04b6b4a56884327c1648 ("xen/x86: Zero out .bss for PV guests"). With this care taken into consideration the paravirt_enabled() check is simply not needed anymore.

---
 arch/x86/kernel/tboot.c | 6 ------
 1 file changed, 6 deletions(-)
arch/x86/kernel/tboot.c +0 -6
index e72a07f..9b0185f 100644
@@ -74,12 +74,6 @@ void __init tboot_probe(void)
 		return;
 	}
 
-	/* only a natively booted kernel should be using TXT */
-	if (paravirt_enabled()) {
-		pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
-		return;
-	}
-
 	/* Map and check for tboot UUID. */
 	set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
 	tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
#24 lore raw

PATCH v6 10/16 x86/cpu/intel: remove not needed paravirt_enabled() for f00f work around

In reply to Luis R. Rodriguez

The X86_BUG_F00F work around is responsible for fixing up the error generated on attempted F00F exploitation from an OOPS to a SIGILL. There is no reason why this code should not be allowed to run on PV guest on a F00F-affected CPU -- it would simply never trigger. The pv_enabled() check was there only to avoid printing the f00f workaround, so removing the check is purely a cosmetic change.

---
 arch/x86/kernel/cpu/intel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/cpu/intel.c +1 -1
index f71a34944b56..66509285ffdd 100644
@@ -233,7 +233,7 @@ static void intel_workarounds(struct cpuinfo_x86 *c)
 	 * The Quark is also family 5, but does not have the same bug.
 	 */
 	clear_cpu_bug(c, X86_BUG_F00F);
-	if (!paravirt_enabled() && c->x86 == 5 && c->x86_model < 9) {
+	if (c->x86 == 5 && c->x86_model < 9) {
 		static int f00f_workaround_enabled;
 
 		set_cpu_bug(c, X86_BUG_F00F);
Signature · 1 line
2.7.2
#25 lore raw

[tip:x86/boot] x86/cpu/intel: Remove not needed paravirt_enabled() use for F00F work around

x86/cpu/intel: Remove not needed paravirt_enabled() use for F00F work around
Commit-ID:  fa392794ed8329379f3f637da7c3c2f078309a77
Gitweb:     http://git.kernel.org/tip/fa392794ed8329379f3f637da7c3c2f078309a77
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:40 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:05 +0200

x86/cpu/intel: Remove not needed paravirt_enabled() use for F00F work around

The X86_BUG_F00F work around is responsible for fixing up the error generated on attempted F00F exploitation from an OOPS to a SIGILL.

There is no reason why this code should not be allowed to run on PV guest on a F00F-affected CPU -- it would simply never trigger. The pv_enabled() check was there only to avoid printing the f00f workaround, so removing the check is purely a cosmetic change.

---
 arch/x86/kernel/cpu/intel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/cpu/intel.c +1 -1
index 1f7fdb9..016b3d9 100644
@@ -233,7 +233,7 @@ static void intel_workarounds(struct cpuinfo_x86 *c)
 	 * The Quark is also family 5, but does not have the same bug.
 	 */
 	clear_cpu_bug(c, X86_BUG_F00F);
-	if (!paravirt_enabled() && c->x86 == 5 && c->x86_model < 9) {
+	if (c->x86 == 5 && c->x86_model < 9) {
 		static int f00f_workaround_enabled;
 
 		set_cpu_bug(c, X86_BUG_F00F);
#26 lore raw

PATCH v6 11/16 pnpbios: replace paravirt_enabled() check with legacy device check

In reply to Luis R. Rodriguez

Since we are removing paravirt_enabled() replace it with a logical equivalent. Even though PNPBIOS is x86 specific we add an arch-specific type call, which can be implemented by any architecture to show how other legacy attribute devices can later be also checked for with other ACPI legacy attribute flags.

This implicates the first ACPI 5.2.9.3 IA-PC Boot Architecture ACPI_FADT_LEGACY_DEVICES flag device, and shows how to add more.

The reason pnpbios gets a defined structure and as such uses a different approach than the RTC legacy quirk is that ACPI has a respective RTC flag, while pnpbios does not. We fold the pnpbios quirk under ACPI_FADT_LEGACY_DEVICES ACPI flag use case, and use a struct of possible devices to enable future extensions of this.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
+32     +28    +28         +28

That's 4 byte overhead total, the rest is cleared out on init as its all __init text.

v2: split out subarch handlng on switch to make it easier
later to add other subarchs. The 'fall-through' switch handling can be confusing and we'll remove it later when we add handling for X86_SUBARCH_CE4100.
v3: document vmlinux size impact as per 0-day, and also
explain why pnpbios is treated differently than the RTC legacy feature.

---
 arch/x86/include/asm/x86_init.h   | 26 ++++++++++++++++++++++++++
 arch/x86/kernel/platform-quirks.c | 11 +++++++++++
 drivers/pnp/pnpbios/core.c        |  3 ++-
 include/linux/pnp.h               |  2 ++
 4 files changed, 41 insertions(+), 1 deletion(-)
arch/x86/include/asm/x86_init.h +26 -0
index 89d9d57e145d..4dcdf74dfed8 100644
@@ -142,15 +142,41 @@ struct x86_cpuinit_ops {
 struct timespec;
 
 /**
+ * struct x86_legacy_devices - legacy x86 devices
+ *
+ * @pnpbios: this platform can have a PNPBIOS. If this is disabled the platform
+ * 	is known to never have a PNPBIOS.
+ *
+ * These are devices known to require LPC or ISA bus. The definition of legacy
+ * devices adheres to the ACPI 5.2.9.3 IA-PC Boot Architecture flag
+ * ACPI_FADT_LEGACY_DEVICES. These devices consist of user visible devices on
+ * the LPC or ISA bus. User visible devices are devices that have end-user
+ * accessible connectors (for example, LPT parallel port). Legacy devices on
+ * the LPC bus consist for example of serial and parallel ports, PS/2 keyboard
+ * / mouse, and the floppy disk controller. A system that lacks all known
+ * legacy devices can assume all devices can be detected exclusively via
+ * standard device enumeration mechanisms including the ACPI namespace.
+ *
+ * A system which has does not have ACPI_FADT_LEGACY_DEVICES enabled must not
+ * have any of the legacy devices enumerated below present.
+ */
+struct x86_legacy_devices {
+	int pnpbios;
+};
+
+/**
  * struct x86_legacy_features - legacy x86 features
  *
  * @rtc: this device has a CMOS real-time clock present
  * @ebda_search: it's safe to search for the EBDA signature in the hardware's
  * 	low RAM
+ * @devices: legacy x86 devices, refer to struct x86_legacy_devices
+ * 	documentation for further details.
  */
 struct x86_legacy_features {
 	int rtc;
 	int ebda_search;
+	struct x86_legacy_devices devices;
 };
 
 /**
arch/x86/kernel/platform-quirks.c +11 -0
index 01b159781d96..ab643825a7aa 100644
@@ -8,6 +8,7 @@ void __init x86_early_init_platform_quirks(void)
 {
 	x86_platform.legacy.rtc = 1;
 	x86_platform.legacy.ebda_search = 0;
+	x86_platform.legacy.devices.pnpbios = 1;
 
 	switch (boot_params.hdr.hardware_subarch) {
 	case X86_SUBARCH_PC:
@@ -15,6 +16,9 @@ void __init x86_early_init_platform_quirks(void)
 		break;
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
+		x86_platform.legacy.devices.pnpbios = 0;
+		x86_platform.legacy.rtc = 0;
+		break;
 	case X86_SUBARCH_INTEL_MID:
 		x86_platform.legacy.rtc = 0;
 		break;
@@ -23,3 +27,10 @@ void __init x86_early_init_platform_quirks(void)
 	if (x86_platform.set_legacy_features)
 		x86_platform.set_legacy_features();
 }
+
+#if defined(CONFIG_PNPBIOS)
+bool __init arch_pnpbios_disabled(void)
+{
+	return x86_platform.legacy.devices.pnpbios == 0;
+}
+#endif
drivers/pnp/pnpbios/core.c +2 -1
index facd43b8516c..81603d99082b 100644
@@ -521,10 +521,11 @@ static int __init pnpbios_init(void)
 	int ret;
 
 	if (pnpbios_disabled || dmi_check_system(pnpbios_dmi_table) ||
-	    paravirt_enabled()) {
+	    arch_pnpbios_disabled()) {
 		printk(KERN_INFO "PnPBIOS: Disabled\n");
 		return -ENODEV;
 	}
+
 #ifdef CONFIG_PNPACPI
 	if (!acpi_disabled && !pnpacpi_disabled) {
 		pnpbios_disabled = 1;
include/linux/pnp.h +2 -0
index 5df733b8f704..2588ca6a9028 100644
@@ -337,9 +337,11 @@ extern struct mutex pnp_res_mutex;
 
 #ifdef CONFIG_PNPBIOS
 extern struct pnp_protocol pnpbios_protocol;
+extern bool arch_pnpbios_disabled(void);
 #define pnp_device_is_pnpbios(dev) ((dev)->protocol == (&pnpbios_protocol))
 #else
 #define pnp_device_is_pnpbios(dev) 0
+#define arch_pnpbios_disabled()	false
 #endif
 
 #ifdef CONFIG_PNPACPI
Signature · 1 line
2.7.2
#27 lore raw

[tip:x86/boot] x86, drivers/pnpbios: Replace paravirt_enabled() check with legacy device check

x86, drivers/pnpbios: Replace paravirt_enabled() check with legacy device check
Commit-ID:  80dfd83dfab6e49a31ab8fc484a801aef1c567bd
Gitweb:     http://git.kernel.org/tip/80dfd83dfab6e49a31ab8fc484a801aef1c567bd
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:41 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:05 +0200

x86, drivers/pnpbios: Replace paravirt_enabled() check with legacy device check

Since we are removing paravirt_enabled() replace it with a logical equivalent. Even though PNPBIOS is x86 specific we add an arch-specific type call, which can be implemented by any architecture to show how other legacy attribute devices can later be also checked for with other ACPI legacy attribute flags.

This implicates the first ACPI 5.2.9.3 IA-PC Boot Architecture ACPI_FADT_LEGACY_DEVICES flag device, and shows how to add more.

The reason pnpbios gets a defined structure and as such uses a different approach than the RTC legacy quirk is that ACPI has a respective RTC flag, while pnpbios does not. We fold the pnpbios quirk under ACPI_FADT_LEGACY_DEVICES ACPI flag use case, and use a struct of possible devices to enable future extensions of this.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
+32     +28    +28         +28

That's 4 byte overhead total, the rest is cleared out on init as its all __init text.

v2: split out subarch handlng on switch to make it easier
later to add other subarchs. The 'fall-through' switch handling can be confusing and we'll remove it later when we add handling for X86_SUBARCH_CE4100.
v3: document vmlinux size impact as per 0-day, and also
explain why pnpbios is treated differently than the RTC legacy feature.

---
 arch/x86/include/asm/x86_init.h   | 26 ++++++++++++++++++++++++++
 arch/x86/kernel/platform-quirks.c | 11 +++++++++++
 drivers/pnp/pnpbios/core.c        |  3 ++-
 include/linux/pnp.h               |  2 ++
 4 files changed, 41 insertions(+), 1 deletion(-)
arch/x86/include/asm/x86_init.h +26 -0
index 89d9d57..4dcdf74 100644
@@ -142,15 +142,41 @@ struct x86_cpuinit_ops {
 struct timespec;
 
 /**
+ * struct x86_legacy_devices - legacy x86 devices
+ *
+ * @pnpbios: this platform can have a PNPBIOS. If this is disabled the platform
+ * 	is known to never have a PNPBIOS.
+ *
+ * These are devices known to require LPC or ISA bus. The definition of legacy
+ * devices adheres to the ACPI 5.2.9.3 IA-PC Boot Architecture flag
+ * ACPI_FADT_LEGACY_DEVICES. These devices consist of user visible devices on
+ * the LPC or ISA bus. User visible devices are devices that have end-user
+ * accessible connectors (for example, LPT parallel port). Legacy devices on
+ * the LPC bus consist for example of serial and parallel ports, PS/2 keyboard
+ * / mouse, and the floppy disk controller. A system that lacks all known
+ * legacy devices can assume all devices can be detected exclusively via
+ * standard device enumeration mechanisms including the ACPI namespace.
+ *
+ * A system which has does not have ACPI_FADT_LEGACY_DEVICES enabled must not
+ * have any of the legacy devices enumerated below present.
+ */
+struct x86_legacy_devices {
+	int pnpbios;
+};
+
+/**
  * struct x86_legacy_features - legacy x86 features
  *
  * @rtc: this device has a CMOS real-time clock present
  * @ebda_search: it's safe to search for the EBDA signature in the hardware's
  * 	low RAM
+ * @devices: legacy x86 devices, refer to struct x86_legacy_devices
+ * 	documentation for further details.
  */
 struct x86_legacy_features {
 	int rtc;
 	int ebda_search;
+	struct x86_legacy_devices devices;
 };
 
 /**
arch/x86/kernel/platform-quirks.c +11 -0
index 01b1597..ab64382 100644
@@ -8,6 +8,7 @@ void __init x86_early_init_platform_quirks(void)
 {
 	x86_platform.legacy.rtc = 1;
 	x86_platform.legacy.ebda_search = 0;
+	x86_platform.legacy.devices.pnpbios = 1;
 
 	switch (boot_params.hdr.hardware_subarch) {
 	case X86_SUBARCH_PC:
@@ -15,6 +16,9 @@ void __init x86_early_init_platform_quirks(void)
 		break;
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
+		x86_platform.legacy.devices.pnpbios = 0;
+		x86_platform.legacy.rtc = 0;
+		break;
 	case X86_SUBARCH_INTEL_MID:
 		x86_platform.legacy.rtc = 0;
 		break;
@@ -23,3 +27,10 @@ void __init x86_early_init_platform_quirks(void)
 	if (x86_platform.set_legacy_features)
 		x86_platform.set_legacy_features();
 }
+
+#if defined(CONFIG_PNPBIOS)
+bool __init arch_pnpbios_disabled(void)
+{
+	return x86_platform.legacy.devices.pnpbios == 0;
+}
+#endif
drivers/pnp/pnpbios/core.c +2 -1
index facd43b..81603d9 100644
@@ -521,10 +521,11 @@ static int __init pnpbios_init(void)
 	int ret;
 
 	if (pnpbios_disabled || dmi_check_system(pnpbios_dmi_table) ||
-	    paravirt_enabled()) {
+	    arch_pnpbios_disabled()) {
 		printk(KERN_INFO "PnPBIOS: Disabled\n");
 		return -ENODEV;
 	}
+
 #ifdef CONFIG_PNPACPI
 	if (!acpi_disabled && !pnpacpi_disabled) {
 		pnpbios_disabled = 1;
include/linux/pnp.h +2 -0
index 5df733b..2588ca6 100644
@@ -337,9 +337,11 @@ extern struct mutex pnp_res_mutex;
 
 #ifdef CONFIG_PNPBIOS
 extern struct pnp_protocol pnpbios_protocol;
+extern bool arch_pnpbios_disabled(void);
 #define pnp_device_is_pnpbios(dev) ((dev)->protocol == (&pnpbios_protocol))
 #else
 #define pnp_device_is_pnpbios(dev) 0
+#define arch_pnpbios_disabled()	false
 #endif
 
 #ifdef CONFIG_PNPACPI
#28 lore raw

PATCH v6 12/16 x86, ACPI: parse ACPI_FADT_LEGACY_DEVICES

In reply to Luis R. Rodriguez

ACPI 5.2.9.3 IA-PC Boot Architecture flag ACPI_FADT_LEGACY_DEVICES can be used to determine if a system has legacy devices LPC or ISA devices. The x86 platform already has a struct which lists known associated legacy devices, we start off careful only by disabling root devices we should not regress with. The struct and device list can be expanded with time to cover more root legacy components.

---
 arch/x86/kernel/acpi/boot.c | 5 +++++
 1 file changed, 5 insertions(+)
arch/x86/kernel/acpi/boot.c +5 -0
index 8c9c2bdba092..c9a06e573fa5 100644
@@ -913,6 +913,11 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (!(acpi_gbl_FADT.boot_flags & ACPI_FADT_LEGACY_DEVICES)) {
+		pr_debug("ACPI: no legacy devices present\n");
+		x86_platform.legacy.devices.pnpbios = 0;
+	}
+
 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
 		pr_debug("ACPI: not registering RTC platform device\n");
 		x86_platform.legacy.rtc = 0;
Signature · 7 lines
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_______________________________________________
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#29 lore raw

[tip:x86/boot] x86/ACPI: Parse ACPI_FADT_LEGACY_DEVICES

x86/ACPI: Parse ACPI_FADT_LEGACY_DEVICES
Commit-ID:  7a17b82ccd6671a4bb436df52eedeff906b02735
Gitweb:     http://git.kernel.org/tip/7a17b82ccd6671a4bb436df52eedeff906b02735
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:42 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:06 +0200

x86/ACPI: Parse ACPI_FADT_LEGACY_DEVICES

ACPI 5.2.9.3 IA-PC Boot Architecture flag ACPI_FADT_LEGACY_DEVICES can be used to determine if a system has legacy devices LPC or ISA devices. The x86 platform already has a struct which lists known associated legacy devices, we start off careful only by disabling root devices we should not regress with. The struct and device list can be expanded with time to cover more root legacy components.

---
 arch/x86/kernel/acpi/boot.c | 5 +++++
 1 file changed, 5 insertions(+)
arch/x86/kernel/acpi/boot.c +5 -0
index 8c9c2bd..c9a06e5 100644
@@ -913,6 +913,11 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (!(acpi_gbl_FADT.boot_flags & ACPI_FADT_LEGACY_DEVICES)) {
+		pr_debug("ACPI: no legacy devices present\n");
+		x86_platform.legacy.devices.pnpbios = 0;
+	}
+
 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
 		pr_debug("ACPI: not registering RTC platform device\n");
 		x86_platform.legacy.rtc = 0;
#30 lore raw

PATCH v6 12/16 x86, ACPI: parse ACPI_FADT_LEGACY_DEVICES

In reply to Luis R. Rodriguez

ACPI 5.2.9.3 IA-PC Boot Architecture flag ACPI_FADT_LEGACY_DEVICES can be used to determine if a system has legacy devices LPC or ISA devices. The x86 platform already has a struct which lists known associated legacy devices, we start off careful only by disabling root devices we should not regress with. The struct and device list can be expanded with time to cover more root legacy components.

---
 arch/x86/kernel/acpi/boot.c | 5 +++++
 1 file changed, 5 insertions(+)
arch/x86/kernel/acpi/boot.c +5 -0
index 8c9c2bdba092..c9a06e573fa5 100644
@@ -913,6 +913,11 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (!(acpi_gbl_FADT.boot_flags & ACPI_FADT_LEGACY_DEVICES)) {
+		pr_debug("ACPI: no legacy devices present\n");
+		x86_platform.legacy.devices.pnpbios = 0;
+	}
+
 	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
 		pr_debug("ACPI: not registering RTC platform device\n");
 		x86_platform.legacy.rtc = 0;
Signature · 1 line
2.7.2
#31 lore raw

PATCH v6 13/16 x86/init: rename ebda code file

In reply to Luis R. Rodriguez

This makes it clearer what this is.

---
 arch/x86/Makefile                  | 2 +-
 arch/x86/kernel/Makefile           | 2 +-
 arch/x86/kernel/{head.c => ebda.c} | 0
 3 files changed, 2 insertions(+), 2 deletions(-)
 rename arch/x86/kernel/{head.c => ebda.c} (100%)
arch/x86/Makefile +1 -1
index f9ed8a7ce2b6..6fce7f096b88 100644
@@ -208,7 +208,7 @@ endif
 
 head-y := arch/x86/kernel/head_$(BITS).o
 head-y += arch/x86/kernel/head$(BITS).o
-head-y += arch/x86/kernel/head.o
+head-y += arch/x86/kernel/ebda.o
 head-y += arch/x86/kernel/platform-quirks.o
 
 libs-y  += arch/x86/lib/
arch/x86/kernel/Makefile +1 -1
index 7a9e44d935de..0503f5bfb18d 100644
@@ -4,7 +4,7 @@
 
 extra-y	:= head_$(BITS).o
 extra-y	+= head$(BITS).o
-extra-y	+= head.o
+extra-y	+= ebda.o
 extra-y	+= platform-quirks.o
 extra-y	+= vmlinux.lds
 
arch/x86/kernel/ebda.c renamed from arch/x86/kernel/head.c +0 -0
similarity index 100%
rename from arch/x86/kernel/head.c
rename to arch/x86/kernel/ebda.c
Signature · 7 lines
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_______________________________________________
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[email protected]
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#32 lore raw

[tip:x86/boot] x86/init: Rename EBDA code file

x86/init: Rename EBDA code file
Commit-ID:  f2d85299b7f11f73cc0a294e396cdae114e75787
Gitweb:     http://git.kernel.org/tip/f2d85299b7f11f73cc0a294e396cdae114e75787
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:43 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:07 +0200

x86/init: Rename EBDA code file

This makes it clearer what this is.

---
 arch/x86/Makefile                  | 2 +-
 arch/x86/kernel/Makefile           | 2 +-
 arch/x86/kernel/{head.c => ebda.c} | 0
 3 files changed, 2 insertions(+), 2 deletions(-)
arch/x86/Makefile +1 -1
index f9ed8a7..6fce7f0 100644
@@ -208,7 +208,7 @@ endif
 
 head-y := arch/x86/kernel/head_$(BITS).o
 head-y += arch/x86/kernel/head$(BITS).o
-head-y += arch/x86/kernel/head.o
+head-y += arch/x86/kernel/ebda.o
 head-y += arch/x86/kernel/platform-quirks.o
 
 libs-y  += arch/x86/lib/
arch/x86/kernel/Makefile +1 -1
index b81b22e..9abf855 100644
@@ -4,7 +4,7 @@
 
 extra-y	:= head_$(BITS).o
 extra-y	+= head$(BITS).o
-extra-y	+= head.o
+extra-y	+= ebda.o
 extra-y	+= platform-quirks.o
 extra-y	+= vmlinux.lds
 
arch/x86/kernel/ebda.c renamed from arch/x86/kernel/head.c +0 -0
similarity index 100%
rename from arch/x86/kernel/head.c
rename to arch/x86/kernel/ebda.c
#33 lore raw

PATCH v6 14/16 x86/paravirt: remove paravirt_enabled()

In reply to Luis R. Rodriguez

That that paravirt_enabled() is replaced with proper x86 semantics we can remove it.

---
 arch/x86/include/asm/paravirt.h       | 5 -----
 arch/x86/include/asm/paravirt_types.h | 1 -
 arch/x86/include/asm/processor.h      | 1 -
 arch/x86/kernel/kvm.c                 | 8 --------
 arch/x86/kernel/paravirt.c            | 1 -
 arch/x86/lguest/boot.c                | 2 --
 arch/x86/xen/enlighten.c              | 1 -
 7 files changed, 19 deletions(-)
arch/x86/include/asm/paravirt.h +0 -5
index 6c7a4a192032..dff26bc91b17 100644
@@ -15,11 +15,6 @@
 #include <linux/cpumask.h>
 #include <asm/frame.h>
 
-static inline int paravirt_enabled(void)
-{
-	return pv_info.paravirt_enabled;
-}
-
 static inline void load_sp0(struct tss_struct *tss,
 			     struct thread_struct *thread)
 {
arch/x86/include/asm/paravirt_types.h +0 -1
index 6acc1b26cf40..7fedf24bd811 100644
@@ -69,7 +69,6 @@ struct pv_info {
 	u16 extra_user_64bit_cs;  /* __USER_CS if none */
 #endif
 
-	int paravirt_enabled;
 	const char *name;
 };
 
arch/x86/include/asm/processor.h +0 -1
index 0c70c7daa6b8..8d326e822cb8 100644
@@ -473,7 +473,6 @@ static inline unsigned long current_top_of_stack(void)
 #include <asm/paravirt.h>
 #else
 #define __cpuid			native_cpuid
-#define paravirt_enabled()	0
 
 static inline void load_sp0(struct tss_struct *tss,
 			    struct thread_struct *thread)
arch/x86/kernel/kvm.c +0 -8
index dc1207e2f193..eea2a6f72b31 100644
@@ -285,14 +285,6 @@ static void __init paravirt_ops_setup(void)
 {
 	pv_info.name = "KVM";
 
-	/*
-	 * KVM isn't paravirt in the sense of paravirt_enabled.  A KVM
-	 * guest kernel works like a bare metal kernel with additional
-	 * features, and paravirt_enabled is about features that are
-	 * missing.
-	 */
-	pv_info.paravirt_enabled = 0;
-
 	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
 		pv_cpu_ops.io_delay = kvm_io_delay;
 
arch/x86/kernel/paravirt.c +0 -1
index f08ac28b8136..71a2d8a05a66 100644
@@ -294,7 +294,6 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 
 struct pv_info pv_info = {
 	.name = "bare hardware",
-	.paravirt_enabled = 0,
 	.kernel_rpl = 0,
 	.shared_kernel_pmd = 1,	/* Only used when CONFIG_X86_PAE is set */
 
arch/x86/lguest/boot.c +0 -2
index f5497ee5fd2f..3847e736702e 100644
@@ -1408,8 +1408,6 @@ __init void lguest_init(void)
 {
 	/* We're under lguest. */
 	pv_info.name = "lguest";
-	/* Paravirt is enabled. */
-	pv_info.paravirt_enabled = 1;
 	/* We're running at privilege level 1, not 0 as normal. */
 	pv_info.kernel_rpl = 1;
 	/* Everyone except Xen runs with this set. */
arch/x86/xen/enlighten.c +0 -1
index b08489ba5051..f9fb90978867 100644
@@ -1186,7 +1186,6 @@ static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
 }
 
 static const struct pv_info xen_info __initconst = {
-	.paravirt_enabled = 1,
 	.shared_kernel_pmd = 0,
 
 #ifdef CONFIG_X86_64
Signature · 1 line
2.7.2
#34 lore raw

[tip:x86/boot] x86/paravirt: Remove paravirt_enabled()

x86/paravirt: Remove paravirt_enabled()
Commit-ID:  867fe800b4c423bce46e66ccb2ce91bebbd5afc6
Gitweb:     http://git.kernel.org/tip/867fe800b4c423bce46e66ccb2ce91bebbd5afc6
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:44 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:07 +0200

x86/paravirt: Remove paravirt_enabled()

Now that all previous paravirt_enabled() uses were replaced with proper x86 semantics by the previous patches we can remove the unused paravirt_enabled() mechanism.

---
 arch/x86/include/asm/paravirt.h       | 5 -----
 arch/x86/include/asm/paravirt_types.h | 1 -
 arch/x86/include/asm/processor.h      | 1 -
 arch/x86/kernel/kvm.c                 | 8 --------
 arch/x86/kernel/paravirt.c            | 1 -
 arch/x86/lguest/boot.c                | 2 --
 arch/x86/xen/enlighten.c              | 1 -
 7 files changed, 19 deletions(-)
arch/x86/include/asm/paravirt.h +0 -5
index 6c7a4a1..dff26bc 100644
@@ -15,11 +15,6 @@
 #include <linux/cpumask.h>
 #include <asm/frame.h>
 
-static inline int paravirt_enabled(void)
-{
-	return pv_info.paravirt_enabled;
-}
-
 static inline void load_sp0(struct tss_struct *tss,
 			     struct thread_struct *thread)
 {
arch/x86/include/asm/paravirt_types.h +0 -1
index 6acc1b2..7fedf24 100644
@@ -69,7 +69,6 @@ struct pv_info {
 	u16 extra_user_64bit_cs;  /* __USER_CS if none */
 #endif
 
-	int paravirt_enabled;
 	const char *name;
 };
 
arch/x86/include/asm/processor.h +0 -1
index 0c70c7d..8d326e8 100644
@@ -473,7 +473,6 @@ static inline unsigned long current_top_of_stack(void)
 #include <asm/paravirt.h>
 #else
 #define __cpuid			native_cpuid
-#define paravirt_enabled()	0
 
 static inline void load_sp0(struct tss_struct *tss,
 			    struct thread_struct *thread)
arch/x86/kernel/kvm.c +0 -8
index 8079508..c66546f 100644
@@ -285,14 +285,6 @@ static void __init paravirt_ops_setup(void)
 {
 	pv_info.name = "KVM";
 
-	/*
-	 * KVM isn't paravirt in the sense of paravirt_enabled.  A KVM
-	 * guest kernel works like a bare metal kernel with additional
-	 * features, and paravirt_enabled is about features that are
-	 * missing.
-	 */
-	pv_info.paravirt_enabled = 0;
-
 	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
 		pv_cpu_ops.io_delay = kvm_io_delay;
 
arch/x86/kernel/paravirt.c +0 -1
index f08ac28..71a2d8a 100644
@@ -294,7 +294,6 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 
 struct pv_info pv_info = {
 	.name = "bare hardware",
-	.paravirt_enabled = 0,
 	.kernel_rpl = 0,
 	.shared_kernel_pmd = 1,	/* Only used when CONFIG_X86_PAE is set */
 
arch/x86/lguest/boot.c +0 -2
index f5497ee..3847e73 100644
@@ -1408,8 +1408,6 @@ __init void lguest_init(void)
 {
 	/* We're under lguest. */
 	pv_info.name = "lguest";
-	/* Paravirt is enabled. */
-	pv_info.paravirt_enabled = 1;
 	/* We're running at privilege level 1, not 0 as normal. */
 	pv_info.kernel_rpl = 1;
 	/* Everyone except Xen runs with this set. */
arch/x86/xen/enlighten.c +0 -1
index 752029d..5fc20a1 100644
@@ -1187,7 +1187,6 @@ static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
 }
 
 static const struct pv_info xen_info __initconst = {
-	.paravirt_enabled = 1,
 	.shared_kernel_pmd = 0,
 
 #ifdef CONFIG_X86_64
#35 lore raw

PATCH v6 15/16 x86/init: disable pnpbios for X86_SUBARCH_INTEL_MID

In reply to Luis R. Rodriguez

As per hpa Intel MID platforms can also disable pnpbios [0].

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
-8      -8     -8          -8

[0] http://lkml.kernel.org/r/[email protected]

v6: add 0-day size impact

---
 arch/x86/kernel/platform-quirks.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
arch/x86/kernel/platform-quirks.c +1 -3
index ab643825a7aa..853919484340 100644
@@ -16,10 +16,8 @@ void __init x86_early_init_platform_quirks(void)
 		break;
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
-		x86_platform.legacy.devices.pnpbios = 0;
-		x86_platform.legacy.rtc = 0;
-		break;
 	case X86_SUBARCH_INTEL_MID:
+		x86_platform.legacy.devices.pnpbios = 0;
 		x86_platform.legacy.rtc = 0;
 		break;
 	}
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#36 lore raw

[tip:x86/boot] x86/init: Disable pnpbios for X86_SUBARCH_INTEL_MID

x86/init: Disable pnpbios for X86_SUBARCH_INTEL_MID
Commit-ID:  f6935b7bfbf8345bea05f73dc48ce81b70f016e0
Gitweb:     http://git.kernel.org/tip/f6935b7bfbf8345bea05f73dc48ce81b70f016e0
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:45 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:08 +0200

x86/init: Disable pnpbios for X86_SUBARCH_INTEL_MID

As per hpa Intel MID platforms can also disable pnpbios:

ttp://lkml.kernel.org/r/[email protected]

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows:

 TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
    -8     -8   -8          -8
---
 arch/x86/kernel/platform-quirks.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
arch/x86/kernel/platform-quirks.c +1 -3
index ab64382..8539194 100644
@@ -16,10 +16,8 @@ void __init x86_early_init_platform_quirks(void)
 		break;
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
-		x86_platform.legacy.devices.pnpbios = 0;
-		x86_platform.legacy.rtc = 0;
-		break;
 	case X86_SUBARCH_INTEL_MID:
+		x86_platform.legacy.devices.pnpbios = 0;
 		x86_platform.legacy.rtc = 0;
 		break;
 	}
#37 lore raw

PATCH v6 16/16 x86/init: disable pnpbios and rtc for X86_SUBARCH_CE4100

In reply to Luis R. Rodriguez

As per hpa CE4100 platforms can also disable pnpbios [0]. Then Sebastian also recently noted that CE4100 also disables RTC probe, to do that Sebastian had long ago added the RTC of_have_populated_dt() check, he noted that it was meant to skip the RTC probe on all OF platforms but as of now, CE4100 was the only x86 DT using this.

We can just fold this requirement into the platform quirk then. This now means that all of these match platform quirks for pnpbios and RTC preferences:

* X86_SUBARCH_XEN
* X86_SUBARCH_LGUEST
* X86_SUBARCH_INTEL_MID
* X86_SUBARCH_CE4100

[0] http://lkml.kernel.org/r/[email protected]
[1] http://lkml.kernel.org/r/[email protected]

---
 arch/x86/kernel/platform-quirks.c | 1 +
 arch/x86/kernel/rtc.c             | 3 ---
 2 files changed, 1 insertion(+), 3 deletions(-)
arch/x86/kernel/platform-quirks.c +1 -0
index 853919484340..b2f8a33b36ff 100644
@@ -17,6 +17,7 @@ void __init x86_early_init_platform_quirks(void)
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
 	case X86_SUBARCH_INTEL_MID:
+	case X86_SUBARCH_CE4100:
 		x86_platform.legacy.devices.pnpbios = 0;
 		x86_platform.legacy.rtc = 0;
 		break;
arch/x86/kernel/rtc.c +0 -3
index ff4f4180fefd..eceaa082ec3f 100644
@@ -186,9 +186,6 @@ static __init int add_rtc_cmos(void)
 		}
 	}
 #endif
-	if (of_have_populated_dt())
-		return 0;
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;
 
Signature · 1 line
2.7.2
#38 lore raw

[tip:x86/boot] x86/init: Disable pnpbios and rtc for X86_SUBARCH_CE4100

x86/init: Disable pnpbios and rtc for X86_SUBARCH_CE4100
Commit-ID:  a50b22a7a1e60c48ca26cada362076b54823c501
Gitweb:     http://git.kernel.org/tip/a50b22a7a1e60c48ca26cada362076b54823c501
Author:     Luis R. Rodriguez <[email protected]>
AuthorDate: Wed, 13 Apr 2016 17:04:46 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 22 Apr 2016 10:29:09 +0200

x86/init: Disable pnpbios and rtc for X86_SUBARCH_CE4100

As per hpa CE4100 platforms can also disable pnpbios:

http://lkml.kernel.org/r/[email protected]

Then Sebastian also recently noted that CE4100 also disables RTC probe, to do that Sebastian had long ago added the RTC of_have_populated_dt() check, he noted that it was meant to skip the RTC probe on all OF platforms but as of now, CE4100 was the only x86 DT using this.

We can just fold this requirement into the platform quirk then. This now means that all of these match platform quirks for pnpbios and RTC preferences:

* X86_SUBARCH_XEN
* X86_SUBARCH_LGUEST
* X86_SUBARCH_INTEL_MID
* X86_SUBARCH_CE4100

Also see:

http://lkml.kernel.org/r/[email protected]

---
 arch/x86/kernel/platform-quirks.c | 1 +
 arch/x86/kernel/rtc.c             | 3 ---
 2 files changed, 1 insertion(+), 3 deletions(-)
arch/x86/kernel/platform-quirks.c +1 -0
index 8539194..b2f8a33 100644
@@ -17,6 +17,7 @@ void __init x86_early_init_platform_quirks(void)
 	case X86_SUBARCH_XEN:
 	case X86_SUBARCH_LGUEST:
 	case X86_SUBARCH_INTEL_MID:
+	case X86_SUBARCH_CE4100:
 		x86_platform.legacy.devices.pnpbios = 0;
 		x86_platform.legacy.rtc = 0;
 		break;
arch/x86/kernel/rtc.c +0 -3
index ff4f418..eceaa08 100644
@@ -186,9 +186,6 @@ static __init int add_rtc_cmos(void)
 		}
 	}
 #endif
-	if (of_have_populated_dt())
-		return 0;
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;