ARM: Introduce function to switch to hypervisor mode

PATCH Superseded Keerthy 4 participants 10 messages Jul 27, 2016 – Jul 29, 2016

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Arm (32-bit) Arm/actions semi architecture

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Keerthy

author

2016-07-27 03:35 UTC #0 lore raw

cover ARM: Introduce function to switch to hypervisor mode

On SoCs like DRA7, OMAP5 one cannot enable hypervisor mode directly from the u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader.

Patch 1: Introduces a weak function which can be overridden specific to SoCs to switch to hypervisor mode.

Patch 2: overrides weak function in patch 1 switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for hypervisor mode on OMAP5 based SoCs.

Based on top of http://patchwork.dal.design.ti.com/patch/24937/.

Keerthy (2):
ARM: Introduce function to switch to hypervisor mode
ARM: OMAP5+: Override switch_to_hypervisor function

 arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 21 +++++++++++++++++++++
 arch/arm/cpu/armv7/start.S                     | 15 +++++++++++++++
 arch/arm/include/asm/system.h                  |  1 +
 3 files changed, 37 insertions(+)

Signature · 1 line

1.9.1

Keerthy

author

2016-07-27 03:35 UTC #1 lore raw

PATCH 1/2 ARM: Introduce function to switch to hypervisor mode

On some of the SoCs one cannot enable hypervisor mode directly from the u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader. Hence introduce a weak function which can be overridden based on the SoC type and switch to hypervisor mode in a custom way.

Cc beagleboard-x15 at googlegroups.com

Signed-off-by Keerthy <[email protected]>

---
 arch/arm/cpu/armv7/start.S    | 15 +++++++++++++++
 arch/arm/include/asm/system.h |  1 +
 2 files changed, 16 insertions(+)

arch/arm/cpu/armv7/start.S +15 -0

index 691e5d3..4fb3d58 100644
@@ -17,6 +17,7 @@
 #include <config.h>
 #include <asm/system.h>
 #include <linux/linkage.h>
+#include <asm/armv7.h>
 
 /*************************************************************************
  *

@@ -30,11 +31,20 @@
 
 	.globl	reset
 	.globl	save_boot_params_ret
+	.global	switch_to_hypervisor_ret
 
 reset:
 	/* Allow the board to save important registers */
 	b	save_boot_params
 save_boot_params_ret:
+/*
+ * check for Hypervisor support
+ */
+	mrc	p15, 0, r0, c0, c1, 1		@ read ID_PFR1
+	and	r0, r0, #CPUID_ARM_VIRT_MASK	@ mask virtualization bits
+	cmp	r0, #(1 << CPUID_ARM_VIRT_SHIFT)
+	beq	switch_to_hypervisor
+switch_to_hypervisor_ret:
 	/*
 	 * disable interrupts (FIQ and IRQ), also set the cpu to SVC32 mode,
 	 * except if in HYP mode already

@@ -103,6 +113,11 @@ ENTRY(save_boot_params)
 ENDPROC(save_boot_params)
 	.weak	save_boot_params
 
+ENTRY(switch_to_hypervisor)
+	b	switch_to_hypervisor_ret
+ENDPROC(switch_to_hypervisor)
+	.weak	switch_to_hypervisor
+
 /*************************************************************************
  *
  * cpu_init_cp15

arch/arm/include/asm/system.h +1 -0

index 2bdc0be..d1a95b0 100644
@@ -226,6 +226,7 @@ void __noreturn psci_system_reset(bool smc);
  * should use 'b' or 'bx' to return to save_boot_params_ret.
  */
 void save_boot_params_ret(void);
+void switch_to_hypervisor_ret(void);
 
 #define isb() __asm__ __volatile__ ("" : : : "memory")

Signature · 1 line

1.9.1

Tom Rini

2016-07-28 13:44 UTC #2 lore raw

PATCH 1/2 ARM: Introduce function to switch to hypervisor mode

Quoted 8 lines · Keerthy

On some of the SoCs one cannot enable hypervisor mode directly from the u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader. Hence introduce a weak function which can be overridden based on the SoC type and switch to hypervisor mode in a custom way.
Cc beagleboard-x15 at googlegroups.com
Signed-off-by Keerthy <[email protected]>

Reviewed-by Tom Rini <[email protected]>

Signature · 8 lines

Tom
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Keerthy

author

2016-07-27 03:35 UTC #3 lore raw

PATCH 2/2 ARM: OMAP5+: Override switch_to_hypervisor function

In reply to Keerthy

Override the switch_to_hypervisor function to switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for HYP mode.

Based on the work done by Jonathan Bergsagel jbergsagel at ti.com.

Cc beagleboard-x15 at googlegroups.com

Signed-off-by Keerthy <[email protected]>

Acked-by Nishanth Menon <[email protected]>

---
 arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

arch/arm/cpu/armv7/omap-common/lowlevel_init.S +21 -0

index 5283135..c7707e5 100644
@@ -23,7 +23,28 @@ ENTRY(save_boot_params)
 	str	r0, [r1]
 	b	save_boot_params_ret
 ENDPROC(save_boot_params)
+
+ENTRY(switch_to_hypervisor)
+/*
+ * Switch to hypervisor mode
+ */
+	adr	r0, save_sp
+	str	sp, [r0]
+	adr	r1, restore_from_hyp
+	ldr	r0, =0x102
+#ifdef CONFIG_TI_SECURE_DEVICE
+	b	omap_smc_sec
+#else
+	b	omap_smc1
+#endif
+restore_from_hyp:
+	adr	r0, save_sp
+	ldr	sp, [r0]
 #endif
+	b	switch_to_hypervisor_ret
+save_sp:
+	.word	0x0
+ENDPROC(switch_to_hypervisor)
 
 ENTRY(omap_smc1)
 	PUSH	{r4-r12, lr}	@ save registers - ROM code may pollute

Signature · 1 line

1.9.1

Tom Rini

2016-07-28 13:44 UTC #4 lore raw

PATCH 2/2 ARM: OMAP5+: Override switch_to_hypervisor function

Quoted 9 lines · Keerthy

Override the switch_to_hypervisor function to switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for HYP mode.
Based on the work done by Jonathan Bergsagel jbergsagel at ti.com.
Cc beagleboard-x15 at googlegroups.com
Signed-off-by Keerthy <[email protected]>
Acked-by Nishanth Menon <[email protected]>

Reviewed-by Tom Rini <[email protected]>

Signature · 8 lines

Tom
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Keerthy

2016-07-27 03:37 UTC #5 lore raw

cover ARM: Introduce function to switch to hypervisor mode

In reply to Keerthy

Quoted 4 lines · Keerthy

On SoCs like DRA7, OMAP5 one cannot enable hypervisor mode directly from the u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader.

Quoted 8 lines

Patch 1: Introduces a weak function which can be overridden specific to SoCs to switch to hypervisor mode.
Patch 2: overrides weak function in patch 1 switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for hypervisor mode on OMAP5 based SoCs.
Based on top of http://patchwork.dal.design.ti.com/patch/24937/.

Please ignore the above link.

Based on:

http://lists.denx.de/pipermail/u-boot/2016-June/258300.html

Quoted 10 lines

Keerthy (2):
ARM: Introduce function to switch to hypervisor mode
ARM: OMAP5+: Override switch_to_hypervisor function
  arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 21 +++++++++++++++++++++
  arch/arm/cpu/armv7/start.S                     | 15 +++++++++++++++
  arch/arm/include/asm/system.h                  |  1 +
  3 files changed, 37 insertions(+)

Marek Vasut

2016-07-28 12:08 UTC #6 lore raw

cover ARM: Introduce function to switch to hypervisor mode

Quoted 15 lines · Keerthy

Quoted 12 lines · Keerthy
On SoCs like DRA7, OMAP5 one cannot enable hypervisor mode directly from the
u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader.
Patch 1: Introduces a weak function which can be overridden specific to SoCs to switch to hypervisor mode.
Patch 2: overrides weak function in patch 1 switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for hypervisor mode on OMAP5 based SoCs.

Quoted 7 lines

Quoted 1 line
Based on top of http://patchwork.dal.design.ti.com/patch/24937/.
Please ignore the above link.
Based on:
http://lists.denx.de/pipermail/u-boot/2016-June/258300.html

Please resubmit fixed patch. Also please add your full name as the author, otherwise the patches can not be applied.

See ie. https://lwn.net/Articles/195643/

Quoted 11 lines

Quoted 11 lines
Keerthy (2):
ARM: Introduce function to switch to hypervisor mode
ARM: OMAP5+: Override switch_to_hypervisor function
  arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 21
+++++++++++++++++++++
  arch/arm/cpu/armv7/start.S                     | 15 +++++++++++++++
  arch/arm/include/asm/system.h                  |  1 +
  3 files changed, 37 insertions(+)

Signature · 2 lines

Best regards,
Marek Vasut

Keerthy

2016-07-28 12:42 UTC #7 lore raw

cover ARM: Introduce function to switch to hypervisor mode

Hi Marek,

Quoted 18 lines · Marek Vasut

Quoted 17 lines · Keerthy
Quoted 13 lines · Keerthy
On SoCs like DRA7, OMAP5 one cannot enable hypervisor mode directly from the
u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader.
Patch 1: Introduces a weak function which can be overridden specific to SoCs to switch to hypervisor mode.
Patch 2: overrides weak function in patch 1 switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for hypervisor mode on OMAP5 based SoCs.
Based on top of http://patchwork.dal.design.ti.com/patch/24937/.

Quoted 9 lines

Quoted 5 lines
Please ignore the above link.
Based on:
http://lists.denx.de/pipermail/u-boot/2016-June/258300.html
Please resubmit fixed patch. Also please add your full name as the author, otherwise the patches can not be applied.

I will re-submit the patches with the correct link.

Coming to the name. My full name is Keerthy and that is the name i have been using for the last 4-5 years in the mailing list. I do not have a surname.

- Keerthy

Quoted 15 lines

See ie. https://lwn.net/Articles/195643/
Quoted 11 lines
Quoted 11 lines
Keerthy (2):
ARM: Introduce function to switch to hypervisor mode
ARM: OMAP5+: Override switch_to_hypervisor function
   arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 21
+++++++++++++++++++++
   arch/arm/cpu/armv7/start.S                     | 15 +++++++++++++++
   arch/arm/include/asm/system.h                  |  1 +
   3 files changed, 37 insertions(+)

Tom Rini

2016-07-28 13:44 UTC #8 lore raw

cover ARM: Introduce function to switch to hypervisor mode

In reply to Marek Vasut

Quoted 18 lines · Marek Vasut

Quoted 17 lines · Keerthy
Quoted 13 lines · Keerthy
On SoCs like DRA7, OMAP5 one cannot enable hypervisor mode directly from the
u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader.
Patch 1: Introduces a weak function which can be overridden specific to SoCs to switch to hypervisor mode.
Patch 2: overrides weak function in patch 1 switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for hypervisor mode on OMAP5 based SoCs.
Based on top of http://patchwork.dal.design.ti.com/patch/24937/.

Quoted 7 lines

Quoted 5 lines
Please ignore the above link.
Based on:
http://lists.denx.de/pipermail/u-boot/2016-June/258300.html
Please resubmit fixed patch.

That's just a bad link in 0/2, nothing to resubmit.

Signature · 8 lines

Tom
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Keerthy

2016-07-29 06:21 UTC #9 lore raw

cover ARM: Introduce function to switch to hypervisor mode

Quoted 21 lines · Tom Rini

Quoted 20 lines · Marek Vasut
Quoted 19 lines · Keerthy
Quoted 5 lines · Keerthy
On SoCs like DRA7, OMAP5 one cannot enable hypervisor mode directly from the
u-boot because the ROM code puts the chip to supervisor mode after it jumps to boot loader.
Quoted 8 lines
Patch 1: Introduces a weak function which can be overridden specific to SoCs to switch to hypervisor mode.
Patch 2: overrides weak function in patch 1 switch cpu to hypervisor mode using the available ROM code hook early in the boot phase before the boot loader checks for hypervisor mode on OMAP5 based SoCs.
Based on top of http://patchwork.dal.design.ti.com/patch/24937/.
Please ignore the above link.

Quoted 7 lines

Quoted 5 lines
Quoted 3 lines
Based on:
http://lists.denx.de/pipermail/u-boot/2016-June/258300.html
Please resubmit fixed patch.
That's just a bad link in 0/2, nothing to resubmit.

Thanks for reviewing Tom!
The series generated a compile error on a bunch of other defconfigs. I have fixed that and send a v2 with your Reviewed-by.

Quoted 1 line