fix 25 section mismatch warnings..

The following set of patches fixes 25 Section mismatch warnings in following directories:

kernel/
mm/
drivers/pci
arch/x86/

When build individually they are now clean.

The shortlog:

Sam Ravnborg (11):
pci: fix section mismatch warnings referring to pci_do_scan_bus
pci: fix 4x section mismatch warnings
cpu: fix section mismatch warnings for enable_nonboot_cpus
cpu: fix section mismatch related to cpu_chain
cpu: do not annotate exported register_cpu_notifier()
cpu: silence section mismatch warnings for hotcpu notifies
mm: fix section mismatch warning in sparse.c
x86: fix section mismatch warning in acpi/boot.c
x86: silence section mismatch warning in smpboot_64.c
x86: fix section mismatch warning in kernel/pci-calgary
x86: fix section mismatch warnings when referencing notifiers

With these patches applied I have a clean build of arch/x86/ with an allyesconfig.

I expect Greg to pick up the pci patches - but as they conflict with patches recently posted by Adrian a qualified selection should be made.

The cpu patches are cc:ed to Gautham R Shenoy but I think they need to go in via Andrew.
The mm patch are cc:ed the Mel, Christoph and Andy but I think this one should also go in via Andrew.

The x86 patches are cc:ed to the x86 gang and should all go in via the x86 tree.

I would like some extra review of the following patches:
-> The pci patches
-> x86: silence section mismatch warning in smpboot_64.c

The others are more strightforward but please eye ball them too.

For my allyesconfig build I still has 116 warnings - but this is without Adrian's patches applied.
Of these 8 happens only when running the final check on vmlinux.o which is due to references between the sub directories (kernel/ <-> arch/x86/kernel/)

Patches follows unnumbered as they are independent of each other.

Sam

Fix following warnings:
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0xb054): Section mismatch in reference from the function cpci_configure_slot() to the function .devinit.text:pci_do_scan_bus()
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0x153ab): Section mismatch in reference from the function shpchp_configure_device() to the function .devinit.text:pci_do_scan_bus()
WARNING: o-x86_64/drivers/pci/built-in.o(__ksymtab+0xc0): Section mismatch in reference from the variable __ksymtab_pci_do_scan_bus to the function .devinit.text:pci_do_scan_bus()

PCI hotplug were the only user of pci_do_scan_bus() so moving this function to the directory of PCI Hotplug was a logical way to fix so
we only include this function in the kernel when the CONFIG_HOTPLUG_PCI is enabled.

Then the abuse of __devinit could be dropped and
we no longer trigger the above warnings.

---
 drivers/pci/hotplug/Makefile   |    1 +
 drivers/pci/hotplug/pci-core.c |   20 ++++++++++++++++++++
 drivers/pci/probe.c            |   15 ---------------
 3 files changed, 21 insertions(+), 15 deletions(-)
 create mode 100644 drivers/pci/hotplug/pci-core.c

index 34a1891..f755a6e 100644
@@ -1,6 +1,7 @@
 #
 # Makefile for the Linux kernel pci hotplug controller drivers.
 #
+obj-y := pci-core.o
 
 obj-$(CONFIG_HOTPLUG_PCI)		+= pci_hotplug.o
 obj-$(CONFIG_HOTPLUG_PCI_FAKE)		+= fakephp.o 

new file mode 100644
index 0000000..e0fb169
@@ -0,0 +1,20 @@
+/* Core PCI functionality used only by PCI hotplug */
+
+#include <linux/pci.h>
+#include "../pci.h"
+
+
+unsigned int pci_do_scan_bus(struct pci_bus *bus)
+{
+	unsigned int max;
+
+	max = pci_scan_child_bus(bus);
+
+	/*
+	 * Make the discovered devices available.
+	 */
+	pci_bus_add_devices(bus);
+
+	return max;
+}
+EXPORT_SYMBOL(pci_do_scan_bus);

index 5fd5852..496fc13 100644
@@ -1050,20 +1050,6 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
 	return max;
 }
 
-unsigned int __devinit pci_do_scan_bus(struct pci_bus *bus)
-{
-	unsigned int max;
-
-	max = pci_scan_child_bus(bus);
-
-	/*
-	 * Make the discovered devices available.
-	 */
-	pci_bus_add_devices(bus);
-
-	return max;
-}
-
 struct pci_bus * pci_create_bus(struct device *parent,
 		int bus, struct pci_ops *ops, void *sysdata)
 {

@@ -1156,7 +1142,6 @@ EXPORT_SYMBOL(pci_scan_bus_parented);
 
 #ifdef CONFIG_HOTPLUG
 EXPORT_SYMBOL(pci_add_new_bus);
-EXPORT_SYMBOL(pci_do_scan_bus);
 EXPORT_SYMBOL(pci_scan_slot);
 EXPORT_SYMBOL(pci_scan_bridge);
 EXPORT_SYMBOL(pci_scan_single_device);

1.5.4.rc3.14.g44397

This patch is bogus - I will send an updated version later this weekend.

Sam

The following warnings were issued during build of
drivers/pci with an allyesconfig build:
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0xdaf): Section mismatch in reference from the function pci_add_new_bus() to the function .devinit.text:pci_alloc_child_bus()
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0x15e2): Section mismatch in reference from the function pci_scan_single_device() to the function .devinit.text:pci_scan_device()
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0x1b0c5): Section mismatch in reference from the function pci_bus_assign_resources() to the function .devinit.text:pci_setup_bridge()
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0x1b32d): Section mismatch in reference from the function pci_bus_size_bridges() to the function .devinit.text:pci_bus_size_cardbus()

Investigating each case closer it looked like all referred functions are only used in the init phase or during hotplug.
So to avoid wasting too much memory in the non-hotplug case the simpler fix was to allow the fuctions to use code/data from the __devinit sections. This was done in all four case by adding the __ref annotation.

---
 drivers/pci/probe.c     |    4 ++--
 drivers/pci/setup-bus.c |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

index 496fc13..f419026 100644
@@ -442,7 +442,7 @@ error_register:
 	return NULL;
 }
 
-struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, int busnr)
+struct pci_bus *__ref pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, int busnr)
 {
 	struct pci_bus *child;
 

@@ -959,7 +959,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	up_write(&pci_bus_sem);
 }
 
-struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
+struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn)
 {
 	struct pci_dev *dev;
 

index 401e03c..86bb6f8 100644
@@ -440,7 +440,7 @@ pci_bus_size_cardbus(struct pci_bus *bus)
 	}
 }
 
-void pci_bus_size_bridges(struct pci_bus *bus)
+void __ref pci_bus_size_bridges(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 	unsigned long mask, prefmask;

@@ -495,7 +495,7 @@ void pci_bus_size_bridges(struct pci_bus *bus)
 }
 EXPORT_SYMBOL(pci_bus_size_bridges);
 
-void pci_bus_assign_resources(struct pci_bus *bus)
+void __ref pci_bus_assign_resources(struct pci_bus *bus)
 {
 	struct pci_bus *b;
 	struct pci_dev *dev;

1.5.4.rc3.14.g44397

The hotcpu_notifier is used to create notifiers to be called later. It really looks like the functions that are registered are only relevant in a HOTPLUG_CPU configuration and the correct fix was to wrap them in an #ifdef / #endif or similar.
But for now just tell modpost to silence the warning by annotating the static variable with __refdata.

This silences the following warnings in kernel/:
WARNING: o-x86_64/kernel/built-in.o(.data+0x960): Section mismatch in reference from the variable profile_cpu_callback_nb.17240 to the function .devinit.text:profile_cpu_callback()
WARNING: o-x86_64/kernel/built-in.o(.data+0x3fa0): Section mismatch in reference from the variable workqueue_cpu_callback_nb.14663 to the function .devinit.text:workqueue_cpu_callback()
WARNING: o-x86_64/kernel/built-in.o(.data+0xe280): Section mismatch in reference from the variable relay_hotcpu_callback_nb.19247 to the function .cpuinit.text:relay_hotcpu_callback()

Additional warnings are silenced with this change but they are left put.

This patch is just a workaround for the bad practice to use __cpuinit to annotate code solely used for HOTPLUG_CPU.

---
 include/linux/cpu.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 0be8d65..cebb8c0 100644
@@ -109,7 +109,7 @@ static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
 extern void get_online_cpus(void);
 extern void put_online_cpus(void);
 #define hotcpu_notifier(fn, pri) {				\
-	static struct notifier_block fn##_nb =			\
+	static struct notifier_block fn##_nb __refdata =	\
 		{ .notifier_call = fn, .priority = pri };	\
 	register_cpu_notifier(&fn##_nb);			\
 }

1.5.4.rc3.14.g44397

Fix following warning:
WARNING: o-x86_64/kernel/built-in.o(__ksymtab+0xfb0): Section mismatch in reference from the variable __ksymtab_register_cpu_notifier to the function .cpuinit.text:register_cpu_notifier()

register_cpu_notifier() are used from modules that may be loaded long after init has completed.
Drop the annotation so the function is kept after init.

---
 kernel/cpu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index df9430f..6fc9864 100644
@@ -136,7 +136,7 @@ static void cpu_hotplug_done(void)
 	mutex_unlock(&cpu_hotplug.lock);
 }
 /* Need to know about CPUs going up/down? */
-int __cpuinit register_cpu_notifier(struct notifier_block *nb)
+int register_cpu_notifier(struct notifier_block *nb)
 {
 	int ret;
 	cpu_maps_update_begin();

1.5.4.rc3.14.g44397

Fix following warning:
WARNING: o-x86_64/kernel/built-in.o(.text+0x36d8b): Section mismatch in reference from the function enable_nonboot_cpus() to the function .cpuinit.text:_cpu_up()

enable_nonboot_cpus() are used solely from CONFIG_CONFIG_PM_SLEEP_SMP=y and PM_SLEEP_SMP imply HOTPLUG_CPU therefore the reference to _cpu_up() is valid.
Annotate enable_nonboot_cpus() with __ref to silence modpost.

---
 kernel/cpu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index e0d3a4f..2eff3f6 100644
@@ -389,7 +389,7 @@ int disable_nonboot_cpus(void)
 	return error;
 }
 
-void enable_nonboot_cpus(void)
+void __ref enable_nonboot_cpus(void)
 {
 	int cpu, error;
 

1.5.4.rc3.14.g44397

Silence the following warning:
WARNING: o-x86_64/arch/x86/kernel/built-in.o(.text+0x17cd3): Section mismatch in reference from the function remove_cpu_from_maps() to the variable .cpuinit.data:cpu_initialized

remove_cpu:maps() had a single user: __cpu_disable() so mark it static and annotate it with __ref to silence the warning from modpost.

_cpu_disable() has a single user in kernel/cpu.c:
=> take_cpu_down()
which again has a single user in the following call:
=> __stop_machine_run(take_cpu_down, &tcd_param, cpu);
Here a kthread is created.

So maybe the warning is correct and the right fix is to remove the __cpuinitdata annotation of cpu_initialized?

Note: The analysis were disturbed by the fact that we had a variable
with the same name in cpu/common.c - but this is 32 bit only]
Note: Should smpboot_64 use cpu_clear()?

---
 arch/x86/kernel/smpboot_64.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index cc64b80..d53bd6f 100644
@@ -1019,7 +1019,7 @@ static void remove_siblinginfo(int cpu)
 	cpu_clear(cpu, cpu_sibling_setup_map);
 }
 
-void remove_cpu_from_maps(void)
+static void __ref remove_cpu_from_maps(void)
 {
 	int cpu = smp_processor_id();
 

1.5.4.rc3.14.g44397

Fix following warning:
WARNING: o-x86_64/arch/x86/kernel/built-in.o(.text+0x13d15): Section mismatch in reference from the function acpi_map_lsapic() to the function .cpuinit.text:mp_register_lapic()

The function acpi_map_lsapic() is exported and thus not annotated. But the sole user is acpi/processor_core.c in a __cpuinit path. So create a small wrapper and put back the annotation thus avoiding the warning.

---
 arch/x86/kernel/acpi/boot.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

index 0ca27c7..d2a5843 100644
@@ -496,7 +496,8 @@ EXPORT_SYMBOL(acpi_register_gsi);
  *  ACPI based hotplug support for CPU
  */
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
-int acpi_map_lsapic(acpi_handle handle, int *pcpu)
+
+static int __cpuinit _acpi_map_lsapic(acpi_handle handle, int *pcpu)
 {
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 	union acpi_object *obj;

@@ -551,6 +552,11 @@ int acpi_map_lsapic(acpi_handle handle, int *pcpu)
 	return 0;
 }
 
+/* wrapper to silence section mismatch warning */
+int __ref acpi_map_lsapic(acpi_handle handle, int *pcpu)
+{
+	return _acpi_map_lsapic(handle, pcpu);
+}
 EXPORT_SYMBOL(acpi_map_lsapic);
 
 int acpi_unmap_lsapic(int cpu)

1.5.4.rc3.14.g44397

Fix following warning:
WARNING: arch/x86/kernel/built-in.o(.text+0x1eb41): Section mismatch in reference from the function calgary_handle_quirks() to the function .init.text:calgary_set_split_completion_timeout()

calgary_handle_quirks() are only called at
__init time (in calgary_init_one() via handle_quirks ops). So annotate this function and the sister function __init.

---
 arch/x86/kernel/pci-calgary_64.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

index 21f34db..1fe7f04 100644
@@ -1006,7 +1006,7 @@ static void __init calgary_set_split_completion_timeout(void __iomem *bbar,
 	readq(target); /* flush */
 }
 
-static void calioc2_handle_quirks(struct iommu_table *tbl, struct pci_dev *dev)
+static void __init calioc2_handle_quirks(struct iommu_table *tbl, struct pci_dev *dev)
 {
 	unsigned char busnum = dev->bus->number;
 	void __iomem *bbar = tbl->bbar;

@@ -1022,7 +1022,7 @@ static void calioc2_handle_quirks(struct iommu_table *tbl, struct pci_dev *dev)
 	writel(cpu_to_be32(val), target);
 }
 
-static void calgary_handle_quirks(struct iommu_table *tbl, struct pci_dev *dev)
+static void __init calgary_handle_quirks(struct iommu_table *tbl, struct pci_dev *dev)
 {
 	unsigned char busnum = dev->bus->number;
 

1.5.4.rc3.14.g44397

Fix following warning:
WARNING: mm/built-in.o(.text+0x22069): Section mismatch in reference from the function sparse_early_usemap_alloc() to the function .init.text:__alloc_bootmem_node()

static sparse_early_usemap_alloc() were used only by sparse_init() and with sparse_init() annotated _init it is safe to annotate sparse_early_usemap_alloc with __init too.

---
 mm/sparse.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index a2183cb..231c7b5 100644
@@ -237,7 +237,7 @@ static unsigned long *__kmalloc_section_usemap(void)
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
-static unsigned long *sparse_early_usemap_alloc(unsigned long pnum)
+static unsigned long *__init sparse_early_usemap_alloc(unsigned long pnum)
 {
 	unsigned long *usemap;
 	struct mem_section *ms = __nr_to_section(pnum);

1.5.4.rc3.14.g44397

Fix following warnings:
WARNING: o-x86_64/kernel/built-in.o(.text+0x36de9): Section mismatch in reference from the function take_cpu_down() to the variable .cpuinit.data:cpu_chain
WARNING: o-x86_64/kernel/built-in.o(.text+0x36e86): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain
WARNING: o-x86_64/kernel/built-in.o(.text+0x36ea9): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain
WARNING: o-x86_64/kernel/built-in.o(.text+0x36f40): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain
WARNING: o-x86_64/kernel/built-in.o(.text+0x36f8f): Section mismatch in reference from the function _cpu_down() to the variable .cpuinit.data:cpu_chain
WARNING: o-x86_64/kernel/built-in.o(.text+0x370aa): Section mismatch in reference from the function unregister_cpu_notifier() to the variable .cpuinit.data:cpu_chain

cpu_chain is used by unregister_cpu_notifier() that is used by the kvm module. So we can call the unregister_cpu_notifier() long after init completed.
Drop the __cpuinitdata annotation to avoid freeing cpu_chain.

---
 kernel/cpu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 2eff3f6..df9430f 100644
@@ -18,7 +18,7 @@
 /* Serializes the updates to cpu_online_map, cpu_present_map */
 static DEFINE_MUTEX(cpu_add_remove_lock);
 
-static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
+static RAW_NOTIFIER_HEAD(cpu_chain);
 
 /* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
  * Should always be manipulated under cpu_add_remove_lock

1.5.4.rc3.14.g44397

Fix the following warnings:
WARNING: arch/x86/kernel/built-in.o(.exit.text+0xf8): Section mismatch in reference from the function msr_exit() to the variable .cpuinit.data:msr_class_cpu_notifier
WARNING: arch/x86/kernel/built-in.o(.exit.text+0x158): Section mismatch in reference from the function cpuid_exit() to the variable .cpuinit.data:cpuid_class_cpu_notifier
WARNING: arch/x86/kernel/built-in.o(.exit.text+0x171): Section mismatch in reference from the function microcode_exit() to the variable .cpuinit.data:mc_cpu_notifier

In all three cases there were a function annotated __exit that referenced a variable annotated __cpuinitdata.

The fix was to replace the annotation of the notifier with __refdata to tell modpost that the reference to a _cpuinit function in the notifier are OK. The unregister call that references the notifier variable will simple delete the function pointer so there is no problem ignoring the reference.

Note: This looks like another case where __cpuinit has been used as replacement for proper use of CONFIG_HOTPLUG_CPU to decide what code are used for HOTPLUG_CPU.

---
 arch/x86/kernel/cpuid.c     |    2 +-
 arch/x86/kernel/microcode.c |    2 +-
 arch/x86/kernel/msr.c       |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

index dec66e4..a63432d 100644
@@ -170,7 +170,7 @@ static int __cpuinit cpuid_class_cpu_callback(struct notifier_block *nfb,
 	return err ? NOTIFY_BAD : NOTIFY_OK;
 }
 
-static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier =
+static struct notifier_block __refdata cpuid_class_cpu_notifier =
 {
 	.notifier_call = cpuid_class_cpu_callback,
 };

index 6ff447f..f2702d0 100644
@@ -797,7 +797,7 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
 	return NOTIFY_OK;
 }
 
-static struct notifier_block __cpuinitdata mc_cpu_notifier = {
+static struct notifier_block __refdata mc_cpu_notifier = {
 	.notifier_call = mc_cpu_callback,
 };
 

index 21f6e3c..bd82850 100644
@@ -168,7 +168,7 @@ static int __cpuinit msr_class_cpu_callback(struct notifier_block *nfb,
 	return err ? NOTIFY_BAD : NOTIFY_OK;
 }
 
-static struct notifier_block __cpuinitdata msr_class_cpu_notifier = {
+static struct notifier_block __refdata msr_class_cpu_notifier = {
 	.notifier_call = msr_class_cpu_callback,
 };
 

1.5.4.rc3.14.g44397

thanks Sam, i've applied your 4 x86 related fixes to x86.git.

Ingo