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Commit fe8e0c25 authored by Alexander van Heukelum's avatar Alexander van Heukelum Committed by Ingo Molnar
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x86, 32-bit: Align percpu area and irq stacks to THREAD_SIZE 



The irq stacks, located in the percpu-area, need to be
THREAD_SIZE aligned. Add the infrastucture to align percpu
variables to larger-than-pagesize amounts within the percpu
area, and use it to specify the alignment for the irq stacks.
Also align the percpu area itself to THREAD_SIZE.

This should make irq stacks work with 8K THREAD_SIZE.

Signed-off-by: default avatarAlexander van Heukelum <heukelum@fastmail.fm>
Cc: Tejun Heo <tj@kernel.org>
Cc: hch@lst.de
LKML-Reference: <1283799222.15941.1393621887@webmail.messagingengine.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1813a684

arch/x86/kernel/irq_32.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -60,8 +60,8 @@ union irq_ctx { 
static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx);

static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx);

static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx);

static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx);





static DEFINE_PER_CPU_PAGE_ALIGNED(union irq_ctx, hardirq_stack);

static DEFINE_PER_CPU_MULTIPAGE_ALIGNED(union irq_ctx, hardirq_stack, THREAD_SIZE);

static DEFINE_PER_CPU_PAGE_ALIGNED(union irq_ctx, softirq_stack);

static DEFINE_PER_CPU_MULTIPAGE_ALIGNED(union irq_ctx, softirq_stack, THREAD_SIZE);





static void call_on_stack(void *func, void *stack)

static void call_on_stack(void *func, void *stack)

{

{

arch/x86/kernel/vmlinux.lds.S

+1 −1
Original line number Original line Diff line number Diff line
@@ -273,7 +273,7 @@ SECTIONS 
	}

	}





#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)

#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)

	PERCPU(PAGE_SIZE)

	PERCPU(THREAD_SIZE)

#endif

#endif





	. = ALIGN(PAGE_SIZE);

	. = ALIGN(PAGE_SIZE);

include/linux/percpu-defs.h

+12 −0
Original line number Original line Diff line number Diff line
@@ -138,6 +138,18 @@ 
	DEFINE_PER_CPU_SECTION(type, name, "..page_aligned")		\

	DEFINE_PER_CPU_SECTION(type, name, "..page_aligned")		\

	__aligned(PAGE_SIZE)

	__aligned(PAGE_SIZE)





/*

 * Declaration/definition used for large per-CPU variables that must be

 * aligned to something larger than the pagesize.

 */

#define DECLARE_PER_CPU_MULTIPAGE_ALIGNED(type, name, size)		\

	DECLARE_PER_CPU_SECTION(type, name, "..page_aligned")		\

	__aligned(size)



#define DEFINE_PER_CPU_MULTIPAGE_ALIGNED(type, name, size)		\

	DEFINE_PER_CPU_SECTION(type, name, "..page_aligned")		\

	__aligned(size)



/*

/*

 * Intermodule exports for per-CPU variables.  sparse forgets about

 * Intermodule exports for per-CPU variables.  sparse forgets about

 * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to

 * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to