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x86, 32-bit: Align percpu area and irq stacks to THREAD_SIZE

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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: Alexander 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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Alexander van Heukelum 2010-09-06 20:53:42 +02:00 • committed by Ingo Molnar
commit fe8e0c25ca
3 changed files with 15 additions and 3 deletions
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4
arch/x86/kernel/irq_32.c
View file

@ -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)
{ {

2
arch/x86/kernel/vmlinux.lds.S
View file

@ -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);

12
include/linux/percpu-defs.h
View file

@ -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