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arm64: Modify stack trace and dump for use with irq_stack

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This patch allows unwind_frame() to traverse from interrupt stack to task
stack correctly. It requires data from a dummy stack frame, created
during irq_stack_entry(), added by a later patch.

A similar approach is taken to modify dump_backtrace(), which expects to
find struct pt_regs underneath any call to functions marked __exception.
When on an irq_stack, the struct pt_regs is stored on the old task stack,
the location of which is stored in the dummy stack frame.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
[james.morse: merged two patches, reworked for per_cpu irq_stacks, and
 no alignment guarantees, added irq_stack definitions]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
AKASHI Takahiro
2015-12-04 11:02:26 +00:00
committed by Will Deacon
parent 6cdf9c7ca6
commit 132cd887b5
4 changed files with 75 additions and 3 deletions
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32
arch/arm64/include/asm/irq.h
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@@ -1,10 +1,32 @@
#ifndef __ASM_IRQ_H
#define __ASM_IRQ_H
#define IRQ_STACK_SIZE THREAD_SIZE
#define IRQ_STACK_START_SP THREAD_START_SP
#ifndef __ASSEMBLER__
#include <linux/percpu.h>
#include <asm-generic/irq.h>
#include <asm/thread_info.h>
struct pt_regs;
DECLARE_PER_CPU(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
/*
* The highest address on the stack, and the first to be used. Used to
* find the dummy-stack frame put down by el?_irq() in entry.S.
*/
#define IRQ_STACK_PTR(cpu) ((unsigned long)per_cpu(irq_stack, cpu) + IRQ_STACK_START_SP)
/*
* The offset from irq_stack_ptr where entry.S will store the original
* stack pointer. Used by unwind_frame() and dump_backtrace().
*/
#define IRQ_STACK_TO_TASK_STACK(ptr) *((unsigned long *)(ptr - 0x10));
extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
static inline int nr_legacy_irqs(void)
@@ -12,4 +34,14 @@ static inline int nr_legacy_irqs(void)
return 0;
}
static inline bool on_irq_stack(unsigned long sp, int cpu)
{
/* variable names the same as kernel/stacktrace.c */
unsigned long low = (unsigned long)per_cpu(irq_stack, cpu);
unsigned long high = low + IRQ_STACK_START_SP;
return (low <= sp && sp <= high);
}
#endif /* !__ASSEMBLER__ */
#endif