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arm64: report correct stack pointer in KSTK_ESP for compat tasks
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The KSTK_ESP macro is used to determine the user stack pointer for a
given task. In particular, this is used to to report the '[stack]' VMA
in /proc/self/maps, which is used by Android to determine the stack
location for children of the main thread.

This patch fixes the macro to use user_stack_pointer instead of directly
returning sp. This means that we report w13 instead of sp, since the
former is used as the stack pointer when executing in AArch32 state.

Cc: <stable@vger.kernel.org>
Reported-by: Serban Constantinescu <Serban.Constantinescu@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Will Deacon committed Aug 29, 2014
1 parent 2520d03 commit 3168a74
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/arm64/include/asm/processor.h
Original file line number Diff line number Diff line change
Expand Up @@ -139,7 +139,7 @@ extern struct task_struct *cpu_switch_to(struct task_struct *prev,
((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)

#define KSTK_EIP(tsk) ((unsigned long)task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) ((unsigned long)task_pt_regs(tsk)->sp)
#define KSTK_ESP(tsk) user_stack_pointer(task_pt_regs(tsk))

/*
* Prefetching support
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