arm64: report correct stack pointer in KSTK_ESP for compat tasks

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>
(cherry picked from commit 3168a743461ecf86adf3e7dcfcd79271828fb263)
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index db3112886968d539c10e291257a1df09b549bb55..3b7bb031f98f666a5adb719f6ee581fa8e8a4cf3 100644 (file)
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -132,7 +132,7 @@ 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