[PATCH 3.13.y-ckt 017/156] ARC: Fix KSTK_ESP()

From: Kamal Mostafa
Date: Tue Apr 07 2015 - 18:52:19 EST

3.13.11-ckt19 -stable review patch. If anyone has any objections, please let me know.


From: Vineet Gupta <vgupta@xxxxxxxxxxxx>

commit 13648b0118a24f4fc76c34e6c7b6ccf447e46a2a upstream.

/proc/<pid>/maps currently don't annotate stack vma with "[stack]"
This is because KSTK_ESP ie expected to return usermode SP of tsk while
currently it returns the kernel mode SP of a sleeping tsk.

While the fix is trivial, we also need to adjust the ARC kernel stack
unwinder to not use KSTK_SP and friends any more.

Reported-and-suggested-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
arch/arc/include/asm/processor.h | 9 +++++----
arch/arc/kernel/stacktrace.c | 6 +++---
2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 15334ab..fb95aa8 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -69,18 +69,19 @@ unsigned long thread_saved_pc(struct task_struct *t);
#define release_segments(mm) do { } while (0)

#define KSTK_EIP(tsk) (task_pt_regs(tsk)->ret)
+#define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp)

* Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
* Look in process.c for details of kernel stack layout
-#define KSTK_ESP(tsk) (tsk->thread.ksp)
+#define TSK_K_ESP(tsk) (tsk->thread.ksp)

-#define KSTK_REG(tsk, off) (*((unsigned int *)(KSTK_ESP(tsk) + \
+#define TSK_K_REG(tsk, off) (*((unsigned int *)(TSK_K_ESP(tsk) + \
sizeof(struct callee_regs) + off)))

-#define KSTK_BLINK(tsk) KSTK_REG(tsk, 4)
-#define KSTK_FP(tsk) KSTK_REG(tsk, 0)
+#define TSK_K_BLINK(tsk) TSK_K_REG(tsk, 4)
+#define TSK_K_FP(tsk) TSK_K_REG(tsk, 0)

* Do necessary setup to start up a newly executed thread.
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 9ce47cf..fb98769 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -64,9 +64,9 @@ static void seed_unwind_frame_info(struct task_struct *tsk,

frame_info->task = tsk;

- frame_info->regs.r27 = KSTK_FP(tsk);
- frame_info->regs.r28 = KSTK_ESP(tsk);
- frame_info->regs.r31 = KSTK_BLINK(tsk);
+ frame_info->regs.r27 = TSK_K_FP(tsk);
+ frame_info->regs.r28 = TSK_K_ESP(tsk);
+ frame_info->regs.r31 = TSK_K_BLINK(tsk);
frame_info->regs.r63 = (unsigned int)__switch_to;

/* In the prologue of __switch_to, first FP is saved on stack

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