3 files changed, 19 insertions, 27 deletions

diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index fdd89715d2d3..98c00a2d4dd9 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -192,29 +192,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
         return 0;
 }
 
-/*
- * API: expected by schedular Code: If thread is sleeping where is that.
- * What is this good for? it will be always the scheduler or ret_from_fork.
- * So we hard code that anyways.
- */
-unsigned long thread_saved_pc(struct task_struct *t)
-{
-        struct pt_regs *regs = task_pt_regs(t);
-        unsigned long blink = 0;
-
-        /*
-         * If the thread being queried for in not itself calling this, then it
-         * implies it is not executing, which in turn implies it is sleeping,
-         * which in turn implies it got switched OUT by the schedular.
-         * In that case, it's kernel mode blink can reliably retrieved as per
-         * the picture above (right above pt_regs).
-         */
-        if (t != current && t->state != TASK_RUNNING)
-                blink = *((unsigned int *)regs - 1);
-
-        return blink;
-}
-
 int elf_check_arch(const struct elf32_hdr *x)
 {
         unsigned int eflags;
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 9ce47cfe2303..92320d6f737c 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -43,6 +43,10 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
                                    struct pt_regs *regs,
                                    struct unwind_frame_info *frame_info)
 {
+        /*
+         * synchronous unwinding (e.g. dump_stack)
+         *  - uses current values of SP and friends
+         */
         if (tsk == NULL && regs == NULL) {
                 unsigned long fp, sp, blink, ret;
                 frame_info->task = current;
@@ -61,12 +65,17 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
                 frame_info->regs.r63 = ret;
                 frame_info->call_frame = 0;
         } else if (regs == NULL) {
+                /*
+                 * Asynchronous unwinding of sleeping task
+                 *  - Gets SP etc from task's pt_regs (saved bottom of kernel
+                 *    mode stack of task)
+                 */
 
                 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
@@ -83,6 +92,10 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
                 frame_info->call_frame = 0;
 
         } else {
+                /*
+                 * Asynchronous unwinding of intr/exception
+                 *  - Just uses the pt_regs passed
+                 */
                 frame_info->task = tsk;
 
                 frame_info->regs.r27 = regs->fp;
@@ -95,7 +108,7 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
 
 #endif
 
-static noinline unsigned int
+notrace noinline unsigned int
 arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
                 int (*consumer_fn) (unsigned int, void *), void *arg)
 {
diff --git a/arch/arc/kernel/unaligned.c b/arch/arc/kernel/unaligned.c
index 7ff5b5c183bb..74db59b6f392 100644
--- a/arch/arc/kernel/unaligned.c
+++ b/arch/arc/kernel/unaligned.c
@@ -12,6 +12,7 @@
  */
 
 #include <linux/types.h>
+#include <linux/perf_event.h>
 #include <linux/ptrace.h>
 #include <linux/uaccess.h>
 #include <asm/disasm.h>
@@ -253,6 +254,7 @@ int misaligned_fixup(unsigned long address, struct pt_regs *regs,
                 }
         }
 
+        perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, address);
         return 0;
 
 fault: