[PATCH] powerpc: Add oprofile calltrace support

Add oprofile calltrace support to powerpc. Disable spinlock backtracing
now we can use calltrace info.

(Updated to work on both 32bit and 64bit by me).

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 126 insertions, 0 deletions

diff --git a/arch/powerpc/oprofile/backtrace.c b/arch/powerpc/oprofile/backtrace.c
new file mode 100644
index 000000000000..75f57bc96b40
--- /dev/null
+++ b/arch/powerpc/oprofile/backtrace.c
@@ -0,0 +1,126 @@
+/**
+ * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+**/
+
+#include <linux/oprofile.h>
+#include <linux/sched.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+
+#define STACK_SP(STACK)         *(STACK)
+
+#define STACK_LR64(STACK)       *((unsigned long *)(STACK) + 2)
+#define STACK_LR32(STACK)       *((unsigned int *)(STACK) + 1)
+
+#ifdef CONFIG_PPC64
+#define STACK_LR(STACK)         STACK_LR64(STACK)
+#else
+#define STACK_LR(STACK)         STACK_LR32(STACK)
+#endif
+
+static unsigned int user_getsp32(unsigned int sp, int is_first)
+{
+        unsigned int stack_frame[2];
+
+        if (!access_ok(VERIFY_READ, sp, sizeof(stack_frame)))
+                return 0;
+
+        /*
+         * The most likely reason for this is that we returned -EFAULT,
+         * which means that we've done all that we can do from
+         * interrupt context.
+         */
+        if (__copy_from_user_inatomic(stack_frame, (void *)(long)sp,
+                                        sizeof(stack_frame)))
+                return 0;
+
+        if (!is_first)
+                oprofile_add_trace(STACK_LR32(stack_frame));
+
+        /*
+         * We do not enforce increasing stack addresses here because
+         * we may transition to a different stack, eg a signal handler.
+         */
+        return STACK_SP(stack_frame);
+}
+
+#ifdef CONFIG_PPC64
+static unsigned long user_getsp64(unsigned long sp, int is_first)
+{
+        unsigned long stack_frame[3];
+
+        if (!access_ok(VERIFY_READ, sp, sizeof(stack_frame)))
+                return 0;
+
+        if (__copy_from_user_inatomic(stack_frame, (void *)sp,
+                                        sizeof(stack_frame)))
+                return 0;
+
+        if (!is_first)
+                oprofile_add_trace(STACK_LR64(stack_frame));
+
+        return STACK_SP(stack_frame);
+}
+#endif
+
+static unsigned long kernel_getsp(unsigned long sp, int is_first)
+{
+        unsigned long *stack_frame = (unsigned long *)sp;
+
+        if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
+                return 0;
+
+        if (!is_first)
+                oprofile_add_trace(STACK_LR(stack_frame));
+
+        /*
+         * We do not enforce increasing stack addresses here because
+         * we might be transitioning from an interrupt stack to a kernel
+         * stack. validate_sp() is designed to understand this, so just
+         * use it.
+         */
+        return STACK_SP(stack_frame);
+}
+
+void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+        unsigned long sp = regs->gpr[1];
+        int first_frame = 1;
+
+        /* We ditch the top stackframe so need to loop through an extra time */
+        depth += 1;
+
+        if (!user_mode(regs)) {
+                while (depth--) {
+                        sp = kernel_getsp(sp, first_frame);
+                        if (!sp)
+                                break;
+                        first_frame = 0;
+                }
+        } else {
+#ifdef CONFIG_PPC64
+                if (!test_thread_flag(TIF_32BIT)) {
+                        while (depth--) {
+                                sp = user_getsp64(sp, first_frame);
+                                if (!sp)
+                                        break;
+                                first_frame = 0;
+                        }
+
+                        return;
+                }
+#endif
+
+                while (depth--) {
+                        sp = user_getsp32(sp, first_frame);
+                        if (!sp)
+                                break;
+                        first_frame = 0;
+                }
+        }
+}