[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>

4 files changed, 130 insertions, 4 deletions

diff --git a/arch/powerpc/oprofile/Makefile b/arch/powerpc/oprofile/Makefile
index 554cd7c7532..f5f9859a833 100644
--- a/arch/powerpc/oprofile/Makefile
+++ b/arch/powerpc/oprofile/Makefile
@@ -6,7 +6,7 @@ DRIVER_OBJS := $(addprefix ../../../drivers/oprofile/, \
                 oprofilefs.o oprofile_stats.o \
                 timer_int.o )
 
-oprofile-y := $(DRIVER_OBJS) common.o
+oprofile-y := $(DRIVER_OBJS) common.o backtrace.o
 oprofile-$(CONFIG_PPC64) += op_model_rs64.o op_model_power4.o
 oprofile-$(CONFIG_FSL_BOOKE) += op_model_fsl_booke.o
 oprofile-$(CONFIG_PPC32) += op_model_7450.o
diff --git a/arch/powerpc/oprofile/backtrace.c b/arch/powerpc/oprofile/backtrace.c
new file mode 100644
index 00000000000..75f57bc96b4
--- /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;
+                }
+        }
+}
diff --git a/arch/powerpc/oprofile/common.c b/arch/powerpc/oprofile/common.c
index cc2535be3a7..2b9143b0f6b 100644
--- a/arch/powerpc/oprofile/common.c
+++ b/arch/powerpc/oprofile/common.c
@@ -126,8 +126,7 @@ static int op_powerpc_create_files(struct super_block *sb, struct dentry *root)
         sys.enable_kernel = 1;
         sys.enable_user = 1;
 #ifdef CONFIG_PPC64
-        /* Turn on backtracing through spinlocks by default */
-        sys.backtrace_spinlocks = 1;
+        sys.backtrace_spinlocks = 0;
 #endif
 
         return 0;
@@ -168,6 +167,7 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
         ops->shutdown = op_powerpc_shutdown;
         ops->start = op_powerpc_start;
         ops->stop = op_powerpc_stop;
+        ops->backtrace = op_powerpc_backtrace;
 
         printk(KERN_INFO "oprofile: using %s performance monitoring.\n",
                ops->cpu_type);
diff --git a/arch/powerpc/oprofile/op_model_power4.c b/arch/powerpc/oprofile/op_model_power4.c
index 4b06e53eb9b..38db2efef3b 100644
--- a/arch/powerpc/oprofile/op_model_power4.c
+++ b/arch/powerpc/oprofile/op_model_power4.c
@@ -293,7 +293,7 @@ static void power4_handle_interrupt(struct pt_regs *regs,
                 val = ctr_read(i);
                 if (val < 0) {
                         if (oprofile_running && ctr[i].enabled) {
-                                oprofile_add_pc(pc, is_kernel, i);
+                                oprofile_add_ext_sample(pc, regs, i, is_kernel);
                                 ctr_write(i, reset_value[i]);
                         } else {
                                 ctr_write(i, 0);