[ARM] Add stacktrace support and make oprofile use it
Add support for stacktrace. Use the new stacktrace code with
oprofile instead of it's version; there's no point having
multiple versions of stacktracing in the kernel.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e7baca2..e25a197 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -67,6 +67,14 @@
bool
default y
+config STACKTRACE_SUPPORT
+ bool
+ default y
+
+config LOCKDEP_SUPPORT
+ bool
+ default y
+
config TRACE_IRQFLAGS_SUPPORT
bool
default y
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index bb28087..593b565 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -7,8 +7,8 @@
# Object file lists.
obj-y := compat.o entry-armv.o entry-common.o irq.o \
- process.o ptrace.o semaphore.o setup.o signal.o sys_arm.o \
- time.o traps.o
+ process.o ptrace.o semaphore.o setup.o signal.o \
+ sys_arm.o stacktrace.o time.o traps.o
obj-$(CONFIG_ISA_DMA_API) += dma.o
obj-$(CONFIG_ARCH_ACORN) += ecard.o
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
new file mode 100644
index 0000000..77ef35e
--- /dev/null
+++ b/arch/arm/kernel/stacktrace.c
@@ -0,0 +1,73 @@
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+
+#include "stacktrace.h"
+
+int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
+ int (*fn)(struct stackframe *, void *), void *data)
+{
+ struct stackframe *frame;
+
+ do {
+ /*
+ * Check current frame pointer is within bounds
+ */
+ if ((fp - 12) < low || fp + 4 >= high)
+ break;
+
+ frame = (struct stackframe *)(fp - 12);
+
+ if (fn(frame, data))
+ break;
+
+ /*
+ * Update the low bound - the next frame must always
+ * be at a higher address than the current frame.
+ */
+ low = fp + 4;
+ fp = frame->fp;
+ } while (fp);
+
+ return 0;
+}
+
+#ifdef CONFIG_STACKTRACE
+struct stack_trace_data {
+ struct stack_trace *trace;
+ unsigned int skip;
+};
+
+static int save_trace(struct stackframe *frame, void *d)
+{
+ struct stack_trace_data *data = d;
+ struct stack_trace *trace = data->trace;
+
+ if (data->skip) {
+ data->skip--;
+ return 0;
+ }
+
+ trace->entries[trace->nr_entries++] = frame->lr;
+
+ return trace->nr_entries >= trace->max_entries;
+}
+
+void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
+{
+ struct stack_trace_data data;
+ unsigned long fp, base;
+
+ data.trace = trace;
+ data.skip = trace->skip;
+
+ if (task) {
+ base = (unsigned long)task_stack_page(task);
+ fp = 0; /* FIXME */
+ } else {
+ base = (unsigned long)task_stack_page(current);
+ asm("mov %0, fp" : "=r" (fp));
+ }
+
+ walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
+}
+#endif
diff --git a/arch/arm/kernel/stacktrace.h b/arch/arm/kernel/stacktrace.h
new file mode 100644
index 0000000..e9fd20cb
--- /dev/null
+++ b/arch/arm/kernel/stacktrace.h
@@ -0,0 +1,9 @@
+struct stackframe {
+ unsigned long fp;
+ unsigned long sp;
+ unsigned long lr;
+ unsigned long pc;
+};
+
+int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
+ int (*fn)(struct stackframe *, void *), void *data);
diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c
index 7c22c1261..f5ebf30 100644
--- a/arch/arm/oprofile/backtrace.c
+++ b/arch/arm/oprofile/backtrace.c
@@ -19,6 +19,19 @@
#include <asm/ptrace.h>
#include <asm/uaccess.h>
+#include "../kernel/stacktrace.h"
+
+static int report_trace(struct stackframe *frame, void *d)
+{
+ unsigned int *depth = d;
+
+ if (*depth) {
+ oprofile_add_trace(frame->lr);
+ (*depth)--;
+ }
+
+ return *depth == 0;
+}
/*
* The registers we're interested in are at the end of the variable
@@ -32,21 +45,6 @@
unsigned long lr;
} __attribute__((packed));
-
-#ifdef CONFIG_FRAME_POINTER
-static struct frame_tail* kernel_backtrace(struct frame_tail *tail)
-{
- oprofile_add_trace(tail->lr);
-
- /* frame pointers should strictly progress back up the stack
- * (towards higher addresses) */
- if (tail >= tail->fp)
- return NULL;
-
- return tail->fp-1;
-}
-#endif
-
static struct frame_tail* user_backtrace(struct frame_tail *tail)
{
struct frame_tail buftail[2];
@@ -67,47 +65,14 @@
return buftail[0].fp-1;
}
-/*
- * | | /\ Higher addresses
- * | |
- * --------------- stack base (address of current_thread_info)
- * | thread info |
- * . .
- * | stack |
- * --------------- saved regs->ARM_fp value if valid (frame_tail address)
- * . .
- * --------------- struct pt_regs stored on stack (struct pt_regs *)
- * | |
- * . .
- * | |
- * --------------- %esp
- * | |
- * | | \/ Lower addresses
- *
- * Thus, &pt_regs <-> stack base restricts the valid(ish) fp values
- */
-static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs)
-{
- unsigned long tailaddr = (unsigned long)tail;
- unsigned long stack = (unsigned long)regs;
- unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;
-
- return (tailaddr > stack) && (tailaddr < stack_base);
-}
-
void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
{
- struct frame_tail *tail;
-
- tail = ((struct frame_tail *) regs->ARM_fp) - 1;
+ struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
if (!user_mode(regs)) {
-
-#ifdef CONFIG_FRAME_POINTER
- while (depth-- && tail && valid_kernel_stack(tail, regs)) {
- tail = kernel_backtrace(tail);
- }
-#endif
+ unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1);
+ walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE,
+ report_trace, &depth);
return;
}