Commit f16fb1ec authored by Russell King's avatar Russell King Committed by Russell King

[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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ed519ded
......@@ -67,6 +67,14 @@ config GENERIC_HARDIRQS
bool
default y
config STACKTRACE_SUPPORT
bool
default y
config LOCKDEP_SUPPORT
bool
default y
config TRACE_IRQFLAGS_SUPPORT
bool
default y
......
......@@ -7,8 +7,8 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
# Object file lists.
obj-y := compat.o entry-armv.o entry-common.o irq.o \
process.o ptrace.o semaphore.o setup.o signal.o sys_arm.o \
time.o traps.o
process.o ptrace.o semaphore.o setup.o signal.o \
sys_arm.o stacktrace.o time.o traps.o
obj-$(CONFIG_ISA_DMA_API) += dma.o
obj-$(CONFIG_ARCH_ACORN) += ecard.o
......
#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
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);
......@@ -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 @@ struct frame_tail {
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 @@ static struct frame_tail* user_backtrace(struct frame_tail *tail)
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;
}
......
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