132 lines
3.1 KiB
C
132 lines
3.1 KiB
C
/*
|
|
* Stack tracing support
|
|
*
|
|
* Copyright (C) 2012 ARM Ltd.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/stacktrace.h>
|
|
|
|
#include <asm/stacktrace.h>
|
|
|
|
/*
|
|
* AArch64 PCS assigns the frame pointer to x29.
|
|
*
|
|
* A simple function prologue looks like this:
|
|
* sub sp, sp, #0x10
|
|
* stp x29, x30, [sp]
|
|
* mov x29, sp
|
|
*
|
|
* A simple function epilogue looks like this:
|
|
* mov sp, x29
|
|
* ldp x29, x30, [sp]
|
|
* add sp, sp, #0x10
|
|
*/
|
|
int unwind_frame(struct stackframe *frame)
|
|
{
|
|
unsigned long high, low;
|
|
unsigned long fp = frame->fp;
|
|
|
|
low = frame->sp;
|
|
high = ALIGN(low, THREAD_SIZE);
|
|
|
|
if (fp < low || fp > high - 0x18 || fp & 0xf)
|
|
return -EINVAL;
|
|
|
|
frame->sp = fp + 0x10;
|
|
frame->fp = *(unsigned long *)(fp);
|
|
/*
|
|
* -4 here because we care about the PC at time of bl,
|
|
* not where the return will go.
|
|
*/
|
|
frame->pc = *(unsigned long *)(fp + 8) - 4;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void notrace walk_stackframe(struct stackframe *frame,
|
|
int (*fn)(struct stackframe *, void *), void *data)
|
|
{
|
|
while (1) {
|
|
int ret;
|
|
|
|
if (fn(frame, data))
|
|
break;
|
|
ret = unwind_frame(frame);
|
|
if (ret < 0)
|
|
break;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(walk_stackframe);
|
|
|
|
#ifdef CONFIG_STACKTRACE
|
|
struct stack_trace_data {
|
|
struct stack_trace *trace;
|
|
unsigned int no_sched_functions;
|
|
unsigned int skip;
|
|
};
|
|
|
|
static int save_trace(struct stackframe *frame, void *d)
|
|
{
|
|
struct stack_trace_data *data = d;
|
|
struct stack_trace *trace = data->trace;
|
|
unsigned long addr = frame->pc;
|
|
|
|
if (data->no_sched_functions && in_sched_functions(addr))
|
|
return 0;
|
|
if (data->skip) {
|
|
data->skip--;
|
|
return 0;
|
|
}
|
|
|
|
trace->entries[trace->nr_entries++] = addr;
|
|
|
|
return trace->nr_entries >= trace->max_entries;
|
|
}
|
|
|
|
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
|
|
{
|
|
struct stack_trace_data data;
|
|
struct stackframe frame;
|
|
|
|
data.trace = trace;
|
|
data.skip = trace->skip;
|
|
|
|
if (tsk != current) {
|
|
data.no_sched_functions = 1;
|
|
frame.fp = thread_saved_fp(tsk);
|
|
frame.sp = thread_saved_sp(tsk);
|
|
frame.pc = thread_saved_pc(tsk);
|
|
} else {
|
|
register unsigned long current_sp asm("sp");
|
|
data.no_sched_functions = 0;
|
|
frame.fp = (unsigned long)__builtin_frame_address(0);
|
|
frame.sp = current_sp;
|
|
frame.pc = (unsigned long)save_stack_trace_tsk;
|
|
}
|
|
|
|
walk_stackframe(&frame, save_trace, &data);
|
|
if (trace->nr_entries < trace->max_entries)
|
|
trace->entries[trace->nr_entries++] = ULONG_MAX;
|
|
}
|
|
|
|
void save_stack_trace(struct stack_trace *trace)
|
|
{
|
|
save_stack_trace_tsk(current, trace);
|
|
}
|
|
EXPORT_SYMBOL_GPL(save_stack_trace);
|
|
#endif
|