251 строка
6.6 KiB
C
251 строка
6.6 KiB
C
/*
|
|
* stacktrace.c : stacktracing APIs needed by rest of kernel
|
|
* (wrappers over ARC dwarf based unwinder)
|
|
*
|
|
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
|
|
*
|
|
* 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.
|
|
*
|
|
* vineetg: aug 2009
|
|
* -Implemented CONFIG_STACKTRACE APIs, primarily save_stack_trace_tsk( )
|
|
* for displaying task's kernel mode call stack in /proc/<pid>/stack
|
|
* -Iterator based approach to have single copy of unwinding core and APIs
|
|
* needing unwinding, implement the logic in iterator regarding:
|
|
* = which frame onwards to start capture
|
|
* = which frame to stop capturing (wchan)
|
|
* = specifics of data structs where trace is saved(CONFIG_STACKTRACE etc)
|
|
*
|
|
* vineetg: March 2009
|
|
* -Implemented correct versions of thread_saved_pc() and get_wchan()
|
|
*
|
|
* rajeshwarr: 2008
|
|
* -Initial implementation
|
|
*/
|
|
|
|
#include <linux/ptrace.h>
|
|
#include <linux/export.h>
|
|
#include <linux/stacktrace.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <asm/arcregs.h>
|
|
#include <asm/unwind.h>
|
|
#include <asm/switch_to.h>
|
|
|
|
/*-------------------------------------------------------------------------
|
|
* Unwinder Iterator
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
|
|
#ifdef CONFIG_ARC_DW2_UNWIND
|
|
|
|
static void seed_unwind_frame_info(struct task_struct *tsk,
|
|
struct pt_regs *regs,
|
|
struct unwind_frame_info *frame_info)
|
|
{
|
|
if (tsk == NULL && regs == NULL) {
|
|
unsigned long fp, sp, blink, ret;
|
|
frame_info->task = current;
|
|
|
|
__asm__ __volatile__(
|
|
"mov %0,r27\n\t"
|
|
"mov %1,r28\n\t"
|
|
"mov %2,r31\n\t"
|
|
"mov %3,r63\n\t"
|
|
: "=r"(fp), "=r"(sp), "=r"(blink), "=r"(ret)
|
|
);
|
|
|
|
frame_info->regs.r27 = fp;
|
|
frame_info->regs.r28 = sp;
|
|
frame_info->regs.r31 = blink;
|
|
frame_info->regs.r63 = ret;
|
|
frame_info->call_frame = 0;
|
|
} else if (regs == NULL) {
|
|
|
|
frame_info->task = tsk;
|
|
|
|
frame_info->regs.r27 = KSTK_FP(tsk);
|
|
frame_info->regs.r28 = KSTK_ESP(tsk);
|
|
frame_info->regs.r31 = KSTK_BLINK(tsk);
|
|
frame_info->regs.r63 = (unsigned int)__switch_to;
|
|
|
|
/* In the prologue of __switch_to, first FP is saved on stack
|
|
* and then SP is copied to FP. Dwarf assumes cfa as FP based
|
|
* but we didn't save FP. The value retrieved above is FP's
|
|
* state in previous frame.
|
|
* As a work around for this, we unwind from __switch_to start
|
|
* and adjust SP accordingly. The other limitation is that
|
|
* __switch_to macro is dwarf rules are not generated for inline
|
|
* assembly code
|
|
*/
|
|
frame_info->regs.r27 = 0;
|
|
frame_info->regs.r28 += 60;
|
|
frame_info->call_frame = 0;
|
|
|
|
} else {
|
|
frame_info->task = tsk;
|
|
|
|
frame_info->regs.r27 = regs->fp;
|
|
frame_info->regs.r28 = regs->sp;
|
|
frame_info->regs.r31 = regs->blink;
|
|
frame_info->regs.r63 = regs->ret;
|
|
frame_info->call_frame = 0;
|
|
}
|
|
}
|
|
|
|
#endif
|
|
|
|
static noinline unsigned int
|
|
arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
|
|
int (*consumer_fn) (unsigned int, void *), void *arg)
|
|
{
|
|
#ifdef CONFIG_ARC_DW2_UNWIND
|
|
int ret = 0;
|
|
unsigned int address;
|
|
struct unwind_frame_info frame_info;
|
|
|
|
seed_unwind_frame_info(tsk, regs, &frame_info);
|
|
|
|
while (1) {
|
|
address = UNW_PC(&frame_info);
|
|
|
|
if (address && __kernel_text_address(address)) {
|
|
if (consumer_fn(address, arg) == -1)
|
|
break;
|
|
}
|
|
|
|
ret = arc_unwind(&frame_info);
|
|
|
|
if (ret == 0) {
|
|
frame_info.regs.r63 = frame_info.regs.r31;
|
|
continue;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
return address; /* return the last address it saw */
|
|
#else
|
|
/* On ARC, only Dward based unwinder works. fp based backtracing is
|
|
* not possible (-fno-omit-frame-pointer) because of the way function
|
|
* prelogue is setup (callee regs saved and then fp set and not other
|
|
* way around
|
|
*/
|
|
pr_warn("CONFIG_ARC_DW2_UNWIND needs to be enabled\n");
|
|
return 0;
|
|
|
|
#endif
|
|
}
|
|
|
|
/*-------------------------------------------------------------------------
|
|
* callbacks called by unwinder iterator to implement kernel APIs
|
|
*
|
|
* The callback can return -1 to force the iterator to stop, which by default
|
|
* keeps going till the bottom-most frame.
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
|
|
/* Call-back which plugs into unwinding core to dump the stack in
|
|
* case of panic/OOPs/BUG etc
|
|
*/
|
|
static int __print_sym(unsigned int address, void *unused)
|
|
{
|
|
__print_symbol(" %s\n", address);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_STACKTRACE
|
|
|
|
/* Call-back which plugs into unwinding core to capture the
|
|
* traces needed by kernel on /proc/<pid>/stack
|
|
*/
|
|
static int __collect_all(unsigned int address, void *arg)
|
|
{
|
|
struct stack_trace *trace = arg;
|
|
|
|
if (trace->skip > 0)
|
|
trace->skip--;
|
|
else
|
|
trace->entries[trace->nr_entries++] = address;
|
|
|
|
if (trace->nr_entries >= trace->max_entries)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __collect_all_but_sched(unsigned int address, void *arg)
|
|
{
|
|
struct stack_trace *trace = arg;
|
|
|
|
if (in_sched_functions(address))
|
|
return 0;
|
|
|
|
if (trace->skip > 0)
|
|
trace->skip--;
|
|
else
|
|
trace->entries[trace->nr_entries++] = address;
|
|
|
|
if (trace->nr_entries >= trace->max_entries)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
static int __get_first_nonsched(unsigned int address, void *unused)
|
|
{
|
|
if (in_sched_functions(address))
|
|
return 0;
|
|
|
|
return -1;
|
|
}
|
|
|
|
/*-------------------------------------------------------------------------
|
|
* APIs expected by various kernel sub-systems
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
|
|
noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs)
|
|
{
|
|
pr_info("\nStack Trace:\n");
|
|
arc_unwind_core(tsk, regs, __print_sym, NULL);
|
|
}
|
|
EXPORT_SYMBOL(show_stacktrace);
|
|
|
|
/* Expected by sched Code */
|
|
void show_stack(struct task_struct *tsk, unsigned long *sp)
|
|
{
|
|
show_stacktrace(tsk, NULL);
|
|
}
|
|
|
|
/* Another API expected by schedular, shows up in "ps" as Wait Channel
|
|
* Ofcourse just returning schedule( ) would be pointless so unwind until
|
|
* the function is not in schedular code
|
|
*/
|
|
unsigned int get_wchan(struct task_struct *tsk)
|
|
{
|
|
return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL);
|
|
}
|
|
|
|
#ifdef CONFIG_STACKTRACE
|
|
|
|
/*
|
|
* API required by CONFIG_STACKTRACE, CONFIG_LATENCYTOP.
|
|
* A typical use is when /proc/<pid>/stack is queried by userland
|
|
*/
|
|
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
|
|
{
|
|
/* Assumes @tsk is sleeping so unwinds from __switch_to */
|
|
arc_unwind_core(tsk, NULL, __collect_all_but_sched, trace);
|
|
}
|
|
|
|
void save_stack_trace(struct stack_trace *trace)
|
|
{
|
|
/* Pass NULL for task so it unwinds the current call frame */
|
|
arc_unwind_core(NULL, NULL, __collect_all, trace);
|
|
}
|
|
EXPORT_SYMBOL_GPL(save_stack_trace);
|
|
#endif
|