[MIPS] Rewrite get_wchan and its helper functions using kallsyms_lookup.
Implement get_wchan() and frame_info_init() using kallsyms_lookup().
This fixes problem with static sched/lock functions and mfinfo[]
maintenance issue. If CONFIG_KALLSYMS was disabled, get_wchan() just
returns thread_saved_pc() value.
Also unwind stackframe based on "addiu sp,-imm" analysis instead of
frame pointer. This fixes problem with functions compiled without
-fomit-frame-pointer.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 5232fc7..092679c 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -25,6 +25,7 @@
#include <linux/a.out.h>
#include <linux/init.h>
#include <linux/completion.h>
+#include <linux/kallsyms.h>
#include <asm/abi.h>
#include <asm/bootinfo.h>
@@ -272,46 +273,19 @@
static struct mips_frame_info {
void *func;
- int omit_fp; /* compiled without fno-omit-frame-pointer */
- int frame_offset;
+ unsigned long func_size;
+ int frame_size;
int pc_offset;
-} schedule_frame, mfinfo[] = {
- { schedule, 0 }, /* must be first */
- /* arch/mips/kernel/semaphore.c */
- { __down, 1 },
- { __down_interruptible, 1 },
- /* kernel/sched.c */
-#ifdef CONFIG_PREEMPT
- { preempt_schedule, 0 },
-#endif
- { wait_for_completion, 0 },
- { interruptible_sleep_on, 0 },
- { interruptible_sleep_on_timeout, 0 },
- { sleep_on, 0 },
- { sleep_on_timeout, 0 },
- { yield, 0 },
- { io_schedule, 0 },
- { io_schedule_timeout, 0 },
-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
- { __preempt_spin_lock, 0 },
- { __preempt_write_lock, 0 },
-#endif
- /* kernel/timer.c */
- { schedule_timeout, 1 },
-/* { nanosleep_restart, 1 }, */
- /* lib/rwsem-spinlock.c */
- { __down_read, 1 },
- { __down_write, 1 },
-};
+} *schedule_frame, mfinfo[64];
+static int mfinfo_num;
-static int mips_frame_info_initialized;
static int __init get_frame_info(struct mips_frame_info *info)
{
int i;
void *func = info->func;
union mips_instruction *ip = (union mips_instruction *)func;
info->pc_offset = -1;
- info->frame_offset = info->omit_fp ? 0 : -1;
+ info->frame_size = 0;
for (i = 0; i < 128; i++, ip++) {
/* if jal, jalr, jr, stop. */
if (ip->j_format.opcode == jal_op ||
@@ -320,6 +294,23 @@
ip->r_format.func == jr_op)))
break;
+ if (info->func_size && i >= info->func_size / 4)
+ break;
+ if (
+#ifdef CONFIG_32BIT
+ ip->i_format.opcode == addiu_op &&
+#endif
+#ifdef CONFIG_64BIT
+ ip->i_format.opcode == daddiu_op &&
+#endif
+ ip->i_format.rs == 29 &&
+ ip->i_format.rt == 29) {
+ /* addiu/daddiu sp,sp,-imm */
+ if (info->frame_size)
+ continue;
+ info->frame_size = - ip->i_format.simmediate;
+ }
+
if (
#ifdef CONFIG_32BIT
ip->i_format.opcode == sw_op &&
@@ -327,31 +318,20 @@
#ifdef CONFIG_64BIT
ip->i_format.opcode == sd_op &&
#endif
- ip->i_format.rs == 29)
- {
+ ip->i_format.rs == 29 &&
+ ip->i_format.rt == 31) {
/* sw / sd $ra, offset($sp) */
- if (ip->i_format.rt == 31) {
- if (info->pc_offset != -1)
- continue;
- info->pc_offset =
- ip->i_format.simmediate / sizeof(long);
- }
- /* sw / sd $s8, offset($sp) */
- if (ip->i_format.rt == 30) {
-//#if 0 /* gcc 3.4 does aggressive optimization... */
- if (info->frame_offset != -1)
- continue;
-//#endif
- info->frame_offset =
- ip->i_format.simmediate / sizeof(long);
- }
+ if (info->pc_offset != -1)
+ continue;
+ info->pc_offset =
+ ip->i_format.simmediate / sizeof(long);
}
}
- if (info->pc_offset == -1 || info->frame_offset == -1) {
- printk("Can't analyze prologue code at %p\n", func);
+ if (info->pc_offset == -1 || info->frame_size == 0) {
+ if (func == schedule)
+ printk("Can't analyze prologue code at %p\n", func);
info->pc_offset = -1;
- info->frame_offset = -1;
- return -1;
+ info->frame_size = 0;
}
return 0;
@@ -359,25 +339,36 @@
static int __init frame_info_init(void)
{
- int i, found;
- for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
- if (get_frame_info(&mfinfo[i]))
- return -1;
- schedule_frame = mfinfo[0];
- /* bubble sort */
- do {
- struct mips_frame_info tmp;
- found = 0;
- for (i = 1; i < ARRAY_SIZE(mfinfo); i++) {
- if (mfinfo[i-1].func > mfinfo[i].func) {
- tmp = mfinfo[i];
- mfinfo[i] = mfinfo[i-1];
- mfinfo[i-1] = tmp;
- found = 1;
- }
- }
- } while (found);
- mips_frame_info_initialized = 1;
+ int i;
+#ifdef CONFIG_KALLSYMS
+ char *modname;
+ char namebuf[KSYM_NAME_LEN + 1];
+ unsigned long start, size, ofs;
+ extern char __sched_text_start[], __sched_text_end[];
+ extern char __lock_text_start[], __lock_text_end[];
+
+ start = (unsigned long)__sched_text_start;
+ for (i = 0; i < ARRAY_SIZE(mfinfo); i++) {
+ if (start == (unsigned long)schedule)
+ schedule_frame = &mfinfo[i];
+ if (!kallsyms_lookup(start, &size, &ofs, &modname, namebuf))
+ break;
+ mfinfo[i].func = (void *)(start + ofs);
+ mfinfo[i].func_size = size;
+ start += size - ofs;
+ if (start >= (unsigned long)__lock_text_end)
+ break;
+ if (start == (unsigned long)__sched_text_end)
+ start = (unsigned long)__lock_text_start;
+ }
+#else
+ mfinfo[0].func = schedule;
+ schedule_frame = &mfinfo[0];
+#endif
+ for (i = 0; i < ARRAY_SIZE(mfinfo) && mfinfo[i].func; i++)
+ get_frame_info(&mfinfo[i]);
+
+ mfinfo_num = i;
return 0;
}
@@ -394,47 +385,52 @@
if (t->reg31 == (unsigned long) ret_from_fork)
return t->reg31;
- if (schedule_frame.pc_offset < 0)
+ if (!schedule_frame || schedule_frame->pc_offset < 0)
return 0;
- return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
+ return ((unsigned long *)t->reg29)[schedule_frame->pc_offset];
}
/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack_page;
- unsigned long frame, pc;
+ unsigned long pc;
+#ifdef CONFIG_KALLSYMS
+ unsigned long frame;
+#endif
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)task_stack_page(p);
- if (!stack_page || !mips_frame_info_initialized)
+ if (!stack_page || !mfinfo_num)
return 0;
pc = thread_saved_pc(p);
+#ifdef CONFIG_KALLSYMS
if (!in_sched_functions(pc))
return pc;
- frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
+ frame = p->thread.reg29 + schedule_frame->frame_size;
do {
int i;
if (frame < stack_page || frame > stack_page + THREAD_SIZE - 32)
return 0;
- for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
+ for (i = mfinfo_num - 1; i >= 0; i--) {
if (pc >= (unsigned long) mfinfo[i].func)
break;
}
if (i < 0)
break;
- if (mfinfo[i].omit_fp)
- break;
pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
- frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
+ if (!mfinfo[i].frame_size)
+ break;
+ frame += mfinfo[i].frame_size;
} while (in_sched_functions(pc));
+#endif
return pc;
}