>>>>> On Fri, 24 Sep 2004 10:52:40 +0200, Thomas Petazzoni <thomas.petazzoni@xxxxxxxx> said:
thomas> In arch/mips/kernel/process.c, the function frame_info_init()
thomas> called at boot time, calls the get_frame_info() to a analyze
thomas> the prologue of a few functions (I don't know why, does anyone
thomas> know ?).
Because thread_saved_pc(), get_wchan() needs those information.
The information of 'schedule' function is required, others are
optional ("ps -l" shows better output with those informations).
thomas> The get_frame_info() seems to search a sw or sd instruction,
thomas> but here is the beginning of the schedule_timeout() function :
This is because now schedule_timeout is in kernel/timer.c (not
kernel/sched.c) which is compiled without -fno-omit-frame-pointer
option.
I rewrote get_wchan() to handle this problem. Please try this patch.
Note that this patch still depends on order of address of sched
functions, so not gcc-3.4 proof. Sorting minfo[] array will make it
more robust. If anyone interested in, I will implement it.
diff -u linux-mips/arch/mips/kernel/process.c linux/arch/mips/kernel/process.c
--- linux-mips/arch/mips/kernel/process.c Wed Sep 22 13:27:59 2004
+++ linux/arch/mips/kernel/process.c Wed Sep 22 17:03:10 2004
@@ -177,21 +177,41 @@
}
struct mips_frame_info {
+ void *func;
+ int omit_fp; /* compiled without fno-omit-frame-pointer */
int frame_offset;
int pc_offset;
+} mfinfo [] = {
+ /* must be in address order */
+ { __down_interruptible, 1 },
+ { schedule, 0 },
+#define schedule_frame 1
+#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 },
+ { __cond_resched, 0 },
+ { yield, 0 },
+ { io_schedule, 0 },
+ { io_schedule_timeout, 0 },
+ { schedule_timeout, 1 },
+/* { nanosleep_restart, 1 }, */
+ { __down_read, 1 },
+ { __down_write, 1 },
};
-static struct mips_frame_info schedule_frame;
-static struct mips_frame_info schedule_timeout_frame;
-static struct mips_frame_info sleep_on_frame;
-static struct mips_frame_info sleep_on_timeout_frame;
-static struct mips_frame_info wait_for_completion_frame;
+
static int mips_frame_info_initialized;
-static int __init get_frame_info(struct mips_frame_info *info, void *func)
+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 = -1;
+ info->frame_offset = info->omit_fp ? 0 : -1;
for (i = 0; i < 128; i++, ip++) {
/* if jal, jalr, jr, stop. */
if (ip->j_format.opcode == jal_op ||
@@ -237,13 +257,11 @@
static int __init frame_info_init(void)
{
- mips_frame_info_initialized =
- !get_frame_info(&schedule_frame, schedule) &&
- !get_frame_info(&schedule_timeout_frame, schedule_timeout) &&
- !get_frame_info(&sleep_on_frame, sleep_on) &&
- !get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) &&
- !get_frame_info(&wait_for_completion_frame, wait_for_completion);
-
+ int i;
+ for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
+ if (get_frame_info(&mfinfo[i]))
+ return -1;
+ mips_frame_info_initialized = 1;
return 0;
}
@@ -261,9 +279,9 @@
if (t->reg31 == (unsigned long) ret_from_fork)
return t->reg31;
- if (schedule_frame.pc_offset < 0)
+ if (mfinfo[schedule_frame].pc_offset < 0)
return 0;
- return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
+ return ((unsigned long *)t->reg29)[mfinfo[schedule_frame].pc_offset];
}
/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
@@ -277,48 +295,27 @@
if (!mips_frame_info_initialized)
return 0;
pc = thread_saved_pc(p);
+
if (!in_sched_functions(pc))
goto out;
- if (pc >= (unsigned long) sleep_on_timeout)
- goto schedule_timeout_caller;
- if (pc >= (unsigned long) sleep_on)
- goto schedule_caller;
- if (pc >= (unsigned long) interruptible_sleep_on_timeout)
- goto schedule_timeout_caller;
- if (pc >= (unsigned long)interruptible_sleep_on)
- goto schedule_caller;
- if (pc >= (unsigned long)wait_for_completion)
- goto schedule_caller;
- goto schedule_timeout_caller;
-
-schedule_caller:
- frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
- if (pc >= (unsigned long) sleep_on)
- pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset];
- else
- pc = ((unsigned long *)frame)[wait_for_completion_frame.pc_offset];
- goto out;
-
-schedule_timeout_caller:
- /*
- * The schedule_timeout frame
- */
- frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
-
- /*
- * frame now points to sleep_on_timeout's frame
- */
- pc = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];
-
- if (in_sched_functions(pc)) {
- /* schedule_timeout called by [interruptible_]sleep_on_timeout */
- frame = ((unsigned long *)frame)[schedule_timeout_frame.frame_offset];
- pc = ((unsigned long *)frame)[sleep_on_timeout_frame.pc_offset];
- }
+ frame = ((unsigned long *)p->thread.reg30)[mfinfo[schedule_frame].frame_offset];
+ do {
+ int i;
+ for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
+ if (pc >= (unsigned long) mfinfo[i].func)
+ break;
+ }
+ if (i < 0)
+ break;
-out:
+ if (mfinfo[i].omit_fp)
+ break;
+ pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
+ frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
+ } while (in_sched_functions(pc));
+out:
#ifdef CONFIG_MIPS64
if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps */
pc &= 0xffffffffUL;
---
Atsushi Nemoto
