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Fix wchan implementation, based on earlier by from Atsushi Nemoto.
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Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Thiemo Seufer authored and Ralf Baechle committed Oct 29, 2005
1 parent 4e6a05f commit dc953df
Showing 1 changed file with 77 additions and 58 deletions.
135 changes: 77 additions & 58 deletions arch/mips/kernel/process.c
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Original file line number Diff line number Diff line change
Expand Up @@ -211,22 +211,48 @@ long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
}

struct mips_frame_info {
static struct mips_frame_info {
void *func;
int omit_fp; /* compiled without fno-omit-frame-pointer */
int frame_offset;
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 },
};
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 ||
Expand All @@ -247,14 +273,16 @@ static int __init get_frame_info(struct mips_frame_info *info, void *func)
/* sw / sd $ra, offset($sp) */
if (ip->i_format.rt == 31) {
if (info->pc_offset != -1)
break;
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)
break;
continue;
//#endif
info->frame_offset =
ip->i_format.simmediate / sizeof(long);
}
Expand All @@ -272,13 +300,25 @@ static int __init get_frame_info(struct mips_frame_info *info, void *func)

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, 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;
return 0;
}

Expand All @@ -303,60 +343,39 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
/* 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;

if (!p || p == current || p->state == TASK_RUNNING)
return 0;

if (!mips_frame_info_initialized)
stack_page = (unsigned long)p->thread_info;
if (!stack_page || !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;
return pc;

schedule_timeout_caller:
/*
* The schedule_timeout frame
*/
frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
do {
int i;

/*
* frame now points to sleep_on_timeout's frame
*/
pc = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];
if (frame < stack_page || frame > stack_page + THREAD_SIZE - 32)
return 0;

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];
}

out:
for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
if (pc >= (unsigned long) mfinfo[i].func)
break;
}
if (i < 0)
break;

#ifdef CONFIG_64BIT
if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps */
pc &= 0xffffffffUL;
#endif
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));

return pc;
}
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