Commit dc953df1 authored by Thiemo Seufer's avatar Thiemo Seufer Committed by Ralf Baechle
Browse files

Fix wchan implementation, based on earlier by from Atsushi Nemoto. 



Signed-off-by: default avatarThiemo Seufer <ths@networkno.de>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 4e6a05fe

arch/mips/kernel/process.c

+77 −58
Original line number Diff line number Diff line
@@ -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 ||
@@ -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);

			}
@@ -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;

}
@@ -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];

		for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {

			if (pc >= (unsigned long) mfinfo[i].func)

				break;

		}

		if (i < 0)

			break;



out:



#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;

}