[deliverable/linux.git] / arch / avr32 / kernel / process.c

/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * 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.
 */
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/fs.h>
#include <linux/pm.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/reboot.h>
#include <linux/tick.h>
#include <linux/uaccess.h>
#include <linux/unistd.h>

#include <asm/sysreg.h>
#include <asm/ocd.h>
#include <asm/syscalls.h>

#include <mach/pm.h>

void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

/*
 * This file handles the architecture-dependent parts of process handling..
 */

void arch_cpu_idle(void)
{
	cpu_enter_idle();
}

void machine_halt(void)
{
	/*
	 * Enter Stop mode. The 32 kHz oscillator will keep running so
	 * the RTC will keep the time properly and the system will
	 * boot quickly.
	 */
	asm volatile("sleep 3\n\t"
		     "sub pc, -2");
}

void machine_power_off(void)
{
	if (pm_power_off)
		pm_power_off();
}

void machine_restart(char *cmd)
{
	ocd_write(DC, (1 << OCD_DC_DBE_BIT));
	ocd_write(DC, (1 << OCD_DC_RES_BIT));
	while (1) ;
}

/*
 * Free current thread data structures etc
 */
void exit_thread(struct task_struct *tsk)
{
	ocd_disable(tsk);
}

void flush_thread(void)
{
	/* nothing to do */
}

void release_thread(struct task_struct *dead_task)
{
	/* do nothing */
}

static void dump_mem(const char *str, const char *log_lvl,
		     unsigned long bottom, unsigned long top)
{
	unsigned long p;
	int i;

	printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);

	for (p = bottom & ~31; p < top; ) {
		printk("%s%04lx: ", log_lvl, p & 0xffff);

		for (i = 0; i < 8; i++, p += 4) {
			unsigned int val;

			if (p < bottom || p >= top)
				printk("         ");
			else {
				if (__get_user(val, (unsigned int __user *)p)) {
					printk("\n");
					goto out;
				}
				printk("%08x ", val);
			}
		}
		printk("\n");
	}

out:
	return;
}

static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
{
	return (p > (unsigned long)tinfo)
		&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
}

#ifdef CONFIG_FRAME_POINTER
static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
			       struct pt_regs *regs, const char *log_lvl)
{
	unsigned long lr, fp;
	struct thread_info *tinfo;

	if (regs)
		fp = regs->r7;
	else if (tsk == current)
		asm("mov %0, r7" : "=r"(fp));
	else
		fp = tsk->thread.cpu_context.r7;

	/*
	 * Walk the stack as long as the frame pointer (a) is within
	 * the kernel stack of the task, and (b) it doesn't move
	 * downwards.
	 */
	tinfo = task_thread_info(tsk);
	printk("%sCall trace:\n", log_lvl);
	while (valid_stack_ptr(tinfo, fp)) {
		unsigned long new_fp;

		lr = *(unsigned long *)fp;
#ifdef CONFIG_KALLSYMS
		printk("%s [<%08lx>] ", log_lvl, lr);
#else
		printk(" [<%08lx>] ", lr);
#endif
		print_symbol("%s\n", lr);

		new_fp = *(unsigned long *)(fp + 4);
		if (new_fp <= fp)
			break;
		fp = new_fp;
	}
	printk("\n");
}
#else
static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
			       struct pt_regs *regs, const char *log_lvl)
{
	unsigned long addr;

	printk("%sCall trace:\n", log_lvl);

	while (!kstack_end(sp)) {
		addr = *sp++;
		if (kernel_text_address(addr)) {
#ifdef CONFIG_KALLSYMS
			printk("%s [<%08lx>] ", log_lvl, addr);
#else
			printk(" [<%08lx>] ", addr);
#endif
			print_symbol("%s\n", addr);
		}
	}
	printk("\n");
}
#endif

void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
			struct pt_regs *regs, const char *log_lvl)
{
	struct thread_info *tinfo;

	if (sp == 0) {
		if (tsk)
			sp = tsk->thread.cpu_context.ksp;
		else
			sp = (unsigned long)&tinfo;
	}
	if (!tsk)
		tsk = current;

	tinfo = task_thread_info(tsk);

	if (valid_stack_ptr(tinfo, sp)) {
		dump_mem("Stack: ", log_lvl, sp,
			 THREAD_SIZE + (unsigned long)tinfo);
		show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
	}
}

void show_stack(struct task_struct *tsk, unsigned long *stack)
{
	show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
}

static const char *cpu_modes[] = {
	"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
	"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
};

void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
{
	unsigned long sp = regs->sp;
	unsigned long lr = regs->lr;
	unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;

	show_regs_print_info(log_lvl);

	if (!user_mode(regs)) {
		sp = (unsigned long)regs + FRAME_SIZE_FULL;

		printk("%s", log_lvl);
		print_symbol("PC is at %s\n", instruction_pointer(regs));
		printk("%s", log_lvl);
		print_symbol("LR is at %s\n", lr);
	}

	printk("%spc : [<%08lx>]    lr : [<%08lx>]    %s\n"
	       "%ssp : %08lx  r12: %08lx  r11: %08lx\n",
	       log_lvl, instruction_pointer(regs), lr, print_tainted(),
	       log_lvl, sp, regs->r12, regs->r11);
	printk("%sr10: %08lx  r9 : %08lx  r8 : %08lx\n",
	       log_lvl, regs->r10, regs->r9, regs->r8);
	printk("%sr7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
	       log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
	printk("%sr3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
	       log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
	printk("%sFlags: %c%c%c%c%c\n", log_lvl,
	       regs->sr & SR_Q ? 'Q' : 'q',
	       regs->sr & SR_V ? 'V' : 'v',
	       regs->sr & SR_N ? 'N' : 'n',
	       regs->sr & SR_Z ? 'Z' : 'z',
	       regs->sr & SR_C ? 'C' : 'c');
	printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
	       regs->sr & SR_H ? 'H' : 'h',
	       regs->sr & SR_J ? 'J' : 'j',
	       regs->sr & SR_DM ? 'M' : 'm',
	       regs->sr & SR_D ? 'D' : 'd',
	       regs->sr & SR_EM ? 'E' : 'e',
	       regs->sr & SR_I3M ? '3' : '.',
	       regs->sr & SR_I2M ? '2' : '.',
	       regs->sr & SR_I1M ? '1' : '.',
	       regs->sr & SR_I0M ? '0' : '.',
	       regs->sr & SR_GM ? 'G' : 'g');
	printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
}

void show_regs(struct pt_regs *regs)
{
	unsigned long sp = regs->sp;

	if (!user_mode(regs))
		sp = (unsigned long)regs + FRAME_SIZE_FULL;

	show_regs_log_lvl(regs, "");
	show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
}
EXPORT_SYMBOL(show_regs);

/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
	/* Not valid */
	return 0;
}

asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(void);
asmlinkage void syscall_return(void);

int copy_thread(unsigned long clone_flags, unsigned long usp,
		unsigned long arg,
		struct task_struct *p)
{
	struct pt_regs *childregs = task_pt_regs(p);

	if (unlikely(p->flags & PF_KTHREAD)) {
		memset(childregs, 0, sizeof(struct pt_regs));
		p->thread.cpu_context.r0 = arg;
		p->thread.cpu_context.r1 = usp; /* fn */
		p->thread.cpu_context.r2 = (unsigned long)syscall_return;
		p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
		childregs->sr = MODE_SUPERVISOR;
	} else {
		*childregs = *current_pt_regs();
		if (usp)
			childregs->sp = usp;
		childregs->r12 = 0; /* Set return value for child */
		p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
	}

	p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
	p->thread.cpu_context.ksp = (unsigned long)childregs;

	clear_tsk_thread_flag(p, TIF_DEBUG);
	if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
		ocd_enable(p);

	return 0;
}

/*
 * This function is supposed to answer the question "who called
 * schedule()?"
 */
unsigned long get_wchan(struct task_struct *p)
{
	unsigned long pc;
	unsigned long stack_page;

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

	stack_page = (unsigned long)task_stack_page(p);
	BUG_ON(!stack_page);

	/*
	 * The stored value of PC is either the address right after
	 * the call to __switch_to() or ret_from_fork.
	 */
	pc = thread_saved_pc(p);
	if (in_sched_functions(pc)) {
#ifdef CONFIG_FRAME_POINTER
		unsigned long fp = p->thread.cpu_context.r7;
		BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
		pc = *(unsigned long *)fp;
#else
		/*
		 * We depend on the frame size of schedule here, which
		 * is actually quite ugly. It might be possible to
		 * determine the frame size automatically at build
		 * time by doing this:
		 *   - compile sched/core.c
		 *   - disassemble the resulting sched.o
		 *   - look for 'sub sp,??' shortly after '<schedule>:'
		 */
		unsigned long sp = p->thread.cpu_context.ksp + 16;
		BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
		pc = *(unsigned long *)sp;
#endif
	}

	return pc;
}
Commit	Line	Data
5f97f7f9 HS	1	/*
	2	* Copyright (C) 2004-2006 Atmel Corporation
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8	#include <linux/sched.h>
	9	#include <linux/module.h>
	10	#include <linux/kallsyms.h>
	11	#include <linux/fs.h>
b3bc2c55	12	#include <linux/pm.h>
5f97f7f9	13	#include <linux/ptrace.h>
5a0e3ad6	14	#include <linux/slab.h>
5f97f7f9	15	#include <linux/reboot.h>
d45ad062	16	#include <linux/tick.h>
623b0355	17	#include <linux/uaccess.h>
5f97f7f9 HS	18	#include <linux/unistd.h>
	19
	20	#include <asm/sysreg.h>
	21	#include <asm/ocd.h>
c80ce2d5	22	#include <asm/syscalls.h>
5f97f7f9	23
3663b736	24	#include <mach/pm.h>
7e59128f	25
b3bc2c55	26	void (*pm_power_off)(void);
5f97f7f9 HS	27	EXPORT_SYMBOL(pm_power_off);
	28
	29	/*
	30	* This file handles the architecture-dependent parts of process handling..
	31	*/
	32
01426478	33	void arch_cpu_idle(void)
5f97f7f9	34	{
01426478	35	cpu_enter_idle();
5f97f7f9 HS	36	}
	37
	38	void machine_halt(void)
	39	{
c2eb5090 HS	40	/*
	41	* Enter Stop mode. The 32 kHz oscillator will keep running so
	42	* the RTC will keep the time properly and the system will
	43	* boot quickly.
	44	*/
	45	asm volatile("sleep 3\n\t"
	46	"sub pc, -2");
5f97f7f9 HS	47	}
	48
	49	void machine_power_off(void)
	50	{
ed3fa7c9 PM	51	if (pm_power_off)
ed3fa7c9 PM	52	pm_power_off();
5f97f7f9 HS	53	}
	54
	55	void machine_restart(char *cmd)
	56	{
8dfe8f29 HS	57	ocd_write(DC, (1 << OCD_DC_DBE_BIT));
8dfe8f29 HS	58	ocd_write(DC, (1 << OCD_DC_RES_BIT));
5f97f7f9 HS	59	while (1) ;
	60	}
	61
5f97f7f9 HS	62	/*
	63	* Free current thread data structures etc
	64	*/
e6464694	65	void exit_thread(struct task_struct *tsk)
5f97f7f9	66	{
e6464694	67	ocd_disable(tsk);
5f97f7f9 HS	68	}
	69
	70	void flush_thread(void)
	71	{
	72	/* nothing to do */
	73	}
	74
	75	void release_thread(struct task_struct *dead_task)
	76	{
	77	/* do nothing */
	78	}
	79
623b0355 HS	80	static void dump_mem(const char str, const char log_lvl,
	81	unsigned long bottom, unsigned long top)
	82	{
	83	unsigned long p;
	84	int i;
	85
	86	printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
	87
	88	for (p = bottom & ~31; p < top; ) {
	89	printk("%s%04lx: ", log_lvl, p & 0xffff);
	90
	91	for (i = 0; i < 8; i++, p += 4) {
	92	unsigned int val;
	93
	94	if (p < bottom \|\| p >= top)
	95	printk(" ");
	96	else {
	97	if (__get_user(val, (unsigned int __user *)p)) {
	98	printk("\n");
	99	goto out;
	100	}
	101	printk("%08x ", val);
	102	}
	103	}
	104	printk("\n");
	105	}
	106
	107	out:
	108	return;
	109	}
	110
	111	static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
	112	{
	113	return (p > (unsigned long)tinfo)
	114	&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
	115	}
	116
	117	#ifdef CONFIG_FRAME_POINTER
	118	static void show_trace_log_lvl(struct task_struct tsk, unsigned long sp,
	119	struct pt_regs regs, const char log_lvl)
	120	{
	121	unsigned long lr, fp;
	122	struct thread_info *tinfo;
	123
	124	if (regs)
	125	fp = regs->r7;
	126	else if (tsk == current)
	127	asm("mov %0, r7" : "=r"(fp));
	128	else
	129	fp = tsk->thread.cpu_context.r7;
	130
	131	/*
	132	* Walk the stack as long as the frame pointer (a) is within
	133	* the kernel stack of the task, and (b) it doesn't move
	134	* downwards.
	135	*/
	136	tinfo = task_thread_info(tsk);
	137	printk("%sCall trace:\n", log_lvl);
	138	while (valid_stack_ptr(tinfo, fp)) {
	139	unsigned long new_fp;
	140
	141	lr = (unsigned long )fp;
	142	#ifdef CONFIG_KALLSYMS
	143	printk("%s [<%08lx>] ", log_lvl, lr);
144	#else
145	printk(" [<%08lx>] ", lr);
146	#endif
147	print_symbol("%s\n", lr);
148
149	new_fp = (unsigned long )(fp + 4);
150	if (new_fp <= fp)
151	break;
152	fp = new_fp;
153	}
154	printk("\n");
155	}
156	#else
157	static void show_trace_log_lvl(struct task_struct tsk, unsigned long sp,
158	struct pt_regs regs, const char log_lvl)
159	{
160	unsigned long addr;
161
162	printk("%sCall trace:\n", log_lvl);
163
164	while (!kstack_end(sp)) {
165	addr = *sp++;
166	if (kernel_text_address(addr)) {
167	#ifdef CONFIG_KALLSYMS
168	printk("%s [<%08lx>] ", log_lvl, addr);
169	#else
170	printk(" [<%08lx>] ", addr);
171	#endif
172	print_symbol("%s\n", addr);
173	}
174	}
175	printk("\n");
176	}
177	#endif
178
179	void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
180	struct pt_regs regs, const char log_lvl)
181	{
182	struct thread_info *tinfo;
183
184	if (sp == 0) {
185	if (tsk)
186	sp = tsk->thread.cpu_context.ksp;
187	else
188	sp = (unsigned long)&tinfo;
189	}
190	if (!tsk)
191	tsk = current;
192
193	tinfo = task_thread_info(tsk);
194
195	if (valid_stack_ptr(tinfo, sp)) {
196	dump_mem("Stack: ", log_lvl, sp,
197	THREAD_SIZE + (unsigned long)tinfo);
198	show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
199	}
200	}
201
202	void show_stack(struct task_struct tsk, unsigned long stack)
203	{
204	show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
205	}
206
5f97f7f9 HS	207	static const char *cpu_modes[] = {
	208	"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
	209	"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
	210	};
	211
623b0355	212	void show_regs_log_lvl(struct pt_regs regs, const char log_lvl)
5f97f7f9 HS	213	{
	214	unsigned long sp = regs->sp;
	215	unsigned long lr = regs->lr;
	216	unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
	217
a43cb95d TH	218	show_regs_print_info(log_lvl);
a43cb95d TH	219
623b0355	220	if (!user_mode(regs)) {
5f97f7f9 HS	221	sp = (unsigned long)regs + FRAME_SIZE_FULL;
5f97f7f9 HS	222
623b0355 HS	223	printk("%s", log_lvl);
	224	print_symbol("PC is at %s\n", instruction_pointer(regs));
	225	printk("%s", log_lvl);
	226	print_symbol("LR is at %s\n", lr);
	227	}
	228
	229	printk("%spc : [<%08lx>] lr : [<%08lx>] %s\n"
	230	"%ssp : %08lx r12: %08lx r11: %08lx\n",
	231	log_lvl, instruction_pointer(regs), lr, print_tainted(),
	232	log_lvl, sp, regs->r12, regs->r11);
	233	printk("%sr10: %08lx r9 : %08lx r8 : %08lx\n",
	234	log_lvl, regs->r10, regs->r9, regs->r8);
	235	printk("%sr7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
	236	log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
	237	printk("%sr3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
	238	log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
	239	printk("%sFlags: %c%c%c%c%c\n", log_lvl,
5f97f7f9 HS	240	regs->sr & SR_Q ? 'Q' : 'q',
	241	regs->sr & SR_V ? 'V' : 'v',
	242	regs->sr & SR_N ? 'N' : 'n',
	243	regs->sr & SR_Z ? 'Z' : 'z',
	244	regs->sr & SR_C ? 'C' : 'c');
df679771	245	printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
5f97f7f9	246	regs->sr & SR_H ? 'H' : 'h',
5f97f7f9	247	regs->sr & SR_J ? 'J' : 'j',
df679771 HS	248	regs->sr & SR_DM ? 'M' : 'm',
df679771 HS	249	regs->sr & SR_D ? 'D' : 'd',
5f97f7f9 HS	250	regs->sr & SR_EM ? 'E' : 'e',
	251	regs->sr & SR_I3M ? '3' : '.',
	252	regs->sr & SR_I2M ? '2' : '.',
	253	regs->sr & SR_I1M ? '1' : '.',
	254	regs->sr & SR_I0M ? '0' : '.',
	255	regs->sr & SR_GM ? 'G' : 'g');
623b0355	256	printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
623b0355 HS	257	}
	258
	259	void show_regs(struct pt_regs *regs)
	260	{
	261	unsigned long sp = regs->sp;
	262
	263	if (!user_mode(regs))
	264	sp = (unsigned long)regs + FRAME_SIZE_FULL;
5f97f7f9	265
623b0355 HS	266	show_regs_log_lvl(regs, "");
623b0355 HS	267	show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
5f97f7f9 HS	268	}
	269	EXPORT_SYMBOL(show_regs);
	270
	271	/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
	272	int dump_fpu(struct pt_regs regs, elf_fpregset_t fpu)
	273	{
	274	/* Not valid */
	275	return 0;
	276	}
	277
	278	asmlinkage void ret_from_fork(void);
5adc807f AV	279	asmlinkage void ret_from_kernel_thread(void);
5adc807f AV	280	asmlinkage void syscall_return(void);
5f97f7f9	281
6f2c55b8	282	int copy_thread(unsigned long clone_flags, unsigned long usp,
5adc807f	283	unsigned long arg,
afa86fc4	284	struct task_struct *p)
5f97f7f9	285	{
5adc807f AV	286	struct pt_regs *childregs = task_pt_regs(p);
5adc807f AV	287
584271bc	288	if (unlikely(p->flags & PF_KTHREAD)) {
5adc807f AV	289	memset(childregs, 0, sizeof(struct pt_regs));
	290	p->thread.cpu_context.r0 = arg;
	291	p->thread.cpu_context.r1 = usp; /* fn */
395e73a2	292	p->thread.cpu_context.r2 = (unsigned long)syscall_return;
5adc807f AV	293	p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
	294	childregs->sr = MODE_SUPERVISOR;
	295	} else {
584271bc AV	296	childregs = current_pt_regs();
	297	if (usp)
	298	childregs->sp = usp;
5adc807f AV	299	childregs->r12 = 0; /* Set return value for child */
	300	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
	301	}
5f97f7f9 HS	302
	303	p->thread.cpu_context.sr = MODE_SUPERVISOR \| SR_GM;
	304	p->thread.cpu_context.ksp = (unsigned long)childregs;
5f97f7f9	305
325d6f55	306	clear_tsk_thread_flag(p, TIF_DEBUG);
13b54a50 HS	307	if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
	308	ocd_enable(p);
	309
5f97f7f9 HS	310	return 0;
	311	}
	312
5f97f7f9 HS	313	/*
	314	* This function is supposed to answer the question "who called
	315	* schedule()?"
	316	*/
	317	unsigned long get_wchan(struct task_struct *p)
	318	{
	319	unsigned long pc;
	320	unsigned long stack_page;
	321
	322	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	323	return 0;
	324
c9f4f06d	325	stack_page = (unsigned long)task_stack_page(p);
5f97f7f9 HS	326	BUG_ON(!stack_page);
	327
	328	/*
	329	* The stored value of PC is either the address right after
	330	* the call to __switch_to() or ret_from_fork.
	331	*/
	332	pc = thread_saved_pc(p);
	333	if (in_sched_functions(pc)) {
	334	#ifdef CONFIG_FRAME_POINTER
	335	unsigned long fp = p->thread.cpu_context.r7;
	336	BUG_ON(fp < stack_page \|\| fp > (THREAD_SIZE + stack_page));
	337	pc = (unsigned long )fp;
	338	#else
	339	/*
	340	* We depend on the frame size of schedule here, which
	341	* is actually quite ugly. It might be possible to
	342	* determine the frame size automatically at build
	343	* time by doing this:
0a0fca9d	344	* - compile sched/core.c
5f97f7f9 HS	345	* - disassemble the resulting sched.o
	346	* - look for 'sub sp,??' shortly after '<schedule>:'
	347	*/
	348	unsigned long sp = p->thread.cpu_context.ksp + 16;
	349	BUG_ON(sp < stack_page \|\| sp > (THREAD_SIZE + stack_page));
	350	pc = (unsigned long )sp;
	351	#endif
	352	}
	353
	354	return pc;
	355	}