[net-next-2.6.git] / arch / powerpc / kernel / perf_callchain.c

/*
 * Performance counter callchain support - powerpc architecture code
 *
 * Copyright © 2009 Paul Mackerras, IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/perf_event.h>
#include <linux/percpu.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
#include <asm/ptrace.h>
#include <asm/pgtable.h>
#include <asm/sigcontext.h>
#include <asm/ucontext.h>
#include <asm/vdso.h>
#ifdef CONFIG_PPC64
#include "ppc32.h"
#endif


/*
 * Is sp valid as the address of the next kernel stack frame after prev_sp?
 * The next frame may be in a different stack area but should not go
 * back down in the same stack area.
 */
static int valid_next_sp(unsigned long sp, unsigned long prev_sp)
{
	if (sp & 0xf)
		return 0;		/* must be 16-byte aligned */
	if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
		return 0;
	if (sp >= prev_sp + STACK_FRAME_OVERHEAD)
		return 1;
	/*
	 * sp could decrease when we jump off an interrupt stack
	 * back to the regular process stack.
	 */
	if ((sp & ~(THREAD_SIZE - 1)) != (prev_sp & ~(THREAD_SIZE - 1)))
		return 1;
	return 0;
}

void
perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
	unsigned long sp, next_sp;
	unsigned long next_ip;
	unsigned long lr;
	long level = 0;
	unsigned long *fp;

	lr = regs->link;
	sp = regs->gpr[1];
	perf_callchain_store(entry, regs->nip);

	if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
		return;

	for (;;) {
		fp = (unsigned long *) sp;
		next_sp = fp[0];

		if (next_sp == sp + STACK_INT_FRAME_SIZE &&
		    fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
			/*
			 * This looks like an interrupt frame for an
			 * interrupt that occurred in the kernel
			 */
			regs = (struct pt_regs *)(sp + STACK_FRAME_OVERHEAD);
			next_ip = regs->nip;
			lr = regs->link;
			level = 0;
			perf_callchain_store(entry, PERF_CONTEXT_KERNEL);

		} else {
			if (level == 0)
				next_ip = lr;
			else
				next_ip = fp[STACK_FRAME_LR_SAVE];

			/*
			 * We can't tell which of the first two addresses
			 * we get are valid, but we can filter out the
			 * obviously bogus ones here.  We replace them
			 * with 0 rather than removing them entirely so
			 * that userspace can tell which is which.
			 */
			if ((level == 1 && next_ip == lr) ||
			    (level <= 1 && !kernel_text_address(next_ip)))
				next_ip = 0;

			++level;
		}

		perf_callchain_store(entry, next_ip);
		if (!valid_next_sp(next_sp, sp))
			return;
		sp = next_sp;
	}
}

#ifdef CONFIG_PPC64
/*
 * On 64-bit we don't want to invoke hash_page on user addresses from
 * interrupt context, so if the access faults, we read the page tables
 * to find which page (if any) is mapped and access it directly.
 */
static int read_user_stack_slow(void __user *ptr, void *ret, int nb)
{
	pgd_t *pgdir;
	pte_t *ptep, pte;
	unsigned shift;
	unsigned long addr = (unsigned long) ptr;
	unsigned long offset;
	unsigned long pfn;
	void *kaddr;

	pgdir = current->mm->pgd;
	if (!pgdir)
		return -EFAULT;

	ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift);
	if (!shift)
		shift = PAGE_SHIFT;

	/* align address to page boundary */
	offset = addr & ((1UL << shift) - 1);
	addr -= offset;

	if (ptep == NULL)
		return -EFAULT;
	pte = *ptep;
	if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER))
		return -EFAULT;
	pfn = pte_pfn(pte);
	if (!page_is_ram(pfn))
		return -EFAULT;

	/* no highmem to worry about here */
	kaddr = pfn_to_kaddr(pfn);
	memcpy(ret, kaddr + offset, nb);
	return 0;
}

static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
{
	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned long) ||
	    ((unsigned long)ptr & 7))
		return -EFAULT;

	if (!__get_user_inatomic(*ret, ptr))
		return 0;

	return read_user_stack_slow(ptr, ret, 8);
}

static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
{
	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
	    ((unsigned long)ptr & 3))
		return -EFAULT;

	if (!__get_user_inatomic(*ret, ptr))
		return 0;

	return read_user_stack_slow(ptr, ret, 4);
}

static inline int valid_user_sp(unsigned long sp, int is_64)
{
	if (!sp || (sp & 7) || sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32)
		return 0;
	return 1;
}

/*
 * 64-bit user processes use the same stack frame for RT and non-RT signals.
 */
struct signal_frame_64 {
	char		dummy[__SIGNAL_FRAMESIZE];
	struct ucontext	uc;
	unsigned long	unused[2];
	unsigned int	tramp[6];
	struct siginfo	*pinfo;
	void		*puc;
	struct siginfo	info;
	char		abigap[288];
};

static int is_sigreturn_64_address(unsigned long nip, unsigned long fp)
{
	if (nip == fp + offsetof(struct signal_frame_64, tramp))
		return 1;
	if (vdso64_rt_sigtramp && current->mm->context.vdso_base &&
	    nip == current->mm->context.vdso_base + vdso64_rt_sigtramp)
		return 1;
	return 0;
}

/*
 * Do some sanity checking on the signal frame pointed to by sp.
 * We check the pinfo and puc pointers in the frame.
 */
static int sane_signal_64_frame(unsigned long sp)
{
	struct signal_frame_64 __user *sf;
	unsigned long pinfo, puc;

	sf = (struct signal_frame_64 __user *) sp;
	if (read_user_stack_64((unsigned long __user *) &sf->pinfo, &pinfo) ||
	    read_user_stack_64((unsigned long __user *) &sf->puc, &puc))
		return 0;
	return pinfo == (unsigned long) &sf->info &&
		puc == (unsigned long) &sf->uc;
}

static void perf_callchain_user_64(struct perf_callchain_entry *entry,
				   struct pt_regs *regs)
{
	unsigned long sp, next_sp;
	unsigned long next_ip;
	unsigned long lr;
	long level = 0;
	struct signal_frame_64 __user *sigframe;
	unsigned long __user *fp, *uregs;

	next_ip = regs->nip;
	lr = regs->link;
	sp = regs->gpr[1];
	perf_callchain_store(entry, next_ip);

	for (;;) {
		fp = (unsigned long __user *) sp;
		if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp))
			return;
		if (level > 0 && read_user_stack_64(&fp[2], &next_ip))
			return;

		/*
		 * Note: the next_sp - sp >= signal frame size check
		 * is true when next_sp < sp, which can happen when
		 * transitioning from an alternate signal stack to the
		 * normal stack.
		 */
		if (next_sp - sp >= sizeof(struct signal_frame_64) &&
		    (is_sigreturn_64_address(next_ip, sp) ||
		     (level <= 1 && is_sigreturn_64_address(lr, sp))) &&
		    sane_signal_64_frame(sp)) {
			/*
			 * This looks like an signal frame
			 */
			sigframe = (struct signal_frame_64 __user *) sp;
			uregs = sigframe->uc.uc_mcontext.gp_regs;
			if (read_user_stack_64(&uregs[PT_NIP], &next_ip) ||
			    read_user_stack_64(&uregs[PT_LNK], &lr) ||
			    read_user_stack_64(&uregs[PT_R1], &sp))
				return;
			level = 0;
			perf_callchain_store(entry, PERF_CONTEXT_USER);
			perf_callchain_store(entry, next_ip);
			continue;
		}

		if (level == 0)
			next_ip = lr;
		perf_callchain_store(entry, next_ip);
		++level;
		sp = next_sp;
	}
}

static inline int current_is_64bit(void)
{
	/*
	 * We can't use test_thread_flag() here because we may be on an
	 * interrupt stack, and the thread flags don't get copied over
	 * from the thread_info on the main stack to the interrupt stack.
	 */
	return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT);
}

#else  /* CONFIG_PPC64 */
/*
 * On 32-bit we just access the address and let hash_page create a
 * HPTE if necessary, so there is no need to fall back to reading
 * the page tables.  Since this is called at interrupt level,
 * do_page_fault() won't treat a DSI as a page fault.
 */
static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
{
	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
	    ((unsigned long)ptr & 3))
		return -EFAULT;

	return __get_user_inatomic(*ret, ptr);
}

static inline void perf_callchain_user_64(struct perf_callchain_entry *entry,
					  struct pt_regs *regs)
{
}

static inline int current_is_64bit(void)
{
	return 0;
}

static inline int valid_user_sp(unsigned long sp, int is_64)
{
	if (!sp || (sp & 7) || sp > TASK_SIZE - 32)
		return 0;
	return 1;
}

#define __SIGNAL_FRAMESIZE32	__SIGNAL_FRAMESIZE
#define sigcontext32		sigcontext
#define mcontext32		mcontext
#define ucontext32		ucontext
#define compat_siginfo_t	struct siginfo

#endif /* CONFIG_PPC64 */

/*
 * Layout for non-RT signal frames
 */
struct signal_frame_32 {
	char			dummy[__SIGNAL_FRAMESIZE32];
	struct sigcontext32	sctx;
	struct mcontext32	mctx;
	int			abigap[56];
};

/*
 * Layout for RT signal frames
 */
struct rt_signal_frame_32 {
	char			dummy[__SIGNAL_FRAMESIZE32 + 16];
	compat_siginfo_t	info;
	struct ucontext32	uc;
	int			abigap[56];
};

static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
{
	if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
		return 1;
	if (vdso32_sigtramp && current->mm->context.vdso_base &&
	    nip == current->mm->context.vdso_base + vdso32_sigtramp)
		return 1;
	return 0;
}

static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
{
	if (nip == fp + offsetof(struct rt_signal_frame_32,
				 uc.uc_mcontext.mc_pad))
		return 1;
	if (vdso32_rt_sigtramp && current->mm->context.vdso_base &&
	    nip == current->mm->context.vdso_base + vdso32_rt_sigtramp)
		return 1;
	return 0;
}

static int sane_signal_32_frame(unsigned int sp)
{
	struct signal_frame_32 __user *sf;
	unsigned int regs;

	sf = (struct signal_frame_32 __user *) (unsigned long) sp;
	if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, &regs))
		return 0;
	return regs == (unsigned long) &sf->mctx;
}

static int sane_rt_signal_32_frame(unsigned int sp)
{
	struct rt_signal_frame_32 __user *sf;
	unsigned int regs;

	sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
	if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, &regs))
		return 0;
	return regs == (unsigned long) &sf->uc.uc_mcontext;
}

static unsigned int __user *signal_frame_32_regs(unsigned int sp,
				unsigned int next_sp, unsigned int next_ip)
{
	struct mcontext32 __user *mctx = NULL;
	struct signal_frame_32 __user *sf;
	struct rt_signal_frame_32 __user *rt_sf;

	/*
	 * Note: the next_sp - sp >= signal frame size check
	 * is true when next_sp < sp, for example, when
	 * transitioning from an alternate signal stack to the
	 * normal stack.
	 */
	if (next_sp - sp >= sizeof(struct signal_frame_32) &&
	    is_sigreturn_32_address(next_ip, sp) &&
	    sane_signal_32_frame(sp)) {
		sf = (struct signal_frame_32 __user *) (unsigned long) sp;
		mctx = &sf->mctx;
	}

	if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) &&
	    is_rt_sigreturn_32_address(next_ip, sp) &&
	    sane_rt_signal_32_frame(sp)) {
		rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
		mctx = &rt_sf->uc.uc_mcontext;
	}

	if (!mctx)
		return NULL;
	return mctx->mc_gregs;
}

static void perf_callchain_user_32(struct perf_callchain_entry *entry,
				   struct pt_regs *regs)
{
	unsigned int sp, next_sp;
	unsigned int next_ip;
	unsigned int lr;
	long level = 0;
	unsigned int __user *fp, *uregs;

	next_ip = regs->nip;
	lr = regs->link;
	sp = regs->gpr[1];
	perf_callchain_store(entry, next_ip);

	while (entry->nr < PERF_MAX_STACK_DEPTH) {
		fp = (unsigned int __user *) (unsigned long) sp;
		if (!valid_user_sp(sp, 0) || read_user_stack_32(fp, &next_sp))
			return;
		if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
			return;

		uregs = signal_frame_32_regs(sp, next_sp, next_ip);
		if (!uregs && level <= 1)
			uregs = signal_frame_32_regs(sp, next_sp, lr);
		if (uregs) {
			/*
			 * This looks like an signal frame, so restart
			 * the stack trace with the values in it.
			 */
			if (read_user_stack_32(&uregs[PT_NIP], &next_ip) ||
			    read_user_stack_32(&uregs[PT_LNK], &lr) ||
			    read_user_stack_32(&uregs[PT_R1], &sp))
				return;
			level = 0;
			perf_callchain_store(entry, PERF_CONTEXT_USER);
			perf_callchain_store(entry, next_ip);
			continue;
		}

		if (level == 0)
			next_ip = lr;
		perf_callchain_store(entry, next_ip);
		++level;
		sp = next_sp;
	}
}

void
perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
	if (current_is_64bit())
		perf_callchain_user_64(entry, regs);
	else
		perf_callchain_user_32(entry, regs);
}
Commit	Line	Data
20002ded PM	1	/*
	2	* Performance counter callchain support - powerpc architecture code
	3	*
	4	* Copyright © 2009 Paul Mackerras, IBM Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11	#include <linux/kernel.h>
	12	#include <linux/sched.h>
cdd6c482	13	#include <linux/perf_event.h>
20002ded PM	14	#include <linux/percpu.h>
	15	#include <linux/uaccess.h>
	16	#include <linux/mm.h>
	17	#include <asm/ptrace.h>
	18	#include <asm/pgtable.h>
	19	#include <asm/sigcontext.h>
	20	#include <asm/ucontext.h>
	21	#include <asm/vdso.h>
	22	#ifdef CONFIG_PPC64
	23	#include "ppc32.h"
	24	#endif
	25
20002ded PM	26
	27	/*
	28	* Is sp valid as the address of the next kernel stack frame after prev_sp?
	29	* The next frame may be in a different stack area but should not go
	30	* back down in the same stack area.
	31	*/
	32	static int valid_next_sp(unsigned long sp, unsigned long prev_sp)
	33	{
	34	if (sp & 0xf)
	35	return 0; /* must be 16-byte aligned */
	36	if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
	37	return 0;
	38	if (sp >= prev_sp + STACK_FRAME_OVERHEAD)
	39	return 1;
	40	/*
	41	* sp could decrease when we jump off an interrupt stack
	42	* back to the regular process stack.
	43	*/
	44	if ((sp & ~(THREAD_SIZE - 1)) != (prev_sp & ~(THREAD_SIZE - 1)))
	45	return 1;
	46	return 0;
	47	}
	48
56962b44 FW	49	void
56962b44 FW	50	perf_callchain_kernel(struct perf_callchain_entry entry, struct pt_regs regs)
20002ded PM	51	{
	52	unsigned long sp, next_sp;
	53	unsigned long next_ip;
	54	unsigned long lr;
	55	long level = 0;
	56	unsigned long *fp;
	57
	58	lr = regs->link;
	59	sp = regs->gpr[1];
70791ce9	60	perf_callchain_store(entry, regs->nip);
20002ded PM	61
	62	if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
	63	return;
	64
	65	for (;;) {
	66	fp = (unsigned long *) sp;
	67	next_sp = fp[0];
	68
	69	if (next_sp == sp + STACK_INT_FRAME_SIZE &&
	70	fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
	71	/*
	72	* This looks like an interrupt frame for an
	73	* interrupt that occurred in the kernel
	74	*/
	75	regs = (struct pt_regs *)(sp + STACK_FRAME_OVERHEAD);
	76	next_ip = regs->nip;
	77	lr = regs->link;
	78	level = 0;
70791ce9	79	perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
20002ded PM	80
	81	} else {
	82	if (level == 0)
	83	next_ip = lr;
	84	else
	85	next_ip = fp[STACK_FRAME_LR_SAVE];
	86
	87	/*
	88	* We can't tell which of the first two addresses
	89	* we get are valid, but we can filter out the
	90	* obviously bogus ones here. We replace them
	91	* with 0 rather than removing them entirely so
	92	* that userspace can tell which is which.
	93	*/
	94	if ((level == 1 && next_ip == lr) \|\|
	95	(level <= 1 && !kernel_text_address(next_ip)))
	96	next_ip = 0;
	97
	98	++level;
	99	}
	100
70791ce9	101	perf_callchain_store(entry, next_ip);
20002ded PM	102	if (!valid_next_sp(next_sp, sp))
	103	return;
	104	sp = next_sp;
	105	}
	106	}
	107
	108	#ifdef CONFIG_PPC64
20002ded PM	109	/*
	110	* On 64-bit we don't want to invoke hash_page on user addresses from
	111	* interrupt context, so if the access faults, we read the page tables
	112	* to find which page (if any) is mapped and access it directly.
	113	*/
	114	static int read_user_stack_slow(void __user ptr, void ret, int nb)
	115	{
	116	pgd_t *pgdir;
	117	pte_t *ptep, pte;
a4fe3ce7	118	unsigned shift;
20002ded PM	119	unsigned long addr = (unsigned long) ptr;
	120	unsigned long offset;
	121	unsigned long pfn;
	122	void *kaddr;
	123
	124	pgdir = current->mm->pgd;
	125	if (!pgdir)
	126	return -EFAULT;
	127
a4fe3ce7 DG	128	ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift);
	129	if (!shift)
	130	shift = PAGE_SHIFT;
20002ded PM	131
20002ded PM	132	/* align address to page boundary */
a4fe3ce7	133	offset = addr & ((1UL << shift) - 1);
20002ded PM	134	addr -= offset;
20002ded PM	135
20002ded PM	136	if (ptep == NULL)
	137	return -EFAULT;
	138	pte = *ptep;
	139	if (!pte_present(pte) \|\| !(pte_val(pte) & _PAGE_USER))
	140	return -EFAULT;
	141	pfn = pte_pfn(pte);
	142	if (!page_is_ram(pfn))
	143	return -EFAULT;
	144
	145	/* no highmem to worry about here */
	146	kaddr = pfn_to_kaddr(pfn);
	147	memcpy(ret, kaddr + offset, nb);
	148	return 0;
	149	}
	150
	151	static int read_user_stack_64(unsigned long __user ptr, unsigned long ret)
	152	{
	153	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned long) \|\|
	154	((unsigned long)ptr & 7))
	155	return -EFAULT;
	156
	157	if (!__get_user_inatomic(*ret, ptr))
	158	return 0;
	159
	160	return read_user_stack_slow(ptr, ret, 8);
	161	}
	162
	163	static int read_user_stack_32(unsigned int __user ptr, unsigned int ret)
	164	{
	165	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) \|\|
	166	((unsigned long)ptr & 3))
	167	return -EFAULT;
	168
	169	if (!__get_user_inatomic(*ret, ptr))
	170	return 0;
	171
	172	return read_user_stack_slow(ptr, ret, 4);
	173	}
	174
	175	static inline int valid_user_sp(unsigned long sp, int is_64)
	176	{
	177	if (!sp \|\| (sp & 7) \|\| sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32)
	178	return 0;
	179	return 1;
	180	}
	181
	182	/*
	183	* 64-bit user processes use the same stack frame for RT and non-RT signals.
	184	*/
	185	struct signal_frame_64 {
	186	char dummy[__SIGNAL_FRAMESIZE];
	187	struct ucontext uc;
	188	unsigned long unused[2];
	189	unsigned int tramp[6];
	190	struct siginfo *pinfo;
	191	void *puc;
	192	struct siginfo info;
	193	char abigap[288];
	194	};
	195
	196	static int is_sigreturn_64_address(unsigned long nip, unsigned long fp)
	197	{
	198	if (nip == fp + offsetof(struct signal_frame_64, tramp))
	199	return 1;
200	if (vdso64_rt_sigtramp && current->mm->context.vdso_base &&
201	nip == current->mm->context.vdso_base + vdso64_rt_sigtramp)
202	return 1;
203	return 0;
204	}
205
206	/*
207	* Do some sanity checking on the signal frame pointed to by sp.
208	* We check the pinfo and puc pointers in the frame.
209	*/
210	static int sane_signal_64_frame(unsigned long sp)
211	{
212	struct signal_frame_64 __user *sf;
213	unsigned long pinfo, puc;
214
215	sf = (struct signal_frame_64 __user *) sp;
216	if (read_user_stack_64((unsigned long __user *) &sf->pinfo, &pinfo) \|\|
217	read_user_stack_64((unsigned long __user *) &sf->puc, &puc))
218	return 0;
219	return pinfo == (unsigned long) &sf->info &&
220	puc == (unsigned long) &sf->uc;
221	}
222
56962b44 FW	223	static void perf_callchain_user_64(struct perf_callchain_entry *entry,
56962b44 FW	224	struct pt_regs *regs)
20002ded PM	225	{
	226	unsigned long sp, next_sp;
	227	unsigned long next_ip;
	228	unsigned long lr;
	229	long level = 0;
	230	struct signal_frame_64 __user *sigframe;
	231	unsigned long __user fp, uregs;
	232
	233	next_ip = regs->nip;
	234	lr = regs->link;
	235	sp = regs->gpr[1];
70791ce9	236	perf_callchain_store(entry, next_ip);
20002ded PM	237
	238	for (;;) {
	239	fp = (unsigned long __user *) sp;
	240	if (!valid_user_sp(sp, 1) \|\| read_user_stack_64(fp, &next_sp))
	241	return;
	242	if (level > 0 && read_user_stack_64(&fp[2], &next_ip))
	243	return;
	244
	245	/*
	246	* Note: the next_sp - sp >= signal frame size check
	247	* is true when next_sp < sp, which can happen when
	248	* transitioning from an alternate signal stack to the
	249	* normal stack.
	250	*/
	251	if (next_sp - sp >= sizeof(struct signal_frame_64) &&
	252	(is_sigreturn_64_address(next_ip, sp) \|\|
	253	(level <= 1 && is_sigreturn_64_address(lr, sp))) &&
	254	sane_signal_64_frame(sp)) {
	255	/*
	256	* This looks like an signal frame
	257	*/
	258	sigframe = (struct signal_frame_64 __user *) sp;
	259	uregs = sigframe->uc.uc_mcontext.gp_regs;
	260	if (read_user_stack_64(&uregs[PT_NIP], &next_ip) \|\|
	261	read_user_stack_64(&uregs[PT_LNK], &lr) \|\|
	262	read_user_stack_64(&uregs[PT_R1], &sp))
	263	return;
	264	level = 0;
70791ce9 FW	265	perf_callchain_store(entry, PERF_CONTEXT_USER);
70791ce9 FW	266	perf_callchain_store(entry, next_ip);
20002ded PM	267	continue;
	268	}
	269
	270	if (level == 0)
	271	next_ip = lr;
70791ce9	272	perf_callchain_store(entry, next_ip);
20002ded PM	273	++level;
	274	sp = next_sp;
	275	}
	276	}
	277
	278	static inline int current_is_64bit(void)
	279	{
	280	/*
	281	* We can't use test_thread_flag() here because we may be on an
	282	* interrupt stack, and the thread flags don't get copied over
	283	* from the thread_info on the main stack to the interrupt stack.
	284	*/
	285	return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT);
	286	}
	287
	288	#else /* CONFIG_PPC64 */
	289	/*
	290	* On 32-bit we just access the address and let hash_page create a
	291	* HPTE if necessary, so there is no need to fall back to reading
	292	* the page tables. Since this is called at interrupt level,
	293	* do_page_fault() won't treat a DSI as a page fault.
	294	*/
	295	static int read_user_stack_32(unsigned int __user ptr, unsigned int ret)
	296	{
	297	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) \|\|
	298	((unsigned long)ptr & 3))
	299	return -EFAULT;
	300
	301	return __get_user_inatomic(*ret, ptr);
	302	}
	303
56962b44 FW	304	static inline void perf_callchain_user_64(struct perf_callchain_entry *entry,
56962b44 FW	305	struct pt_regs *regs)
20002ded PM	306	{
	307	}
	308
	309	static inline int current_is_64bit(void)
	310	{
	311	return 0;
	312	}
	313
	314	static inline int valid_user_sp(unsigned long sp, int is_64)
	315	{
	316	if (!sp \|\| (sp & 7) \|\| sp > TASK_SIZE - 32)
	317	return 0;
	318	return 1;
	319	}
	320
	321	#define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE
	322	#define sigcontext32 sigcontext
	323	#define mcontext32 mcontext
	324	#define ucontext32 ucontext
	325	#define compat_siginfo_t struct siginfo
	326
	327	#endif /* CONFIG_PPC64 */
	328
	329	/*
	330	* Layout for non-RT signal frames
	331	*/
	332	struct signal_frame_32 {
	333	char dummy[__SIGNAL_FRAMESIZE32];
	334	struct sigcontext32 sctx;
	335	struct mcontext32 mctx;
	336	int abigap[56];
	337	};
	338
	339	/*
	340	* Layout for RT signal frames
	341	*/
	342	struct rt_signal_frame_32 {
	343	char dummy[__SIGNAL_FRAMESIZE32 + 16];
	344	compat_siginfo_t info;
	345	struct ucontext32 uc;
	346	int abigap[56];
	347	};
	348
	349	static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
	350	{
	351	if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
	352	return 1;
	353	if (vdso32_sigtramp && current->mm->context.vdso_base &&
	354	nip == current->mm->context.vdso_base + vdso32_sigtramp)
	355	return 1;
	356	return 0;
	357	}
	358
	359	static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
	360	{
	361	if (nip == fp + offsetof(struct rt_signal_frame_32,
	362	uc.uc_mcontext.mc_pad))
	363	return 1;
	364	if (vdso32_rt_sigtramp && current->mm->context.vdso_base &&
	365	nip == current->mm->context.vdso_base + vdso32_rt_sigtramp)
	366	return 1;
	367	return 0;
	368	}
	369
370	static int sane_signal_32_frame(unsigned int sp)
371	{
372	struct signal_frame_32 __user *sf;
373	unsigned int regs;
374
375	sf = (struct signal_frame_32 __user *) (unsigned long) sp;
376	if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, &regs))
377	return 0;
378	return regs == (unsigned long) &sf->mctx;
379	}
380
381	static int sane_rt_signal_32_frame(unsigned int sp)
382	{
383	struct rt_signal_frame_32 __user *sf;
384	unsigned int regs;
385
386	sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
387	if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, &regs))
388	return 0;
389	return regs == (unsigned long) &sf->uc.uc_mcontext;
390	}
391
392	static unsigned int __user *signal_frame_32_regs(unsigned int sp,
393	unsigned int next_sp, unsigned int next_ip)
394	{
395	struct mcontext32 __user *mctx = NULL;
396	struct signal_frame_32 __user *sf;
397	struct rt_signal_frame_32 __user *rt_sf;
398
399	/*
400	* Note: the next_sp - sp >= signal frame size check
401	* is true when next_sp < sp, for example, when
402	* transitioning from an alternate signal stack to the
403	* normal stack.
404	*/
405	if (next_sp - sp >= sizeof(struct signal_frame_32) &&
406	is_sigreturn_32_address(next_ip, sp) &&
407	sane_signal_32_frame(sp)) {
408	sf = (struct signal_frame_32 __user *) (unsigned long) sp;
409	mctx = &sf->mctx;
410	}
411
412	if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) &&
413	is_rt_sigreturn_32_address(next_ip, sp) &&
414	sane_rt_signal_32_frame(sp)) {
415	rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
416	mctx = &rt_sf->uc.uc_mcontext;
417	}
418
419	if (!mctx)
420	return NULL;
421	return mctx->mc_gregs;
422	}
423
56962b44 FW	424	static void perf_callchain_user_32(struct perf_callchain_entry *entry,
56962b44 FW	425	struct pt_regs *regs)
20002ded PM	426	{
	427	unsigned int sp, next_sp;
	428	unsigned int next_ip;
	429	unsigned int lr;
	430	long level = 0;
	431	unsigned int __user fp, uregs;
	432
	433	next_ip = regs->nip;
	434	lr = regs->link;
	435	sp = regs->gpr[1];
70791ce9	436	perf_callchain_store(entry, next_ip);
20002ded PM	437
	438	while (entry->nr < PERF_MAX_STACK_DEPTH) {
	439	fp = (unsigned int __user *) (unsigned long) sp;
	440	if (!valid_user_sp(sp, 0) \|\| read_user_stack_32(fp, &next_sp))
	441	return;
	442	if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
	443	return;
	444
	445	uregs = signal_frame_32_regs(sp, next_sp, next_ip);
	446	if (!uregs && level <= 1)
	447	uregs = signal_frame_32_regs(sp, next_sp, lr);
	448	if (uregs) {
	449	/*
	450	* This looks like an signal frame, so restart
	451	* the stack trace with the values in it.
	452	*/
	453	if (read_user_stack_32(&uregs[PT_NIP], &next_ip) \|\|
	454	read_user_stack_32(&uregs[PT_LNK], &lr) \|\|
	455	read_user_stack_32(&uregs[PT_R1], &sp))
	456	return;
	457	level = 0;
70791ce9 FW	458	perf_callchain_store(entry, PERF_CONTEXT_USER);
70791ce9 FW	459	perf_callchain_store(entry, next_ip);
20002ded PM	460	continue;
	461	}
	462
	463	if (level == 0)
	464	next_ip = lr;
70791ce9	465	perf_callchain_store(entry, next_ip);
20002ded PM	466	++level;
	467	sp = next_sp;
	468	}
	469	}
	470
56962b44 FW	471	void
56962b44 FW	472	perf_callchain_user(struct perf_callchain_entry entry, struct pt_regs regs)
20002ded	473	{
56962b44 FW	474	if (current_is_64bit())
	475	perf_callchain_user_64(entry, regs);
	476	else
	477	perf_callchain_user_32(entry, regs);
20002ded	478	}