[deliverable/linux.git] / arch / powerpc / 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 "../kernel/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_MIN_SIZE)
		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, perf_instruction_pointer(regs));

	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 *buf, int nb)
{
	int ret = -EFAULT;
	pgd_t *pgdir;
	pte_t *ptep, pte;
	unsigned shift;
	unsigned long addr = (unsigned long) ptr;
	unsigned long offset;
	unsigned long pfn, flags;
	void *kaddr;

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

	local_irq_save(flags);
	ptep = find_linux_pte_or_hugepte(pgdir, addr, NULL, &shift);
	if (!ptep)
		goto err_out;
	if (!shift)
		shift = PAGE_SHIFT;

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

	pte = READ_ONCE(*ptep);
	if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER))
		goto err_out;
	pfn = pte_pfn(pte);
	if (!page_is_ram(pfn))
		goto err_out;

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

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;

	pagefault_disable();
	if (!__get_user_inatomic(*ret, ptr)) {
		pagefault_enable();
		return 0;
	}
	pagefault_enable();

	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;

	pagefault_disable();
	if (!__get_user_inatomic(*ret, ptr)) {
		pagefault_enable();
		return 0;
	}
	pagefault_enable();

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

	while (entry->nr < PERF_MAX_STACK_DEPTH) {
		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)
{
	int rc;

	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
	    ((unsigned long)ptr & 3))
		return -EFAULT;

	pagefault_disable();
	rc = __get_user_inatomic(*ret, ptr);
	pagefault_enable();

	return rc;
}

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 = perf_instruction_pointer(regs);
	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
f2699491	23	#include "../kernel/ppc32.h"
20002ded PM	24	#endif
20002ded PM	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;
85101af1	38	if (sp >= prev_sp + STACK_FRAME_MIN_SIZE)
20002ded PM	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];
6da70948	60	perf_callchain_store(entry, perf_instruction_pointer(regs));
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	*/
691e95fd	114	static int read_user_stack_slow(void __user ptr, void buf, int nb)
20002ded	115	{
691e95fd	116	int ret = -EFAULT;
20002ded PM	117	pgd_t *pgdir;
20002ded PM	118	pte_t *ptep, pte;
a4fe3ce7	119	unsigned shift;
20002ded PM	120	unsigned long addr = (unsigned long) ptr;
20002ded PM	121	unsigned long offset;
691e95fd	122	unsigned long pfn, flags;
20002ded PM	123	void *kaddr;
	124
	125	pgdir = current->mm->pgd;
	126	if (!pgdir)
	127	return -EFAULT;
	128
691e95fd	129	local_irq_save(flags);
891121e6	130	ptep = find_linux_pte_or_hugepte(pgdir, addr, NULL, &shift);
691e95fd AK	131	if (!ptep)
691e95fd AK	132	goto err_out;
a4fe3ce7 DG	133	if (!shift)
a4fe3ce7 DG	134	shift = PAGE_SHIFT;
20002ded PM	135
20002ded PM	136	/* align address to page boundary */
a4fe3ce7	137	offset = addr & ((1UL << shift) - 1);
20002ded	138
691e95fd	139	pte = READ_ONCE(*ptep);
20002ded	140	if (!pte_present(pte) \|\| !(pte_val(pte) & _PAGE_USER))
691e95fd	141	goto err_out;
20002ded PM	142	pfn = pte_pfn(pte);
20002ded PM	143	if (!page_is_ram(pfn))
691e95fd	144	goto err_out;
20002ded PM	145
	146	/* no highmem to worry about here */
	147	kaddr = pfn_to_kaddr(pfn);
691e95fd AK	148	memcpy(buf, kaddr + offset, nb);
	149	ret = 0;
	150	err_out:
	151	local_irq_restore(flags);
	152	return ret;
20002ded PM	153	}
	154
	155	static int read_user_stack_64(unsigned long __user ptr, unsigned long ret)
	156	{
	157	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned long) \|\|
	158	((unsigned long)ptr & 7))
	159	return -EFAULT;
	160
b59a1bfc DA	161	pagefault_disable();
	162	if (!__get_user_inatomic(*ret, ptr)) {
	163	pagefault_enable();
20002ded	164	return 0;
b59a1bfc DA	165	}
b59a1bfc DA	166	pagefault_enable();
20002ded PM	167
	168	return read_user_stack_slow(ptr, ret, 8);
	169	}
	170
	171	static int read_user_stack_32(unsigned int __user ptr, unsigned int ret)
	172	{
	173	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) \|\|
	174	((unsigned long)ptr & 3))
	175	return -EFAULT;
	176
b59a1bfc DA	177	pagefault_disable();
	178	if (!__get_user_inatomic(*ret, ptr)) {
	179	pagefault_enable();
20002ded	180	return 0;
b59a1bfc DA	181	}
b59a1bfc DA	182	pagefault_enable();
20002ded PM	183
	184	return read_user_stack_slow(ptr, ret, 4);
	185	}
	186
	187	static inline int valid_user_sp(unsigned long sp, int is_64)
	188	{
	189	if (!sp \|\| (sp & 7) \|\| sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32)
	190	return 0;
	191	return 1;
	192	}
	193
	194	/*
	195	* 64-bit user processes use the same stack frame for RT and non-RT signals.
	196	*/
	197	struct signal_frame_64 {
	198	char dummy[__SIGNAL_FRAMESIZE];
	199	struct ucontext uc;
	200	unsigned long unused[2];
	201	unsigned int tramp[6];
	202	struct siginfo *pinfo;
	203	void *puc;
	204	struct siginfo info;
	205	char abigap[288];
	206	};
	207
	208	static int is_sigreturn_64_address(unsigned long nip, unsigned long fp)
	209	{
	210	if (nip == fp + offsetof(struct signal_frame_64, tramp))
	211	return 1;
	212	if (vdso64_rt_sigtramp && current->mm->context.vdso_base &&
	213	nip == current->mm->context.vdso_base + vdso64_rt_sigtramp)
	214	return 1;
	215	return 0;
	216	}
	217
	218	/*
	219	* Do some sanity checking on the signal frame pointed to by sp.
	220	* We check the pinfo and puc pointers in the frame.
	221	*/
	222	static int sane_signal_64_frame(unsigned long sp)
	223	{
	224	struct signal_frame_64 __user *sf;
	225	unsigned long pinfo, puc;
	226
	227	sf = (struct signal_frame_64 __user *) sp;
	228	if (read_user_stack_64((unsigned long __user *) &sf->pinfo, &pinfo) \|\|
	229	read_user_stack_64((unsigned long __user *) &sf->puc, &puc))
	230	return 0;
	231	return pinfo == (unsigned long) &sf->info &&
	232	puc == (unsigned long) &sf->uc;
	233	}
	234
56962b44 FW	235	static void perf_callchain_user_64(struct perf_callchain_entry *entry,
56962b44 FW	236	struct pt_regs *regs)
20002ded PM	237	{
	238	unsigned long sp, next_sp;
	239	unsigned long next_ip;
	240	unsigned long lr;
	241	long level = 0;
	242	struct signal_frame_64 __user *sigframe;
	243	unsigned long __user fp, uregs;
	244
6da70948	245	next_ip = perf_instruction_pointer(regs);
20002ded PM	246	lr = regs->link;
20002ded PM	247	sp = regs->gpr[1];
70791ce9	248	perf_callchain_store(entry, next_ip);
20002ded	249
9a5cbce4	250	while (entry->nr < PERF_MAX_STACK_DEPTH) {
20002ded PM	251	fp = (unsigned long __user *) sp;
	252	if (!valid_user_sp(sp, 1) \|\| read_user_stack_64(fp, &next_sp))
	253	return;
	254	if (level > 0 && read_user_stack_64(&fp[2], &next_ip))
	255	return;
	256
	257	/*
	258	* Note: the next_sp - sp >= signal frame size check
	259	* is true when next_sp < sp, which can happen when
	260	* transitioning from an alternate signal stack to the
	261	* normal stack.
	262	*/
	263	if (next_sp - sp >= sizeof(struct signal_frame_64) &&
	264	(is_sigreturn_64_address(next_ip, sp) \|\|
	265	(level <= 1 && is_sigreturn_64_address(lr, sp))) &&
	266	sane_signal_64_frame(sp)) {
	267	/*
	268	* This looks like an signal frame
	269	*/
	270	sigframe = (struct signal_frame_64 __user *) sp;
	271	uregs = sigframe->uc.uc_mcontext.gp_regs;
	272	if (read_user_stack_64(&uregs[PT_NIP], &next_ip) \|\|
	273	read_user_stack_64(&uregs[PT_LNK], &lr) \|\|
	274	read_user_stack_64(&uregs[PT_R1], &sp))
	275	return;
	276	level = 0;
70791ce9 FW	277	perf_callchain_store(entry, PERF_CONTEXT_USER);
70791ce9 FW	278	perf_callchain_store(entry, next_ip);
20002ded PM	279	continue;
	280	}
	281
	282	if (level == 0)
	283	next_ip = lr;
70791ce9	284	perf_callchain_store(entry, next_ip);
20002ded PM	285	++level;
	286	sp = next_sp;
	287	}
	288	}
	289
	290	static inline int current_is_64bit(void)
	291	{
	292	/*
	293	* We can't use test_thread_flag() here because we may be on an
	294	* interrupt stack, and the thread flags don't get copied over
	295	* from the thread_info on the main stack to the interrupt stack.
	296	*/
	297	return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT);
	298	}
	299
	300	#else /* CONFIG_PPC64 */
	301	/*
	302	* On 32-bit we just access the address and let hash_page create a
	303	* HPTE if necessary, so there is no need to fall back to reading
	304	* the page tables. Since this is called at interrupt level,
	305	* do_page_fault() won't treat a DSI as a page fault.
	306	*/
	307	static int read_user_stack_32(unsigned int __user ptr, unsigned int ret)
	308	{
b59a1bfc DA	309	int rc;
b59a1bfc DA	310
20002ded PM	311	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) \|\|
	312	((unsigned long)ptr & 3))
	313	return -EFAULT;
	314
b59a1bfc DA	315	pagefault_disable();
	316	rc = __get_user_inatomic(*ret, ptr);
	317	pagefault_enable();
	318
	319	return rc;
20002ded PM	320	}
20002ded PM	321
56962b44 FW	322	static inline void perf_callchain_user_64(struct perf_callchain_entry *entry,
56962b44 FW	323	struct pt_regs *regs)
20002ded PM	324	{
	325	}
	326
	327	static inline int current_is_64bit(void)
	328	{
	329	return 0;
	330	}
	331
	332	static inline int valid_user_sp(unsigned long sp, int is_64)
	333	{
	334	if (!sp \|\| (sp & 7) \|\| sp > TASK_SIZE - 32)
	335	return 0;
	336	return 1;
	337	}
	338
	339	#define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE
	340	#define sigcontext32 sigcontext
	341	#define mcontext32 mcontext
	342	#define ucontext32 ucontext
	343	#define compat_siginfo_t struct siginfo
	344
	345	#endif /* CONFIG_PPC64 */
	346
	347	/*
	348	* Layout for non-RT signal frames
	349	*/
	350	struct signal_frame_32 {
	351	char dummy[__SIGNAL_FRAMESIZE32];
	352	struct sigcontext32 sctx;
	353	struct mcontext32 mctx;
	354	int abigap[56];
	355	};
	356
	357	/*
	358	* Layout for RT signal frames
	359	*/
	360	struct rt_signal_frame_32 {
	361	char dummy[__SIGNAL_FRAMESIZE32 + 16];
	362	compat_siginfo_t info;
	363	struct ucontext32 uc;
	364	int abigap[56];
	365	};
	366
	367	static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
	368	{
	369	if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
	370	return 1;
	371	if (vdso32_sigtramp && current->mm->context.vdso_base &&
	372	nip == current->mm->context.vdso_base + vdso32_sigtramp)
	373	return 1;
	374	return 0;
	375	}
	376
	377	static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
	378	{
	379	if (nip == fp + offsetof(struct rt_signal_frame_32,
	380	uc.uc_mcontext.mc_pad))
	381	return 1;
	382	if (vdso32_rt_sigtramp && current->mm->context.vdso_base &&
	383	nip == current->mm->context.vdso_base + vdso32_rt_sigtramp)
	384	return 1;
	385	return 0;
	386	}
	387
388	static int sane_signal_32_frame(unsigned int sp)
389	{
390	struct signal_frame_32 __user *sf;
391	unsigned int regs;
392
393	sf = (struct signal_frame_32 __user *) (unsigned long) sp;
394	if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, &regs))
395	return 0;
396	return regs == (unsigned long) &sf->mctx;
397	}
398
399	static int sane_rt_signal_32_frame(unsigned int sp)
400	{
401	struct rt_signal_frame_32 __user *sf;
402	unsigned int regs;
403
404	sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
405	if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, &regs))
406	return 0;
407	return regs == (unsigned long) &sf->uc.uc_mcontext;
408	}
409
410	static unsigned int __user *signal_frame_32_regs(unsigned int sp,
411	unsigned int next_sp, unsigned int next_ip)
412	{
413	struct mcontext32 __user *mctx = NULL;
414	struct signal_frame_32 __user *sf;
415	struct rt_signal_frame_32 __user *rt_sf;
416
417	/*
418	* Note: the next_sp - sp >= signal frame size check
419	* is true when next_sp < sp, for example, when
420	* transitioning from an alternate signal stack to the
421	* normal stack.
422	*/
423	if (next_sp - sp >= sizeof(struct signal_frame_32) &&
424	is_sigreturn_32_address(next_ip, sp) &&
425	sane_signal_32_frame(sp)) {
426	sf = (struct signal_frame_32 __user *) (unsigned long) sp;
427	mctx = &sf->mctx;
428	}
429
430	if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) &&
431	is_rt_sigreturn_32_address(next_ip, sp) &&
432	sane_rt_signal_32_frame(sp)) {
433	rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
434	mctx = &rt_sf->uc.uc_mcontext;
435	}
436
437	if (!mctx)
438	return NULL;
439	return mctx->mc_gregs;
440	}
441
56962b44 FW	442	static void perf_callchain_user_32(struct perf_callchain_entry *entry,
56962b44 FW	443	struct pt_regs *regs)
20002ded PM	444	{
	445	unsigned int sp, next_sp;
	446	unsigned int next_ip;
	447	unsigned int lr;
	448	long level = 0;
	449	unsigned int __user fp, uregs;
	450
6da70948	451	next_ip = perf_instruction_pointer(regs);
20002ded PM	452	lr = regs->link;
20002ded PM	453	sp = regs->gpr[1];
70791ce9	454	perf_callchain_store(entry, next_ip);
20002ded PM	455
	456	while (entry->nr < PERF_MAX_STACK_DEPTH) {
	457	fp = (unsigned int __user *) (unsigned long) sp;
	458	if (!valid_user_sp(sp, 0) \|\| read_user_stack_32(fp, &next_sp))
	459	return;
	460	if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
	461	return;
	462
	463	uregs = signal_frame_32_regs(sp, next_sp, next_ip);
	464	if (!uregs && level <= 1)
	465	uregs = signal_frame_32_regs(sp, next_sp, lr);
	466	if (uregs) {
	467	/*
	468	* This looks like an signal frame, so restart
	469	* the stack trace with the values in it.
	470	*/
	471	if (read_user_stack_32(&uregs[PT_NIP], &next_ip) \|\|
	472	read_user_stack_32(&uregs[PT_LNK], &lr) \|\|
	473	read_user_stack_32(&uregs[PT_R1], &sp))
	474	return;
	475	level = 0;
70791ce9 FW	476	perf_callchain_store(entry, PERF_CONTEXT_USER);
70791ce9 FW	477	perf_callchain_store(entry, next_ip);
20002ded PM	478	continue;
	479	}
	480
	481	if (level == 0)
	482	next_ip = lr;
70791ce9	483	perf_callchain_store(entry, next_ip);
20002ded PM	484	++level;
	485	sp = next_sp;
	486	}
	487	}
	488
56962b44 FW	489	void
56962b44 FW	490	perf_callchain_user(struct perf_callchain_entry entry, struct pt_regs regs)
20002ded	491	{
56962b44 FW	492	if (current_is_64bit())
	493	perf_callchain_user_64(entry, regs);
	494	else
	495	perf_callchain_user_32(entry, regs);
20002ded	496	}