diff options
| -rw-r--r-- | arch/powerpc/perf/Makefile | 5 | ||||
| -rw-r--r-- | arch/powerpc/perf/callchain.c | 356 | ||||
| -rw-r--r-- | arch/powerpc/perf/callchain.h | 19 | ||||
| -rw-r--r-- | arch/powerpc/perf/callchain_32.c | 196 | ||||
| -rw-r--r-- | arch/powerpc/perf/callchain_64.c | 174 |
5 files changed, 394 insertions, 356 deletions
diff --git a/arch/powerpc/perf/Makefile b/arch/powerpc/perf/Makefile index c155dcbb8691..53d614e98537 100644 --- a/arch/powerpc/perf/Makefile +++ b/arch/powerpc/perf/Makefile @@ -1,6 +1,9 @@ # SPDX-License-Identifier: GPL-2.0 -obj-$(CONFIG_PERF_EVENTS) += callchain.o perf_regs.o +obj-$(CONFIG_PERF_EVENTS) += callchain.o callchain_$(BITS).o perf_regs.o +ifdef CONFIG_COMPAT +obj-$(CONFIG_PERF_EVENTS) += callchain_32.o +endif obj-$(CONFIG_PPC_PERF_CTRS) += core-book3s.o bhrb.o obj64-$(CONFIG_PPC_PERF_CTRS) += ppc970-pmu.o power5-pmu.o \ diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index b5afd0bec4f8..dd5051015008 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -15,11 +15,9 @@ #include <asm/sigcontext.h> #include <asm/ucontext.h> #include <asm/vdso.h> -#ifdef CONFIG_COMPAT -#include "../kernel/ppc32.h" -#endif #include <asm/pte-walk.h> +#include "callchain.h" /* * Is sp valid as the address of the next kernel stack frame after prev_sp? @@ -102,358 +100,6 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re } } -static inline bool invalid_user_sp(unsigned long sp) -{ - unsigned long mask = is_32bit_task() ? 3 : 7; - unsigned long top = STACK_TOP - (is_32bit_task() ? 16 : 32); - - return (!sp || (sp & mask) || (sp > top)); -} - -#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_current_mm_pte(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_user(pte)) - 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; - - if (!probe_user_read(ret, ptr, sizeof(*ret))) - return 0; - - return read_user_stack_slow(ptr, ret, 8); -} - -/* - * 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_ctx *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 < entry->max_stack) { - fp = (unsigned long __user *) sp; - if (invalid_user_sp(sp) || 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_context(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; - } -} - -#else /* CONFIG_PPC64 */ -static int read_user_stack_slow(void __user *ptr, void *buf, int nb) -{ - return 0; -} - -static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry, - struct pt_regs *regs) -{ -} - -#define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE -#define sigcontext32 sigcontext -#define mcontext32 mcontext -#define ucontext32 ucontext -#define compat_siginfo_t struct siginfo - -#endif /* CONFIG_PPC64 */ - -#if defined(CONFIG_PPC32) || defined(CONFIG_COMPAT) -/* - * 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; - - rc = probe_user_read(ret, ptr, sizeof(*ret)); - - if (IS_ENABLED(CONFIG_PPC64) && rc) - return read_user_stack_slow(ptr, ret, 4); - - return rc; -} - -/* - * 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, ®s)) - 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, ®s)) - 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_ctx *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 < entry->max_stack) { - fp = (unsigned int __user *) (unsigned long) sp; - if (invalid_user_sp(sp) || 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_context(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; - } -} -#else /* 32bit */ -static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry, - struct pt_regs *regs) -{} -#endif /* 32bit */ - void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { diff --git a/arch/powerpc/perf/callchain.h b/arch/powerpc/perf/callchain.h new file mode 100644 index 000000000000..7a2cb9e1181a --- /dev/null +++ b/arch/powerpc/perf/callchain.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _POWERPC_PERF_CALLCHAIN_H +#define _POWERPC_PERF_CALLCHAIN_H + +int read_user_stack_slow(void __user *ptr, void *buf, int nb); +void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry, + struct pt_regs *regs); +void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry, + struct pt_regs *regs); + +static inline bool invalid_user_sp(unsigned long sp) +{ + unsigned long mask = is_32bit_task() ? 3 : 7; + unsigned long top = STACK_TOP - (is_32bit_task() ? 16 : 32); + + return (!sp || (sp & mask) || (sp > top)); +} + +#endif /* _POWERPC_PERF_CALLCHAIN_H */ diff --git a/arch/powerpc/perf/callchain_32.c b/arch/powerpc/perf/callchain_32.c new file mode 100644 index 000000000000..8aa951003141 --- /dev/null +++ b/arch/powerpc/perf/callchain_32.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Performance counter callchain support - powerpc architecture code + * + * Copyright © 2009 Paul Mackerras, IBM Corporation. + */ +#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> +#include <asm/pte-walk.h> + +#include "callchain.h" + +#ifdef CONFIG_PPC64 +#include "../kernel/ppc32.h" +#else /* CONFIG_PPC64 */ + +#define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE +#define sigcontext32 sigcontext +#define mcontext32 mcontext +#define ucontext32 ucontext +#define compat_siginfo_t struct siginfo + +#endif /* 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; + + rc = probe_user_read(ret, ptr, sizeof(*ret)); + + if (IS_ENABLED(CONFIG_PPC64) && rc) + return read_user_stack_slow(ptr, ret, 4); + + return rc; +} + +/* + * 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, ®s)) + 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, ®s)) + 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; +} + +void perf_callchain_user_32(struct perf_callchain_entry_ctx *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 < entry->max_stack) { + fp = (unsigned int __user *) (unsigned long) sp; + if (invalid_user_sp(sp) || 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_context(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; + } +} diff --git a/arch/powerpc/perf/callchain_64.c b/arch/powerpc/perf/callchain_64.c new file mode 100644 index 000000000000..df1ffd8b20f2 --- /dev/null +++ b/arch/powerpc/perf/callchain_64.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Performance counter callchain support - powerpc architecture code + * + * Copyright © 2009 Paul Mackerras, IBM Corporation. + */ +#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> +#include <asm/pte-walk.h> + +#include "callchain.h" + +/* + * 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. + */ +int read_user_stack_slow(void __user *ptr, void *buf, int nb) +{ + int ret = -EFAULT; + pgd_t *pgdir; + pte_t *ptep, pte; + unsigned int 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_current_mm_pte(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_user(pte)) + 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; + + if (!probe_user_read(ret, ptr, sizeof(*ret))) + return 0; + + return read_user_stack_slow(ptr, ret, 8); +} + +/* + * 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; +} + +void perf_callchain_user_64(struct perf_callchain_entry_ctx *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 < entry->max_stack) { + fp = (unsigned long __user *) sp; + if (invalid_user_sp(sp) || 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_context(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; + } +} |