121 lines
3.2 KiB
C
121 lines
3.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Performance counter callchain support - powerpc architecture code
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*
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* Copyright © 2009 Paul Mackerras, IBM Corporation.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/perf_event.h>
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#include <linux/percpu.h>
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#include <linux/uaccess.h>
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#include <linux/mm.h>
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#include <asm/ptrace.h>
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#include <asm/sigcontext.h>
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#include <asm/ucontext.h>
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#include <asm/vdso.h>
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#include <asm/pte-walk.h>
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#include "callchain.h"
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static int read_user_stack_64(const unsigned long __user *ptr, unsigned long *ret)
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{
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return __read_user_stack(ptr, ret, sizeof(*ret));
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}
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/*
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* 64-bit user processes use the same stack frame for RT and non-RT signals.
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*/
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struct signal_frame_64 {
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char dummy[__SIGNAL_FRAMESIZE];
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struct ucontext uc;
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unsigned long unused[2];
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unsigned int tramp[6];
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struct siginfo *pinfo;
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void *puc;
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struct siginfo info;
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char abigap[288];
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};
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static int is_sigreturn_64_address(unsigned long nip, unsigned long fp)
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{
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if (nip == fp + offsetof(struct signal_frame_64, tramp))
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return 1;
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if (current->mm->context.vdso &&
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nip == VDSO64_SYMBOL(current->mm->context.vdso, sigtramp_rt64))
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return 1;
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return 0;
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}
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/*
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* Do some sanity checking on the signal frame pointed to by sp.
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* We check the pinfo and puc pointers in the frame.
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*/
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static int sane_signal_64_frame(unsigned long sp)
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{
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struct signal_frame_64 __user *sf;
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unsigned long pinfo, puc;
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sf = (struct signal_frame_64 __user *) sp;
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if (read_user_stack_64((unsigned long __user *) &sf->pinfo, &pinfo) ||
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read_user_stack_64((unsigned long __user *) &sf->puc, &puc))
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return 0;
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return pinfo == (unsigned long) &sf->info &&
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puc == (unsigned long) &sf->uc;
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}
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void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
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struct pt_regs *regs)
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{
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unsigned long sp, next_sp;
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unsigned long next_ip;
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unsigned long lr;
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long level = 0;
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struct signal_frame_64 __user *sigframe;
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unsigned long __user *fp, *uregs;
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next_ip = perf_instruction_pointer(regs);
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lr = regs->link;
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sp = regs->gpr[1];
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perf_callchain_store(entry, next_ip);
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while (entry->nr < entry->max_stack) {
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fp = (unsigned long __user *) sp;
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if (invalid_user_sp(sp) || read_user_stack_64(fp, &next_sp))
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return;
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if (level > 0 && read_user_stack_64(&fp[2], &next_ip))
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return;
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/*
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* Note: the next_sp - sp >= signal frame size check
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* is true when next_sp < sp, which can happen when
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* transitioning from an alternate signal stack to the
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* normal stack.
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*/
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if (next_sp - sp >= sizeof(struct signal_frame_64) &&
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(is_sigreturn_64_address(next_ip, sp) ||
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(level <= 1 && is_sigreturn_64_address(lr, sp))) &&
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sane_signal_64_frame(sp)) {
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/*
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* This looks like an signal frame
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*/
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sigframe = (struct signal_frame_64 __user *) sp;
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uregs = sigframe->uc.uc_mcontext.gp_regs;
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if (read_user_stack_64(&uregs[PT_NIP], &next_ip) ||
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read_user_stack_64(&uregs[PT_LNK], &lr) ||
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read_user_stack_64(&uregs[PT_R1], &sp))
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return;
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level = 0;
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perf_callchain_store_context(entry, PERF_CONTEXT_USER);
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perf_callchain_store(entry, next_ip);
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continue;
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}
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if (level == 0)
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next_ip = lr;
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perf_callchain_store(entry, next_ip);
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++level;
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sp = next_sp;
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}
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}
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