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![Christophe Leroy](/assets/img/avatar_default.png)
This is copied from arm64. Instead of using runtime generated signal trampoline offsets, get offsets at buildtime. If the said trampoline doesn't exist, build will fail. So no need to check whether the trampoline exists or not in the VDSO. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/f8bfd6812c3e3678b1cdb4d55a52f9eb022b40d3.1601197618.git.christophe.leroy@csgroup.eu
178 lines
4.5 KiB
C
178 lines
4.5 KiB
C
// 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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#ifdef CONFIG_PPC64
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#include "../kernel/ppc32.h"
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#else /* CONFIG_PPC64 */
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#define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE
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#define sigcontext32 sigcontext
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#define mcontext32 mcontext
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#define ucontext32 ucontext
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#define compat_siginfo_t struct siginfo
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#endif /* CONFIG_PPC64 */
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static int read_user_stack_32(const unsigned int __user *ptr, unsigned int *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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* Layout for non-RT signal frames
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*/
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struct signal_frame_32 {
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char dummy[__SIGNAL_FRAMESIZE32];
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struct sigcontext32 sctx;
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struct mcontext32 mctx;
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int abigap[56];
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};
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/*
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* Layout for RT signal frames
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*/
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struct rt_signal_frame_32 {
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char dummy[__SIGNAL_FRAMESIZE32 + 16];
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compat_siginfo_t info;
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struct ucontext32 uc;
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int abigap[56];
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};
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static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
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{
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if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
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return 1;
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if (current->mm->context.vdso &&
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nip == VDSO32_SYMBOL(current->mm->context.vdso, sigtramp32))
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return 1;
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return 0;
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}
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static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
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{
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if (nip == fp + offsetof(struct rt_signal_frame_32,
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uc.uc_mcontext.mc_pad))
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return 1;
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if (current->mm->context.vdso &&
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nip == VDSO32_SYMBOL(current->mm->context.vdso, sigtramp_rt32))
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return 1;
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return 0;
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}
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static int sane_signal_32_frame(unsigned int sp)
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{
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struct signal_frame_32 __user *sf;
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unsigned int regs;
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sf = (struct signal_frame_32 __user *) (unsigned long) sp;
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if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, ®s))
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return 0;
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return regs == (unsigned long) &sf->mctx;
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}
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static int sane_rt_signal_32_frame(unsigned int sp)
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{
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struct rt_signal_frame_32 __user *sf;
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unsigned int regs;
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sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
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if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, ®s))
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return 0;
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return regs == (unsigned long) &sf->uc.uc_mcontext;
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}
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static unsigned int __user *signal_frame_32_regs(unsigned int sp,
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unsigned int next_sp, unsigned int next_ip)
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{
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struct mcontext32 __user *mctx = NULL;
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struct signal_frame_32 __user *sf;
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struct rt_signal_frame_32 __user *rt_sf;
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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, for example, 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_32) &&
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is_sigreturn_32_address(next_ip, sp) &&
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sane_signal_32_frame(sp)) {
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sf = (struct signal_frame_32 __user *) (unsigned long) sp;
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mctx = &sf->mctx;
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}
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if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) &&
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is_rt_sigreturn_32_address(next_ip, sp) &&
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sane_rt_signal_32_frame(sp)) {
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rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
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mctx = &rt_sf->uc.uc_mcontext;
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}
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if (!mctx)
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return NULL;
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return mctx->mc_gregs;
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}
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void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
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struct pt_regs *regs)
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{
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unsigned int sp, next_sp;
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unsigned int next_ip;
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unsigned int lr;
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long level = 0;
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unsigned int __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 int __user *) (unsigned long) sp;
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if (invalid_user_sp(sp) || read_user_stack_32(fp, &next_sp))
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return;
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if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
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return;
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uregs = signal_frame_32_regs(sp, next_sp, next_ip);
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if (!uregs && level <= 1)
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uregs = signal_frame_32_regs(sp, next_sp, lr);
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if (uregs) {
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/*
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* This looks like an signal frame, so restart
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* the stack trace with the values in it.
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*/
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if (read_user_stack_32(&uregs[PT_NIP], &next_ip) ||
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read_user_stack_32(&uregs[PT_LNK], &lr) ||
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read_user_stack_32(&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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