1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Performance counter callchain support - powerpc architecture code
5 * Copyright © 2009 Paul Mackerras, IBM Corporation.
7 #include <linux/kernel.h>
8 #include <linux/sched.h>
9 #include <linux/perf_event.h>
10 #include <linux/percpu.h>
11 #include <linux/uaccess.h>
13 #include <asm/ptrace.h>
14 #include <asm/sigcontext.h>
15 #include <asm/ucontext.h>
17 #include <asm/pte-walk.h>
19 #include "callchain.h"
22 #include "../kernel/ppc32.h"
23 #else /* CONFIG_PPC64 */
25 #define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE
26 #define sigcontext32 sigcontext
27 #define mcontext32 mcontext
28 #define ucontext32 ucontext
29 #define compat_siginfo_t struct siginfo
31 #endif /* CONFIG_PPC64 */
33 static int read_user_stack_32(const unsigned int __user *ptr, unsigned int *ret)
35 return __read_user_stack(ptr, ret, sizeof(*ret));
39 * Layout for non-RT signal frames
41 struct signal_frame_32 {
42 char dummy[__SIGNAL_FRAMESIZE32];
43 struct sigcontext32 sctx;
44 struct mcontext32 mctx;
49 * Layout for RT signal frames
51 struct rt_signal_frame_32 {
52 char dummy[__SIGNAL_FRAMESIZE32 + 16];
53 compat_siginfo_t info;
58 static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
60 if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
62 if (current->mm->context.vdso &&
63 nip == VDSO32_SYMBOL(current->mm->context.vdso, sigtramp32))
68 static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
70 if (nip == fp + offsetof(struct rt_signal_frame_32,
71 uc.uc_mcontext.mc_pad))
73 if (current->mm->context.vdso &&
74 nip == VDSO32_SYMBOL(current->mm->context.vdso, sigtramp_rt32))
79 static int sane_signal_32_frame(unsigned int sp)
81 struct signal_frame_32 __user *sf;
84 sf = (struct signal_frame_32 __user *) (unsigned long) sp;
85 if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, ®s))
87 return regs == (unsigned long) &sf->mctx;
90 static int sane_rt_signal_32_frame(unsigned int sp)
92 struct rt_signal_frame_32 __user *sf;
95 sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
96 if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, ®s))
98 return regs == (unsigned long) &sf->uc.uc_mcontext;
101 static unsigned int __user *signal_frame_32_regs(unsigned int sp,
102 unsigned int next_sp, unsigned int next_ip)
104 struct mcontext32 __user *mctx = NULL;
105 struct signal_frame_32 __user *sf;
106 struct rt_signal_frame_32 __user *rt_sf;
109 * Note: the next_sp - sp >= signal frame size check
110 * is true when next_sp < sp, for example, when
111 * transitioning from an alternate signal stack to the
114 if (next_sp - sp >= sizeof(struct signal_frame_32) &&
115 is_sigreturn_32_address(next_ip, sp) &&
116 sane_signal_32_frame(sp)) {
117 sf = (struct signal_frame_32 __user *) (unsigned long) sp;
121 if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) &&
122 is_rt_sigreturn_32_address(next_ip, sp) &&
123 sane_rt_signal_32_frame(sp)) {
124 rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
125 mctx = &rt_sf->uc.uc_mcontext;
130 return mctx->mc_gregs;
133 void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
134 struct pt_regs *regs)
136 unsigned int sp, next_sp;
137 unsigned int next_ip;
140 unsigned int __user *fp, *uregs;
142 next_ip = perf_instruction_pointer(regs);
145 perf_callchain_store(entry, next_ip);
147 while (entry->nr < entry->max_stack) {
148 fp = (unsigned int __user *) (unsigned long) sp;
149 if (invalid_user_sp(sp) || read_user_stack_32(fp, &next_sp))
151 if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
154 uregs = signal_frame_32_regs(sp, next_sp, next_ip);
155 if (!uregs && level <= 1)
156 uregs = signal_frame_32_regs(sp, next_sp, lr);
159 * This looks like an signal frame, so restart
160 * the stack trace with the values in it.
162 if (read_user_stack_32(&uregs[PT_NIP], &next_ip) ||
163 read_user_stack_32(&uregs[PT_LNK], &lr) ||
164 read_user_stack_32(&uregs[PT_R1], &sp))
167 perf_callchain_store_context(entry, PERF_CONTEXT_USER);
168 perf_callchain_store(entry, next_ip);
174 perf_callchain_store(entry, next_ip);