1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Performance counter callchain support - powerpc architecture code |
4 | * |
5 | * Copyright © 2009 Paul Mackerras, IBM Corporation. |
6 | */ |
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> |
12 | #include <linux/mm.h> |
13 | #include <asm/ptrace.h> |
14 | #include <asm/sigcontext.h> |
15 | #include <asm/ucontext.h> |
16 | #include <asm/vdso.h> |
17 | #include <asm/pte-walk.h> |
18 | |
19 | #include "callchain.h" |
20 | |
21 | #ifdef CONFIG_PPC64 |
22 | #include <asm/syscalls_32.h> |
23 | #else /* CONFIG_PPC64 */ |
24 | |
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 |
30 | |
31 | #endif /* CONFIG_PPC64 */ |
32 | |
33 | static int read_user_stack_32(const unsigned int __user *ptr, unsigned int *ret) |
34 | { |
35 | return __read_user_stack(ptr, ret, size: sizeof(*ret)); |
36 | } |
37 | |
38 | /* |
39 | * Layout for non-RT signal frames |
40 | */ |
41 | struct signal_frame_32 { |
42 | char dummy[__SIGNAL_FRAMESIZE32]; |
43 | struct sigcontext32 sctx; |
44 | struct mcontext32 mctx; |
45 | int abigap[56]; |
46 | }; |
47 | |
48 | /* |
49 | * Layout for RT signal frames |
50 | */ |
51 | struct rt_signal_frame_32 { |
52 | char dummy[__SIGNAL_FRAMESIZE32 + 16]; |
53 | compat_siginfo_t info; |
54 | struct ucontext32 uc; |
55 | int abigap[56]; |
56 | }; |
57 | |
58 | static int is_sigreturn_32_address(unsigned int nip, unsigned int fp) |
59 | { |
60 | if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad)) |
61 | return 1; |
62 | if (current->mm->context.vdso && |
63 | nip == VDSO32_SYMBOL(current->mm->context.vdso, sigtramp32)) |
64 | return 1; |
65 | return 0; |
66 | } |
67 | |
68 | static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp) |
69 | { |
70 | if (nip == fp + offsetof(struct rt_signal_frame_32, |
71 | uc.uc_mcontext.mc_pad)) |
72 | return 1; |
73 | if (current->mm->context.vdso && |
74 | nip == VDSO32_SYMBOL(current->mm->context.vdso, sigtramp_rt32)) |
75 | return 1; |
76 | return 0; |
77 | } |
78 | |
79 | static int sane_signal_32_frame(unsigned int sp) |
80 | { |
81 | struct signal_frame_32 __user *sf; |
82 | unsigned int regs; |
83 | |
84 | sf = (struct signal_frame_32 __user *) (unsigned long) sp; |
85 | if (read_user_stack_32(ptr: (unsigned int __user *) &sf->sctx.regs, ret: ®s)) |
86 | return 0; |
87 | return regs == (unsigned long) &sf->mctx; |
88 | } |
89 | |
90 | static int sane_rt_signal_32_frame(unsigned int sp) |
91 | { |
92 | struct rt_signal_frame_32 __user *sf; |
93 | unsigned int regs; |
94 | |
95 | sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp; |
96 | if (read_user_stack_32(ptr: (unsigned int __user *) &sf->uc.uc_regs, ret: ®s)) |
97 | return 0; |
98 | return regs == (unsigned long) &sf->uc.uc_mcontext; |
99 | } |
100 | |
101 | static unsigned int __user *signal_frame_32_regs(unsigned int sp, |
102 | unsigned int next_sp, unsigned int next_ip) |
103 | { |
104 | struct mcontext32 __user *mctx = NULL; |
105 | struct signal_frame_32 __user *sf; |
106 | struct rt_signal_frame_32 __user *rt_sf; |
107 | |
108 | /* |
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 |
112 | * normal stack. |
113 | */ |
114 | if (next_sp - sp >= sizeof(struct signal_frame_32) && |
115 | is_sigreturn_32_address(nip: next_ip, fp: sp) && |
116 | sane_signal_32_frame(sp)) { |
117 | sf = (struct signal_frame_32 __user *) (unsigned long) sp; |
118 | mctx = &sf->mctx; |
119 | } |
120 | |
121 | if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) && |
122 | is_rt_sigreturn_32_address(nip: next_ip, fp: 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; |
126 | } |
127 | |
128 | if (!mctx) |
129 | return NULL; |
130 | return mctx->mc_gregs; |
131 | } |
132 | |
133 | void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry, |
134 | struct pt_regs *regs) |
135 | { |
136 | unsigned int sp, next_sp; |
137 | unsigned int next_ip; |
138 | unsigned int lr; |
139 | long level = 0; |
140 | unsigned int __user *fp, *uregs; |
141 | |
142 | next_ip = perf_instruction_pointer(regs); |
143 | lr = regs->link; |
144 | sp = regs->gpr[1]; |
145 | perf_callchain_store(ctx: entry, ip: next_ip); |
146 | |
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(ptr: fp, ret: &next_sp)) |
150 | return; |
151 | if (level > 0 && read_user_stack_32(ptr: &fp[1], ret: &next_ip)) |
152 | return; |
153 | |
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, next_ip: lr); |
157 | if (uregs) { |
158 | /* |
159 | * This looks like an signal frame, so restart |
160 | * the stack trace with the values in it. |
161 | */ |
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)) |
165 | return; |
166 | level = 0; |
167 | perf_callchain_store_context(ctx: entry, ip: PERF_CONTEXT_USER); |
168 | perf_callchain_store(ctx: entry, ip: next_ip); |
169 | continue; |
170 | } |
171 | |
172 | if (level == 0) |
173 | next_ip = lr; |
174 | perf_callchain_store(ctx: entry, ip: next_ip); |
175 | ++level; |
176 | sp = next_sp; |
177 | } |
178 | } |
179 | |