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 */
34 * On 32-bit we just access the address and let hash_page create a
35 * HPTE if necessary, so there is no need to fall back to reading
36 * the page tables. Since this is called at interrupt level,
37 * do_page_fault() won't treat a DSI as a page fault.
39 static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
43 if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
44 ((unsigned long)ptr & 3))
47 rc = probe_user_read(ret, ptr, sizeof(*ret));
49 if (IS_ENABLED(CONFIG_PPC64) && rc)
50 return read_user_stack_slow(ptr, ret, 4);
56 * Layout for non-RT signal frames
58 struct signal_frame_32 {
59 char dummy[__SIGNAL_FRAMESIZE32];
60 struct sigcontext32 sctx;
61 struct mcontext32 mctx;
66 * Layout for RT signal frames
68 struct rt_signal_frame_32 {
69 char dummy[__SIGNAL_FRAMESIZE32 + 16];
70 compat_siginfo_t info;
75 static int is_sigreturn_32_address(unsigned int nip, unsigned int fp)
77 if (nip == fp + offsetof(struct signal_frame_32, mctx.mc_pad))
79 if (vdso32_sigtramp && current->mm->context.vdso_base &&
80 nip == current->mm->context.vdso_base + vdso32_sigtramp)
85 static int is_rt_sigreturn_32_address(unsigned int nip, unsigned int fp)
87 if (nip == fp + offsetof(struct rt_signal_frame_32,
88 uc.uc_mcontext.mc_pad))
90 if (vdso32_rt_sigtramp && current->mm->context.vdso_base &&
91 nip == current->mm->context.vdso_base + vdso32_rt_sigtramp)
96 static int sane_signal_32_frame(unsigned int sp)
98 struct signal_frame_32 __user *sf;
101 sf = (struct signal_frame_32 __user *) (unsigned long) sp;
102 if (read_user_stack_32((unsigned int __user *) &sf->sctx.regs, ®s))
104 return regs == (unsigned long) &sf->mctx;
107 static int sane_rt_signal_32_frame(unsigned int sp)
109 struct rt_signal_frame_32 __user *sf;
112 sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
113 if (read_user_stack_32((unsigned int __user *) &sf->uc.uc_regs, ®s))
115 return regs == (unsigned long) &sf->uc.uc_mcontext;
118 static unsigned int __user *signal_frame_32_regs(unsigned int sp,
119 unsigned int next_sp, unsigned int next_ip)
121 struct mcontext32 __user *mctx = NULL;
122 struct signal_frame_32 __user *sf;
123 struct rt_signal_frame_32 __user *rt_sf;
126 * Note: the next_sp - sp >= signal frame size check
127 * is true when next_sp < sp, for example, when
128 * transitioning from an alternate signal stack to the
131 if (next_sp - sp >= sizeof(struct signal_frame_32) &&
132 is_sigreturn_32_address(next_ip, sp) &&
133 sane_signal_32_frame(sp)) {
134 sf = (struct signal_frame_32 __user *) (unsigned long) sp;
138 if (!mctx && next_sp - sp >= sizeof(struct rt_signal_frame_32) &&
139 is_rt_sigreturn_32_address(next_ip, sp) &&
140 sane_rt_signal_32_frame(sp)) {
141 rt_sf = (struct rt_signal_frame_32 __user *) (unsigned long) sp;
142 mctx = &rt_sf->uc.uc_mcontext;
147 return mctx->mc_gregs;
150 void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
151 struct pt_regs *regs)
153 unsigned int sp, next_sp;
154 unsigned int next_ip;
157 unsigned int __user *fp, *uregs;
159 next_ip = perf_instruction_pointer(regs);
162 perf_callchain_store(entry, next_ip);
164 while (entry->nr < entry->max_stack) {
165 fp = (unsigned int __user *) (unsigned long) sp;
166 if (invalid_user_sp(sp) || read_user_stack_32(fp, &next_sp))
168 if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
171 uregs = signal_frame_32_regs(sp, next_sp, next_ip);
172 if (!uregs && level <= 1)
173 uregs = signal_frame_32_regs(sp, next_sp, lr);
176 * This looks like an signal frame, so restart
177 * the stack trace with the values in it.
179 if (read_user_stack_32(&uregs[PT_NIP], &next_ip) ||
180 read_user_stack_32(&uregs[PT_LNK], &lr) ||
181 read_user_stack_32(&uregs[PT_R1], &sp))
184 perf_callchain_store_context(entry, PERF_CONTEXT_USER);
185 perf_callchain_store(entry, next_ip);
191 perf_callchain_store(entry, next_ip);