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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 | // SPDX-License-Identifier: GPL-2.0-only /* * arm64 callchain support * * Copyright (C) 2015 ARM Limited */ #include <linux/perf_event.h> #include <linux/stacktrace.h> #include <linux/uaccess.h> #include <asm/pointer_auth.h> struct frame_tail { struct frame_tail __user *fp; unsigned long lr; } __attribute__((packed)); /* * Get the return address for a single stackframe and return a pointer to the * next frame tail. */ static struct frame_tail __user * user_backtrace(struct frame_tail __user *tail, struct perf_callchain_entry_ctx *entry) { struct frame_tail buftail; unsigned long err; unsigned long lr; /* Also check accessibility of one struct frame_tail beyond */ if (!access_ok(tail, sizeof(buftail))) return NULL; pagefault_disable(); err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail)); pagefault_enable(); if (err) return NULL; lr = ptrauth_strip_insn_pac(buftail.lr); perf_callchain_store(entry, lr); /* * Frame pointers should strictly progress back up the stack * (towards higher addresses). */ if (tail >= buftail.fp) return NULL; return buftail.fp; } #ifdef CONFIG_COMPAT /* * The registers we're interested in are at the end of the variable * length saved register structure. The fp points at the end of this * structure so the address of this struct is: * (struct compat_frame_tail *)(xxx->fp)-1 * * This code has been adapted from the ARM OProfile support. */ struct compat_frame_tail { compat_uptr_t fp; /* a (struct compat_frame_tail *) in compat mode */ u32 sp; u32 lr; } __attribute__((packed)); static struct compat_frame_tail __user * compat_user_backtrace(struct compat_frame_tail __user *tail, struct perf_callchain_entry_ctx *entry) { struct compat_frame_tail buftail; unsigned long err; /* Also check accessibility of one struct frame_tail beyond */ if (!access_ok(tail, sizeof(buftail))) return NULL; pagefault_disable(); err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail)); pagefault_enable(); if (err) return NULL; perf_callchain_store(entry, buftail.lr); /* * Frame pointers should strictly progress back up the stack * (towards higher addresses). */ if (tail + 1 >= (struct compat_frame_tail __user *) compat_ptr(buftail.fp)) return NULL; return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1; } #endif /* CONFIG_COMPAT */ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { if (perf_guest_state()) { /* We don't support guest os callchain now */ return; } perf_callchain_store(entry, regs->pc); if (!compat_user_mode(regs)) { /* AARCH64 mode */ struct frame_tail __user *tail; tail = (struct frame_tail __user *)regs->regs[29]; while (entry->nr < entry->max_stack && tail && !((unsigned long)tail & 0x7)) tail = user_backtrace(tail, entry); } else { #ifdef CONFIG_COMPAT /* AARCH32 compat mode */ struct compat_frame_tail __user *tail; tail = (struct compat_frame_tail __user *)regs->compat_fp - 1; while ((entry->nr < entry->max_stack) && tail && !((unsigned long)tail & 0x3)) tail = compat_user_backtrace(tail, entry); #endif } } static bool callchain_trace(void *data, unsigned long pc) { struct perf_callchain_entry_ctx *entry = data; return perf_callchain_store(entry, pc) == 0; } void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { if (perf_guest_state()) { /* We don't support guest os callchain now */ return; } arch_stack_walk(callchain_trace, entry, current, regs); } unsigned long perf_instruction_pointer(struct pt_regs *regs) { if (perf_guest_state()) return perf_guest_get_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { unsigned int guest_state = perf_guest_state(); int misc = 0; if (guest_state) { if (guest_state & PERF_GUEST_USER) misc |= PERF_RECORD_MISC_GUEST_USER; else misc |= PERF_RECORD_MISC_GUEST_KERNEL; } else { if (user_mode(regs)) misc |= PERF_RECORD_MISC_USER; else misc |= PERF_RECORD_MISC_KERNEL; } return misc; } |