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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 | // SPDX-License-Identifier: GPL-2.0 /* * ARM callchain support * * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com> * * This code is based on the ARM OProfile backtrace code. */ #include <linux/perf_event.h> #include <linux/uaccess.h> #include <asm/stacktrace.h> /* * 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 frame_tail *)(xxx->fp)-1 * * This code has been adapted from the ARM OProfile support. */ struct frame_tail { struct frame_tail __user *fp; unsigned long sp; 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; 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 >= buftail.fp) return NULL; return buftail.fp - 1; } void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct frame_tail __user *tail; if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } perf_callchain_store(entry, regs->ARM_pc); if (!current->mm) return; tail = (struct frame_tail __user *)regs->ARM_fp - 1; while ((entry->nr < entry->max_stack) && tail && !((unsigned long)tail & 0x3)) tail = user_backtrace(tail, entry); } /* * Gets called by walk_stackframe() for every stackframe. This will be called * whist unwinding the stackframe and is like a subroutine return so we use * the PC. */ static int callchain_trace(struct stackframe *fr, void *data) { struct perf_callchain_entry_ctx *entry = data; perf_callchain_store(entry, fr->pc); return 0; } void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; if (guest_cbs && guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } arm_get_current_stackframe(regs, &fr); walk_stackframe(&fr, callchain_trace, entry); } unsigned long perf_instruction_pointer(struct pt_regs *regs) { struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); if (guest_cbs && guest_cbs->is_in_guest()) return guest_cbs->get_guest_ip(); return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; if (guest_cbs && guest_cbs->is_in_guest()) { if (guest_cbs->is_user_mode()) 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; } |