tools/perf/util/arm64-frame-pointer-unwind-support.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "arm64-frame-pointer-unwind-support.h"
   3 #include "callchain.h"
   4 #include "event.h"
   5 #include "perf_regs.h" // SMPL_REG_MASK
   6 #include "unwind.h"
   7
   8 #define perf_event_arm_regs perf_event_arm64_regs
   9 #include "../../arch/arm64/include/uapi/asm/perf_regs.h"
  10 #undef perf_event_arm_regs
  11
  12 struct entries {
  13         u64 stack[2];
  14         size_t length;
  15 };
  16
  17 static bool get_leaf_frame_caller_enabled(struct perf_sample *sample)
  18 {
  19         return callchain_param.record_mode == CALLCHAIN_FP && sample->user_regs.regs
  20                 && sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_LR);
  21 }
  22
  23 static int add_entry(struct unwind_entry *entry, void *arg)
  24 {
  25         struct entries *entries = arg;
  26
  27         entries->stack[entries->length++] = entry->ip;
  28         return 0;
  29 }
  30
  31 u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thread, int usr_idx)
  32 {
  33         int ret;
  34         struct entries entries = {};
  35         struct regs_dump old_regs = sample->user_regs;
  36
  37         if (!get_leaf_frame_caller_enabled(sample))
  38                 return 0;
  39
  40         /*
  41          * If PC and SP are not recorded, get the value of PC from the stack
  42          * and set its mask. SP is not used when doing the unwinding but it
  43          * still needs to be set to prevent failures.
  44          */
  45
  46         if (!(sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_PC))) {
  47                 sample->user_regs.cache_mask |= SMPL_REG_MASK(PERF_REG_ARM64_PC);
  48                 sample->user_regs.cache_regs[PERF_REG_ARM64_PC] = sample->callchain->ips[usr_idx+1];
  49         }
  50
  51         if (!(sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_SP))) {
  52                 sample->user_regs.cache_mask |= SMPL_REG_MASK(PERF_REG_ARM64_SP);
  53                 sample->user_regs.cache_regs[PERF_REG_ARM64_SP] = 0;
  54         }
  55
  56         ret = unwind__get_entries(add_entry, &entries, thread, sample, 2, true);
  57         sample->user_regs = old_regs;
  58
  59         if (ret || entries.length != 2)
  60                 return ret;
  61
  62         return callchain_param.order == ORDER_CALLER ? entries.stack[0] : entries.stack[1];
  63 }