arch/arm64/kernel/perf_regs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/errno.h>
   3 #include <linux/kernel.h>
   4 #include <linux/perf_event.h>
   5 #include <linux/bug.h>
   6 #include <linux/sched/task_stack.h>
   7
   8 #include <asm/compat.h>
   9 #include <asm/perf_regs.h>
  10 #include <asm/ptrace.h>
  11
  12 u64 perf_reg_value(struct pt_regs *regs, int idx)
  13 {
  14         if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
  15                 return 0;
  16
  17         /*
  18          * Compat (i.e. 32 bit) mode:
  19          * - PC has been set in the pt_regs struct in kernel_entry,
  20          * - Handle SP and LR here.
  21          */
  22         if (compat_user_mode(regs)) {
  23                 if ((u32)idx == PERF_REG_ARM64_SP)
  24                         return regs->compat_sp;
  25                 if ((u32)idx == PERF_REG_ARM64_LR)
  26                         return regs->compat_lr;
  27         }
  28
  29         if ((u32)idx == PERF_REG_ARM64_SP)
  30                 return regs->sp;
  31
  32         if ((u32)idx == PERF_REG_ARM64_PC)
  33                 return regs->pc;
  34
  35         return regs->regs[idx];
  36 }
  37
  38 #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
  39
  40 int perf_reg_validate(u64 mask)
  41 {
  42         if (!mask || mask & REG_RESERVED)
  43                 return -EINVAL;
  44
  45         return 0;
  46 }
  47
  48 u64 perf_reg_abi(struct task_struct *task)
  49 {
  50         if (is_compat_thread(task_thread_info(task)))
  51                 return PERF_SAMPLE_REGS_ABI_32;
  52         else
  53                 return PERF_SAMPLE_REGS_ABI_64;
  54 }
  55
  56 void perf_get_regs_user(struct perf_regs *regs_user,
  57                         struct pt_regs *regs,
  58                         struct pt_regs *regs_user_copy)
  59 {
  60         regs_user->regs = task_pt_regs(current);
  61         regs_user->abi = perf_reg_abi(current);
  62 }