arch/arm64/include/asm/ftrace.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * arch/arm64/include/asm/ftrace.h
   4  *
   5  * Copyright (C) 2013 Linaro Limited
   6  * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
   7  */
   8 #ifndef __ASM_FTRACE_H
   9 #define __ASM_FTRACE_H
  10
  11 #include <asm/insn.h>
  12
  13 #define HAVE_FUNCTION_GRAPH_FP_TEST
  14
  15 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
  16 #define ARCH_SUPPORTS_FTRACE_OPS 1
  17 #else
  18 #define MCOUNT_ADDR             ((unsigned long)_mcount)
  19 #endif
  20
  21 /* The BL at the callsite's adjusted rec->ip */
  22 #define MCOUNT_INSN_SIZE        AARCH64_INSN_SIZE
  23
  24 #define FTRACE_PLT_IDX          0
  25 #define FTRACE_REGS_PLT_IDX     1
  26 #define NR_FTRACE_PLTS          2
  27
  28 /*
  29  * Currently, gcc tends to save the link register after the local variables
  30  * on the stack. This causes the max stack tracer to report the function
  31  * frame sizes for the wrong functions. By defining
  32  * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect
  33  * to find the return address on the stack after the local variables have
  34  * been set up.
  35  *
  36  * Note, this may change in the future, and we will need to deal with that
  37  * if it were to happen.
  38  */
  39 #define ARCH_FTRACE_SHIFT_STACK_TRACER 1
  40
  41 #ifndef __ASSEMBLY__
  42 #include <linux/compat.h>
  43
  44 extern void _mcount(unsigned long);
  45 extern void *return_address(unsigned int);
  46
  47 struct dyn_arch_ftrace {
  48         /* No extra data needed for arm64 */
  49 };
  50
  51 extern unsigned long ftrace_graph_call;
  52
  53 extern void return_to_handler(void);
  54
  55 static inline unsigned long ftrace_call_adjust(unsigned long addr)
  56 {
  57         /*
  58          * Adjust addr to point at the BL in the callsite.
  59          * See ftrace_init_nop() for the callsite sequence.
  60          */
  61         if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
  62                 return addr + AARCH64_INSN_SIZE;
  63         /*
  64          * addr is the address of the mcount call instruction.
  65          * recordmcount does the necessary offset calculation.
  66          */
  67         return addr;
  68 }
  69
  70 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
  71 struct dyn_ftrace;
  72 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
  73 #define ftrace_init_nop ftrace_init_nop
  74 #endif
  75
  76 #define ftrace_return_address(n) return_address(n)
  77
  78 /*
  79  * Because AArch32 mode does not share the same syscall table with AArch64,
  80  * tracing compat syscalls may result in reporting bogus syscalls or even
  81  * hang-up, so just do not trace them.
  82  * See kernel/trace/trace_syscalls.c
  83  *
  84  * x86 code says:
  85  * If the user really wants these, then they should use the
  86  * raw syscall tracepoints with filtering.
  87  */
  88 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
  89 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
  90 {
  91         return is_compat_task();
  92 }
  93
  94 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
  95
  96 static inline bool arch_syscall_match_sym_name(const char *sym,
  97                                                const char *name)
  98 {
  99         /*
 100          * Since all syscall functions have __arm64_ prefix, we must skip it.
 101          * However, as we described above, we decided to ignore compat
 102          * syscalls, so we don't care about __arm64_compat_ prefix here.
 103          */
 104         return !strcmp(sym + 8, name);
 105 }
 106 #endif /* ifndef __ASSEMBLY__ */
 107
 108 #endif /* __ASM_FTRACE_H */