Loading...
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 | // SPDX-License-Identifier: GPL-2.0-or-later /* * dwarf-regs.c : Mapping of DWARF debug register numbers into register names. * Extracted from probe-finder.c * * Written by Masami Hiramatsu <mhiramat@redhat.com> */ #include <stddef.h> #include <errno.h> /* for EINVAL */ #include <string.h> /* for strcmp */ #include <linux/ptrace.h> /* for struct pt_regs */ #include <linux/kernel.h> /* for offsetof */ #include <dwarf-regs.h> /* * See arch/x86/kernel/ptrace.c. * Different from it: * * - Since struct pt_regs is defined differently for user and kernel, * but we want to use 'ax, bx' instead of 'rax, rbx' (which is struct * field name of user's pt_regs), we make REG_OFFSET_NAME to accept * both string name and reg field name. * * - Since accessing x86_32's pt_regs from x86_64 building is difficult * and vise versa, we simply fill offset with -1, so * get_arch_regstr() still works but regs_query_register_offset() * returns error. * The only inconvenience caused by it now is that we are not allowed * to generate BPF prologue for a x86_64 kernel if perf is built for * x86_32. This is really a rare usecase. * * - Order is different from kernel's ptrace.c for get_arch_regstr(). Use * the order defined by dwarf. */ struct pt_regs_offset { const char *name; int offset; }; #define REG_OFFSET_END {.name = NULL, .offset = 0} #ifdef __x86_64__ # define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)} # define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = -1} #else # define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = -1} # define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)} #endif /* TODO: switching by dwarf address size */ #ifndef __x86_64__ static const struct pt_regs_offset x86_32_regoffset_table[] = { REG_OFFSET_NAME_32("%ax", eax), REG_OFFSET_NAME_32("%cx", ecx), REG_OFFSET_NAME_32("%dx", edx), REG_OFFSET_NAME_32("%bx", ebx), REG_OFFSET_NAME_32("$stack", esp), /* Stack address instead of %sp */ REG_OFFSET_NAME_32("%bp", ebp), REG_OFFSET_NAME_32("%si", esi), REG_OFFSET_NAME_32("%di", edi), REG_OFFSET_END, }; #define regoffset_table x86_32_regoffset_table #else static const struct pt_regs_offset x86_64_regoffset_table[] = { REG_OFFSET_NAME_64("%ax", rax), REG_OFFSET_NAME_64("%dx", rdx), REG_OFFSET_NAME_64("%cx", rcx), REG_OFFSET_NAME_64("%bx", rbx), REG_OFFSET_NAME_64("%si", rsi), REG_OFFSET_NAME_64("%di", rdi), REG_OFFSET_NAME_64("%bp", rbp), REG_OFFSET_NAME_64("%sp", rsp), REG_OFFSET_NAME_64("%r8", r8), REG_OFFSET_NAME_64("%r9", r9), REG_OFFSET_NAME_64("%r10", r10), REG_OFFSET_NAME_64("%r11", r11), REG_OFFSET_NAME_64("%r12", r12), REG_OFFSET_NAME_64("%r13", r13), REG_OFFSET_NAME_64("%r14", r14), REG_OFFSET_NAME_64("%r15", r15), REG_OFFSET_END, }; #define regoffset_table x86_64_regoffset_table #endif /* Minus 1 for the ending REG_OFFSET_END */ #define ARCH_MAX_REGS ((sizeof(regoffset_table) / sizeof(regoffset_table[0])) - 1) /* Return architecture dependent register string (for kprobe-tracer) */ const char *get_arch_regstr(unsigned int n) { return (n < ARCH_MAX_REGS) ? regoffset_table[n].name : NULL; } /* Reuse code from arch/x86/kernel/ptrace.c */ /** * regs_query_register_offset() - query register offset from its name * @name: the name of a register * * regs_query_register_offset() returns the offset of a register in struct * pt_regs from its name. If the name is invalid, this returns -EINVAL; */ int regs_query_register_offset(const char *name) { const struct pt_regs_offset *roff; for (roff = regoffset_table; roff->name != NULL; roff++) if (!strcmp(roff->name, name)) return roff->offset; return -EINVAL; } |