| /* |
| * dwarf-regs.c : Mapping of DWARF debug register numbers into register names. |
| * Extracted from probe-finder.c |
| * |
| * Written by Masami Hiramatsu <mhiramat@redhat.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| * |
| */ |
| |
| #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 |
| |
| 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, |
| }; |
| |
| 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, |
| }; |
| |
| /* TODO: switching by dwarf address size */ |
| #ifdef __x86_64__ |
| #define regoffset_table x86_64_regoffset_table |
| #else |
| #define regoffset_table x86_32_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; |
| } |