diff options
Diffstat (limited to 'tools/perf/arch/x86/util/dwarf-regs.c')
| -rw-r--r-- | tools/perf/arch/x86/util/dwarf-regs.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/tools/perf/arch/x86/util/dwarf-regs.c b/tools/perf/arch/x86/util/dwarf-regs.c new file mode 100644 index 000000000..1f86ee8fb --- /dev/null +++ b/tools/perf/arch/x86/util/dwarf-regs.c @@ -0,0 +1,129 @@ +/* + * 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 + +/* 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; +} |