| /* Target-dependent code for GNU/Linux running on x86-64, for GDB. |
| |
| Copyright 2001, 2003 Free Software Foundation, Inc. |
| |
| Contributed by Jiri Smid, SuSE Labs. |
| |
| This file is part of GDB. |
| |
| 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 "defs.h" |
| #include "inferior.h" |
| #include "gdbcore.h" |
| #include "regcache.h" |
| #include "osabi.h" |
| |
| #include "gdb_string.h" |
| |
| #include "x86-64-tdep.h" |
| |
| #define LINUX_SIGTRAMP_INSN0 0x48 /* mov $NNNNNNNN, %rax */ |
| #define LINUX_SIGTRAMP_OFFSET0 0 |
| #define LINUX_SIGTRAMP_INSN1 0x0f /* syscall */ |
| #define LINUX_SIGTRAMP_OFFSET1 7 |
| |
| static const unsigned char linux_sigtramp_code[] = |
| { |
| /* mov $__NR_rt_sigreturn, %rax */ |
| LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00, |
| /* syscall */ |
| LINUX_SIGTRAMP_INSN1, 0x05 |
| }; |
| |
| #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) |
| |
| /* If PC is in a sigtramp routine, return the address of the start of |
| the routine. Otherwise, return 0. */ |
| |
| static CORE_ADDR |
| x86_64_linux_sigtramp_start (CORE_ADDR pc) |
| { |
| unsigned char buf[LINUX_SIGTRAMP_LEN]; |
| |
| /* We only recognize a signal trampoline if PC is at the start of |
| one of the two instructions. We optimize for finding the PC at |
| the start, as will be the case when the trampoline is not the |
| first frame on the stack. We assume that in the case where the |
| PC is not at the start of the instruction sequence, there will be |
| a few trailing readable bytes on the stack. */ |
| |
| if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| return 0; |
| |
| if (buf[0] != LINUX_SIGTRAMP_INSN0) |
| { |
| if (buf[0] != LINUX_SIGTRAMP_INSN1) |
| return 0; |
| |
| pc -= LINUX_SIGTRAMP_OFFSET1; |
| |
| if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| return 0; |
| } |
| |
| if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) |
| return 0; |
| |
| return pc; |
| } |
| |
| /* Return whether PC is in a GNU/Linux sigtramp routine. */ |
| |
| static int |
| x86_64_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) |
| { |
| /* If we have NAME, we can optimize the search. The trampoline is |
| named __restore_rt. However, it isn't dynamically exported from |
| the shared C library, so the trampoline may appear to be part of |
| the preceding function. This should always be sigaction, |
| __sigaction, or __libc_sigaction (all aliases to the same |
| function). */ |
| if (name == NULL || strstr (name, "sigaction") != NULL) |
| return (x86_64_linux_sigtramp_start (pc) != 0); |
| |
| return (strcmp ("__restore_rt", name) == 0); |
| } |
| |
| /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
| #define X86_64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40 |
| |
| /* Assuming NEXT_FRAME is a frame following a GNU/Linux sigtramp |
| routine, return the address of the associated sigcontext structure. */ |
| |
| static CORE_ADDR |
| x86_64_linux_sigcontext_addr (struct frame_info *next_frame) |
| { |
| CORE_ADDR sp; |
| char buf[8]; |
| |
| frame_unwind_register (next_frame, SP_REGNUM, buf); |
| sp = extract_unsigned_integer (buf, 8); |
| |
| /* The sigcontext structure is part of the user context. A pointer |
| to the user context is passed as the third argument to the signal |
| handler, i.e. in %rdx. Unfortunately %rdx isn't preserved across |
| function calls so we can't use it. Fortunately the user context |
| is part of the signal frame and the unwound %rsp directly points |
| at it. */ |
| return sp + X86_64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| } |
| |
| |
| /* From <asm/sigcontext.h>. */ |
| static int x86_64_linux_sc_reg_offset[X86_64_NUM_GREGS] = |
| { |
| 13 * 8, /* %rax */ |
| 11 * 8, /* %rbx */ |
| 14 * 8, /* %rcx */ |
| 12 * 8, /* %rdx */ |
| 9 * 8, /* %rsi */ |
| 8 * 8, /* %rdi */ |
| 10 * 8, /* %rbp */ |
| 15 * 8, /* %rsp */ |
| 0 * 8, /* %r8 */ |
| 1 * 8, /* %r9 */ |
| 2 * 8, /* %r10 */ |
| 3 * 8, /* %r11 */ |
| 4 * 8, /* %r12 */ |
| 5 * 8, /* %r13 */ |
| 6 * 8, /* %r14 */ |
| 7 * 8, /* %r15 */ |
| 16 * 8, /* %rip */ |
| 17 * 8, /* %eflags */ |
| -1, /* %ds */ |
| -1, /* %es */ |
| |
| /* FIXME: kettenis/2002030531: The registers %fs and %gs are |
| available in `struct sigcontext'. However, they only occupy two |
| bytes instead of four, which makes using them here rather |
| difficult. Leave them out for now. */ |
| -1, /* %fs */ |
| -1 /* %gs */ |
| }; |
| |
| static void |
| x86_64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| { |
| struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| x86_64_init_abi (info, gdbarch); |
| |
| set_gdbarch_pc_in_sigtramp (gdbarch, x86_64_linux_pc_in_sigtramp); |
| |
| tdep->sigcontext_addr = x86_64_linux_sigcontext_addr; |
| tdep->sc_reg_offset = x86_64_linux_sc_reg_offset; |
| tdep->sc_num_regs = X86_64_NUM_GREGS; |
| } |
| |
| |
| /* Provide a prototype to silence -Wmissing-prototypes. */ |
| extern void _initialize_x86_64_linux_tdep (void); |
| |
| void |
| _initialize_x86_64_linux_tdep (void) |
| { |
| gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_LINUX, |
| x86_64_linux_init_abi); |
| } |