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c55a47e723
Ref: https://sourceware.org/ml/gdb-patches/2017-07/msg00162.html Debugging x86-64 GNU/Linux programs currently crashes GDB in tdesc_use_registers during gdbarch initialization: Program received signal SIGSEGV, Segmentation fault. 0x0000000001093eaf in htab_remove_elt_with_hash (htab=0x2ef9fa0, element=0x26af960, hash=557151073) at src/libiberty/hashtab.c:728 728 if (*slot == HTAB_EMPTY_ENTRY) (top-gdb) p slot $1 = (void **) 0x0 (top-gdb) bt #0 0x0000000001093eaf in htab_remove_elt_with_hash (htab=0x2ef9fa0, element=0x26af960, hash=557151073) at src/libiberty/hashtab.c:728 #1 0x0000000001093e79 in htab_remove_elt (htab=0x2ef9fa0, element=0x26af960) at src/libiberty/hashtab.c:714 #2 0x00000000009121b0 in tdesc_use_registers (gdbarch=0x3001240, target_desc=0x2659cb0, early_data=0x2881cb0) at src/gdb/target-descriptions.c:1328 #3 0x000000000047c93e in i386_gdbarch_init (info=..., arches=0x0) at src/gdb/i386-tdep.c:8634 #4 0x0000000000818d5f in gdbarch_find_by_info (info=...) at src/gdb/gdbarch.c:5394 #5 0x00000000007198a8 in set_gdbarch_from_file (abfd=0x2f48250) at src/gdb/arch-utils.c:618 #6 0x00000000007f21cb in exec_file_attach (filename=0x7fffffffddb0 "/home/pedro/gdb/tests/threads", from_tty=1) at src/gdb/exec.c:380 #7 0x0000000000865c18 in catch_command_errors_const (command=0x7f1d83 <exec_file_attach(char const*, int)>, arg=0x7fffffffddb0 "/home/pedro/gdb/tests/threads", from_tty=1) at src/gdb/main.c:403 #8 0x00000000008669cf in captured_main_1 (context=0x7fffffffd860) at src/gdb/main.c:1035 #9 0x0000000000866de2 in captured_main (data=0x7fffffffd860) at src/gdb/main.c:1142 #10 0x0000000000866e24 in gdb_main (args=0x7fffffffd860) at src/gdb/main.c:1160 #11 0x000000000041312d in main (argc=3, argv=0x7fffffffd968) at src/gdb/gdb.c:32 The direct cause of the crash is that we tried to remove an element from the hash which supposedly exists, but does not. (htab_remove_elt shouldn't really crash in this case, but that's secondary.) The real problem is that early_data passed to tdesc_use_registers includes regs from a target description that is not the target_desc, which violates its assumptions. The registers in question are the fs_base/gs_base registers, added by amd64_init_abi: tdesc_numbered_register (feature, tdesc_data_segments, AMD64_FSBASE_REGNUM, "fs_base"); tdesc_numbered_register (feature, tdesc_data_segments, AMD64_GSBASE_REGNUM, "gs_base"); and that happens because amd64_linux_init_abi uses amd64_init_abi as helper, but they don't coordinate on which fallback tdesc to use. amd64_init_abi does: if (! tdesc_has_registers (tdesc)) tdesc = tdesc_amd64; and then adds the fs_base/gs_base registers of the "tdesc_amd64" tdesc to the tdesc_arch_data. After amd64_init_abi returns, amd64_linux_init_abi does: if (! tdesc_has_registers (tdesc)) tdesc = tdesc_amd64_linux; tdep->tdesc = tdesc; and we end up tdesc_amd64_linux installed in tdep->tdesc. The fix is to make sure that amd64_linux_init_abi and amd64_init_abi agree on default tdesc, by adding a "default tdesc" parameter to amd64_init_abi, instead of having amd64_init_abi hardcode a default. With this, amd64_init_abi creates the fs_base/gs_base registers using the tdesc_amd64_linux tdesc. Tested on x86-64 GNU/Linux, -m64. I don't have an x32 setup handy. Thanks to John Baldwin, Yao Qi and Simon Marchi for the investigation. gdb/ChangeLog: 2017-07-13 Pedro Alves <palves@redhat.com> * amd64-darwin-tdep.c (x86_darwin_init_abi_64): Pass tdesc_amd64 as default tdesc. * amd64-dicos-tdep.c (amd64_dicos_init_abi): * amd64-fbsd-tdep.c (amd64fbsd_init_abi): * amd64-linux-tdep.c (amd64_linux_init_abi): Pass tdesc_amd64_linux as default tdesc. Get final tdesc from the tdep. (amd64_x32_linux_init_abi): Pass tdesc_x32_linux as default tdesc. Get final tdesc from the tdep. * amd64-nbsd-tdep.c (amd64nbsd_init_abi): Pass tdesc_amd64 as default tdesc. * amd64-obsd-tdep.c (amd64obsd_init_abi): Likewise. * amd64-sol2-tdep.c (amd64_sol2_init_abi): Likewise. * amd64-tdep.c (amd64_init_abi): Add 'default_tdesc' parameter. Use it as default tdesc. (amd64_x32_init_abi): Add 'default_tdesc' parameter, and pass it down to amd_init_abi. No longer handle fallback tdesc here. * amd64-tdep.h (tdesc_x32): Declare. (amd64_init_abi, amd64_x32_init_abi): Add 'default_tdesc' parameter. * amd64-windows-tdep.c (amd64_windows_init_abi): Pass tdesc_amd64 as default tdesc.
155 lines
5.2 KiB
C
155 lines
5.2 KiB
C
/* Target-dependent definitions for AMD64.
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Copyright (C) 2001-2017 Free Software Foundation, Inc.
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Contributed by Jiri Smid, SuSE Labs.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef AMD64_TDEP_H
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#define AMD64_TDEP_H
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struct gdbarch;
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struct frame_info;
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struct regcache;
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#include "i386-tdep.h"
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/* Register numbers of various important registers. */
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enum amd64_regnum
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{
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AMD64_RAX_REGNUM, /* %rax */
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AMD64_RBX_REGNUM, /* %rbx */
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AMD64_RCX_REGNUM, /* %rcx */
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AMD64_RDX_REGNUM, /* %rdx */
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AMD64_RSI_REGNUM, /* %rsi */
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AMD64_RDI_REGNUM, /* %rdi */
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AMD64_RBP_REGNUM, /* %rbp */
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AMD64_RSP_REGNUM, /* %rsp */
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AMD64_R8_REGNUM, /* %r8 */
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AMD64_R9_REGNUM, /* %r9 */
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AMD64_R10_REGNUM, /* %r10 */
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AMD64_R11_REGNUM, /* %r11 */
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AMD64_R12_REGNUM, /* %r12 */
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AMD64_R13_REGNUM, /* %r13 */
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AMD64_R14_REGNUM, /* %r14 */
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AMD64_R15_REGNUM, /* %r15 */
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AMD64_RIP_REGNUM, /* %rip */
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AMD64_EFLAGS_REGNUM, /* %eflags */
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AMD64_CS_REGNUM, /* %cs */
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AMD64_SS_REGNUM, /* %ss */
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AMD64_DS_REGNUM, /* %ds */
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AMD64_ES_REGNUM, /* %es */
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AMD64_FS_REGNUM, /* %fs */
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AMD64_GS_REGNUM, /* %gs */
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AMD64_ST0_REGNUM = 24, /* %st0 */
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AMD64_ST1_REGNUM, /* %st1 */
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AMD64_FCTRL_REGNUM = AMD64_ST0_REGNUM + 8,
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AMD64_FSTAT_REGNUM = AMD64_ST0_REGNUM + 9,
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AMD64_FTAG_REGNUM = AMD64_ST0_REGNUM + 10,
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AMD64_XMM0_REGNUM = 40, /* %xmm0 */
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AMD64_XMM1_REGNUM, /* %xmm1 */
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AMD64_MXCSR_REGNUM = AMD64_XMM0_REGNUM + 16,
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AMD64_YMM0H_REGNUM, /* %ymm0h */
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AMD64_YMM15H_REGNUM = AMD64_YMM0H_REGNUM + 15,
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AMD64_BND0R_REGNUM = AMD64_YMM15H_REGNUM + 1,
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AMD64_BND3R_REGNUM = AMD64_BND0R_REGNUM + 3,
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AMD64_BNDCFGU_REGNUM,
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AMD64_BNDSTATUS_REGNUM,
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AMD64_XMM16_REGNUM,
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AMD64_XMM31_REGNUM = AMD64_XMM16_REGNUM + 15,
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AMD64_YMM16H_REGNUM,
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AMD64_YMM31H_REGNUM = AMD64_YMM16H_REGNUM + 15,
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AMD64_K0_REGNUM,
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AMD64_K7_REGNUM = AMD64_K0_REGNUM + 7,
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AMD64_ZMM0H_REGNUM,
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AMD64_ZMM31H_REGNUM = AMD64_ZMM0H_REGNUM + 31,
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AMD64_PKRU_REGNUM,
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AMD64_FSBASE_REGNUM,
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AMD64_GSBASE_REGNUM
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};
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/* Number of general purpose registers. */
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#define AMD64_NUM_GREGS 24
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#define AMD64_NUM_REGS (AMD64_GSBASE_REGNUM + 1)
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extern struct target_desc *tdesc_amd64;
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extern struct target_desc *tdesc_x32;
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extern struct displaced_step_closure *amd64_displaced_step_copy_insn
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(struct gdbarch *gdbarch, CORE_ADDR from, CORE_ADDR to,
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struct regcache *regs);
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extern void amd64_displaced_step_fixup (struct gdbarch *gdbarch,
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struct displaced_step_closure *closure,
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CORE_ADDR from, CORE_ADDR to,
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struct regcache *regs);
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/* Initialize the ABI for amd64. Uses DEFAULT_TDESC as fallback
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tdesc, if INFO does not specify one. */
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extern void amd64_init_abi (struct gdbarch_info info,
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struct gdbarch *gdbarch,
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target_desc *default_tdesc);
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/* Initialize the ABI for x32. Uses DEFAULT_TDESC as fallback tdesc,
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if INFO does not specify one. */
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extern void amd64_x32_init_abi (struct gdbarch_info info,
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struct gdbarch *gdbarch,
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target_desc *default_tdesc);
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extern const struct target_desc *amd64_target_description (uint64_t xcr0);
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/* Fill register REGNUM in REGCACHE with the appropriate
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floating-point or SSE register value from *FXSAVE. If REGNUM is
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-1, do this for all registers. This function masks off any of the
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reserved bits in *FXSAVE. */
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extern void amd64_supply_fxsave (struct regcache *regcache, int regnum,
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const void *fxsave);
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/* Similar to amd64_supply_fxsave, but use XSAVE extended state. */
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extern void amd64_supply_xsave (struct regcache *regcache, int regnum,
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const void *xsave);
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/* Fill register REGNUM (if it is a floating-point or SSE register) in
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*FXSAVE with the value from REGCACHE. If REGNUM is -1, do this for
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all registers. This function doesn't touch any of the reserved
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bits in *FXSAVE. */
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extern void amd64_collect_fxsave (const struct regcache *regcache, int regnum,
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void *fxsave);
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/* Similar to amd64_collect_fxsave, but use XSAVE extended state. */
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extern void amd64_collect_xsave (const struct regcache *regcache,
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int regnum, void *xsave, int gcore);
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/* Floating-point register set. */
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extern const struct regset amd64_fpregset;
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/* Variables exported from amd64-linux-tdep.c. */
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extern int amd64_linux_gregset_reg_offset[];
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/* Variables exported from amd64-nbsd-tdep.c. */
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extern int amd64nbsd_r_reg_offset[];
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/* Variables exported from amd64-obsd-tdep.c. */
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extern int amd64obsd_r_reg_offset[];
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/* Variables exported from amd64-fbsd-tdep.c. */
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extern CORE_ADDR amd64fbsd_sigtramp_start_addr;
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extern CORE_ADDR amd64fbsd_sigtramp_end_addr;
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extern int amd64fbsd_sc_reg_offset[];
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#endif /* amd64-tdep.h */
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