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Diffstat (limited to 'gdb/amd64-gnu-tdep.c')
| -rw-r--r-- | gdb/amd64-gnu-tdep.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/gdb/amd64-gnu-tdep.c b/gdb/amd64-gnu-tdep.c new file mode 100644 index 0000000..435095e --- /dev/null +++ b/gdb/amd64-gnu-tdep.c @@ -0,0 +1,231 @@ +/* Target-dependent code for the GNU Hurd. + Copyright (C) 2024 Free Software Foundation, Inc. + + 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 3 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, see <http://www.gnu.org/licenses/>. */ + +#include "defs.h" +#include "extract-store-integer.h" +#include "gdbcore.h" +#include "osabi.h" +#include "solib-svr4.h" + +#include "amd64-tdep.h" +#include "glibc-tdep.h" + +/* Recognizing signal handler frames. */ + +/* When the GNU/Hurd libc calls a signal handler, the return address points + inside the trampoline assembly snippet. + + If the trampoline function name can not be identified, we resort to reading + memory from the process in order to identify it. */ + +static const gdb_byte gnu_sigtramp_code[] = +{ +/* rpc_wait_trampoline: */ + 0x48, 0xc7, 0xc0, 0xe7, 0xff, 0xff, 0xff, /* mov $-25,%rax */ + 0x0f, 0x05, /* syscall */ + 0x49, 0x89, 0x04, 0x24, /* mov %rax,(%r12) */ + 0x48, 0x89, 0xdc, /* mov %rbx,%rsp */ + +/* trampoline: */ + 0x5f, /* pop %rdi */ + 0x5e, /* pop %rsi */ + 0x5a, /* pop %rdx */ + 0x48, 0x83, 0xc4, 0x08, /* add $0x8,%rsp */ + 0x41, 0xff, 0xd5, /* call *%r13 */ + +/* RA HERE */ + 0x48, 0x8b, 0x7c, 0x24, 0x10, /* mov 0x10(%rsp),%rdi */ + 0xc3, /* ret */ + +/* firewall: */ + 0xf4, /* hlt */ +}; + +#define GNU_SIGTRAMP_LEN (sizeof gnu_sigtramp_code) +#define GNU_SIGTRAMP_TAIL 7 /* length of tail after RA */ + +/* If THIS_FRAME is a sigtramp routine, return the address of the + start of the routine. Otherwise, return 0. */ + +static CORE_ADDR +amd64_gnu_sigtramp_start (frame_info_ptr this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_frame); + gdb_byte buf[GNU_SIGTRAMP_LEN]; + + if (!safe_frame_unwind_memory (this_frame, + pc + GNU_SIGTRAMP_TAIL - GNU_SIGTRAMP_LEN, + buf)) + return 0; + + if (memcmp (buf, gnu_sigtramp_code, GNU_SIGTRAMP_LEN) != 0) + return 0; + + return pc; +} + +/* Return whether THIS_FRAME corresponds to a Hurd sigtramp routine. */ + +static int +amd64_gnu_sigtramp_p (const frame_info_ptr &this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_frame); + const char *name; + + find_pc_partial_function (pc, &name, NULL, NULL); + + /* If we have a NAME, we can check for the trampoline function */ + if (name != NULL && strcmp (name, "trampoline") == 0) + return 1; + + return amd64_gnu_sigtramp_start (this_frame) != 0; +} + +/* Offset to sc_i386_thread_state in sigcontext, from <bits/sigcontext.h>. */ +#define AMD64_GNU_SIGCONTEXT_THREAD_STATE_OFFSET 32 + +/* Assuming THIS_FRAME is a Hurd sigtramp routine, return the + address of the associated sigcontext structure. */ + +static CORE_ADDR +amd64_gnu_sigcontext_addr (const frame_info_ptr &this_frame) +{ + struct gdbarch *gdbarch = get_frame_arch (this_frame); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + CORE_ADDR pc; + CORE_ADDR sp; + gdb_byte buf[8]; + + get_frame_register (this_frame, AMD64_RSP_REGNUM, buf); + sp = extract_unsigned_integer (buf, 8, byte_order); + + pc = amd64_gnu_sigtramp_start (this_frame); + if (pc) + { + CORE_ADDR sigcontext_addr; + + /* The sigcontext structure address is passed as the third argument + * of the signal handler but %RDX is not saved across calls. Luckily, + * the structured is saved underneath the &__sigreturn and a dummy word + * to fill the slot for the address for __sigreturn to return to. + */ + read_memory (sp + 16, buf, 8); + sigcontext_addr = extract_unsigned_integer (buf, 8, byte_order); + return sigcontext_addr + AMD64_GNU_SIGCONTEXT_THREAD_STATE_OFFSET; + } + + error (_("Couldn't recognize signal trampoline.")); + return 0; +} + +/* Mapping between the general-purpose registers in `struct + sigcontext' format (starting at sc_i386_thread_state) + and GDB's register cache layout. */ + +/* From <bits/sigcontext.h>. */ +static int amd64_gnu_sc_reg_offset[] = +{ + 15 * 8, /* %rax */ + 12 * 8, /* %rbx */ + 14 * 8, /* %rcx */ + 13 * 8, /* %rdx */ + 10 * 8, /* %rsi */ + 9 * 8, /* %rdi */ + 10 * 8, /* %rbp */ + 11 * 8, /* %rsp */ + 0 * 8, /* %r8 ... */ + 8 * 8, + 7 * 8, + 6 * 8, + 3 * 8, + 2 * 8, + 1 * 8, + 0 * 8, /* ... %r15 */ + 16 * 8, /* %rip */ + 18 * 8, /* %eflags */ + 17 * 8, /* %cs */ +}; + +/* From <sys/ucontext.h>. */ +static int amd64_gnu_gregset_reg_offset[] = +{ + 10 * 8, /* %rax */ + 5 * 8, /* %rbx */ + 11 * 8, /* %rcx */ + 12 * 8, /* %rdx */ + 13 * 8, /* %rsi */ + 14 * 8, /* %rdi */ + 4 * 8, /* %rbp */ + 19 * 8, /* %rsp */ + 9 * 8, /* %r8 ... */ + 8 * 8, + 7 * 8, + 6 * 8, + 3 * 8, + 2 * 8, + 1 * 8, + 0 * 8, /* ... %r15 */ + 16 * 8, /* %rip */ + 18 * 8, /* %eflags */ + 17 * 8, /* %cs */ + -1, /* %ss */ + -1, /* %ds */ + -1, /* %es */ + -1, /* %fs */ + -1, /* %gs */ +}; + +static void +amd64_gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) +{ + i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch); + + amd64_init_abi (info, gdbarch, + amd64_target_description (X86_XSTATE_SSE_MASK, true)); + + /* Enable TLS support. */ + set_gdbarch_fetch_tls_load_module_address (gdbarch, + svr4_fetch_objfile_link_map); + + /* Hurd uses SVR4-style shared libraries. */ + set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); + + /* Hurd uses the dynamic linker included in the GNU C Library. */ + set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); + + tdep->gregset_reg_offset = amd64_gnu_gregset_reg_offset; + tdep->gregset_num_regs = ARRAY_SIZE (amd64_gnu_gregset_reg_offset); + tdep->sizeof_gregset = 21 * 8; /* sizeof (struct i386_thread_state); */ + + tdep->sigtramp_p = amd64_gnu_sigtramp_p; + tdep->sigcontext_addr = amd64_gnu_sigcontext_addr; + tdep->sc_reg_offset = amd64_gnu_sc_reg_offset; + tdep->sc_num_regs = ARRAY_SIZE (amd64_gnu_sc_reg_offset); + + /* Hurd uses SVR4-style shared libraries. */ + set_solib_svr4_fetch_link_map_offsets + (gdbarch, svr4_lp64_fetch_link_map_offsets); +} + +void _initialize_amd64_gnu_tdep (); +void +_initialize_amd64_gnu_tdep () +{ + gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, + GDB_OSABI_HURD, amd64_gnu_init_abi); +} |