/* Target-dependent code for OpenBSD/amd64. Copyright 2003, 2004, 2005 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 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 "frame.h" #include "frame-unwind.h" #include "gdbcore.h" #include "symtab.h" #include "objfiles.h" #include "osabi.h" #include "regcache.h" #include "regset.h" #include "target.h" #include "trad-frame.h" #include "gdb_assert.h" #include "gdb_string.h" #include "amd64-tdep.h" #include "i387-tdep.h" #include "solib-svr4.h" #include "bsd-uthread.h" /* Support for core dumps. */ static void amd64obsd_supply_regset (const struct regset *regset, struct regcache *regcache, int regnum, const void *regs, size_t len) { const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch); gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE); i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); amd64_supply_fxsave (regcache, regnum, (char *)regs + tdep->sizeof_gregset); } static const struct regset * amd64obsd_regset_from_core_section (struct gdbarch *gdbarch, const char *sect_name, size_t sect_size) { struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); /* OpenBSD core dumps don't use seperate register sets for the general-purpose and floating-point registers. */ if (strcmp (sect_name, ".reg") == 0 && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE) { if (tdep->gregset == NULL) tdep->gregset = regset_alloc (gdbarch, amd64obsd_supply_regset, NULL); return tdep->gregset; } return NULL; } /* Support for signal handlers. */ /* Default page size. */ static const int amd64obsd_page_size = 4096; /* Offset for sigreturn(2). */ static const int amd64obsd_sigreturn_offset[] = { 9, /* OpenBSD 6.4+ */ 6, /* OpenBSD 5.1+ */ 7, /* OpenBSD 5.1+ */ -1 }; /* Return whether the frame preceding NEXT_FRAME corresponds to an OpenBSD sigtramp routine. */ static int amd64obsd_sigtramp_p (struct frame_info *next_frame) { CORE_ADDR pc = frame_pc_unwind (next_frame); CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1)); const char sigreturn[] = { 0x48, 0xc7, 0xc0, 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */ 0x0f, 0x05 /* syscall */ }; char buf[sizeof sigreturn]; const int *offset; char *name; /* If the function has a valid symbol name, it isn't a trampoline. */ find_pc_partial_function (pc, &name, NULL, NULL); if (name != NULL) return 0; /* If the function lives in a valid section (even without a starting point) it isn't a trampoline. */ if (find_pc_section (pc) != NULL) return 0; for (offset = amd64obsd_sigreturn_offset; *offset != -1; offset++) { if (!safe_frame_unwind_memory (next_frame, start_pc + *offset, buf, sizeof buf)) continue; /* Check for sigreturn(2). */ if (memcmp (buf, sigreturn, sizeof sigreturn)) continue; return 1; } return 0; } /* Assuming NEXT_FRAME is for a frame following a BSD sigtramp routine, return the address of the associated sigcontext structure. */ static CORE_ADDR amd64obsd_sigcontext_addr (struct frame_info *next_frame) { CORE_ADDR pc = frame_pc_unwind (next_frame); ULONGEST offset = (pc & (amd64obsd_page_size - 1)); /* The %rsp register points at `struct sigcontext' upon entry of a signal trampoline. The relevant part of the trampoline is call *%rax movq %rsp, %rdi pushq %rdi movq $SYS_sigreturn,%rax int $0x80 (see /usr/src/sys/arch/amd64/amd64/locore.S). The `pushq' instruction clobbers %rsp, but its value is saved in `%rdi'. */ if (offset > 5) return frame_unwind_register_unsigned (next_frame, AMD64_RDI_REGNUM); else return frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM); } /* OpenBSD 3.5 or later. */ /* Mapping between the general-purpose registers in `struct reg' format and GDB's register cache layout. */ /* From . */ int amd64obsd_r_reg_offset[] = { 14 * 8, /* %rax */ 13 * 8, /* %rbx */ 3 * 8, /* %rcx */ 2 * 8, /* %rdx */ 1 * 8, /* %rsi */ 0 * 8, /* %rdi */ 12 * 8, /* %rbp */ 15 * 8, /* %rsp */ 4 * 8, /* %r8 .. */ 5 * 8, 6 * 8, 7 * 8, 8 * 8, 9 * 8, 10 * 8, 11 * 8, /* ... %r15 */ 16 * 8, /* %rip */ 17 * 8, /* %eflags */ 18 * 8, /* %cs */ 19 * 8, /* %ss */ 20 * 8, /* %ds */ 21 * 8, /* %es */ 22 * 8, /* %fs */ 23 * 8 /* %gs */ }; /* From . */ static int amd64obsd_sc_reg_offset[] = { 14 * 8, /* %rax */ 13 * 8, /* %rbx */ 3 * 8, /* %rcx */ 2 * 8, /* %rdx */ 1 * 8, /* %rsi */ 0 * 8, /* %rdi */ 12 * 8, /* %rbp */ 24 * 8, /* %rsp */ 4 * 8, /* %r8 ... */ 5 * 8, 6 * 8, 7 * 8, 8 * 8, 9 * 8, 10 * 8, 11 * 8, /* ... %r15 */ 21 * 8, /* %rip */ 23 * 8, /* %eflags */ 22 * 8, /* %cs */ 25 * 8, /* %ss */ 18 * 8, /* %ds */ 17 * 8, /* %es */ 16 * 8, /* %fs */ 15 * 8 /* %gs */ }; /* From /usr/src/lib/libpthread/arch/amd64/uthread_machdep.c. */ static int amd64obsd_uthread_reg_offset[] = { 19 * 8, /* %rax */ 16 * 8, /* %rbx */ 18 * 8, /* %rcx */ 17 * 8, /* %rdx */ 14 * 8, /* %rsi */ 13 * 8, /* %rdi */ 15 * 8, /* %rbp */ -1, /* %rsp */ 12 * 8, /* %r8 ... */ 11 * 8, 10 * 8, 9 * 8, 8 * 8, 7 * 8, 6 * 8, 5 * 8, /* ... %r15 */ 20 * 8, /* %rip */ 4 * 8, /* %eflags */ 21 * 8, /* %cs */ -1, /* %ss */ 3 * 8, /* %ds */ 2 * 8, /* %es */ 1 * 8, /* %fs */ 0 * 8 /* %gs */ }; /* Offset within the thread structure where we can find the saved stack pointer (%esp). */ #define AMD64OBSD_UTHREAD_RSP_OFFSET 400 static void amd64obsd_supply_uthread (struct regcache *regcache, int regnum, CORE_ADDR addr, int ctx_offset) { CORE_ADDR sp_addr = addr + ctx_offset; CORE_ADDR sp = 0; char buf[8]; int i; gdb_assert (regnum >= -1); /* if ctx_offset is 0 use old fixed offset */ if (ctx_offset == 0) sp_addr += AMD64OBSD_UTHREAD_RSP_OFFSET; if (regnum == -1 || regnum == AMD64_RSP_REGNUM) { int offset; /* Fetch stack pointer from thread structure. */ sp = read_memory_unsigned_integer (sp_addr, 8); /* Adjust the stack pointer such that it looks as if we just returned from _thread_machdep_switch. */ offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8; store_unsigned_integer (buf, 8, sp + offset); regcache_raw_supply (regcache, AMD64_RSP_REGNUM, buf); } for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++) { if (amd64obsd_uthread_reg_offset[i] != -1 && (regnum == -1 || regnum == i)) { /* Fetch stack pointer from thread structure (if we didn't do so already). */ if (sp == 0) sp = read_memory_unsigned_integer (sp_addr, 8); /* Read the saved register from the stack frame. */ read_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8); regcache_raw_supply (regcache, i, buf); } } } static void amd64obsd_collect_uthread (const struct regcache *regcache, int regnum, CORE_ADDR addr, int ctx_offset) { CORE_ADDR sp_addr = addr + ctx_offset; CORE_ADDR sp = 0; char buf[8]; int i; gdb_assert (regnum >= -1); /* if ctx_offset is 0 use old fixed offset */ if (ctx_offset == 0) sp_addr += AMD64OBSD_UTHREAD_RSP_OFFSET; if (regnum == -1 || regnum == AMD64_RSP_REGNUM) { int offset; /* Calculate the stack pointer (frame pointer) that will be stored into the thread structure. */ offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8; regcache_raw_collect (regcache, AMD64_RSP_REGNUM, buf); sp = extract_unsigned_integer (buf, 8) - offset; /* Store the stack pointer. */ write_memory_unsigned_integer (sp_addr, 8, sp); /* The stack pointer was (potentially) modified. Make sure we build a proper stack frame. */ regnum = -1; } for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++) { if (amd64obsd_uthread_reg_offset[i] != -1 && (regnum == -1 || regnum == i)) { /* Fetch stack pointer from thread structure (if we didn't calculate it already). */ if (sp == 0) sp = read_memory_unsigned_integer (sp_addr, 8); /* Write the register into the stack frame. */ regcache_raw_collect (regcache, i, buf); write_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8); } } } /* Kernel debugging support. */ /* From */ static int amd64obsd_tf_reg_offset[] = { 14 * 8, /* %rax */ 13 * 8, /* %rbx */ 3 * 8, /* %rcx */ 2 * 8, /* %rdx */ 1 * 8, /* %rsi */ 0 * 8, /* %rdi */ 16 * 8, /* %rbp */ 20 * 8, /* %rsp */ 4 * 8, /* %r8 ... */ 5 * 8, 6 * 8, 7 * 8, 8 * 8, 9 * 8, 10 * 8, 11 * 8, /* ... %r15 */ 17 * 8, /* %rip */ 19 * 8, /* %rflags */ 18 * 8, /* %cs */ 21 * 8, /* %ss */ }; static int amd64obsd_fromspllower_reg_offset[] = { -1, /* %rax */ 2 * 8, /* %rbx */ -1, /* %rcx */ -1, /* %rdx */ -1, /* %rsi */ -1, /* %rdi */ -1, /* %rbp */ -1, /* %rsp */ -1, /* %r8 ... */ -1, -1, 0 * 8, -1, 1 * 8, -1, -1, /* ... %r15 */ 3 * 8, /* %rip */ -1, /* %rflags */ -1, /* %cs */ -1, /* %ss */ }; /* from trad-frame.c */ struct trad_frame_cache { struct frame_info *next_frame; CORE_ADDR this_base; struct trad_frame_saved_reg *prev_regs; struct frame_id this_id; }; static struct trad_frame_cache * amd64obsd_trapframe_cache(struct frame_info *next_frame, void **this_cache) { struct trad_frame_cache *cache; CORE_ADDR func, sp, addr, trapcheck; ULONGEST cs; int i; char *name = NULL; if (*this_cache) return *this_cache; cache = trad_frame_cache_zalloc (next_frame); *this_cache = cache; func = frame_func_unwind (next_frame); sp = frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM); addr = sp; /* adhoc check: from trap/intr? or from spllower()? */ /* Xspllower() pushes %rbx, %r13, %r11. so, if *(sp+(8*3)) == spllower(), this frame may not be trapframe, but a frame created by Xspllower(). */ trapcheck = read_memory_unsigned_integer (sp+(8*3), 8); find_pc_partial_function (trapcheck, &name, NULL, NULL); if (name != NULL && (strcmp (name, "spllower") == 0)) { /* from spllower(). */ for (i = 0; i < ARRAY_SIZE (amd64obsd_fromspllower_reg_offset); i++) if (amd64obsd_fromspllower_reg_offset[i] != -1) trad_frame_set_reg_addr (cache, i, addr + amd64obsd_fromspllower_reg_offset[i]); /* skip rbx,r13,r11(pushed by Xspllower()), rip(pushd by spllower()). */ trad_frame_set_value (cache->prev_regs, AMD64_RSP_REGNUM, addr+(8*4)); /* Construct the frame ID using the function start. */ trad_frame_set_id (cache, frame_id_build (sp + (8*4), func)); } else { /* from trap/intr. */ for (i = 0; i < ARRAY_SIZE (amd64obsd_tf_reg_offset); i++) if (amd64obsd_tf_reg_offset[i] != -1) trad_frame_set_reg_addr (cache, i, addr + amd64obsd_tf_reg_offset[i]); /* Read %cs from trap frame. */ addr += amd64obsd_tf_reg_offset[AMD64_CS_REGNUM]; cs = read_memory_unsigned_integer (addr, 8); if ((cs & I386_SEL_RPL) == I386_SEL_UPL) { /* Trap from use space; terminate backtrace. */ trad_frame_set_id (cache, null_frame_id); } else { /* Construct the frame ID using the function start. */ trad_frame_set_id (cache, frame_id_build (sp + 16, func)); } } return cache; } static void amd64obsd_trapframe_this_id (struct frame_info *next_frame, void **this_cache, struct frame_id *this_id) { struct trad_frame_cache *cache = amd64obsd_trapframe_cache (next_frame, this_cache); trad_frame_get_id (cache, this_id); } static void amd64obsd_trapframe_prev_register (struct frame_info *next_frame, void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp, CORE_ADDR *addrp, int *realnump, void *valuep) { struct trad_frame_cache *cache = amd64obsd_trapframe_cache (next_frame, this_cache); trad_frame_get_register (cache, next_frame, regnum, optimizedp, lvalp, addrp, realnump, valuep); } static int amd64obsd_trapframe_sniffer (const struct frame_unwind *self, struct frame_info *next_frame, void **this_prologue_cache) { ULONGEST cs; char *name; cs = frame_unwind_register_unsigned (next_frame, AMD64_CS_REGNUM); if ((cs & I386_SEL_RPL) == I386_SEL_UPL) return 0; find_pc_partial_function (frame_pc_unwind (next_frame), &name, NULL, NULL); return (name && ((strcmp (name, "calltrap") == 0) || (name[0] == 'X' && strncmp(name, "Xipi_", 5) != 0) || (strcmp (name, "alltraps") == 0) || (strcmp (name, "alltraps_kern") == 0) || (strcmp (name, "alltraps_kern_meltdown") == 0) || (strcmp (name, "intr_fast_exit") == 0) || (strcmp (name, "intr_exit_recurse") == 0))); } static const struct frame_unwind amd64obsd_trapframe_unwind = { /* FIXME: kettenis/20051219: This really is more like an interrupt frame, but SIGTRAMP_FRAME would print , which really is not what we want here. */ NORMAL_FRAME, amd64obsd_trapframe_this_id, amd64obsd_trapframe_prev_register, NULL, amd64obsd_trapframe_sniffer }; static void amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); amd64_init_abi (info, gdbarch); /* Initialize general-purpose register set details. */ tdep->gregset_reg_offset = amd64obsd_r_reg_offset; tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset); tdep->sizeof_gregset = 24 * 8; tdep->jb_pc_offset = 7 * 8; tdep->sigtramp_p = amd64obsd_sigtramp_p; tdep->sigcontext_addr = amd64obsd_sigcontext_addr; tdep->sc_reg_offset = amd64obsd_sc_reg_offset; tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset); /* OpenBSD provides a user-level threads implementation. */ bsd_uthread_set_supply_uthread (gdbarch, amd64obsd_supply_uthread); bsd_uthread_set_collect_uthread (gdbarch, amd64obsd_collect_uthread); /* OpenBSD uses SVR4-style shared libraries. */ set_solib_svr4_fetch_link_map_offsets (gdbarch, svr4_lp64_fetch_link_map_offsets); /* Unwind kernel trap frames correctly. */ frame_unwind_prepend_unwinder (gdbarch, &amd64obsd_trapframe_unwind); } /* Traditional (a.out) NetBSD-style core dumps. */ static void amd64obsd_core_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { amd64obsd_init_abi (info, gdbarch); set_gdbarch_regset_from_core_section (gdbarch, amd64obsd_regset_from_core_section); } /* Provide a prototype to silence -Wmissing-prototypes. */ void _initialize_amd64obsd_tdep (void); void _initialize_amd64obsd_tdep (void) { /* The OpenBSD/amd64 native dependent code makes this assumption. */ gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS); gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi); /* OpenBSD uses traditional (a.out) NetBSD-style core dumps. */ gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_NETBSD_AOUT, amd64obsd_core_init_abi); }