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Diffstat (limited to 'gdb/amd64-obsd-tdep.c')
| -rw-r--r-- | gdb/amd64-obsd-tdep.c | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/gdb/amd64-obsd-tdep.c b/gdb/amd64-obsd-tdep.c new file mode 100644 index 0000000..7c79e44 --- /dev/null +++ b/gdb/amd64-obsd-tdep.c @@ -0,0 +1,514 @@ +/* Target-dependent code for OpenBSD/amd64. + + Copyright (C) 2003-2016 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 "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 "obsd-tdep.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) +{ + struct gdbarch *gdbarch = get_regcache_arch (regcache); + const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + + gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE); + + i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); + amd64_supply_fxsave (regcache, regnum, + ((const gdb_byte *)regs) + tdep->sizeof_gregset); +} + +static const struct regset amd64obsd_combined_regset = + { + NULL, amd64obsd_supply_regset, NULL + }; + +static void +amd64obsd_iterate_over_regset_sections (struct gdbarch *gdbarch, + iterate_over_regset_sections_cb *cb, + void *cb_data, + const struct regcache *regcache) +{ + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + + /* OpenBSD core dumps don't use seperate register sets for the + general-purpose and floating-point registers. */ + + cb (".reg", tdep->sizeof_gregset + I387_SIZEOF_FXSAVE, + &amd64obsd_combined_regset, NULL, cb_data); +} + + +/* Support for signal handlers. */ + +/* Default page size. */ +static const int amd64obsd_page_size = 4096; + +/* Return whether THIS_FRAME corresponds to an OpenBSD sigtramp + routine. */ + +static int +amd64obsd_sigtramp_p (struct frame_info *this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_frame); + CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1)); + const gdb_byte osigreturn[] = + { + 0x48, 0xc7, 0xc0, + 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */ + 0xcd, 0x80 /* int $0x80 */ + }; + const gdb_byte sigreturn[] = + { + 0x48, 0xc7, 0xc0, + 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */ + 0x0f, 0x05 /* syscall */ + }; + size_t buflen = (sizeof sigreturn) + 1; + gdb_byte *buf; + const 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; + + /* If we can't read the instructions at START_PC, return zero. */ + buf = (gdb_byte *) alloca ((sizeof sigreturn) + 1); + if (!safe_frame_unwind_memory (this_frame, start_pc + 6, buf, buflen)) + return 0; + + /* Check for sigreturn(2). Depending on how the assembler encoded + the `movq %rsp, %rdi' instruction, the code starts at offset 6 or + 7. OpenBSD 5.0 and later use the `syscall' instruction. Older + versions use `int $0x80'. Check for both. */ + if (memcmp (buf, sigreturn, sizeof sigreturn) + && memcmp (buf + 1, sigreturn, sizeof sigreturn) + && memcmp (buf, osigreturn, sizeof osigreturn) + && memcmp (buf + 1, osigreturn, sizeof osigreturn)) + return 0; + + return 1; +} + +/* Assuming THIS_FRAME is for a BSD sigtramp routine, return the + address of the associated sigcontext structure. */ + +static CORE_ADDR +amd64obsd_sigcontext_addr (struct frame_info *this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_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 get_frame_register_unsigned (this_frame, AMD64_RDI_REGNUM); + else + return get_frame_register_unsigned (this_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 <machine/reg.h>. */ +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 <machine/signal.h>. */ +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) +{ + struct gdbarch *gdbarch = get_regcache_arch (regcache); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + CORE_ADDR sp_addr = addr + AMD64OBSD_UTHREAD_RSP_OFFSET; + CORE_ADDR sp = 0; + gdb_byte buf[8]; + int i; + + gdb_assert (regnum >= -1); + + if (regnum == -1 || regnum == AMD64_RSP_REGNUM) + { + int offset; + + /* Fetch stack pointer from thread structure. */ + sp = read_memory_unsigned_integer (sp_addr, 8, byte_order); + + /* 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, byte_order, 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, byte_order); + + /* 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) +{ + struct gdbarch *gdbarch = get_regcache_arch (regcache); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + CORE_ADDR sp_addr = addr + AMD64OBSD_UTHREAD_RSP_OFFSET; + CORE_ADDR sp = 0; + gdb_byte buf[8]; + int i; + + gdb_assert (regnum >= -1); + + 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, byte_order) - offset; + + /* Store the stack pointer. */ + write_memory_unsigned_integer (sp_addr, 8, byte_order, 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, byte_order); + + /* 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 <machine/frame.h>. Easy since `struct trapframe' matches + `struct sigcontext'. */ +#define amd64obsd_tf_reg_offset amd64obsd_sc_reg_offset + +static struct trad_frame_cache * +amd64obsd_trapframe_cache (struct frame_info *this_frame, void **this_cache) +{ + struct gdbarch *gdbarch = get_frame_arch (this_frame); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + struct trad_frame_cache *cache; + CORE_ADDR func, sp, addr; + ULONGEST cs; + const char *name; + int i; + + if (*this_cache) + return (struct trad_frame_cache *) *this_cache; + + cache = trad_frame_cache_zalloc (this_frame); + *this_cache = cache; + + func = get_frame_func (this_frame); + sp = get_frame_register_unsigned (this_frame, AMD64_RSP_REGNUM); + + find_pc_partial_function (func, &name, NULL, NULL); + if (name && startswith (name, "Xintr")) + addr = sp + 8; /* It's an interrupt frame. */ + else + addr = sp; + + 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, byte_order); + if ((cs & I386_SEL_RPL) == I386_SEL_UPL) + { + /* Trap from user space; terminate backtrace. */ + trad_frame_set_id (cache, outer_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 *this_frame, + void **this_cache, struct frame_id *this_id) +{ + struct trad_frame_cache *cache = + amd64obsd_trapframe_cache (this_frame, this_cache); + + trad_frame_get_id (cache, this_id); +} + +static struct value * +amd64obsd_trapframe_prev_register (struct frame_info *this_frame, + void **this_cache, int regnum) +{ + struct trad_frame_cache *cache = + amd64obsd_trapframe_cache (this_frame, this_cache); + + return trad_frame_get_register (cache, this_frame, regnum); +} + +static int +amd64obsd_trapframe_sniffer (const struct frame_unwind *self, + struct frame_info *this_frame, + void **this_prologue_cache) +{ + ULONGEST cs; + const char *name; + + /* Check Current Privilege Level and bail out if we're not executing + in kernel space. */ + cs = get_frame_register_unsigned (this_frame, AMD64_CS_REGNUM); + if ((cs & I386_SEL_RPL) == I386_SEL_UPL) + return 0; + + find_pc_partial_function (get_frame_pc (this_frame), &name, NULL, NULL); + return (name && ((strcmp (name, "calltrap") == 0) + || (strcmp (name, "osyscall1") == 0) + || (strcmp (name, "Xsyscall") == 0) + || (startswith (name, "Xintr")))); +} + +static const struct frame_unwind amd64obsd_trapframe_unwind = { + /* FIXME: kettenis/20051219: This really is more like an interrupt + frame, but SIGTRAMP_FRAME would print <signal handler called>, + which really is not what we want here. */ + NORMAL_FRAME, + default_frame_unwind_stop_reason, + 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); + obsd_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_iterate_over_regset_sections + (gdbarch, amd64obsd_iterate_over_regset_sections); +} + + +/* 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); +} |