| 1 | /* Native-dependent code for OpenBSD/amd64. |
| 2 | |
| 3 | Copyright (C) 2003, 2004, 2007, 2008, 2009 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "gdbcore.h" |
| 22 | #include "regcache.h" |
| 23 | #include "target.h" |
| 24 | |
| 25 | #include "gdb_assert.h" |
| 26 | |
| 27 | #include "amd64-tdep.h" |
| 28 | #include "amd64-nat.h" |
| 29 | |
| 30 | /* Mapping between the general-purpose registers in OpenBSD/amd64 |
| 31 | `struct reg' format and GDB's register cache layout for |
| 32 | OpenBSD/i386. |
| 33 | |
| 34 | Note that most (if not all) OpenBSD/amd64 registers are 64-bit, |
| 35 | while the OpenBSD/i386 registers are all 32-bit, but since we're |
| 36 | little-endian we get away with that. */ |
| 37 | |
| 38 | /* From <machine/reg.h>. */ |
| 39 | static int amd64obsd32_r_reg_offset[] = |
| 40 | { |
| 41 | 14 * 8, /* %eax */ |
| 42 | 3 * 8, /* %ecx */ |
| 43 | 2 * 8, /* %edx */ |
| 44 | 13 * 8, /* %ebx */ |
| 45 | 15 * 8, /* %esp */ |
| 46 | 12 * 8, /* %ebp */ |
| 47 | 1 * 8, /* %esi */ |
| 48 | 0 * 8, /* %edi */ |
| 49 | 16 * 8, /* %eip */ |
| 50 | 17 * 8, /* %eflags */ |
| 51 | 18 * 8, /* %cs */ |
| 52 | 19 * 8, /* %ss */ |
| 53 | 20 * 8, /* %ds */ |
| 54 | 21 * 8, /* %es */ |
| 55 | 22 * 8, /* %fs */ |
| 56 | 23 * 8 /* %gs */ |
| 57 | }; |
| 58 | \f |
| 59 | |
| 60 | /* Support for debugging kernel virtual memory images. */ |
| 61 | |
| 62 | #include <sys/types.h> |
| 63 | #include <machine/frame.h> |
| 64 | #include <machine/pcb.h> |
| 65 | |
| 66 | #include "bsd-kvm.h" |
| 67 | |
| 68 | static int |
| 69 | amd64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) |
| 70 | { |
| 71 | struct switchframe sf; |
| 72 | int regnum; |
| 73 | |
| 74 | /* The following is true for OpenBSD 3.5: |
| 75 | |
| 76 | The pcb contains the stack pointer at the point of the context |
| 77 | switch in cpu_switch(). At that point we have a stack frame as |
| 78 | described by `struct switchframe', which for OpenBSD 3.5 has the |
| 79 | following layout: |
| 80 | |
| 81 | interrupt level |
| 82 | %r15 |
| 83 | %r14 |
| 84 | %r13 |
| 85 | %r12 |
| 86 | %rbp |
| 87 | %rbx |
| 88 | return address |
| 89 | |
| 90 | Together with %rsp in the pcb, this accounts for all callee-saved |
| 91 | registers specified by the psABI. From this information we |
| 92 | reconstruct the register state as it would look when we just |
| 93 | returned from cpu_switch(). |
| 94 | |
| 95 | For core dumps the pcb is saved by savectx(). In that case the |
| 96 | stack frame only contains the return address, and there is no way |
| 97 | to recover the other registers. */ |
| 98 | |
| 99 | /* The stack pointer shouldn't be zero. */ |
| 100 | if (pcb->pcb_rsp == 0) |
| 101 | return 0; |
| 102 | |
| 103 | /* Read the stack frame, and check its validity. */ |
| 104 | read_memory (pcb->pcb_rsp, (gdb_byte *) &sf, sizeof sf); |
| 105 | if (sf.sf_rbp == pcb->pcb_rbp) |
| 106 | { |
| 107 | /* Yes, we have a frame that matches cpu_switch(). */ |
| 108 | pcb->pcb_rsp += sizeof (struct switchframe); |
| 109 | regcache_raw_supply (regcache, 12, &sf.sf_r12); |
| 110 | regcache_raw_supply (regcache, 13, &sf.sf_r13); |
| 111 | regcache_raw_supply (regcache, 14, &sf.sf_r14); |
| 112 | regcache_raw_supply (regcache, 15, &sf.sf_r15); |
| 113 | regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &sf.sf_rbx); |
| 114 | regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf.sf_rip); |
| 115 | } |
| 116 | else |
| 117 | { |
| 118 | /* No, the pcb must have been last updated by savectx(). */ |
| 119 | pcb->pcb_rsp += 8; |
| 120 | regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf); |
| 121 | } |
| 122 | |
| 123 | regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp); |
| 124 | regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp); |
| 125 | |
| 126 | return 1; |
| 127 | } |
| 128 | \f |
| 129 | |
| 130 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 131 | void _initialize_amd64obsd_nat (void); |
| 132 | |
| 133 | void |
| 134 | _initialize_amd64obsd_nat (void) |
| 135 | { |
| 136 | amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset; |
| 137 | amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset); |
| 138 | amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset; |
| 139 | |
| 140 | /* We've got nothing to add to the common *BSD/amd64 target. */ |
| 141 | add_target (amd64bsd_target ()); |
| 142 | |
| 143 | /* Support debugging kernel virtual memory images. */ |
| 144 | bsd_kvm_add_target (amd64obsd_supply_pcb); |
| 145 | } |