amd64-obsd-nat.c revision 1.1.1.3
1/* Native-dependent code for OpenBSD/amd64. 2 3 Copyright (C) 2003-2020 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 "amd64-tdep.h" 26#include "amd64-bsd-nat.h" 27#include "amd64-nat.h" 28#include "obsd-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>. */ 39static 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 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 68static int 69amd64obsd_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 (12, &sf.sf_r12); 110 regcache->raw_supply (13, &sf.sf_r13); 111 regcache->raw_supply (14, &sf.sf_r14); 112 regcache->raw_supply (15, &sf.sf_r15); 113 regcache->raw_supply (AMD64_RBX_REGNUM, &sf.sf_rbx); 114 regcache->raw_supply (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 (AMD64_RIP_REGNUM, &sf); 121 } 122 123 regcache->raw_supply (AMD64_RSP_REGNUM, &pcb->pcb_rsp); 124 regcache->raw_supply (AMD64_RBP_REGNUM, &pcb->pcb_rbp); 125 126 return 1; 127} 128 129static amd64_bsd_nat_target<obsd_nat_target> the_amd64_obsd_nat_target; 130 131void _initialize_amd64obsd_nat (); 132void 133_initialize_amd64obsd_nat () 134{ 135 amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset; 136 amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset); 137 amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset; 138 139 add_inf_child_target (&the_amd64_obsd_nat_target); 140 141 /* Support debugging kernel virtual memory images. */ 142 bsd_kvm_add_target (amd64obsd_supply_pcb); 143} 144