1 /* Native-dependent code for FreeBSD/amd64. 2 3 Copyright (C) 2003-2017 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 "inferior.h" 22 #include "regcache.h" 23 #include "target.h" 24 25 #include <signal.h> 26 #include <sys/types.h> 27 #include <sys/ptrace.h> 28 #include <sys/sysctl.h> 29 #include <sys/user.h> 30 #include <machine/reg.h> 31 32 #include "fbsd-nat.h" 33 #include "amd64-tdep.h" 34 #include "amd64-nat.h" 35 #include "x86-bsd-nat.h" 36 #include "x86-nat.h" 37 38 39 /* Offset in `struct reg' where MEMBER is stored. */ 40 #define REG_OFFSET(member) offsetof (struct reg, member) 41 42 /* At amd64fbsd64_r_reg_offset[REGNUM] you'll find the offset in 43 `struct reg' location where the GDB register REGNUM is stored. 44 Unsupported registers are marked with `-1'. */ 45 static int amd64fbsd64_r_reg_offset[] = 46 { 47 REG_OFFSET (r_rax), 48 REG_OFFSET (r_rbx), 49 REG_OFFSET (r_rcx), 50 REG_OFFSET (r_rdx), 51 REG_OFFSET (r_rsi), 52 REG_OFFSET (r_rdi), 53 REG_OFFSET (r_rbp), 54 REG_OFFSET (r_rsp), 55 REG_OFFSET (r_r8), 56 REG_OFFSET (r_r9), 57 REG_OFFSET (r_r10), 58 REG_OFFSET (r_r11), 59 REG_OFFSET (r_r12), 60 REG_OFFSET (r_r13), 61 REG_OFFSET (r_r14), 62 REG_OFFSET (r_r15), 63 REG_OFFSET (r_rip), 64 REG_OFFSET (r_rflags), 65 REG_OFFSET (r_cs), 66 REG_OFFSET (r_ss), 67 -1, 68 -1, 69 -1, 70 -1 71 }; 72 73 74 /* Mapping between the general-purpose registers in FreeBSD/amd64 75 `struct reg' format and GDB's register cache layout for 76 FreeBSD/i386. 77 78 Note that most FreeBSD/amd64 registers are 64-bit, while the 79 FreeBSD/i386 registers are all 32-bit, but since we're 80 little-endian we get away with that. */ 81 82 /* From <machine/reg.h>. */ 83 static int amd64fbsd32_r_reg_offset[I386_NUM_GREGS] = 84 { 85 14 * 8, 13 * 8, /* %eax, %ecx */ 86 12 * 8, 11 * 8, /* %edx, %ebx */ 87 20 * 8, 10 * 8, /* %esp, %ebp */ 88 9 * 8, 8 * 8, /* %esi, %edi */ 89 17 * 8, 19 * 8, /* %eip, %eflags */ 90 18 * 8, 21 * 8, /* %cs, %ss */ 91 -1, -1, -1, -1 /* %ds, %es, %fs, %gs */ 92 }; 93 94 95 /* Support for debugging kernel virtual memory images. */ 96 97 #include <machine/pcb.h> 98 #include <osreldate.h> 99 100 #include "bsd-kvm.h" 101 102 static int 103 amd64fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) 104 { 105 /* The following is true for FreeBSD 5.2: 106 107 The pcb contains %rip, %rbx, %rsp, %rbp, %r12, %r13, %r14, %r15, 108 %ds, %es, %fs and %gs. This accounts for all callee-saved 109 registers specified by the psABI and then some. Here %esp 110 contains the stack pointer at the point just after the call to 111 cpu_switch(). From this information we reconstruct the register 112 state as it would like when we just returned from cpu_switch(). */ 113 114 /* The stack pointer shouldn't be zero. */ 115 if (pcb->pcb_rsp == 0) 116 return 0; 117 118 pcb->pcb_rsp += 8; 119 regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &pcb->pcb_rip); 120 regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &pcb->pcb_rbx); 121 regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp); 122 regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp); 123 regcache_raw_supply (regcache, 12, &pcb->pcb_r12); 124 regcache_raw_supply (regcache, 13, &pcb->pcb_r13); 125 regcache_raw_supply (regcache, 14, &pcb->pcb_r14); 126 regcache_raw_supply (regcache, 15, &pcb->pcb_r15); 127 #if (__FreeBSD_version < 800075) && (__FreeBSD_kernel_version < 800075) 128 /* struct pcb provides the pcb_ds/pcb_es/pcb_fs/pcb_gs fields only 129 up until __FreeBSD_version 800074: The removal of these fields 130 occurred on 2009-04-01 while the __FreeBSD_version number was 131 bumped to 800075 on 2009-04-06. So 800075 is the closest version 132 number where we should not try to access these fields. */ 133 regcache_raw_supply (regcache, AMD64_DS_REGNUM, &pcb->pcb_ds); 134 regcache_raw_supply (regcache, AMD64_ES_REGNUM, &pcb->pcb_es); 135 regcache_raw_supply (regcache, AMD64_FS_REGNUM, &pcb->pcb_fs); 136 regcache_raw_supply (regcache, AMD64_GS_REGNUM, &pcb->pcb_gs); 137 #endif 138 139 return 1; 140 } 141 142 143 /* Implement the to_read_description method. */ 144 145 static const struct target_desc * 146 amd64fbsd_read_description (struct target_ops *ops) 147 { 148 #ifdef PT_GETXSTATE_INFO 149 static int xsave_probed; 150 static uint64_t xcr0; 151 #endif 152 struct reg regs; 153 int is64; 154 155 if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid), 156 (PTRACE_TYPE_ARG3) ®s, 0) == -1) 157 perror_with_name (_("Couldn't get registers")); 158 is64 = (regs.r_cs == GSEL (GUCODE_SEL, SEL_UPL)); 159 #ifdef PT_GETXSTATE_INFO 160 if (!xsave_probed) 161 { 162 struct ptrace_xstate_info info; 163 164 if (ptrace (PT_GETXSTATE_INFO, ptid_get_pid (inferior_ptid), 165 (PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0) 166 { 167 x86bsd_xsave_len = info.xsave_len; 168 xcr0 = info.xsave_mask; 169 } 170 xsave_probed = 1; 171 } 172 173 if (x86bsd_xsave_len != 0) 174 { 175 if (is64) 176 return amd64_target_description (xcr0); 177 else 178 return i386_target_description (xcr0); 179 } 180 #endif 181 if (is64) 182 return tdesc_amd64; 183 else 184 return tdesc_i386; 185 } 186 187 /* Provide a prototype to silence -Wmissing-prototypes. */ 188 void _initialize_amd64fbsd_nat (void); 189 190 void 191 _initialize_amd64fbsd_nat (void) 192 { 193 struct target_ops *t; 194 int offset; 195 196 amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset; 197 amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset; 198 199 /* Add some extra features to the common *BSD/i386 target. */ 200 t = amd64bsd_target (); 201 t->to_read_description = amd64fbsd_read_description; 202 203 fbsd_nat_add_target (t); 204 205 /* Support debugging kernel virtual memory images. */ 206 bsd_kvm_add_target (amd64fbsd_supply_pcb); 207 208 /* To support the recognition of signal handlers, i386-bsd-tdep.c 209 hardcodes some constants. Inclusion of this file means that we 210 are compiling a native debugger, which means that we can use the 211 system header files and sysctl(3) to get at the relevant 212 information. */ 213 214 #define SC_REG_OFFSET amd64fbsd_sc_reg_offset 215 216 /* We only check the program counter, stack pointer and frame 217 pointer since these members of `struct sigcontext' are essential 218 for providing backtraces. */ 219 220 #define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM] 221 #define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM] 222 #define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM] 223 224 /* Override the default value for the offset of the program counter 225 in the sigcontext structure. */ 226 offset = offsetof (struct sigcontext, sc_rip); 227 228 if (SC_RIP_OFFSET != offset) 229 { 230 warning (_("\ 231 offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\ 232 Please report this to <bug-gdb@gnu.org>."), 233 offset, SC_RIP_OFFSET); 234 } 235 236 SC_RIP_OFFSET = offset; 237 238 /* Likewise for the stack pointer. */ 239 offset = offsetof (struct sigcontext, sc_rsp); 240 241 if (SC_RSP_OFFSET != offset) 242 { 243 warning (_("\ 244 offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\ 245 Please report this to <bug-gdb@gnu.org>."), 246 offset, SC_RSP_OFFSET); 247 } 248 249 SC_RSP_OFFSET = offset; 250 251 /* And the frame pointer. */ 252 offset = offsetof (struct sigcontext, sc_rbp); 253 254 if (SC_RBP_OFFSET != offset) 255 { 256 warning (_("\ 257 offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\ 258 Please report this to <bug-gdb@gnu.org>."), 259 offset, SC_RBP_OFFSET); 260 } 261 262 SC_RBP_OFFSET = offset; 263 264 #ifdef KERN_PROC_SIGTRAMP 265 /* Normally signal frames are detected via amd64fbsd_sigtramp_p. 266 However, FreeBSD 9.2 through 10.1 do not include the page holding 267 the signal code in core dumps. These releases do provide a 268 kern.proc.sigtramp.<pid> sysctl that returns the location of the 269 signal trampoline for a running process. We fetch the location 270 of the current (gdb) process and use this to identify signal 271 frames in core dumps from these releases. Note that this only 272 works for core dumps of 64-bit (FreeBSD/amd64) processes and does 273 not handle core dumps of 32-bit (FreeBSD/i386) processes. */ 274 { 275 int mib[4]; 276 struct kinfo_sigtramp kst; 277 size_t len; 278 279 mib[0] = CTL_KERN; 280 mib[1] = KERN_PROC; 281 mib[2] = KERN_PROC_SIGTRAMP; 282 mib[3] = getpid (); 283 len = sizeof (kst); 284 if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0) 285 { 286 amd64fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start; 287 amd64fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end; 288 } 289 } 290 #endif 291 } 292