| 1 | /* GNU/Linux/x86-64 specific low level interface, for the in-process |
| 2 | agent library for GDB. |
| 3 | |
| 4 | Copyright (C) 2010-2020 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "server.h" |
| 22 | #include <sys/mman.h> |
| 23 | #include "tracepoint.h" |
| 24 | #include "linux-x86-tdesc.h" |
| 25 | #include "gdbsupport/x86-xstate.h" |
| 26 | |
| 27 | /* Defined in auto-generated file amd64-linux.c. */ |
| 28 | void init_registers_amd64_linux (void); |
| 29 | extern const struct target_desc *tdesc_amd64_linux; |
| 30 | |
| 31 | /* fast tracepoints collect registers. */ |
| 32 | |
| 33 | #define FT_CR_RIP 0 |
| 34 | #define FT_CR_EFLAGS 1 |
| 35 | #define FT_CR_R8 2 |
| 36 | #define FT_CR_R9 3 |
| 37 | #define FT_CR_R10 4 |
| 38 | #define FT_CR_R11 5 |
| 39 | #define FT_CR_R12 6 |
| 40 | #define FT_CR_R13 7 |
| 41 | #define FT_CR_R14 8 |
| 42 | #define FT_CR_R15 9 |
| 43 | #define FT_CR_RAX 10 |
| 44 | #define FT_CR_RBX 11 |
| 45 | #define FT_CR_RCX 12 |
| 46 | #define FT_CR_RDX 13 |
| 47 | #define FT_CR_RSI 14 |
| 48 | #define FT_CR_RDI 15 |
| 49 | #define FT_CR_RBP 16 |
| 50 | #define FT_CR_RSP 17 |
| 51 | |
| 52 | static const int x86_64_ft_collect_regmap[] = { |
| 53 | FT_CR_RAX * 8, FT_CR_RBX * 8, FT_CR_RCX * 8, FT_CR_RDX * 8, |
| 54 | FT_CR_RSI * 8, FT_CR_RDI * 8, FT_CR_RBP * 8, FT_CR_RSP * 8, |
| 55 | FT_CR_R8 * 8, FT_CR_R9 * 8, FT_CR_R10 * 8, FT_CR_R11 * 8, |
| 56 | FT_CR_R12 * 8, FT_CR_R13 * 8, FT_CR_R14 * 8, FT_CR_R15 * 8, |
| 57 | FT_CR_RIP * 8, FT_CR_EFLAGS * 8 |
| 58 | }; |
| 59 | |
| 60 | #define X86_64_NUM_FT_COLLECT_GREGS \ |
| 61 | (sizeof (x86_64_ft_collect_regmap) / sizeof(x86_64_ft_collect_regmap[0])) |
| 62 | |
| 63 | void |
| 64 | supply_fast_tracepoint_registers (struct regcache *regcache, |
| 65 | const unsigned char *buf) |
| 66 | { |
| 67 | int i; |
| 68 | |
| 69 | for (i = 0; i < X86_64_NUM_FT_COLLECT_GREGS; i++) |
| 70 | supply_register (regcache, i, |
| 71 | ((char *) buf) + x86_64_ft_collect_regmap[i]); |
| 72 | } |
| 73 | |
| 74 | ULONGEST |
| 75 | get_raw_reg (const unsigned char *raw_regs, int regnum) |
| 76 | { |
| 77 | if (regnum >= X86_64_NUM_FT_COLLECT_GREGS) |
| 78 | return 0; |
| 79 | |
| 80 | return *(ULONGEST *) (raw_regs + x86_64_ft_collect_regmap[regnum]); |
| 81 | } |
| 82 | |
| 83 | #ifdef HAVE_UST |
| 84 | |
| 85 | #include <ust/processor.h> |
| 86 | |
| 87 | /* "struct registers" is the UST object type holding the registers at |
| 88 | the time of the static tracepoint marker call. This doesn't |
| 89 | contain RIP, but we know what it must have been (the marker |
| 90 | address). */ |
| 91 | |
| 92 | #define ST_REGENTRY(REG) \ |
| 93 | { \ |
| 94 | offsetof (struct registers, REG), \ |
| 95 | sizeof (((struct registers *) NULL)->REG) \ |
| 96 | } |
| 97 | |
| 98 | static struct |
| 99 | { |
| 100 | int offset; |
| 101 | int size; |
| 102 | } x86_64_st_collect_regmap[] = |
| 103 | { |
| 104 | ST_REGENTRY(rax), |
| 105 | ST_REGENTRY(rbx), |
| 106 | ST_REGENTRY(rcx), |
| 107 | ST_REGENTRY(rdx), |
| 108 | ST_REGENTRY(rsi), |
| 109 | ST_REGENTRY(rdi), |
| 110 | ST_REGENTRY(rbp), |
| 111 | ST_REGENTRY(rsp), |
| 112 | ST_REGENTRY(r8), |
| 113 | ST_REGENTRY(r9), |
| 114 | ST_REGENTRY(r10), |
| 115 | ST_REGENTRY(r11), |
| 116 | ST_REGENTRY(r12), |
| 117 | ST_REGENTRY(r13), |
| 118 | ST_REGENTRY(r14), |
| 119 | ST_REGENTRY(r15), |
| 120 | { -1, 0 }, |
| 121 | ST_REGENTRY(rflags), |
| 122 | ST_REGENTRY(cs), |
| 123 | ST_REGENTRY(ss), |
| 124 | }; |
| 125 | |
| 126 | #define X86_64_NUM_ST_COLLECT_GREGS \ |
| 127 | (sizeof (x86_64_st_collect_regmap) / sizeof (x86_64_st_collect_regmap[0])) |
| 128 | |
| 129 | /* GDB's RIP register number. */ |
| 130 | #define AMD64_RIP_REGNUM 16 |
| 131 | |
| 132 | void |
| 133 | supply_static_tracepoint_registers (struct regcache *regcache, |
| 134 | const unsigned char *buf, |
| 135 | CORE_ADDR pc) |
| 136 | { |
| 137 | int i; |
| 138 | unsigned long newpc = pc; |
| 139 | |
| 140 | supply_register (regcache, AMD64_RIP_REGNUM, &newpc); |
| 141 | |
| 142 | for (i = 0; i < X86_64_NUM_ST_COLLECT_GREGS; i++) |
| 143 | if (x86_64_st_collect_regmap[i].offset != -1) |
| 144 | { |
| 145 | switch (x86_64_st_collect_regmap[i].size) |
| 146 | { |
| 147 | case 8: |
| 148 | supply_register (regcache, i, |
| 149 | ((char *) buf) |
| 150 | + x86_64_st_collect_regmap[i].offset); |
| 151 | break; |
| 152 | case 2: |
| 153 | { |
| 154 | unsigned long reg |
| 155 | = * (short *) (((char *) buf) |
| 156 | + x86_64_st_collect_regmap[i].offset); |
| 157 | reg &= 0xffff; |
| 158 | supply_register (regcache, i, ®); |
| 159 | } |
| 160 | break; |
| 161 | default: |
| 162 | internal_error (__FILE__, __LINE__, |
| 163 | "unhandled register size: %d", |
| 164 | x86_64_st_collect_regmap[i].size); |
| 165 | break; |
| 166 | } |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | #endif /* HAVE_UST */ |
| 171 | |
| 172 | #if !defined __ILP32__ |
| 173 | /* Map the tdesc index to xcr0 mask. */ |
| 174 | static uint64_t idx2mask[X86_TDESC_LAST] = { |
| 175 | X86_XSTATE_X87_MASK, |
| 176 | X86_XSTATE_SSE_MASK, |
| 177 | X86_XSTATE_AVX_MASK, |
| 178 | X86_XSTATE_MPX_MASK, |
| 179 | X86_XSTATE_AVX_MPX_MASK, |
| 180 | X86_XSTATE_AVX_AVX512_MASK, |
| 181 | X86_XSTATE_AVX_MPX_AVX512_PKU_MASK, |
| 182 | }; |
| 183 | #endif |
| 184 | |
| 185 | /* Return target_desc to use for IPA, given the tdesc index passed by |
| 186 | gdbserver. */ |
| 187 | |
| 188 | const struct target_desc * |
| 189 | get_ipa_tdesc (int idx) |
| 190 | { |
| 191 | if (idx >= X86_TDESC_LAST) |
| 192 | { |
| 193 | internal_error (__FILE__, __LINE__, |
| 194 | "unknown ipa tdesc index: %d", idx); |
| 195 | } |
| 196 | |
| 197 | #if defined __ILP32__ |
| 198 | switch (idx) |
| 199 | { |
| 200 | case X86_TDESC_SSE: |
| 201 | return amd64_linux_read_description (X86_XSTATE_SSE_MASK, true); |
| 202 | case X86_TDESC_AVX: |
| 203 | return amd64_linux_read_description (X86_XSTATE_AVX_MASK, true); |
| 204 | case X86_TDESC_AVX_AVX512: |
| 205 | return amd64_linux_read_description (X86_XSTATE_AVX_AVX512_MASK, true); |
| 206 | default: |
| 207 | break; |
| 208 | } |
| 209 | #else |
| 210 | return amd64_linux_read_description (idx2mask[idx], false); |
| 211 | #endif |
| 212 | |
| 213 | internal_error (__FILE__, __LINE__, |
| 214 | "unknown ipa tdesc index: %d", idx); |
| 215 | } |
| 216 | |
| 217 | /* Allocate buffer for the jump pads. The branch instruction has a |
| 218 | reach of +/- 31-bit, and the executable is loaded at low addresses. |
| 219 | |
| 220 | 64-bit: Use MAP_32BIT to allocate in the first 2GB. Shared |
| 221 | libraries, being allocated at the top, are unfortunately out of |
| 222 | luck. |
| 223 | |
| 224 | x32: Since MAP_32BIT is 64-bit only, do the placement manually. |
| 225 | Try allocating at '0x80000000 - SIZE' initially, decreasing until |
| 226 | we hit a free area. This ensures the executable is fully covered, |
| 227 | and is as close as possible to the shared libraries, which are |
| 228 | usually mapped at the top of the first 4GB of the address space. |
| 229 | */ |
| 230 | |
| 231 | void * |
| 232 | alloc_jump_pad_buffer (size_t size) |
| 233 | { |
| 234 | #if __ILP32__ |
| 235 | uintptr_t addr; |
| 236 | int pagesize; |
| 237 | |
| 238 | pagesize = sysconf (_SC_PAGE_SIZE); |
| 239 | if (pagesize == -1) |
| 240 | perror_with_name ("sysconf"); |
| 241 | |
| 242 | addr = 0x80000000 - size; |
| 243 | |
| 244 | /* size should already be page-aligned, but this can't hurt. */ |
| 245 | addr &= ~(pagesize - 1); |
| 246 | |
| 247 | /* Search for a free area. If we hit 0, we're out of luck. */ |
| 248 | for (; addr; addr -= pagesize) |
| 249 | { |
| 250 | void *res; |
| 251 | |
| 252 | /* No MAP_FIXED - we don't want to zap someone's mapping. */ |
| 253 | res = mmap ((void *) addr, size, |
| 254 | PROT_READ | PROT_WRITE | PROT_EXEC, |
| 255 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| 256 | |
| 257 | /* If we got what we wanted, return. */ |
| 258 | if ((uintptr_t) res == addr) |
| 259 | return res; |
| 260 | |
| 261 | /* If we got a mapping, but at a wrong address, undo it. */ |
| 262 | if (res != MAP_FAILED) |
| 263 | munmap (res, size); |
| 264 | } |
| 265 | |
| 266 | return NULL; |
| 267 | #else |
| 268 | void *res = mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC, |
| 269 | MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0); |
| 270 | |
| 271 | if (res == MAP_FAILED) |
| 272 | return NULL; |
| 273 | |
| 274 | return res; |
| 275 | #endif |
| 276 | } |
| 277 | |
| 278 | void |
| 279 | initialize_low_tracepoint (void) |
| 280 | { |
| 281 | #if defined __ILP32__ |
| 282 | amd64_linux_read_description (X86_XSTATE_SSE_MASK, true); |
| 283 | amd64_linux_read_description (X86_XSTATE_AVX_MASK, true); |
| 284 | amd64_linux_read_description (X86_XSTATE_AVX_AVX512_MASK, true); |
| 285 | #else |
| 286 | for (auto i = 0; i < X86_TDESC_LAST; i++) |
| 287 | amd64_linux_read_description (idx2mask[i], false); |
| 288 | #endif |
| 289 | } |