| 1 | /* GNU/Linux/AArch64 specific low level interface, for the in-process |
| 2 | agent library for GDB. |
| 3 | |
| 4 | Copyright (C) 2015-2020 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 <elf.h> |
| 25 | #ifdef HAVE_GETAUXVAL |
| 26 | #include <sys/auxv.h> |
| 27 | #endif |
| 28 | #include "linux-aarch64-tdesc.h" |
| 29 | |
| 30 | /* Each register saved by the jump pad is in a 16 byte cell. */ |
| 31 | #define FT_CR_SIZE 16 |
| 32 | |
| 33 | #define FT_CR_FPCR 0 |
| 34 | #define FT_CR_FPSR 1 |
| 35 | #define FT_CR_CPSR 2 |
| 36 | #define FT_CR_PC 3 |
| 37 | #define FT_CR_SP 4 |
| 38 | #define FT_CR_X0 5 |
| 39 | #define FT_CR_GPR(n) (FT_CR_X0 + (n)) |
| 40 | #define FT_CR_FPR(n) (FT_CR_GPR (31) + (n)) |
| 41 | |
| 42 | /* Mapping between registers collected by the jump pad and GDB's register |
| 43 | array layout used by regcache. |
| 44 | |
| 45 | See linux-aarch64-low.c (aarch64_install_fast_tracepoint_jump_pad) for |
| 46 | more details. */ |
| 47 | |
| 48 | static const int aarch64_ft_collect_regmap[] = { |
| 49 | FT_CR_GPR (0), |
| 50 | FT_CR_GPR (1), |
| 51 | FT_CR_GPR (2), |
| 52 | FT_CR_GPR (3), |
| 53 | FT_CR_GPR (4), |
| 54 | FT_CR_GPR (5), |
| 55 | FT_CR_GPR (6), |
| 56 | FT_CR_GPR (7), |
| 57 | FT_CR_GPR (8), |
| 58 | FT_CR_GPR (9), |
| 59 | FT_CR_GPR (10), |
| 60 | FT_CR_GPR (11), |
| 61 | FT_CR_GPR (12), |
| 62 | FT_CR_GPR (13), |
| 63 | FT_CR_GPR (14), |
| 64 | FT_CR_GPR (15), |
| 65 | FT_CR_GPR (16), |
| 66 | FT_CR_GPR (17), |
| 67 | FT_CR_GPR (18), |
| 68 | FT_CR_GPR (19), |
| 69 | FT_CR_GPR (20), |
| 70 | FT_CR_GPR (21), |
| 71 | FT_CR_GPR (22), |
| 72 | FT_CR_GPR (23), |
| 73 | FT_CR_GPR (24), |
| 74 | FT_CR_GPR (25), |
| 75 | FT_CR_GPR (26), |
| 76 | FT_CR_GPR (27), |
| 77 | FT_CR_GPR (28), |
| 78 | /* FP */ |
| 79 | FT_CR_GPR (29), |
| 80 | /* LR */ |
| 81 | FT_CR_GPR (30), |
| 82 | FT_CR_SP, |
| 83 | FT_CR_PC, |
| 84 | FT_CR_CPSR, |
| 85 | FT_CR_FPR (0), |
| 86 | FT_CR_FPR (1), |
| 87 | FT_CR_FPR (2), |
| 88 | FT_CR_FPR (3), |
| 89 | FT_CR_FPR (4), |
| 90 | FT_CR_FPR (5), |
| 91 | FT_CR_FPR (6), |
| 92 | FT_CR_FPR (7), |
| 93 | FT_CR_FPR (8), |
| 94 | FT_CR_FPR (9), |
| 95 | FT_CR_FPR (10), |
| 96 | FT_CR_FPR (11), |
| 97 | FT_CR_FPR (12), |
| 98 | FT_CR_FPR (13), |
| 99 | FT_CR_FPR (14), |
| 100 | FT_CR_FPR (15), |
| 101 | FT_CR_FPR (16), |
| 102 | FT_CR_FPR (17), |
| 103 | FT_CR_FPR (18), |
| 104 | FT_CR_FPR (19), |
| 105 | FT_CR_FPR (20), |
| 106 | FT_CR_FPR (21), |
| 107 | FT_CR_FPR (22), |
| 108 | FT_CR_FPR (23), |
| 109 | FT_CR_FPR (24), |
| 110 | FT_CR_FPR (25), |
| 111 | FT_CR_FPR (26), |
| 112 | FT_CR_FPR (27), |
| 113 | FT_CR_FPR (28), |
| 114 | FT_CR_FPR (29), |
| 115 | FT_CR_FPR (30), |
| 116 | FT_CR_FPR (31), |
| 117 | FT_CR_FPSR, |
| 118 | FT_CR_FPCR |
| 119 | }; |
| 120 | |
| 121 | #define AARCH64_NUM_FT_COLLECT_GREGS \ |
| 122 | (sizeof (aarch64_ft_collect_regmap) / sizeof(aarch64_ft_collect_regmap[0])) |
| 123 | |
| 124 | /* Fill in REGCACHE with registers saved by the jump pad in BUF. */ |
| 125 | |
| 126 | void |
| 127 | supply_fast_tracepoint_registers (struct regcache *regcache, |
| 128 | const unsigned char *buf) |
| 129 | { |
| 130 | int i; |
| 131 | |
| 132 | for (i = 0; i < AARCH64_NUM_FT_COLLECT_GREGS; i++) |
| 133 | supply_register (regcache, i, |
| 134 | ((char *) buf) |
| 135 | + (aarch64_ft_collect_regmap[i] * FT_CR_SIZE)); |
| 136 | } |
| 137 | |
| 138 | ULONGEST |
| 139 | get_raw_reg (const unsigned char *raw_regs, int regnum) |
| 140 | { |
| 141 | if (regnum >= AARCH64_NUM_FT_COLLECT_GREGS) |
| 142 | return 0; |
| 143 | |
| 144 | return *(ULONGEST *) (raw_regs |
| 145 | + aarch64_ft_collect_regmap[regnum] * FT_CR_SIZE); |
| 146 | } |
| 147 | |
| 148 | /* Return target_desc to use for IPA, given the tdesc index passed by |
| 149 | gdbserver. Index is ignored, since we have only one tdesc |
| 150 | at the moment. SVE and pauth not yet supported. */ |
| 151 | |
| 152 | const struct target_desc * |
| 153 | get_ipa_tdesc (int idx) |
| 154 | { |
| 155 | return aarch64_linux_read_description (0, false); |
| 156 | } |
| 157 | |
| 158 | /* Allocate buffer for the jump pads. The branch instruction has a reach |
| 159 | of +/- 128MiB, and the executable is loaded at 0x400000 (4MiB). |
| 160 | To maximize the area of executable that can use tracepoints, try |
| 161 | allocating at 0x400000 - size initially, decreasing until we hit |
| 162 | a free area. */ |
| 163 | |
| 164 | void * |
| 165 | alloc_jump_pad_buffer (size_t size) |
| 166 | { |
| 167 | uintptr_t addr; |
| 168 | uintptr_t exec_base = getauxval (AT_PHDR); |
| 169 | int pagesize; |
| 170 | void *res; |
| 171 | |
| 172 | if (exec_base == 0) |
| 173 | exec_base = 0x400000; |
| 174 | |
| 175 | pagesize = sysconf (_SC_PAGE_SIZE); |
| 176 | if (pagesize == -1) |
| 177 | perror_with_name ("sysconf"); |
| 178 | |
| 179 | addr = exec_base - size; |
| 180 | |
| 181 | /* size should already be page-aligned, but this can't hurt. */ |
| 182 | addr &= ~(pagesize - 1); |
| 183 | |
| 184 | /* Search for a free area. If we hit 0, we're out of luck. */ |
| 185 | for (; addr; addr -= pagesize) |
| 186 | { |
| 187 | /* No MAP_FIXED - we don't want to zap someone's mapping. */ |
| 188 | res = mmap ((void *) addr, size, |
| 189 | PROT_READ | PROT_WRITE | PROT_EXEC, |
| 190 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| 191 | |
| 192 | /* If we got what we wanted, return. */ |
| 193 | if ((uintptr_t) res == addr) |
| 194 | return res; |
| 195 | |
| 196 | /* If we got a mapping, but at a wrong address, undo it. */ |
| 197 | if (res != MAP_FAILED) |
| 198 | munmap (res, size); |
| 199 | } |
| 200 | |
| 201 | return NULL; |
| 202 | } |
| 203 | |
| 204 | void |
| 205 | initialize_low_tracepoint (void) |
| 206 | { |
| 207 | /* SVE and pauth not yet supported. */ |
| 208 | aarch64_linux_read_description (0, false); |
| 209 | } |