| 1 | /* Native-dependent code for GNU/Linux ARC. |
| 2 | |
| 3 | Copyright 2020-2021 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 "frame.h" |
| 22 | #include "inferior.h" |
| 23 | #include "gdbcore.h" |
| 24 | #include "regcache.h" |
| 25 | #include "gdbsupport/gdb_assert.h" |
| 26 | #include "target.h" |
| 27 | #include "linux-nat.h" |
| 28 | #include "nat/gdb_ptrace.h" |
| 29 | |
| 30 | #include <stdint.h> |
| 31 | #include <sys/types.h> |
| 32 | #include <sys/param.h> |
| 33 | #include <signal.h> |
| 34 | #include <sys/user.h> |
| 35 | #include <sys/ioctl.h> |
| 36 | #include "gdbsupport/gdb_wait.h" |
| 37 | #include <fcntl.h> |
| 38 | #include <sys/procfs.h> |
| 39 | #include <linux/elf.h> |
| 40 | |
| 41 | #include "gregset.h" |
| 42 | #include "arc-tdep.h" |
| 43 | #include "arc-linux-tdep.h" |
| 44 | #include "arch/arc.h" |
| 45 | |
| 46 | /* Defines ps_err_e, struct ps_prochandle. */ |
| 47 | #include "gdb_proc_service.h" |
| 48 | |
| 49 | /* Print an "arc-linux-nat" debug statement. */ |
| 50 | |
| 51 | #define arc_linux_nat_debug_printf(fmt, ...) \ |
| 52 | debug_prefixed_printf_cond (arc_debug, "arc-linux-nat", fmt, ##__VA_ARGS__) |
| 53 | |
| 54 | /* Linux starting with 4.12 supports NT_ARC_V2 note type, which adds R30, |
| 55 | R58 and R59 registers, which are specific to ARC HS and aren't |
| 56 | available in ARC 700. */ |
| 57 | #if defined (NT_ARC_V2) && defined (__ARCHS__) |
| 58 | #define ARC_HAS_V2_REGSET |
| 59 | #endif |
| 60 | |
| 61 | class arc_linux_nat_target final : public linux_nat_target |
| 62 | { |
| 63 | public: |
| 64 | /* Add ARC register access methods. */ |
| 65 | void fetch_registers (struct regcache *, int) override; |
| 66 | void store_registers (struct regcache *, int) override; |
| 67 | |
| 68 | const struct target_desc *read_description () override; |
| 69 | |
| 70 | /* Handle threads */ |
| 71 | void low_prepare_to_resume (struct lwp_info *lp) override; |
| 72 | }; |
| 73 | |
| 74 | static arc_linux_nat_target the_arc_linux_nat_target; |
| 75 | |
| 76 | /* Read general registers from target process/thread (via ptrace) |
| 77 | into REGCACHE. */ |
| 78 | |
| 79 | static void |
| 80 | fetch_gregs (struct regcache *regcache, int regnum) |
| 81 | { |
| 82 | const int tid = get_ptrace_pid (regcache->ptid ()); |
| 83 | struct iovec iov; |
| 84 | gdb_gregset_t regs; |
| 85 | |
| 86 | iov.iov_base = ®s; |
| 87 | iov.iov_len = sizeof (gdb_gregset_t); |
| 88 | |
| 89 | if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0) |
| 90 | perror_with_name (_("Couldn't get general registers")); |
| 91 | else |
| 92 | arc_linux_supply_gregset (NULL, regcache, regnum, ®s, 0); |
| 93 | } |
| 94 | |
| 95 | #ifdef ARC_HAS_V2_REGSET |
| 96 | /* Read ARC v2 registers from target process/thread (via ptrace) |
| 97 | into REGCACHE. */ |
| 98 | |
| 99 | static void |
| 100 | fetch_v2_regs (struct regcache *regcache, int regnum) |
| 101 | { |
| 102 | const int tid = get_ptrace_pid (regcache->ptid ()); |
| 103 | struct iovec iov; |
| 104 | bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET]; |
| 105 | |
| 106 | iov.iov_base = &v2_buffer; |
| 107 | iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET; |
| 108 | |
| 109 | if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0) |
| 110 | perror_with_name (_("Couldn't get ARC HS registers")); |
| 111 | else |
| 112 | arc_linux_supply_v2_regset (NULL, regcache, regnum, v2_buffer, 0); |
| 113 | } |
| 114 | #endif |
| 115 | |
| 116 | /* Store general registers from REGCACHE into the target process/thread. */ |
| 117 | |
| 118 | static void |
| 119 | store_gregs (const struct regcache *regcache, int regnum) |
| 120 | { |
| 121 | const int tid = get_ptrace_pid (regcache->ptid ()); |
| 122 | struct iovec iov; |
| 123 | gdb_gregset_t regs; |
| 124 | |
| 125 | iov.iov_base = ®s; |
| 126 | iov.iov_len = sizeof (gdb_gregset_t); |
| 127 | |
| 128 | if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0) |
| 129 | perror_with_name (_("Couldn't get general registers")); |
| 130 | else |
| 131 | { |
| 132 | arc_linux_collect_gregset (NULL, regcache, regnum, regs, 0); |
| 133 | |
| 134 | if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0) |
| 135 | perror_with_name (_("Couldn't write general registers")); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | #ifdef ARC_HAS_V2_REGSET |
| 140 | /* Store ARC v2 registers from REGCACHE into the target process/thread. */ |
| 141 | |
| 142 | static void |
| 143 | store_v2_regs (const struct regcache *regcache, int regnum) |
| 144 | { |
| 145 | const int tid = get_ptrace_pid (regcache->ptid ()); |
| 146 | struct iovec iov; |
| 147 | bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET]; |
| 148 | |
| 149 | iov.iov_base = &v2_buffer; |
| 150 | iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET; |
| 151 | |
| 152 | if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0) |
| 153 | perror_with_name (_("Couldn't get ARC HS registers")); |
| 154 | else |
| 155 | { |
| 156 | arc_linux_collect_v2_regset (NULL, regcache, regnum, v2_buffer, 0); |
| 157 | |
| 158 | if (ptrace (PTRACE_SETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0) |
| 159 | perror_with_name (_("Couldn't write ARC HS registers")); |
| 160 | } |
| 161 | } |
| 162 | #endif |
| 163 | |
| 164 | /* Target operation: Read REGNUM register (all registers if REGNUM == -1) |
| 165 | from target process into REGCACHE. */ |
| 166 | |
| 167 | void |
| 168 | arc_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum) |
| 169 | { |
| 170 | |
| 171 | if (regnum == -1 || regnum <= ARC_LAST_REGNUM) |
| 172 | fetch_gregs (regcache, regnum); |
| 173 | |
| 174 | #ifdef ARC_HAS_V2_REGSET |
| 175 | if (regnum == -1 |
| 176 | || regnum == ARC_R30_REGNUM |
| 177 | || regnum == ARC_R58_REGNUM |
| 178 | || regnum == ARC_R59_REGNUM) |
| 179 | fetch_v2_regs (regcache, regnum); |
| 180 | #endif |
| 181 | } |
| 182 | |
| 183 | /* Target operation: Store REGNUM register (all registers if REGNUM == -1) |
| 184 | to the target process from REGCACHE. */ |
| 185 | |
| 186 | void |
| 187 | arc_linux_nat_target::store_registers (struct regcache *regcache, int regnum) |
| 188 | { |
| 189 | if (regnum == -1 || regnum <= ARC_LAST_REGNUM) |
| 190 | store_gregs (regcache, regnum); |
| 191 | |
| 192 | #ifdef ARC_HAS_V2_REGSET |
| 193 | if (regnum == -1 |
| 194 | || regnum == ARC_R30_REGNUM |
| 195 | || regnum == ARC_R58_REGNUM |
| 196 | || regnum == ARC_R59_REGNUM) |
| 197 | store_v2_regs (regcache, regnum); |
| 198 | #endif |
| 199 | } |
| 200 | |
| 201 | /* Copy general purpose register(s) from REGCACHE into regset GREGS. |
| 202 | This function is exported to proc-service.c */ |
| 203 | |
| 204 | void |
| 205 | fill_gregset (const struct regcache *regcache, |
| 206 | gdb_gregset_t *gregs, int regnum) |
| 207 | { |
| 208 | arc_linux_collect_gregset (NULL, regcache, regnum, gregs, 0); |
| 209 | } |
| 210 | |
| 211 | /* Copy all the general purpose registers from regset GREGS into REGCACHE. |
| 212 | This function is exported to proc-service.c. */ |
| 213 | |
| 214 | void |
| 215 | supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregs) |
| 216 | { |
| 217 | arc_linux_supply_gregset (NULL, regcache, -1, gregs, 0); |
| 218 | } |
| 219 | |
| 220 | /* ARC doesn't have separate FP registers. This function is exported |
| 221 | to proc-service.c. */ |
| 222 | |
| 223 | void |
| 224 | fill_fpregset (const struct regcache *regcache, |
| 225 | gdb_fpregset_t *fpregsetp, int regnum) |
| 226 | { |
| 227 | arc_linux_nat_debug_printf ("called"); |
| 228 | } |
| 229 | |
| 230 | /* ARC doesn't have separate FP registers. This function is exported |
| 231 | to proc-service.c. */ |
| 232 | |
| 233 | void |
| 234 | supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp) |
| 235 | { |
| 236 | arc_linux_nat_debug_printf ("called"); |
| 237 | } |
| 238 | |
| 239 | /* Implement the "read_description" method of linux_nat_target. */ |
| 240 | |
| 241 | const struct target_desc * |
| 242 | arc_linux_nat_target::read_description () |
| 243 | { |
| 244 | /* This is a native target, hence description is hardcoded. */ |
| 245 | #ifdef __ARCHS__ |
| 246 | arc_arch_features features (4, ARC_ISA_ARCV2); |
| 247 | #else |
| 248 | arc_arch_features features (4, ARC_ISA_ARCV1); |
| 249 | #endif |
| 250 | return arc_lookup_target_description (features); |
| 251 | } |
| 252 | |
| 253 | /* As described in arc_linux_collect_gregset(), we need to write resume-PC |
| 254 | to ERET. However by default GDB for native targets doesn't write |
| 255 | registers if they haven't been changed. This is a callback called by |
| 256 | generic GDB, and in this callback we have to rewrite PC value so it |
| 257 | would force rewrite of register on target. It seems that the only |
| 258 | other arch that utilizes this hook is x86/x86-64 for HW breakpoint |
| 259 | support. But then, AFAIK no other arch has this stop_pc/eret |
| 260 | complexity. |
| 261 | |
| 262 | No better way was found, other than this fake write of register value, |
| 263 | to force GDB into writing register to target. Is there any? */ |
| 264 | |
| 265 | void |
| 266 | arc_linux_nat_target::low_prepare_to_resume (struct lwp_info *lwp) |
| 267 | { |
| 268 | /* When new processes and threads are created we do not have the address |
| 269 | space for them and calling get_thread_regcache will cause an internal |
| 270 | error in GDB. It looks like that checking for last_resume_kind is the |
| 271 | sensible way to determine processes for which we cannot get regcache. |
| 272 | Ultimately, a better way would be removing the need for |
| 273 | low_prepare_to_resume in the first place. */ |
| 274 | if (lwp->last_resume_kind == resume_stop) |
| 275 | return; |
| 276 | |
| 277 | struct regcache *regcache = get_thread_regcache (this, lwp->ptid); |
| 278 | struct gdbarch *gdbarch = regcache->arch (); |
| 279 | |
| 280 | /* Read current PC value, then write it back. It is required to call |
| 281 | invalidate(), otherwise GDB will note that new value is equal to old |
| 282 | value and will skip write. */ |
| 283 | ULONGEST new_pc; |
| 284 | regcache_cooked_read_unsigned (regcache, gdbarch_pc_regnum (gdbarch), |
| 285 | &new_pc); |
| 286 | regcache->invalidate (gdbarch_pc_regnum (gdbarch)); |
| 287 | regcache_cooked_write_unsigned (regcache, gdbarch_pc_regnum (gdbarch), |
| 288 | new_pc); |
| 289 | } |
| 290 | |
| 291 | /* Fetch the thread-local storage pointer for libthread_db. Note that |
| 292 | this function is not called from GDB, but is called from libthread_db. |
| 293 | This is required to debug multithreaded applications with NPTL. */ |
| 294 | |
| 295 | ps_err_e |
| 296 | ps_get_thread_area (struct ps_prochandle *ph, lwpid_t lwpid, int idx, |
| 297 | void **base) |
| 298 | { |
| 299 | arc_linux_nat_debug_printf ("called"); |
| 300 | |
| 301 | if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0) |
| 302 | return PS_ERR; |
| 303 | |
| 304 | /* IDX is the bias from the thread pointer to the beginning of the |
| 305 | thread descriptor. It has to be subtracted due to implementation |
| 306 | quirks in libthread_db. */ |
| 307 | *base = (void *) ((char *) *base - idx); |
| 308 | |
| 309 | return PS_OK; |
| 310 | } |
| 311 | |
| 312 | /* Suppress warning from -Wmissing-prototypes. */ |
| 313 | void _initialize_arc_linux_nat (); |
| 314 | void |
| 315 | _initialize_arc_linux_nat () |
| 316 | { |
| 317 | /* Register the target. */ |
| 318 | linux_target = &the_arc_linux_nat_target; |
| 319 | add_inf_child_target (&the_arc_linux_nat_target); |
| 320 | } |