| 1 | /* Target-dependent code for GNU/Linux SPARC. |
| 2 | |
| 3 | Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009 |
| 4 | 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 "defs.h" |
| 22 | #include "dwarf2-frame.h" |
| 23 | #include "frame.h" |
| 24 | #include "frame-unwind.h" |
| 25 | #include "gdbtypes.h" |
| 26 | #include "regset.h" |
| 27 | #include "gdbarch.h" |
| 28 | #include "gdbcore.h" |
| 29 | #include "osabi.h" |
| 30 | #include "regcache.h" |
| 31 | #include "solib-svr4.h" |
| 32 | #include "symtab.h" |
| 33 | #include "trad-frame.h" |
| 34 | #include "tramp-frame.h" |
| 35 | |
| 36 | #include "sparc-tdep.h" |
| 37 | |
| 38 | /* Signal trampoline support. */ |
| 39 | |
| 40 | static void sparc32_linux_sigframe_init (const struct tramp_frame *self, |
| 41 | struct frame_info *this_frame, |
| 42 | struct trad_frame_cache *this_cache, |
| 43 | CORE_ADDR func); |
| 44 | |
| 45 | /* GNU/Linux has two flavors of signals. Normal signal handlers, and |
| 46 | "realtime" (RT) signals. The RT signals can provide additional |
| 47 | information to the signal handler if the SA_SIGINFO flag is set |
| 48 | when establishing a signal handler using `sigaction'. It is not |
| 49 | unlikely that future versions of GNU/Linux will support SA_SIGINFO |
| 50 | for normal signals too. */ |
| 51 | |
| 52 | /* When the sparc Linux kernel calls a signal handler and the |
| 53 | SA_RESTORER flag isn't set, the return address points to a bit of |
| 54 | code on the stack. This code checks whether the PC appears to be |
| 55 | within this bit of code. |
| 56 | |
| 57 | The instruction sequence for normal signals is encoded below. |
| 58 | Checking for the code sequence should be somewhat reliable, because |
| 59 | the effect is to call the system call sigreturn. This is unlikely |
| 60 | to occur anywhere other than a signal trampoline. */ |
| 61 | |
| 62 | static const struct tramp_frame sparc32_linux_sigframe = |
| 63 | { |
| 64 | SIGTRAMP_FRAME, |
| 65 | 4, |
| 66 | { |
| 67 | { 0x821020d8, -1 }, /* mov __NR_sugreturn, %g1 */ |
| 68 | { 0x91d02010, -1 }, /* ta 0x10 */ |
| 69 | { TRAMP_SENTINEL_INSN, -1 } |
| 70 | }, |
| 71 | sparc32_linux_sigframe_init |
| 72 | }; |
| 73 | |
| 74 | /* The instruction sequence for RT signals is slightly different. The |
| 75 | effect is to call the system call rt_sigreturn. */ |
| 76 | |
| 77 | static const struct tramp_frame sparc32_linux_rt_sigframe = |
| 78 | { |
| 79 | SIGTRAMP_FRAME, |
| 80 | 4, |
| 81 | { |
| 82 | { 0x82102065, -1 }, /* mov __NR_rt_sigreturn, %g1 */ |
| 83 | { 0x91d02010, -1 }, /* ta 0x10 */ |
| 84 | { TRAMP_SENTINEL_INSN, -1 } |
| 85 | }, |
| 86 | sparc32_linux_sigframe_init |
| 87 | }; |
| 88 | |
| 89 | static void |
| 90 | sparc32_linux_sigframe_init (const struct tramp_frame *self, |
| 91 | struct frame_info *this_frame, |
| 92 | struct trad_frame_cache *this_cache, |
| 93 | CORE_ADDR func) |
| 94 | { |
| 95 | CORE_ADDR base, addr, sp_addr; |
| 96 | int regnum; |
| 97 | |
| 98 | base = get_frame_register_unsigned (this_frame, SPARC_O1_REGNUM); |
| 99 | if (self == &sparc32_linux_rt_sigframe) |
| 100 | base += 128; |
| 101 | |
| 102 | /* Offsets from <bits/sigcontext.h>. */ |
| 103 | |
| 104 | trad_frame_set_reg_addr (this_cache, SPARC32_PSR_REGNUM, base + 0); |
| 105 | trad_frame_set_reg_addr (this_cache, SPARC32_PC_REGNUM, base + 4); |
| 106 | trad_frame_set_reg_addr (this_cache, SPARC32_NPC_REGNUM, base + 8); |
| 107 | trad_frame_set_reg_addr (this_cache, SPARC32_Y_REGNUM, base + 12); |
| 108 | |
| 109 | /* Since %g0 is always zero, keep the identity encoding. */ |
| 110 | addr = base + 20; |
| 111 | sp_addr = base + 16 + ((SPARC_SP_REGNUM - SPARC_G0_REGNUM) * 4); |
| 112 | for (regnum = SPARC_G1_REGNUM; regnum <= SPARC_O7_REGNUM; regnum++) |
| 113 | { |
| 114 | trad_frame_set_reg_addr (this_cache, regnum, addr); |
| 115 | addr += 4; |
| 116 | } |
| 117 | |
| 118 | base = get_frame_register_unsigned (this_frame, SPARC_SP_REGNUM); |
| 119 | addr = get_frame_memory_unsigned (this_frame, sp_addr, 4); |
| 120 | |
| 121 | for (regnum = SPARC_L0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++) |
| 122 | { |
| 123 | trad_frame_set_reg_addr (this_cache, regnum, addr); |
| 124 | addr += 4; |
| 125 | } |
| 126 | trad_frame_set_id (this_cache, frame_id_build (base, func)); |
| 127 | } |
| 128 | \f |
| 129 | /* Return the address of a system call's alternative return |
| 130 | address. */ |
| 131 | |
| 132 | static CORE_ADDR |
| 133 | sparc32_linux_step_trap (struct frame_info *frame, unsigned long insn) |
| 134 | { |
| 135 | if (insn == 0x91d02010) |
| 136 | { |
| 137 | ULONGEST sc_num = get_frame_register_unsigned (frame, SPARC_G1_REGNUM); |
| 138 | |
| 139 | /* __NR_rt_sigreturn is 101 and __NR_sigreturn is 216 */ |
| 140 | if (sc_num == 101 || sc_num == 216) |
| 141 | { |
| 142 | ULONGEST sp, pc_offset; |
| 143 | |
| 144 | sp = get_frame_register_unsigned (frame, SPARC_SP_REGNUM); |
| 145 | |
| 146 | /* The kernel puts the sigreturn registers on the stack, |
| 147 | and this is where the signal unwinding state is take from |
| 148 | when returning from a signal. |
| 149 | |
| 150 | For __NR_sigreturn, this register area sits 96 bytes from |
| 151 | the base of the stack. The saved PC sits 4 bytes into the |
| 152 | sigreturn register save area. |
| 153 | |
| 154 | For __NR_rt_sigreturn a siginfo_t, which is 128 bytes, sits |
| 155 | right before the sigreturn register save area. */ |
| 156 | |
| 157 | pc_offset = 96 + 4; |
| 158 | if (sc_num == 101) |
| 159 | pc_offset += 128; |
| 160 | |
| 161 | return read_memory_unsigned_integer (sp + pc_offset, 4); |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | return 0; |
| 166 | } |
| 167 | \f |
| 168 | |
| 169 | const struct sparc_gregset sparc32_linux_core_gregset = |
| 170 | { |
| 171 | 32 * 4, /* %psr */ |
| 172 | 33 * 4, /* %pc */ |
| 173 | 34 * 4, /* %npc */ |
| 174 | 35 * 4, /* %y */ |
| 175 | -1, /* %wim */ |
| 176 | -1, /* %tbr */ |
| 177 | 1 * 4, /* %g1 */ |
| 178 | 16 * 4, /* %l0 */ |
| 179 | 4, /* y size */ |
| 180 | }; |
| 181 | \f |
| 182 | |
| 183 | static void |
| 184 | sparc32_linux_supply_core_gregset (const struct regset *regset, |
| 185 | struct regcache *regcache, |
| 186 | int regnum, const void *gregs, size_t len) |
| 187 | { |
| 188 | sparc32_supply_gregset (&sparc32_linux_core_gregset, regcache, regnum, gregs); |
| 189 | } |
| 190 | |
| 191 | static void |
| 192 | sparc32_linux_collect_core_gregset (const struct regset *regset, |
| 193 | const struct regcache *regcache, |
| 194 | int regnum, void *gregs, size_t len) |
| 195 | { |
| 196 | sparc32_collect_gregset (&sparc32_linux_core_gregset, regcache, regnum, gregs); |
| 197 | } |
| 198 | |
| 199 | static void |
| 200 | sparc32_linux_supply_core_fpregset (const struct regset *regset, |
| 201 | struct regcache *regcache, |
| 202 | int regnum, const void *fpregs, size_t len) |
| 203 | { |
| 204 | sparc32_supply_fpregset (regcache, regnum, fpregs); |
| 205 | } |
| 206 | |
| 207 | static void |
| 208 | sparc32_linux_collect_core_fpregset (const struct regset *regset, |
| 209 | const struct regcache *regcache, |
| 210 | int regnum, void *fpregs, size_t len) |
| 211 | { |
| 212 | sparc32_collect_fpregset (regcache, regnum, fpregs); |
| 213 | } |
| 214 | |
| 215 | /* Set the program counter for process PTID to PC. */ |
| 216 | |
| 217 | #define PSR_SYSCALL 0x00004000 |
| 218 | |
| 219 | static void |
| 220 | sparc_linux_write_pc (struct regcache *regcache, CORE_ADDR pc) |
| 221 | { |
| 222 | struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache)); |
| 223 | ULONGEST psr; |
| 224 | |
| 225 | regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc); |
| 226 | regcache_cooked_write_unsigned (regcache, tdep->npc_regnum, pc + 4); |
| 227 | |
| 228 | /* Clear the "in syscall" bit to prevent the kernel from |
| 229 | messing with the PCs we just installed, if we happen to be |
| 230 | within an interrupted system call that the kernel wants to |
| 231 | restart. |
| 232 | |
| 233 | Note that after we return from the dummy call, the PSR et al. |
| 234 | registers will be automatically restored, and the kernel |
| 235 | continues to restart the system call at this point. */ |
| 236 | regcache_cooked_read_unsigned (regcache, SPARC32_PSR_REGNUM, &psr); |
| 237 | psr &= ~PSR_SYSCALL; |
| 238 | regcache_cooked_write_unsigned (regcache, SPARC32_PSR_REGNUM, psr); |
| 239 | } |
| 240 | |
| 241 | \f |
| 242 | |
| 243 | static void |
| 244 | sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 245 | { |
| 246 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 247 | |
| 248 | tdep->gregset = regset_alloc (gdbarch, sparc32_linux_supply_core_gregset, |
| 249 | sparc32_linux_collect_core_gregset); |
| 250 | tdep->sizeof_gregset = 152; |
| 251 | |
| 252 | tdep->fpregset = regset_alloc (gdbarch, sparc32_linux_supply_core_fpregset, |
| 253 | sparc32_linux_collect_core_fpregset); |
| 254 | tdep->sizeof_fpregset = 396; |
| 255 | |
| 256 | tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_sigframe); |
| 257 | tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_rt_sigframe); |
| 258 | |
| 259 | /* GNU/Linux has SVR4-style shared libraries... */ |
| 260 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
| 261 | set_solib_svr4_fetch_link_map_offsets |
| 262 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
| 263 | |
| 264 | /* ...which means that we need some special handling when doing |
| 265 | prologue analysis. */ |
| 266 | tdep->plt_entry_size = 12; |
| 267 | |
| 268 | /* Enable TLS support. */ |
| 269 | set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| 270 | svr4_fetch_objfile_link_map); |
| 271 | |
| 272 | /* Make sure we can single-step over signal return system calls. */ |
| 273 | tdep->step_trap = sparc32_linux_step_trap; |
| 274 | |
| 275 | /* Hook in the DWARF CFI frame unwinder. */ |
| 276 | dwarf2_append_unwinders (gdbarch); |
| 277 | |
| 278 | set_gdbarch_write_pc (gdbarch, sparc_linux_write_pc); |
| 279 | } |
| 280 | |
| 281 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 282 | extern void _initialize_sparc_linux_tdep (void); |
| 283 | |
| 284 | void |
| 285 | _initialize_sparc_linux_tdep (void) |
| 286 | { |
| 287 | gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_LINUX, |
| 288 | sparc32_linux_init_abi); |
| 289 | } |