| /* Target-dependent code for GNU/Linux SPARC. |
| |
| Copyright 2003 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| #include "floatformat.h" |
| #include "frame.h" |
| #include "frame-unwind.h" |
| #include "gdbarch.h" |
| #include "gdbcore.h" |
| #include "osabi.h" |
| #include "regcache.h" |
| #include "solib-svr4.h" |
| #include "symtab.h" |
| #include "trad-frame.h" |
| |
| #include "gdb_assert.h" |
| #include "gdb_string.h" |
| |
| #include "sparc-tdep.h" |
| |
| /* Recognizing signal handler frames. */ |
| |
| /* GNU/Linux has two flavors of signals. Normal signal handlers, and |
| "realtime" (RT) signals. The RT signals can provide additional |
| information to the signal handler if the SA_SIGINFO flag is set |
| when establishing a signal handler using `sigaction'. It is not |
| unlikely that future versions of GNU/Linux will support SA_SIGINFO |
| for normal signals too. */ |
| |
| /* When the sparc Linux kernel calls a signal handler and the |
| SA_RESTORER flag isn't set, the return address points to a bit of |
| code on the stack. This function returns whether the PC appears to |
| be within this bit of code. |
| |
| The instruction sequence for normal signals is |
| mov __NR_sigreturn, %g1 ! hex: 0x821020d8 |
| ta 0x10 ! hex: 0x91d02010 |
| |
| Checking for the code sequence should be somewhat reliable, because |
| the effect is to call the system call sigreturn. This is unlikely |
| to occur anywhere other than a signal trampoline. |
| |
| It kind of sucks that we have to read memory from the process in |
| order to identify a signal trampoline, but there doesn't seem to be |
| any other way. However, sparc32_linux_pc_in_sigtramp arranges to |
| only call us if no function name could be identified, which should |
| be the case since the code is on the stack. */ |
| |
| #define LINUX32_SIGTRAMP_INSN0 0x821020d8 /* mov __NR_sigreturn, %g1 */ |
| #define LINUX32_SIGTRAMP_INSN1 0x91d02010 /* ta 0x10 */ |
| |
| /* The instruction sequence for RT signals is |
| mov __NR_rt_sigreturn, %g1 ! hex: 0x82102065 |
| ta {0x10,0x6d} ! hex: 0x91d02010 or 0x91d0206d |
| |
| The effect is to call the system call rt_sigreturn. The trap number |
| is variable based upon whether this is a 32-bit or 64-bit sparc binary. |
| Note that 64-bit binaries only use this RT signal return method. */ |
| |
| #define LINUX32_RT_SIGTRAMP_INSN0 0x82102065 |
| #define LINUX32_RT_SIGTRAMP_INSN1 0x91d02010 |
| |
| /* If PC is in a sigtramp routine consisting of the instructions INSN0 |
| and INSN1, return the address of the start of the routine. |
| Otherwise, return 0. */ |
| |
| CORE_ADDR |
| sparc_linux_sigtramp_start (CORE_ADDR pc, ULONGEST insn0, ULONGEST insn1) |
| { |
| ULONGEST word0, word1; |
| char buf[8]; /* Two instructions. */ |
| |
| /* We only recognize a signal trampoline if PC is at the start of |
| one of the instructions. We optimize for finding the PC at the |
| start of the instruction sequence, as will be the case when the |
| trampoline is not the first frame on the stack. We assume that |
| in the case where the PC is not at the start of the instruction |
| sequence, there will be a few trailing readable bytes on the |
| stack. */ |
| |
| if (read_memory_nobpt (pc, buf, sizeof buf) != 0) |
| return 0; |
| |
| word0 = extract_unsigned_integer (buf, 4); |
| if (word0 != insn0) |
| { |
| if (word0 != insn1) |
| return 0; |
| |
| pc -= 4; |
| if (read_memory_nobpt (pc, buf, sizeof buf) != 0) |
| return 0; |
| |
| word0 = extract_unsigned_integer (buf, 4); |
| } |
| |
| word1 = extract_unsigned_integer (buf + 4, 4); |
| if (word0 != insn0 || word1 != insn1) |
| return 0; |
| |
| return pc; |
| } |
| |
| static CORE_ADDR |
| sparc32_linux_sigtramp_start (CORE_ADDR pc) |
| { |
| return sparc_linux_sigtramp_start (pc, LINUX32_SIGTRAMP_INSN0, |
| LINUX32_SIGTRAMP_INSN1); |
| } |
| |
| static CORE_ADDR |
| sparc32_linux_rt_sigtramp_start (CORE_ADDR pc) |
| { |
| return sparc_linux_sigtramp_start (pc, LINUX32_RT_SIGTRAMP_INSN0, |
| LINUX32_RT_SIGTRAMP_INSN1); |
| } |
| |
| static int |
| sparc32_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) |
| { |
| /* If we have NAME, we can optimize the search. The trampolines are |
| named __restore and __restore_rt. However, they aren't dynamically |
| exported from the shared C library, so the trampoline may appear to |
| be part of the preceding function. This should always be sigaction, |
| __sigaction, or __libc_sigaction (all aliases to the same function). */ |
| if (name == NULL || strstr (name, "sigaction") != NULL) |
| return (sparc32_linux_sigtramp_start (pc) != 0 |
| || sparc32_linux_rt_sigtramp_start (pc) != 0); |
| |
| return (strcmp ("__restore", name) == 0 |
| || strcmp ("__restore_rt", name) == 0); |
| } |
| |
| static struct sparc_frame_cache * |
| sparc32_linux_sigtramp_frame_cache (struct frame_info *next_frame, |
| void **this_cache) |
| { |
| struct sparc_frame_cache *cache; |
| CORE_ADDR sigcontext_addr, addr; |
| int regnum; |
| |
| if (*this_cache) |
| return *this_cache; |
| |
| cache = sparc32_frame_cache (next_frame, this_cache); |
| gdb_assert (cache == *this_cache); |
| |
| /* ??? What about signal trampolines that aren't frameless? */ |
| regnum = SPARC_SP_REGNUM; |
| cache->base = frame_unwind_register_unsigned (next_frame, regnum); |
| |
| regnum = SPARC_O1_REGNUM; |
| sigcontext_addr = frame_unwind_register_unsigned (next_frame, regnum); |
| |
| cache->pc = frame_pc_unwind (next_frame); |
| addr = sparc32_linux_sigtramp_start (cache->pc); |
| if (addr == 0) |
| { |
| /* If this is a RT signal trampoline, adjust SIGCONTEXT_ADDR |
| accordingly. */ |
| addr = sparc32_linux_rt_sigtramp_start (cache->pc); |
| if (addr) |
| sigcontext_addr += 128; |
| else |
| addr = frame_func_unwind (next_frame); |
| } |
| cache->pc = addr; |
| |
| cache->saved_regs = trad_frame_alloc_saved_regs (next_frame); |
| |
| cache->saved_regs[SPARC32_PSR_REGNUM].addr = sigcontext_addr + 0; |
| cache->saved_regs[SPARC32_PC_REGNUM].addr = sigcontext_addr + 4; |
| cache->saved_regs[SPARC32_NPC_REGNUM].addr = sigcontext_addr + 8; |
| cache->saved_regs[SPARC32_Y_REGNUM].addr = sigcontext_addr + 12; |
| |
| /* Since %g0 is always zero, keep the identity encoding. */ |
| for (regnum = SPARC_G1_REGNUM, addr = sigcontext_addr + 20; |
| regnum <= SPARC_O7_REGNUM; regnum++, addr += 4) |
| cache->saved_regs[regnum].addr = addr; |
| |
| for (regnum = SPARC_L0_REGNUM, addr = cache->base; |
| regnum <= SPARC_I7_REGNUM; regnum++, addr += 4) |
| cache->saved_regs[regnum].addr = addr; |
| |
| return cache; |
| } |
| |
| static void |
| sparc32_linux_sigtramp_frame_this_id (struct frame_info *next_frame, |
| void **this_cache, |
| struct frame_id *this_id) |
| { |
| struct sparc_frame_cache *cache = |
| sparc32_linux_sigtramp_frame_cache (next_frame, this_cache); |
| |
| (*this_id) = frame_id_build (cache->base, cache->pc); |
| } |
| |
| static void |
| sparc32_linux_sigtramp_frame_prev_register (struct frame_info *next_frame, |
| void **this_cache, |
| int regnum, int *optimizedp, |
| enum lval_type *lvalp, |
| CORE_ADDR *addrp, |
| int *realnump, void *valuep) |
| { |
| struct sparc_frame_cache *cache = |
| sparc32_linux_sigtramp_frame_cache (next_frame, this_cache); |
| |
| trad_frame_prev_register (next_frame, cache->saved_regs, regnum, |
| optimizedp, lvalp, addrp, realnump, valuep); |
| } |
| |
| static const struct frame_unwind sparc32_linux_sigtramp_frame_unwind = |
| { |
| SIGTRAMP_FRAME, |
| sparc32_linux_sigtramp_frame_this_id, |
| sparc32_linux_sigtramp_frame_prev_register |
| }; |
| |
| static const struct frame_unwind * |
| sparc32_linux_sigtramp_frame_sniffer (struct frame_info *next_frame) |
| { |
| CORE_ADDR pc = frame_pc_unwind (next_frame); |
| char *name; |
| |
| find_pc_partial_function (pc, &name, NULL, NULL); |
| if (sparc32_linux_pc_in_sigtramp (pc, name)) |
| return &sparc32_linux_sigtramp_frame_unwind; |
| |
| return NULL; |
| } |
| |
| |
| static struct link_map_offsets * |
| sparc32_linux_svr4_fetch_link_map_offsets (void) |
| { |
| static struct link_map_offsets lmo; |
| static struct link_map_offsets *lmp = NULL; |
| |
| if (lmp == NULL) |
| { |
| lmp = &lmo; |
| |
| /* Everything we need is in the first 8 bytes. */ |
| lmo.r_debug_size = 8; |
| lmo.r_map_offset = 4; |
| lmo.r_map_size = 4; |
| |
| /* Everything we need is in the first 20 bytes. */ |
| lmo.link_map_size = 20; |
| lmo.l_addr_offset = 0; |
| lmo.l_addr_size = 4; |
| lmo.l_name_offset = 4; |
| lmo.l_name_size = 4; |
| lmo.l_next_offset = 12; |
| lmo.l_next_size = 4; |
| lmo.l_prev_offset = 16; |
| lmo.l_prev_size = 4; |
| } |
| |
| return lmp; |
| } |
| |
| static void |
| sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| { |
| /* GNU/Linux is very similar to Solaris ... */ |
| sparc32_sol2_init_abi (info, gdbarch); |
| |
| /* ... but doesn't have kernel-assisted single-stepping support. */ |
| set_gdbarch_software_single_step (gdbarch, sparc_software_single_step); |
| |
| /* GNU/Linux doesn't support the 128-bit `long double' from the psABI. */ |
| set_gdbarch_long_double_bit (gdbarch, 64); |
| set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big); |
| |
| set_gdbarch_pc_in_sigtramp (gdbarch, sparc32_linux_pc_in_sigtramp); |
| frame_unwind_append_sniffer (gdbarch, sparc32_linux_sigtramp_frame_sniffer); |
| |
| set_solib_svr4_fetch_link_map_offsets |
| (gdbarch, sparc32_linux_svr4_fetch_link_map_offsets); |
| } |
| |
| /* Provide a prototype to silence -Wmissing-prototypes. */ |
| extern void _initialize_sparc_linux_tdep (void); |
| |
| void |
| _initialize_sparc_linux_tdep (void) |
| { |
| gdbarch_register_osabi (bfd_arch_sparc, 0, GDB_OSABI_LINUX, |
| sparc32_linux_init_abi); |
| } |