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Diffstat (limited to 'gdb/sparc-linux-tdep.c')
| -rw-r--r-- | gdb/sparc-linux-tdep.c | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/gdb/sparc-linux-tdep.c b/gdb/sparc-linux-tdep.c new file mode 100644 index 00000000000..13875af438e --- /dev/null +++ b/gdb/sparc-linux-tdep.c @@ -0,0 +1,311 @@ +/* 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); +} |