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Diffstat (limited to 'gdb/ppc-obsd-tdep.c')
-rw-r--r-- | gdb/ppc-obsd-tdep.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/gdb/ppc-obsd-tdep.c b/gdb/ppc-obsd-tdep.c new file mode 100644 index 0000000..f61dd24 --- /dev/null +++ b/gdb/ppc-obsd-tdep.c @@ -0,0 +1,327 @@ +/* Target-dependent code for OpenBSD/powerpc. + + Copyright (C) 2004-2016 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 3 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, see <http://www.gnu.org/licenses/>. */ + +#include "defs.h" +#include "arch-utils.h" +#include "frame.h" +#include "frame-unwind.h" +#include "gdbtypes.h" +#include "osabi.h" +#include "regcache.h" +#include "regset.h" +#include "symtab.h" +#include "trad-frame.h" + +#include "ppc-tdep.h" +#include "ppc-obsd-tdep.h" +#include "solib-svr4.h" + +/* Register offsets from <machine/reg.h>. */ +struct ppc_reg_offsets ppcobsd_reg_offsets; +struct ppc_reg_offsets ppcobsd_fpreg_offsets; + + +/* Core file support. */ + +/* Supply register REGNUM in the general-purpose register set REGSET + from the buffer specified by GREGS and LEN to register cache + REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ + +void +ppcobsd_supply_gregset (const struct regset *regset, + struct regcache *regcache, int regnum, + const void *gregs, size_t len) +{ + ppc_supply_gregset (regset, regcache, regnum, gregs, len); + ppc_supply_fpregset (regset, regcache, regnum, gregs, len); +} + +/* Collect register REGNUM in the general-purpose register set + REGSET, from register cache REGCACHE into the buffer specified by + GREGS and LEN. If REGNUM is -1, do this for all registers in + REGSET. */ + +void +ppcobsd_collect_gregset (const struct regset *regset, + const struct regcache *regcache, int regnum, + void *gregs, size_t len) +{ + ppc_collect_gregset (regset, regcache, regnum, gregs, len); + ppc_collect_fpregset (regset, regcache, regnum, gregs, len); +} + +/* OpenBSD/powerpc register set. */ + +const struct regset ppcobsd_gregset = +{ + &ppcobsd_reg_offsets, + ppcobsd_supply_gregset +}; + +const struct regset ppcobsd_fpregset = +{ + &ppcobsd_fpreg_offsets, + ppc_supply_fpregset +}; + +/* Iterate over core file register note sections. */ + +static void +ppcobsd_iterate_over_regset_sections (struct gdbarch *gdbarch, + iterate_over_regset_sections_cb *cb, + void *cb_data, + const struct regcache *regcache) +{ + cb (".reg", 412, &ppcobsd_gregset, NULL, cb_data); +} + + +/* Signal trampolines. */ + +/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page + in virtual memory. The randomness makes it somewhat tricky to + detect it, but fortunately we can rely on the fact that the start + of the sigtramp routine is page-aligned. We recognize the + trampoline by looking for the code that invokes the sigreturn + system call. The offset where we can find that code varies from + release to release. + + By the way, the mapping mentioned above is read-only, so you cannot + place a breakpoint in the signal trampoline. */ + +/* Default page size. */ +static const int ppcobsd_page_size = 4096; + +/* Offset for sigreturn(2). */ +static const int ppcobsd_sigreturn_offset[] = { + 0x98, /* OpenBSD 3.8 */ + 0x0c, /* OpenBSD 3.2 */ + -1 +}; + +static int +ppcobsd_sigtramp_frame_sniffer (const struct frame_unwind *self, + struct frame_info *this_frame, + void **this_cache) +{ + struct gdbarch *gdbarch = get_frame_arch (this_frame); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + CORE_ADDR pc = get_frame_pc (this_frame); + CORE_ADDR start_pc = (pc & ~(ppcobsd_page_size - 1)); + const int *offset; + const char *name; + + find_pc_partial_function (pc, &name, NULL, NULL); + if (name) + return 0; + + for (offset = ppcobsd_sigreturn_offset; *offset != -1; offset++) + { + gdb_byte buf[2 * PPC_INSN_SIZE]; + unsigned long insn; + + if (!safe_frame_unwind_memory (this_frame, start_pc + *offset, + buf, sizeof buf)) + continue; + + /* Check for "li r0,SYS_sigreturn". */ + insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order); + if (insn != 0x38000067) + continue; + + /* Check for "sc". */ + insn = extract_unsigned_integer (buf + PPC_INSN_SIZE, + PPC_INSN_SIZE, byte_order); + if (insn != 0x44000002) + continue; + + return 1; + } + + return 0; +} + +static struct trad_frame_cache * +ppcobsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache) +{ + struct gdbarch *gdbarch = get_frame_arch (this_frame); + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + struct trad_frame_cache *cache; + CORE_ADDR addr, base, func; + gdb_byte buf[PPC_INSN_SIZE]; + unsigned long insn, sigcontext_offset; + int i; + + if (*this_cache) + return (struct trad_frame_cache *) *this_cache; + + cache = trad_frame_cache_zalloc (this_frame); + *this_cache = cache; + + func = get_frame_pc (this_frame); + func &= ~(ppcobsd_page_size - 1); + if (!safe_frame_unwind_memory (this_frame, func, buf, sizeof buf)) + return cache; + + /* Calculate the offset where we can find `struct sigcontext'. We + base our calculation on the amount of stack space reserved by the + first instruction of the signal trampoline. */ + insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order); + sigcontext_offset = (0x10000 - (insn & 0x0000ffff)) + 8; + + base = get_frame_register_unsigned (this_frame, gdbarch_sp_regnum (gdbarch)); + addr = base + sigcontext_offset + 2 * tdep->wordsize; + for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize) + { + int regnum = i + tdep->ppc_gp0_regnum; + trad_frame_set_reg_addr (cache, regnum, addr); + } + trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr); + addr += tdep->wordsize; + trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr); + addr += tdep->wordsize; + trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr); + addr += tdep->wordsize; + trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr); + addr += tdep->wordsize; + trad_frame_set_reg_addr (cache, gdbarch_pc_regnum (gdbarch), addr); + /* SRR0? */ + addr += tdep->wordsize; + + /* Construct the frame ID using the function start. */ + trad_frame_set_id (cache, frame_id_build (base, func)); + + return cache; +} + +static void +ppcobsd_sigtramp_frame_this_id (struct frame_info *this_frame, + void **this_cache, struct frame_id *this_id) +{ + struct trad_frame_cache *cache = + ppcobsd_sigtramp_frame_cache (this_frame, this_cache); + + trad_frame_get_id (cache, this_id); +} + +static struct value * +ppcobsd_sigtramp_frame_prev_register (struct frame_info *this_frame, + void **this_cache, int regnum) +{ + struct trad_frame_cache *cache = + ppcobsd_sigtramp_frame_cache (this_frame, this_cache); + + return trad_frame_get_register (cache, this_frame, regnum); +} + +static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = { + SIGTRAMP_FRAME, + default_frame_unwind_stop_reason, + ppcobsd_sigtramp_frame_this_id, + ppcobsd_sigtramp_frame_prev_register, + NULL, + ppcobsd_sigtramp_frame_sniffer +}; + + +static void +ppcobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) +{ + /* OpenBSD doesn't support the 128-bit `long double' from the psABI. */ + set_gdbarch_long_double_bit (gdbarch, 64); + set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double); + + /* OpenBSD currently uses a broken GCC. */ + set_gdbarch_return_value (gdbarch, ppc_sysv_abi_broken_return_value); + + /* OpenBSD uses SVR4-style shared libraries. */ + set_solib_svr4_fetch_link_map_offsets + (gdbarch, svr4_ilp32_fetch_link_map_offsets); + + set_gdbarch_iterate_over_regset_sections + (gdbarch, ppcobsd_iterate_over_regset_sections); + + frame_unwind_append_unwinder (gdbarch, &ppcobsd_sigtramp_frame_unwind); +} + + +/* OpenBSD uses uses the traditional NetBSD core file format, even for + ports that use ELF. */ +#define GDB_OSABI_NETBSD_CORE GDB_OSABI_OPENBSD_ELF + +static enum gdb_osabi +ppcobsd_core_osabi_sniffer (bfd *abfd) +{ + if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0) + return GDB_OSABI_NETBSD_CORE; + + return GDB_OSABI_UNKNOWN; +} + + +/* Provide a prototype to silence -Wmissing-prototypes. */ +void _initialize_ppcobsd_tdep (void); + +void +_initialize_ppcobsd_tdep (void) +{ + /* BFD doesn't set a flavour for NetBSD style a.out core files. */ + gdbarch_register_osabi_sniffer (bfd_arch_powerpc, bfd_target_unknown_flavour, + ppcobsd_core_osabi_sniffer); + + gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_OPENBSD_ELF, + ppcobsd_init_abi); + gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_OPENBSD_ELF, + ppcobsd_init_abi); + + /* Avoid initializing the register offsets again if they were + already initialized by ppcobsd-nat.c. */ + if (ppcobsd_reg_offsets.pc_offset == 0) + { + /* General-purpose registers. */ + ppcobsd_reg_offsets.r0_offset = 0; + ppcobsd_reg_offsets.gpr_size = 4; + ppcobsd_reg_offsets.xr_size = 4; + ppcobsd_reg_offsets.pc_offset = 384; + ppcobsd_reg_offsets.ps_offset = 388; + ppcobsd_reg_offsets.cr_offset = 392; + ppcobsd_reg_offsets.lr_offset = 396; + ppcobsd_reg_offsets.ctr_offset = 400; + ppcobsd_reg_offsets.xer_offset = 404; + ppcobsd_reg_offsets.mq_offset = 408; + + /* Floating-point registers. */ + ppcobsd_reg_offsets.f0_offset = 128; + ppcobsd_reg_offsets.fpscr_offset = -1; + + /* AltiVec registers. */ + ppcobsd_reg_offsets.vr0_offset = 0; + ppcobsd_reg_offsets.vscr_offset = 512; + ppcobsd_reg_offsets.vrsave_offset = 520; + } + + if (ppcobsd_fpreg_offsets.fpscr_offset == 0) + { + /* Floating-point registers. */ + ppcobsd_reg_offsets.f0_offset = 0; + ppcobsd_reg_offsets.fpscr_offset = 256; + ppcobsd_reg_offsets.fpscr_size = 4; + } +} |