/* Target-dependent code for GNU/Linux SPARC. Copyright (C) 2003-2005, 2007-2012 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 "dwarf2-frame.h" #include "frame.h" #include "frame-unwind.h" #include "gdbtypes.h" #include "regset.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 "tramp-frame.h" #include "xml-syscall.h" #include "linux-tdep.h" /* The syscall's XML filename for sparc 32-bit. */ #define XML_SYSCALL_FILENAME_SPARC32 "syscalls/sparc-linux.xml" #include "sparc-tdep.h" /* Signal trampoline support. */ static void sparc32_linux_sigframe_init (const struct tramp_frame *self, struct frame_info *this_frame, struct trad_frame_cache *this_cache, CORE_ADDR func); /* 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 code checks whether the PC appears to be within this bit of code. The instruction sequence for normal signals is encoded below. 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. */ static const struct tramp_frame sparc32_linux_sigframe = { SIGTRAMP_FRAME, 4, { { 0x821020d8, -1 }, /* mov __NR_sugreturn, %g1 */ { 0x91d02010, -1 }, /* ta 0x10 */ { TRAMP_SENTINEL_INSN, -1 } }, sparc32_linux_sigframe_init }; /* The instruction sequence for RT signals is slightly different. The effect is to call the system call rt_sigreturn. */ static const struct tramp_frame sparc32_linux_rt_sigframe = { SIGTRAMP_FRAME, 4, { { 0x82102065, -1 }, /* mov __NR_rt_sigreturn, %g1 */ { 0x91d02010, -1 }, /* ta 0x10 */ { TRAMP_SENTINEL_INSN, -1 } }, sparc32_linux_sigframe_init }; static void sparc32_linux_sigframe_init (const struct tramp_frame *self, struct frame_info *this_frame, struct trad_frame_cache *this_cache, CORE_ADDR func) { CORE_ADDR base, addr, sp_addr; int regnum; base = get_frame_register_unsigned (this_frame, SPARC_O1_REGNUM); if (self == &sparc32_linux_rt_sigframe) base += 128; /* Offsets from <bits/sigcontext.h>. */ trad_frame_set_reg_addr (this_cache, SPARC32_PSR_REGNUM, base + 0); trad_frame_set_reg_addr (this_cache, SPARC32_PC_REGNUM, base + 4); trad_frame_set_reg_addr (this_cache, SPARC32_NPC_REGNUM, base + 8); trad_frame_set_reg_addr (this_cache, SPARC32_Y_REGNUM, base + 12); /* Since %g0 is always zero, keep the identity encoding. */ addr = base + 20; sp_addr = base + 16 + ((SPARC_SP_REGNUM - SPARC_G0_REGNUM) * 4); for (regnum = SPARC_G1_REGNUM; regnum <= SPARC_O7_REGNUM; regnum++) { trad_frame_set_reg_addr (this_cache, regnum, addr); addr += 4; } base = get_frame_register_unsigned (this_frame, SPARC_SP_REGNUM); addr = get_frame_memory_unsigned (this_frame, sp_addr, 4); for (regnum = SPARC_L0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++) { trad_frame_set_reg_addr (this_cache, regnum, addr); addr += 4; } trad_frame_set_id (this_cache, frame_id_build (base, func)); } /* Return the address of a system call's alternative return address. */ static CORE_ADDR sparc32_linux_step_trap (struct frame_info *frame, unsigned long insn) { if (insn == 0x91d02010) { ULONGEST sc_num = get_frame_register_unsigned (frame, SPARC_G1_REGNUM); /* __NR_rt_sigreturn is 101 and __NR_sigreturn is 216. */ if (sc_num == 101 || sc_num == 216) { struct gdbarch *gdbarch = get_frame_arch (frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); ULONGEST sp, pc_offset; sp = get_frame_register_unsigned (frame, SPARC_SP_REGNUM); /* The kernel puts the sigreturn registers on the stack, and this is where the signal unwinding state is take from when returning from a signal. For __NR_sigreturn, this register area sits 96 bytes from the base of the stack. The saved PC sits 4 bytes into the sigreturn register save area. For __NR_rt_sigreturn a siginfo_t, which is 128 bytes, sits right before the sigreturn register save area. */ pc_offset = 96 + 4; if (sc_num == 101) pc_offset += 128; return read_memory_unsigned_integer (sp + pc_offset, 4, byte_order); } } return 0; } const struct sparc_gregset sparc32_linux_core_gregset = { 32 * 4, /* %psr */ 33 * 4, /* %pc */ 34 * 4, /* %npc */ 35 * 4, /* %y */ -1, /* %wim */ -1, /* %tbr */ 1 * 4, /* %g1 */ 16 * 4, /* %l0 */ 4, /* y size */ }; static void sparc32_linux_supply_core_gregset (const struct regset *regset, struct regcache *regcache, int regnum, const void *gregs, size_t len) { sparc32_supply_gregset (&sparc32_linux_core_gregset, regcache, regnum, gregs); } static void sparc32_linux_collect_core_gregset (const struct regset *regset, const struct regcache *regcache, int regnum, void *gregs, size_t len) { sparc32_collect_gregset (&sparc32_linux_core_gregset, regcache, regnum, gregs); } static void sparc32_linux_supply_core_fpregset (const struct regset *regset, struct regcache *regcache, int regnum, const void *fpregs, size_t len) { sparc32_supply_fpregset (regcache, regnum, fpregs); } static void sparc32_linux_collect_core_fpregset (const struct regset *regset, const struct regcache *regcache, int regnum, void *fpregs, size_t len) { sparc32_collect_fpregset (regcache, regnum, fpregs); } /* Set the program counter for process PTID to PC. */ #define PSR_SYSCALL 0x00004000 static void sparc_linux_write_pc (struct regcache *regcache, CORE_ADDR pc) { struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache)); ULONGEST psr; regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc); regcache_cooked_write_unsigned (regcache, tdep->npc_regnum, pc + 4); /* Clear the "in syscall" bit to prevent the kernel from messing with the PCs we just installed, if we happen to be within an interrupted system call that the kernel wants to restart. Note that after we return from the dummy call, the PSR et al. registers will be automatically restored, and the kernel continues to restart the system call at this point. */ regcache_cooked_read_unsigned (regcache, SPARC32_PSR_REGNUM, &psr); psr &= ~PSR_SYSCALL; regcache_cooked_write_unsigned (regcache, SPARC32_PSR_REGNUM, psr); } static LONGEST sparc32_linux_get_syscall_number (struct gdbarch *gdbarch, ptid_t ptid) { struct regcache *regcache = get_thread_regcache (ptid); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); /* The content of a register. */ gdb_byte buf[4]; /* The result. */ LONGEST ret; /* Getting the system call number from the register. When dealing with the sparc architecture, this information is stored at the %g1 register. */ regcache_cooked_read (regcache, SPARC_G1_REGNUM, buf); ret = extract_signed_integer (buf, 4, byte_order); return ret; } static void sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); linux_init_abi (info, gdbarch); tdep->gregset = regset_alloc (gdbarch, sparc32_linux_supply_core_gregset, sparc32_linux_collect_core_gregset); tdep->sizeof_gregset = 152; tdep->fpregset = regset_alloc (gdbarch, sparc32_linux_supply_core_fpregset, sparc32_linux_collect_core_fpregset); tdep->sizeof_fpregset = 396; tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_sigframe); tramp_frame_prepend_unwinder (gdbarch, &sparc32_linux_rt_sigframe); /* GNU/Linux has SVR4-style shared libraries... */ set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); set_solib_svr4_fetch_link_map_offsets (gdbarch, svr4_ilp32_fetch_link_map_offsets); /* ...which means that we need some special handling when doing prologue analysis. */ tdep->plt_entry_size = 12; /* Enable TLS support. */ set_gdbarch_fetch_tls_load_module_address (gdbarch, svr4_fetch_objfile_link_map); /* Make sure we can single-step over signal return system calls. */ tdep->step_trap = sparc32_linux_step_trap; /* Hook in the DWARF CFI frame unwinder. */ dwarf2_append_unwinders (gdbarch); set_gdbarch_write_pc (gdbarch, sparc_linux_write_pc); /* Functions for 'catch syscall'. */ set_xml_syscall_file_name (XML_SYSCALL_FILENAME_SPARC32); set_gdbarch_get_syscall_number (gdbarch, sparc32_linux_get_syscall_number); } /* 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); }