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Diffstat (limited to 'libgcc/config/mips/linux-unwind.h')
| -rw-r--r-- | libgcc/config/mips/linux-unwind.h | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/libgcc/config/mips/linux-unwind.h b/libgcc/config/mips/linux-unwind.h new file mode 100644 index 00000000000..02f7cd54c5a --- /dev/null +++ b/libgcc/config/mips/linux-unwind.h @@ -0,0 +1,120 @@ +/* DWARF2 EH unwinding support for MIPS Linux. + Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC 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, or (at your option) +any later version. + +GCC 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. + +Under Section 7 of GPL version 3, you are granted additional +permissions described in the GCC Runtime Library Exception, version +3.1, as published by the Free Software Foundation. + +You should have received a copy of the GNU General Public License and +a copy of the GCC Runtime Library Exception along with this program; +see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +<http://www.gnu.org/licenses/>. */ + +#ifndef inhibit_libc +/* Do code reading to identify a signal frame, and set the frame + state data appropriately. See unwind-dw2.c for the structs. */ + +#include <signal.h> +#include <asm/unistd.h> + +/* The third parameter to the signal handler points to something with + * this structure defined in asm/ucontext.h, but the name clashes with + * struct ucontext from sys/ucontext.h so this private copy is used. */ +typedef struct _sig_ucontext { + unsigned long uc_flags; + struct _sig_ucontext *uc_link; + stack_t uc_stack; + struct sigcontext uc_mcontext; + sigset_t uc_sigmask; +} _sig_ucontext_t; + +#define MD_FALLBACK_FRAME_STATE_FOR mips_fallback_frame_state + +static _Unwind_Reason_Code +mips_fallback_frame_state (struct _Unwind_Context *context, + _Unwind_FrameState *fs) +{ + u_int32_t *pc = (u_int32_t *) context->ra; + struct sigcontext *sc; + _Unwind_Ptr new_cfa, reg_offset; + int i; + + /* 24021061 li v0, 0x1061 (rt_sigreturn)*/ + /* 0000000c syscall */ + /* or */ + /* 24021017 li v0, 0x1017 (sigreturn) */ + /* 0000000c syscall */ + if (pc[1] != 0x0000000c) + return _URC_END_OF_STACK; +#if _MIPS_SIM == _ABIO32 + if (pc[0] == (0x24020000 | __NR_sigreturn)) + { + struct sigframe { + u_int32_t ass[4]; /* Argument save space for o32. */ + u_int32_t trampoline[2]; + struct sigcontext sigctx; + } *rt_ = context->cfa; + sc = &rt_->sigctx; + } + else +#endif + if (pc[0] == (0x24020000 | __NR_rt_sigreturn)) + { + struct rt_sigframe { + u_int32_t ass[4]; /* Argument save space for o32. */ + u_int32_t trampoline[2]; + struct siginfo info; + _sig_ucontext_t uc; + } *rt_ = context->cfa; + sc = &rt_->uc.uc_mcontext; + } + else + return _URC_END_OF_STACK; + + new_cfa = (_Unwind_Ptr) sc; + fs->regs.cfa_how = CFA_REG_OFFSET; + fs->regs.cfa_reg = STACK_POINTER_REGNUM; + fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa; + + /* On o32 Linux, the register save slots in the sigcontext are + eight bytes. We need the lower half of each register slot, + so slide our view of the structure back four bytes. */ +#if _MIPS_SIM == _ABIO32 && defined __MIPSEB__ + reg_offset = 4; +#else + reg_offset = 0; +#endif + + for (i = 0; i < 32; i++) { + fs->regs.reg[i].how = REG_SAVED_OFFSET; + fs->regs.reg[i].loc.offset + = (_Unwind_Ptr)&(sc->sc_regs[i]) + reg_offset - new_cfa; + } + /* "PC & -2" points to the faulting instruction, but the unwind code + searches for "(ADDR & -2) - 1". (See MASK_RETURN_ADDR for the source + of the -2 mask.) Adding 2 here ensures that "(ADDR & -2) - 1" is the + address of the second byte of the faulting instruction. + + Note that setting fs->signal_frame would not work. As the comment + above MASK_RETURN_ADDR explains, MIPS unwinders must earch for an + odd-valued address. */ + fs->regs.reg[DWARF_ALT_FRAME_RETURN_COLUMN].how = REG_SAVED_VAL_OFFSET; + fs->regs.reg[DWARF_ALT_FRAME_RETURN_COLUMN].loc.offset + = (_Unwind_Ptr)(sc->sc_pc) + 2 - new_cfa; + fs->retaddr_column = DWARF_ALT_FRAME_RETURN_COLUMN; + + return _URC_NO_REASON; +} +#endif |