127 lines
4.2 KiB
C
127 lines
4.2 KiB
C
/* DWARF2 EH unwinding support for MIPS Linux.
|
|
Copyright (C) 2004-2020 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 <sys/syscall.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;
|
|
|
|
/* A MIPS16 or microMIPS frame. Signal frames always use the standard
|
|
ISA encoding. */
|
|
if ((_Unwind_Ptr) pc & 3)
|
|
return _URC_END_OF_STACK;
|
|
|
|
/* 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];
|
|
siginfo_t 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 = __LIBGCC_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[__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__].how
|
|
= REG_SAVED_VAL_OFFSET;
|
|
fs->regs.reg[__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__].loc.offset
|
|
= (_Unwind_Ptr)(sc->sc_pc) + 2 - new_cfa;
|
|
fs->retaddr_column = __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__;
|
|
|
|
return _URC_NO_REASON;
|
|
}
|
|
#endif
|