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144 lines
4.7 KiB
C
144 lines
4.7 KiB
C
/* DWARF2 EH unwinding support for NDS32 Linux signal frame.
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Copyright (C) 2014-2022 Free Software Foundation, Inc.
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Contributed by Andes Technology Corporation.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published
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by the Free Software Foundation; either version 3, or (at your
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option) any later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef inhibit_libc
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/* Do code reading to identify a signal frame, and set the frame
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state data appropriately. See unwind-dw2.c for the structs.
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The corresponding bits in the Linux kernel are in
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arch/nds32/kernel/signal.c. */
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#include <signal.h>
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#include <asm/unistd.h>
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#include <sys/ucontext.h>
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/* Exactly the same layout as the kernel structures, unique names. */
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/* arch/nds32/kernel/signal.c */
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struct _rt_sigframe {
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siginfo_t info;
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struct ucontext_t uc;
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};
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#define RT_SIGRETURN 0x8b00f044
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#define MD_FALLBACK_FRAME_STATE_FOR nds32_fallback_frame_state
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/* This function is supposed to be invoked by uw_frame_state_for()
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when there is no unwind data available.
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Generally, given the _Unwind_Context CONTEXT for a stack frame,
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we need to look up its caller and decode information into FS.
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However, if the exception handling happens within a signal handler,
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the return address of signal handler is a special module, which
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contains signal return syscall and has no FDE in the .eh_frame section.
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We need to implement MD_FALLBACK_FRAME_STATE_FOR so that we can
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unwind through signal frames. */
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static _Unwind_Reason_Code
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nds32_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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u_int32_t *pc = (u_int32_t *) context->ra;
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struct sigcontext *sc_;
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_Unwind_Ptr new_cfa;
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#ifdef __NDS32_EB__
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#error "Signal handler is not supported for force unwind."
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#endif
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if ((_Unwind_Ptr) pc & 3)
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return _URC_END_OF_STACK;
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/* Check if we are going through a signal handler.
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See arch/nds32/kernel/signal.c implementation.
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FIXME: Currently we only handle little endian (EL) case. */
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if (pc[0] == RT_SIGRETURN)
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{
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/* Using '_sigfame' memory address to locate kernal's sigcontext.
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The sigcontext structures in arch/nds32/include/asm/sigcontext.h. */
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struct _rt_sigframe *rt_;
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rt_ = context->cfa;
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sc_ = &rt_->uc.uc_mcontext;
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}
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else
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return _URC_END_OF_STACK;
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/* Update cfa from sigcontext. */
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new_cfa = (_Unwind_Ptr) sc_;
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fs->regs.cfa_how = CFA_REG_OFFSET;
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fs->regs.cfa_reg = STACK_POINTER_REGNUM;
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fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
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#define NDS32_PUT_FS_REG(NUM, NAME) \
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(fs->regs.reg[NUM].how = REG_SAVED_OFFSET, \
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fs->regs.reg[NUM].loc.offset = (_Unwind_Ptr) &(sc_->NAME) - new_cfa)
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/* Restore all registers value. */
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NDS32_PUT_FS_REG (0, nds32_r0);
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NDS32_PUT_FS_REG (1, nds32_r1);
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NDS32_PUT_FS_REG (2, nds32_r2);
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NDS32_PUT_FS_REG (3, nds32_r3);
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NDS32_PUT_FS_REG (4, nds32_r4);
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NDS32_PUT_FS_REG (5, nds32_r5);
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NDS32_PUT_FS_REG (6, nds32_r6);
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NDS32_PUT_FS_REG (7, nds32_r7);
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NDS32_PUT_FS_REG (8, nds32_r8);
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NDS32_PUT_FS_REG (9, nds32_r9);
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NDS32_PUT_FS_REG (10, nds32_r10);
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NDS32_PUT_FS_REG (11, nds32_r11);
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NDS32_PUT_FS_REG (12, nds32_r12);
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NDS32_PUT_FS_REG (13, nds32_r13);
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NDS32_PUT_FS_REG (14, nds32_r14);
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NDS32_PUT_FS_REG (15, nds32_r15);
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NDS32_PUT_FS_REG (16, nds32_r16);
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NDS32_PUT_FS_REG (17, nds32_r17);
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NDS32_PUT_FS_REG (18, nds32_r18);
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NDS32_PUT_FS_REG (19, nds32_r19);
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NDS32_PUT_FS_REG (20, nds32_r20);
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NDS32_PUT_FS_REG (21, nds32_r21);
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NDS32_PUT_FS_REG (22, nds32_r22);
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NDS32_PUT_FS_REG (23, nds32_r23);
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NDS32_PUT_FS_REG (24, nds32_r24);
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NDS32_PUT_FS_REG (25, nds32_r25);
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NDS32_PUT_FS_REG (28, nds32_fp);
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NDS32_PUT_FS_REG (29, nds32_gp);
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NDS32_PUT_FS_REG (30, nds32_lp);
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NDS32_PUT_FS_REG (31, nds32_sp);
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/* Restore PC, point to trigger signal instruction. */
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NDS32_PUT_FS_REG (32, nds32_ipc);
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#undef NDS32_PUT_FS_REG
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/* The retaddr is PC, use PC to find FDE. */
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fs->retaddr_column = 32;
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fs->signal_frame = 1;
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return _URC_NO_REASON;
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}
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#endif
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