| /* DWARF2 EH unwinding support for NDS32 Linux signal frame. |
| Copyright (C) 2014-2021 Free Software Foundation, Inc. |
| Contributed by Andes Technology Corporation. |
| |
| 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. |
| The corresponding bits in the Linux kernel are in |
| arch/nds32/kernel/signal.c. */ |
| |
| #include <signal.h> |
| #include <asm/unistd.h> |
| #include <sys/ucontext.h> |
| |
| /* Exactly the same layout as the kernel structures, unique names. */ |
| |
| /* arch/nds32/kernel/signal.c */ |
| struct _rt_sigframe { |
| siginfo_t info; |
| struct ucontext_t uc; |
| }; |
| |
| #define RT_SIGRETURN 0x8b00f044 |
| |
| #define MD_FALLBACK_FRAME_STATE_FOR nds32_fallback_frame_state |
| |
| /* This function is supposed to be invoked by uw_frame_state_for() |
| when there is no unwind data available. |
| |
| Generally, given the _Unwind_Context CONTEXT for a stack frame, |
| we need to look up its caller and decode information into FS. |
| However, if the exception handling happens within a signal handler, |
| the return address of signal handler is a special module, which |
| contains signal return syscall and has no FDE in the .eh_frame section. |
| We need to implement MD_FALLBACK_FRAME_STATE_FOR so that we can |
| unwind through signal frames. */ |
| static _Unwind_Reason_Code |
| nds32_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; |
| |
| #ifdef __NDS32_EB__ |
| #error "Signal handler is not supported for force unwind." |
| #endif |
| |
| if ((_Unwind_Ptr) pc & 3) |
| return _URC_END_OF_STACK; |
| |
| /* Check if we are going through a signal handler. |
| See arch/nds32/kernel/signal.c implementation. |
| FIXME: Currently we only handle little endian (EL) case. */ |
| if (pc[0] == RT_SIGRETURN) |
| { |
| /* Using '_sigfame' memory address to locate kernal's sigcontext. |
| The sigcontext structures in arch/nds32/include/asm/sigcontext.h. */ |
| struct _rt_sigframe *rt_; |
| rt_ = context->cfa; |
| sc_ = &rt_->uc.uc_mcontext; |
| } |
| else |
| return _URC_END_OF_STACK; |
| |
| /* Update cfa from sigcontext. */ |
| 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; |
| |
| #define NDS32_PUT_FS_REG(NUM, NAME) \ |
| (fs->regs.reg[NUM].how = REG_SAVED_OFFSET, \ |
| fs->regs.reg[NUM].loc.offset = (_Unwind_Ptr) &(sc_->NAME) - new_cfa) |
| |
| /* Restore all registers value. */ |
| NDS32_PUT_FS_REG (0, nds32_r0); |
| NDS32_PUT_FS_REG (1, nds32_r1); |
| NDS32_PUT_FS_REG (2, nds32_r2); |
| NDS32_PUT_FS_REG (3, nds32_r3); |
| NDS32_PUT_FS_REG (4, nds32_r4); |
| NDS32_PUT_FS_REG (5, nds32_r5); |
| NDS32_PUT_FS_REG (6, nds32_r6); |
| NDS32_PUT_FS_REG (7, nds32_r7); |
| NDS32_PUT_FS_REG (8, nds32_r8); |
| NDS32_PUT_FS_REG (9, nds32_r9); |
| NDS32_PUT_FS_REG (10, nds32_r10); |
| NDS32_PUT_FS_REG (11, nds32_r11); |
| NDS32_PUT_FS_REG (12, nds32_r12); |
| NDS32_PUT_FS_REG (13, nds32_r13); |
| NDS32_PUT_FS_REG (14, nds32_r14); |
| NDS32_PUT_FS_REG (15, nds32_r15); |
| NDS32_PUT_FS_REG (16, nds32_r16); |
| NDS32_PUT_FS_REG (17, nds32_r17); |
| NDS32_PUT_FS_REG (18, nds32_r18); |
| NDS32_PUT_FS_REG (19, nds32_r19); |
| NDS32_PUT_FS_REG (20, nds32_r20); |
| NDS32_PUT_FS_REG (21, nds32_r21); |
| NDS32_PUT_FS_REG (22, nds32_r22); |
| NDS32_PUT_FS_REG (23, nds32_r23); |
| NDS32_PUT_FS_REG (24, nds32_r24); |
| NDS32_PUT_FS_REG (25, nds32_r25); |
| |
| NDS32_PUT_FS_REG (28, nds32_fp); |
| NDS32_PUT_FS_REG (29, nds32_gp); |
| NDS32_PUT_FS_REG (30, nds32_lp); |
| NDS32_PUT_FS_REG (31, nds32_sp); |
| |
| /* Restore PC, point to trigger signal instruction. */ |
| NDS32_PUT_FS_REG (32, nds32_ipc); |
| |
| #undef NDS32_PUT_FS_REG |
| |
| /* The retaddr is PC, use PC to find FDE. */ |
| fs->retaddr_column = 32; |
| fs->signal_frame = 1; |
| |
| return _URC_NO_REASON; |
| } |
| |
| #endif |