/* DWARF2 EH unwinding support for GNU Hurd: x86. Copyright (C) 2020-2024 Free Software Foundation, Inc. Contributed by Samuel Thibault 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 . */ /* Do code reading to identify a signal frame, and set the frame state data appropriately. See unwind-dw2.c for the structs. */ #ifndef inhibit_libc #include #ifdef __x86_64__ #define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state static _Unwind_Reason_Code x86_gnu_fallback_frame_state (struct _Unwind_Context *context, _Unwind_FrameState *fs) { static const unsigned char gnu_sigtramp_code[] = { /* rpc_wait_trampoline: */ 0x48, 0xc7, 0xc0, 0xe7, 0xff, 0xff, 0xff, /* mov $-25,%rax */ 0x0f, 0x05, /* syscall */ 0x49, 0x89, 0x04, 0x24, /* mov %rax,(%r12) */ 0x48, 0x89, 0xdc, /* mov %rbx,%rsp */ /* trampoline: */ 0x5f, /* pop %rdi */ 0x5e, /* pop %rsi */ 0x5a, /* pop %rdx */ 0x48, 0x83, 0xc4, 0x08, /* add $0x8,%rsp */ 0x41, 0xff, 0xd5, /* call *%r13 */ /* RA HERE */ 0x48, 0x8b, 0x7c, 0x24, 0x10, /* mov 0x10(%rsp),%rdi */ 0xc3, /* ret */ /* firewall: */ 0xf4, /* hlt */ }; const size_t gnu_sigtramp_len = sizeof gnu_sigtramp_code; const size_t gnu_sigtramp_tail = 7; /* length of tail after RA */ struct stack_contents { void *sigreturn_addr; void *sigreturn_returns_here; struct sigcontext *return_scp; } *stack_contents; struct sigcontext *scp; unsigned long usp; unsigned char *adjusted_pc = (unsigned char*)(context->ra) + gnu_sigtramp_tail - gnu_sigtramp_len; if (memcmp (adjusted_pc, gnu_sigtramp_code, gnu_sigtramp_len)) return _URC_END_OF_STACK; stack_contents = context->cfa; scp = stack_contents->return_scp; usp = scp->sc_ursp; fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_rax - usp; fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_rdx - usp; fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_rcx - usp; fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_rbx - usp; fs->regs.reg[4].loc.offset = (unsigned long)&scp->sc_rsi - usp; fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_rdi - usp; fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_rbp - usp; fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_r8 - usp; fs->regs.reg[9].loc.offset = (unsigned long)&scp->sc_r9 - usp; fs->regs.reg[10].loc.offset = (unsigned long)&scp->sc_r10 - usp; fs->regs.reg[11].loc.offset = (unsigned long)&scp->sc_r11 - usp; fs->regs.reg[12].loc.offset = (unsigned long)&scp->sc_r12 - usp; fs->regs.reg[13].loc.offset = (unsigned long)&scp->sc_r13 - usp; fs->regs.reg[14].loc.offset = (unsigned long)&scp->sc_r14 - usp; fs->regs.reg[15].loc.offset = (unsigned long)&scp->sc_r15 - usp; fs->regs.reg[16].loc.offset = (unsigned long)&scp->sc_rip - usp; /* Register 7 is rsp */ fs->regs.cfa_how = CFA_REG_OFFSET; fs->regs.cfa_reg = 7; fs->regs.cfa_offset = usp - (unsigned long) context->cfa; fs->regs.how[0] = REG_SAVED_OFFSET; fs->regs.how[1] = REG_SAVED_OFFSET; fs->regs.how[2] = REG_SAVED_OFFSET; fs->regs.how[3] = REG_SAVED_OFFSET; fs->regs.how[4] = REG_SAVED_OFFSET; fs->regs.how[5] = REG_SAVED_OFFSET; fs->regs.how[6] = REG_SAVED_OFFSET; fs->regs.how[8] = REG_SAVED_OFFSET; fs->regs.how[9] = REG_SAVED_OFFSET; fs->regs.how[10] = REG_SAVED_OFFSET; fs->regs.how[11] = REG_SAVED_OFFSET; fs->regs.how[12] = REG_SAVED_OFFSET; fs->regs.how[13] = REG_SAVED_OFFSET; fs->regs.how[14] = REG_SAVED_OFFSET; fs->regs.how[15] = REG_SAVED_OFFSET; fs->regs.how[16] = REG_SAVED_OFFSET; fs->retaddr_column = 16; fs->signal_frame = 1; return _URC_NO_REASON; } #else /* ifdef __x86_64__ */ #define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state static _Unwind_Reason_Code x86_gnu_fallback_frame_state (struct _Unwind_Context *context, _Unwind_FrameState *fs) { struct handler_args { int signo; union { struct { long int sigcode; struct sigcontext *scp; } legacy; struct { siginfo_t *siginfop; ucontext_t *uctxp; } posix; }; } *handler_args; long int sigcode; unsigned long usp; /* * i386 sigtramp frame we are looking for follows. * (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly) * * rpc_wait_trampoline: * 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap * 5: 9a 00 00 00 00 07 00 lcall $7,$0 * 12: 89 01 movl %eax, (%ecx) * 14: 89 dc movl %ebx, %esp switch to signal stack * * trampoline: * 16: ff d2 call *%edx call the handler function * RA HERE * 18: 83 c4 0c addl $12, %esp pop its args * 21: c3 ret return to sigreturn * * firewall: * 22: f4 hlt */ if (!( *(unsigned int *)(context->ra ) == 0xc30cc483 && *(unsigned char *)(context->ra + 4) == 0xf4 && *(unsigned int *)(context->ra - 4) == 0xd2ffdc89 && *(unsigned int *)(context->ra - 8) == 0x01890007 && *(unsigned int *)(context->ra - 12) == 0x00000000 && *(unsigned int *)(context->ra - 16) == 0x9affffff && *(unsigned short *)(context->ra - 18) == 0xe7b8)) return _URC_END_OF_STACK; handler_args = context->cfa; sigcode = handler_args->legacy.sigcode; if (sigcode >= -16 && sigcode < 4096) { /* This cannot be a SIGINFO pointer, assume legacy. */ struct sigcontext *scp = handler_args->legacy.scp; usp = scp->sc_uesp; fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp; fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp; fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp; fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp; fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp; fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp; fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp; fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp; } else { /* This is not a valid sigcode, assume SIGINFO. */ ucontext_t *uctxp = handler_args->posix.uctxp; gregset_t *gregset = &uctxp->uc_mcontext.gregs; usp = (*gregset)[REG_UESP]; fs->regs.reg[0].loc.offset = (unsigned long)&(*gregset)[REG_EAX] - usp; fs->regs.reg[1].loc.offset = (unsigned long)&(*gregset)[REG_ECX] - usp; fs->regs.reg[2].loc.offset = (unsigned long)&(*gregset)[REG_EDX] - usp; fs->regs.reg[3].loc.offset = (unsigned long)&(*gregset)[REG_EBX] - usp; fs->regs.reg[5].loc.offset = (unsigned long)&(*gregset)[REG_EBP] - usp; fs->regs.reg[6].loc.offset = (unsigned long)&(*gregset)[REG_ESI] - usp; fs->regs.reg[7].loc.offset = (unsigned long)&(*gregset)[REG_EDI] - usp; fs->regs.reg[8].loc.offset = (unsigned long)&(*gregset)[REG_EIP] - usp; } fs->regs.cfa_how = CFA_REG_OFFSET; fs->regs.cfa_reg = 4; fs->regs.cfa_offset = usp - (unsigned long) context->cfa; fs->regs.how[0] = REG_SAVED_OFFSET; fs->regs.how[1] = REG_SAVED_OFFSET; fs->regs.how[2] = REG_SAVED_OFFSET; fs->regs.how[3] = REG_SAVED_OFFSET; fs->regs.how[5] = REG_SAVED_OFFSET; fs->regs.how[6] = REG_SAVED_OFFSET; fs->regs.how[7] = REG_SAVED_OFFSET; fs->regs.how[8] = REG_SAVED_OFFSET; fs->retaddr_column = 8; fs->signal_frame = 1; return _URC_NO_REASON; } #endif /* ifdef __x86_64__ */ #endif /* ifndef inhibit_libc */