/* DWARF2 EH unwinding support for PowerPC and PowerPC64 Linux. Copyright (C) 2004-2014 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 . */ #define R_LR 65 #define R_CR2 70 #define R_CR3 71 #define R_CR4 72 #define R_VR0 77 #define R_VRSAVE 109 #ifdef __powerpc64__ #if _CALL_ELF == 2 #define TOC_SAVE_SLOT 24 #else #define TOC_SAVE_SLOT 40 #endif #endif struct gcc_vregs { __attribute__ ((vector_size (16))) int vr[32]; #ifdef __powerpc64__ unsigned int pad1[3]; unsigned int vscr; unsigned int vsave; unsigned int pad2[3]; #else unsigned int vsave; unsigned int pad[2]; unsigned int vscr; #endif }; struct gcc_regs { unsigned long gpr[32]; unsigned long nip; unsigned long msr; unsigned long orig_gpr3; unsigned long ctr; unsigned long link; unsigned long xer; unsigned long ccr; unsigned long softe; unsigned long trap; unsigned long dar; unsigned long dsisr; unsigned long result; unsigned long pad1[4]; double fpr[32]; unsigned int pad2; unsigned int fpscr; #ifdef __powerpc64__ struct gcc_vregs *vp; #else unsigned int pad3[2]; #endif struct gcc_vregs vregs; }; struct gcc_ucontext { #ifdef __powerpc64__ unsigned long pad[28]; #else unsigned long pad[12]; #endif struct gcc_regs *regs; struct gcc_regs rsave; }; #ifdef __powerpc64__ enum { SIGNAL_FRAMESIZE = 128 }; /* If PC is at a sigreturn trampoline, return a pointer to the regs. Otherwise return NULL. */ static struct gcc_regs * get_regs (struct _Unwind_Context *context) { const unsigned int *pc = context->ra; /* addi r1, r1, 128; li r0, 0x0077; sc (sigreturn) */ /* addi r1, r1, 128; li r0, 0x00AC; sc (rt_sigreturn) */ if (pc[0] != 0x38210000 + SIGNAL_FRAMESIZE || pc[2] != 0x44000002) return NULL; if (pc[1] == 0x38000077) { struct sigframe { char gap[SIGNAL_FRAMESIZE]; unsigned long pad[7]; struct gcc_regs *regs; } *frame = (struct sigframe *) context->cfa; return frame->regs; } else if (pc[1] == 0x380000AC) { #if _CALL_ELF != 2 /* These old kernel versions never supported ELFv2. */ /* This works for 2.4 kernels, but not for 2.6 kernels with vdso because pc isn't pointing into the stack. Can be removed when no one is running 2.4.19 or 2.4.20, the first two ppc64 kernels released. */ const struct rt_sigframe_24 { int tramp[6]; void *pinfo; struct gcc_ucontext *puc; } *frame24 = (const struct rt_sigframe_24 *) context->ra; /* Test for magic value in *puc of vdso. */ if ((long) frame24->puc != -21 * 8) return frame24->puc->regs; else #endif { /* This works for 2.4.21 and later kernels. */ struct rt_sigframe { char gap[SIGNAL_FRAMESIZE]; struct gcc_ucontext uc; unsigned long pad[2]; int tramp[6]; void *pinfo; struct gcc_ucontext *puc; } *frame = (struct rt_sigframe *) context->cfa; return frame->uc.regs; } } return NULL; } #else /* !__powerpc64__ */ enum { SIGNAL_FRAMESIZE = 64 }; static struct gcc_regs * get_regs (struct _Unwind_Context *context) { const unsigned int *pc = context->ra; /* li r0, 0x7777; sc (sigreturn old) */ /* li r0, 0x0077; sc (sigreturn new) */ /* li r0, 0x6666; sc (rt_sigreturn old) */ /* li r0, 0x00AC; sc (rt_sigreturn new) */ if (pc[1] != 0x44000002) return NULL; if (pc[0] == 0x38007777 || pc[0] == 0x38000077) { struct sigframe { char gap[SIGNAL_FRAMESIZE]; unsigned long pad[7]; struct gcc_regs *regs; } *frame = (struct sigframe *) context->cfa; return frame->regs; } else if (pc[0] == 0x38006666 || pc[0] == 0x380000AC) { struct rt_sigframe { char gap[SIGNAL_FRAMESIZE + 16]; char siginfo[128]; struct gcc_ucontext uc; } *frame = (struct rt_sigframe *) context->cfa; return frame->uc.regs; } return NULL; } #endif /* Do code reading to identify a signal frame, and set the frame state data appropriately. See unwind-dw2.c for the structs. */ #define MD_FALLBACK_FRAME_STATE_FOR ppc_fallback_frame_state static _Unwind_Reason_Code ppc_fallback_frame_state (struct _Unwind_Context *context, _Unwind_FrameState *fs) { struct gcc_regs *regs = get_regs (context); struct gcc_vregs *vregs; long cr_offset; long new_cfa; int i; if (regs == NULL) return _URC_END_OF_STACK; new_cfa = regs->gpr[STACK_POINTER_REGNUM]; fs->regs.cfa_how = CFA_REG_OFFSET; fs->regs.cfa_reg = STACK_POINTER_REGNUM; fs->regs.cfa_offset = new_cfa - (long) context->cfa; #ifdef __powerpc64__ fs->regs.reg[2].how = REG_SAVED_OFFSET; fs->regs.reg[2].loc.offset = (long) ®s->gpr[2] - new_cfa; #endif for (i = 14; i < 32; i++) { fs->regs.reg[i].how = REG_SAVED_OFFSET; fs->regs.reg[i].loc.offset = (long) ®s->gpr[i] - new_cfa; } /* The CR is saved in the low 32 bits of regs->ccr. */ cr_offset = (long) ®s->ccr - new_cfa; #ifndef __LITTLE_ENDIAN__ cr_offset += sizeof (long) - 4; #endif /* In the ELFv1 ABI, CR2 stands in for the whole CR. */ fs->regs.reg[R_CR2].how = REG_SAVED_OFFSET; fs->regs.reg[R_CR2].loc.offset = cr_offset; #if _CALL_ELF == 2 /* In the ELFv2 ABI, every CR field has a separate CFI entry. */ fs->regs.reg[R_CR3].how = REG_SAVED_OFFSET; fs->regs.reg[R_CR3].loc.offset = cr_offset; fs->regs.reg[R_CR4].how = REG_SAVED_OFFSET; fs->regs.reg[R_CR4].loc.offset = cr_offset; #endif fs->regs.reg[R_LR].how = REG_SAVED_OFFSET; fs->regs.reg[R_LR].loc.offset = (long) ®s->link - new_cfa; fs->regs.reg[ARG_POINTER_REGNUM].how = REG_SAVED_OFFSET; fs->regs.reg[ARG_POINTER_REGNUM].loc.offset = (long) ®s->nip - new_cfa; fs->retaddr_column = ARG_POINTER_REGNUM; fs->signal_frame = 1; /* If we have a FPU... */ for (i = 14; i < 32; i++) { fs->regs.reg[i + 32].how = REG_SAVED_OFFSET; fs->regs.reg[i + 32].loc.offset = (long) ®s->fpr[i] - new_cfa; } /* If we have a VMX unit... */ #ifdef __powerpc64__ vregs = regs->vp; #else vregs = ®s->vregs; #endif if (regs->msr & (1 << 25)) { for (i = 20; i < 32; i++) { fs->regs.reg[i + R_VR0].how = REG_SAVED_OFFSET; fs->regs.reg[i + R_VR0].loc.offset = (long) &vregs->vr[i] - new_cfa; } } fs->regs.reg[R_VRSAVE].how = REG_SAVED_OFFSET; fs->regs.reg[R_VRSAVE].loc.offset = (long) &vregs->vsave - new_cfa; /* If we have SPE register high-parts... we check at compile-time to avoid expanding the code for all other PowerPC. */ #ifdef __SPE__ for (i = 14; i < 32; i++) { fs->regs.reg[i + FIRST_SPE_HIGH_REGNO - 4].how = REG_SAVED_OFFSET; fs->regs.reg[i + FIRST_SPE_HIGH_REGNO - 4].loc.offset = (long) ®s->vregs - new_cfa + 4 * i; } #endif return _URC_NO_REASON; } #define MD_FROB_UPDATE_CONTEXT frob_update_context static void frob_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs ATTRIBUTE_UNUSED) { const unsigned int *pc = (const unsigned int *) context->ra; /* Fix up for 2.6.12 - 2.6.16 Linux kernels that have vDSO, but don't have S flag in it. */ #ifdef __powerpc64__ /* addi r1, r1, 128; li r0, 0x0077; sc (sigreturn) */ /* addi r1, r1, 128; li r0, 0x00AC; sc (rt_sigreturn) */ if (pc[0] == 0x38210000 + SIGNAL_FRAMESIZE && (pc[1] == 0x38000077 || pc[1] == 0x380000AC) && pc[2] == 0x44000002) _Unwind_SetSignalFrame (context, 1); #else /* li r0, 0x7777; sc (sigreturn old) */ /* li r0, 0x0077; sc (sigreturn new) */ /* li r0, 0x6666; sc (rt_sigreturn old) */ /* li r0, 0x00AC; sc (rt_sigreturn new) */ if ((pc[0] == 0x38007777 || pc[0] == 0x38000077 || pc[0] == 0x38006666 || pc[0] == 0x380000AC) && pc[1] == 0x44000002) _Unwind_SetSignalFrame (context, 1); #endif #ifdef __powerpc64__ if (fs->regs.reg[2].how == REG_UNSAVED) { /* If the current unwind info (FS) does not contain explicit info saving R2, then we have to do a minor amount of code reading to figure out if it was saved. The big problem here is that the code that does the save/restore is generated by the linker, so we have no good way to determine at compile time what to do. */ if (pc[0] == 0xF8410000 + TOC_SAVE_SLOT #if _CALL_ELF != 2 /* The ELFv2 linker never generates the old PLT stub form. */ || ((pc[0] & 0xFFFF0000) == 0x3D820000 && pc[1] == 0xF8410000 + TOC_SAVE_SLOT) #endif ) { /* We are in a plt call stub or r2 adjusting long branch stub, before r2 has been saved. Keep REG_UNSAVED. */ } else { unsigned int *insn = (unsigned int *) _Unwind_GetGR (context, R_LR); if (insn && *insn == 0xE8410000 + TOC_SAVE_SLOT) _Unwind_SetGRPtr (context, 2, context->cfa + TOC_SAVE_SLOT); #if _CALL_ELF != 2 /* ELFv2 does not use this function pointer call sequence. */ else if (pc[0] == 0x4E800421 && pc[1] == 0xE8410000 + TOC_SAVE_SLOT) { /* We are at the bctrl instruction in a call via function pointer. gcc always emits the load of the new R2 just before the bctrl so this is the first and only place we need to use the stored R2. */ _Unwind_Word sp = _Unwind_GetGR (context, 1); _Unwind_SetGRPtr (context, 2, (void *)(sp + TOC_SAVE_SLOT)); } #endif } } #endif }