355 lines
10 KiB
C
355 lines
10 KiB
C
/* DWARF2 EH unwinding support for PowerPC and PowerPC64 Linux.
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Copyright (C) 2004-2020 Free Software Foundation, Inc.
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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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#define R_LR 65
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#define R_CR2 70
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#define R_CR3 71
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#define R_CR4 72
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#define R_VR0 77
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#define R_VRSAVE 109
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#ifdef __powerpc64__
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#if _CALL_ELF == 2
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#define TOC_SAVE_SLOT 24
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#else
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#define TOC_SAVE_SLOT 40
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#endif
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#endif
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struct gcc_vregs
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{
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__attribute__ ((vector_size (16))) int vr[32];
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#ifdef __powerpc64__
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unsigned int pad1[3];
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unsigned int vscr;
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unsigned int vsave;
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unsigned int pad2[3];
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#else
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unsigned int vsave;
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unsigned int pad[2];
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unsigned int vscr;
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#endif
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};
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struct gcc_regs
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{
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unsigned long gpr[32];
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unsigned long nip;
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unsigned long msr;
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unsigned long orig_gpr3;
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unsigned long ctr;
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unsigned long link;
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unsigned long xer;
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unsigned long ccr;
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unsigned long softe;
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unsigned long trap;
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unsigned long dar;
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unsigned long dsisr;
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unsigned long result;
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unsigned long pad1[4];
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double fpr[32];
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unsigned int pad2;
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unsigned int fpscr;
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#ifdef __powerpc64__
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struct gcc_vregs *vp;
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#else
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unsigned int pad3[2];
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#endif
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struct gcc_vregs vregs;
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};
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struct gcc_ucontext
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{
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#ifdef __powerpc64__
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unsigned long pad[28];
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#else
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unsigned long pad[12];
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#endif
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struct gcc_regs *regs;
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struct gcc_regs rsave;
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};
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#ifdef __powerpc64__
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enum { SIGNAL_FRAMESIZE = 128 };
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/* If PC is at a sigreturn trampoline, return a pointer to the
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regs. Otherwise return NULL. */
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static struct gcc_regs *
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get_regs (struct _Unwind_Context *context)
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{
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const unsigned int *pc = context->ra;
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/* addi r1, r1, 128; li r0, 0x0077; sc (sigreturn) */
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/* addi r1, r1, 128; li r0, 0x00AC; sc (rt_sigreturn) */
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if (pc[0] != 0x38210000 + SIGNAL_FRAMESIZE || pc[2] != 0x44000002)
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return NULL;
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if (pc[1] == 0x38000077)
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{
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struct sigframe {
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char gap[SIGNAL_FRAMESIZE];
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unsigned long pad[7];
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struct gcc_regs *regs;
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} *frame = (struct sigframe *) context->cfa;
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return frame->regs;
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}
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else if (pc[1] == 0x380000AC)
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{
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#if _CALL_ELF != 2
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/* These old kernel versions never supported ELFv2. */
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/* This works for 2.4 kernels, but not for 2.6 kernels with vdso
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because pc isn't pointing into the stack. Can be removed when
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no one is running 2.4.19 or 2.4.20, the first two ppc64
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kernels released. */
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const struct rt_sigframe_24 {
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int tramp[6];
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void *pinfo;
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struct gcc_ucontext *puc;
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} *frame24 = (const struct rt_sigframe_24 *) context->ra;
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/* Test for magic value in *puc of vdso. */
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if ((long) frame24->puc != -21 * 8)
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return frame24->puc->regs;
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else
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#endif
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{
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/* This works for 2.4.21 and later kernels. */
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struct rt_sigframe {
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char gap[SIGNAL_FRAMESIZE];
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struct gcc_ucontext uc;
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unsigned long pad[2];
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int tramp[6];
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void *pinfo;
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struct gcc_ucontext *puc;
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} *frame = (struct rt_sigframe *) context->cfa;
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return frame->uc.regs;
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}
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}
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return NULL;
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}
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#else /* !__powerpc64__ */
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enum { SIGNAL_FRAMESIZE = 64 };
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static struct gcc_regs *
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get_regs (struct _Unwind_Context *context)
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{
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const unsigned int *pc = context->ra;
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/* li r0, 0x7777; sc (sigreturn old) */
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/* li r0, 0x0077; sc (sigreturn new) */
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/* li r0, 0x6666; sc (rt_sigreturn old) */
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/* li r0, 0x00AC; sc (rt_sigreturn new) */
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if (pc[1] != 0x44000002)
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return NULL;
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if (pc[0] == 0x38007777 || pc[0] == 0x38000077)
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{
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struct sigframe {
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char gap[SIGNAL_FRAMESIZE];
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unsigned long pad[7];
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struct gcc_regs *regs;
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} *frame = (struct sigframe *) context->cfa;
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return frame->regs;
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}
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else if (pc[0] == 0x38006666 || pc[0] == 0x380000AC)
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{
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struct rt_sigframe {
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char gap[SIGNAL_FRAMESIZE + 16];
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char siginfo[128];
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struct gcc_ucontext uc;
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} *frame = (struct rt_sigframe *) context->cfa;
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return frame->uc.regs;
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}
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return NULL;
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}
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#endif
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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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#define MD_FALLBACK_FRAME_STATE_FOR ppc_fallback_frame_state
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static _Unwind_Reason_Code
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ppc_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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struct gcc_regs *regs = get_regs (context);
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struct gcc_vregs *vregs;
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long cr_offset;
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long new_cfa;
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int i;
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if (regs == NULL)
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return _URC_END_OF_STACK;
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new_cfa = regs->gpr[__LIBGCC_STACK_POINTER_REGNUM__];
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fs->regs.cfa_how = CFA_REG_OFFSET;
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fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
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fs->regs.cfa_offset = new_cfa - (long) context->cfa;
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#ifdef __powerpc64__
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fs->regs.reg[2].how = REG_SAVED_OFFSET;
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fs->regs.reg[2].loc.offset = (long) ®s->gpr[2] - new_cfa;
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#endif
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for (i = 14; i < 32; i++)
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{
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fs->regs.reg[i].how = REG_SAVED_OFFSET;
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fs->regs.reg[i].loc.offset = (long) ®s->gpr[i] - new_cfa;
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}
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/* The CR is saved in the low 32 bits of regs->ccr. */
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cr_offset = (long) ®s->ccr - new_cfa;
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#ifndef __LITTLE_ENDIAN__
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cr_offset += sizeof (long) - 4;
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#endif
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/* In the ELFv1 ABI, CR2 stands in for the whole CR. */
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fs->regs.reg[R_CR2].how = REG_SAVED_OFFSET;
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fs->regs.reg[R_CR2].loc.offset = cr_offset;
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#if _CALL_ELF == 2
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/* In the ELFv2 ABI, every CR field has a separate CFI entry. */
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fs->regs.reg[R_CR3].how = REG_SAVED_OFFSET;
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fs->regs.reg[R_CR3].loc.offset = cr_offset;
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fs->regs.reg[R_CR4].how = REG_SAVED_OFFSET;
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fs->regs.reg[R_CR4].loc.offset = cr_offset;
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#endif
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fs->regs.reg[R_LR].how = REG_SAVED_OFFSET;
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fs->regs.reg[R_LR].loc.offset = (long) ®s->link - new_cfa;
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fs->regs.reg[ARG_POINTER_REGNUM].how = REG_SAVED_OFFSET;
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fs->regs.reg[ARG_POINTER_REGNUM].loc.offset = (long) ®s->nip - new_cfa;
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fs->retaddr_column = ARG_POINTER_REGNUM;
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fs->signal_frame = 1;
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/* If we have a FPU... */
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for (i = 14; i < 32; i++)
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{
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fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
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fs->regs.reg[i + 32].loc.offset = (long) ®s->fpr[i] - new_cfa;
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}
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/* If we have a VMX unit... */
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#ifdef __powerpc64__
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vregs = regs->vp;
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#else
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vregs = ®s->vregs;
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#endif
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if (regs->msr & (1 << 25))
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{
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for (i = 20; i < 32; i++)
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{
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fs->regs.reg[i + R_VR0].how = REG_SAVED_OFFSET;
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fs->regs.reg[i + R_VR0].loc.offset = (long) &vregs->vr[i] - new_cfa;
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}
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}
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fs->regs.reg[R_VRSAVE].how = REG_SAVED_OFFSET;
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fs->regs.reg[R_VRSAVE].loc.offset = (long) &vregs->vsave - new_cfa;
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/* If we have SPE register high-parts... we check at compile-time to
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avoid expanding the code for all other PowerPC. */
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#ifdef __SPE__
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for (i = 14; i < 32; i++)
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{
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fs->regs.reg[i + FIRST_SPE_HIGH_REGNO - 4].how = REG_SAVED_OFFSET;
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fs->regs.reg[i + FIRST_SPE_HIGH_REGNO - 4].loc.offset
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= (long) ®s->vregs - new_cfa + 4 * i;
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}
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#endif
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return _URC_NO_REASON;
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}
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#define MD_FROB_UPDATE_CONTEXT frob_update_context
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static void
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frob_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs ATTRIBUTE_UNUSED)
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{
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const unsigned int *pc = (const unsigned int *) context->ra;
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/* Fix up for 2.6.12 - 2.6.16 Linux kernels that have vDSO, but don't
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have S flag in it. */
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#ifdef __powerpc64__
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/* addi r1, r1, 128; li r0, 0x0077; sc (sigreturn) */
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/* addi r1, r1, 128; li r0, 0x00AC; sc (rt_sigreturn) */
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if (pc[0] == 0x38210000 + SIGNAL_FRAMESIZE
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&& (pc[1] == 0x38000077 || pc[1] == 0x380000AC)
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&& pc[2] == 0x44000002)
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_Unwind_SetSignalFrame (context, 1);
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#else
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/* li r0, 0x7777; sc (sigreturn old) */
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/* li r0, 0x0077; sc (sigreturn new) */
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/* li r0, 0x6666; sc (rt_sigreturn old) */
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/* li r0, 0x00AC; sc (rt_sigreturn new) */
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if ((pc[0] == 0x38007777 || pc[0] == 0x38000077
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|| pc[0] == 0x38006666 || pc[0] == 0x380000AC)
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&& pc[1] == 0x44000002)
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_Unwind_SetSignalFrame (context, 1);
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#endif
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#ifdef __powerpc64__
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if (fs->regs.reg[2].how == REG_UNSAVED)
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{
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/* If the current unwind info (FS) does not contain explicit info
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saving R2, then we have to do a minor amount of code reading to
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figure out if it was saved. The big problem here is that the
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code that does the save/restore is generated by the linker, so
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we have no good way to determine at compile time what to do. */
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if (pc[0] == 0xF8410000 + TOC_SAVE_SLOT
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#if _CALL_ELF != 2
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/* The ELFv2 linker never generates the old PLT stub form. */
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|| ((pc[0] & 0xFFFF0000) == 0x3D820000
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&& pc[1] == 0xF8410000 + TOC_SAVE_SLOT)
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#endif
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)
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{
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/* We are in a plt call stub or r2 adjusting long branch stub,
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before r2 has been saved. Keep REG_UNSAVED. */
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}
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else
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{
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unsigned int *insn
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= (unsigned int *) _Unwind_GetGR (context, R_LR);
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if (insn && *insn == 0xE8410000 + TOC_SAVE_SLOT)
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_Unwind_SetGRPtr (context, 2, context->cfa + TOC_SAVE_SLOT);
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#if _CALL_ELF != 2
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/* ELFv2 does not use this function pointer call sequence. */
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else if (pc[0] == 0x4E800421
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&& pc[1] == 0xE8410000 + TOC_SAVE_SLOT)
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{
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/* We are at the bctrl instruction in a call via function
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pointer. gcc always emits the load of the new R2 just
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before the bctrl so this is the first and only place
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we need to use the stored R2. */
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_Unwind_Word sp = _Unwind_GetGR (context, 1);
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_Unwind_SetGRPtr (context, 2, (void *)(sp + TOC_SAVE_SLOT));
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}
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#endif
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}
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}
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#endif
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}
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