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- /* DWARF2 EH unwinding support for PowerPC and PowerPC64 Linux.
- Copyright (C) 2004-2022 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
- <http://www.gnu.org/licenses/>. */
- #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 };
- struct rt_sigframe {
- char gap[SIGNAL_FRAMESIZE];
- struct gcc_ucontext uc;
- unsigned long pad[2];
- int tramp[6];
- void *pinfo;
- struct gcc_ucontext *puc;
- };
- /* 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 *frame = (struct rt_sigframe *) context->cfa;
- return frame->uc.regs;
- }
- }
- return NULL;
- }
- #else /* !__powerpc64__ */
- enum { SIGNAL_FRAMESIZE = 64 };
- struct rt_sigframe {
- char gap[SIGNAL_FRAMESIZE + 16];
- char siginfo[128];
- struct gcc_ucontext uc;
- };
- 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 *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_NORMAL_STOP;
- new_cfa = regs->gpr[__LIBGCC_STACK_POINTER_REGNUM__];
- fs->regs.cfa_how = CFA_REG_OFFSET;
- fs->regs.cfa_reg = __LIBGCC_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
- }
- #define MD_BACKCHAIN_FALLBACK ppc_backchain_fallback
- struct trace_arg
- {
- /* Stores the list of addresses. */
- void **array;
- struct unwind_link *unwind_link;
- _Unwind_Word cfa;
- /* Number of addresses currently stored. */
- int count;
- /* Maximum number of addresses. */
- int size;
- };
- /* This is the stack layout we see with every stack frame.
- Note that every routine is required by the ABI to lay out the stack
- like this.
- +----------------+ +-----------------+
- %r1 -> | previous frame--------> | previous frame--->... --> NULL
- | | | |
- | cr save | | cr save |
- | | | |
- | (unused) | | lr save |
- +----------------+ +-----------------+
- The CR save is only present on 64-bit ABIs.
- */
- struct frame_layout
- {
- struct frame_layout *backchain;
- #ifdef __powerpc64__
- long int cr_save;
- #endif
- void *lr_save;
- };
- static void
- ppc_backchain_fallback (struct _Unwind_Context *context, void *a)
- {
- struct frame_layout *current;
- struct trace_arg *arg = a;
- int count;
- /* Get the last address computed. */
- current = context->cfa;
- /* If the trace CFA is not the context CFA the backtrace is done. */
- if (arg == NULL || arg->cfa != current)
- return;
- /* Start with next address. */
- current = current->backchain;
- for (count = arg->count; current != NULL; current = current->backchain)
- {
- arg->array[count] = current->lr_save;
- /* Check if the symbol is the signal trampoline and get the interrupted
- symbol address from the trampoline saved area. */
- context->ra = current->lr_save;
- if (current->lr_save && get_regs (context))
- {
- struct rt_sigframe *sigframe = (struct rt_sigframe *) current;
- if (count + 1 == arg->size)
- break;
- arg->array[++count] = (void *) sigframe->uc.rsave.nip;
- current = (void *) sigframe->uc.rsave.gpr[1];
- }
- if (count++ >= arg->size)
- break;
- }
- arg->count = count-1;
- }
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