| /* DWARF2 EH unwinding support for PA Linux. |
| Copyright (C) 2004, 2005 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 2, or (at your option) |
| any later version. |
| |
| In addition to the permissions in the GNU General Public License, the |
| Free Software Foundation gives you unlimited permission to link the |
| compiled version of this file with other programs, and to distribute |
| those programs without any restriction coming from the use of this |
| file. (The General Public License restrictions do apply in other |
| respects; for example, they cover modification of the file, and |
| distribution when not linked into another program.) |
| |
| 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. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING. If not, write to |
| the Free Software Foundation, 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| /* Do code reading to identify a signal frame, and set the frame |
| state data appropriately. See unwind-dw2.c for the structs. */ |
| |
| #include <signal.h> |
| #include <sys/ucontext.h> |
| |
| /* Unfortunately, because of various bugs and changes to the kernel, |
| we have several cases to deal with. |
| |
| In 2.4, the signal trampoline is 4 words, and (CONTEXT)->ra should |
| point directly at the beginning of the trampoline and struct rt_sigframe. |
| |
| In <= 2.6.5-rc2-pa3, the signal trampoline is 9 words, and |
| (CONTEXT)->ra points at the 4th word in the trampoline structure. This |
| is wrong, it should point at the 5th word. This is fixed in 2.6.5-rc2-pa4. |
| |
| To detect these cases, we first take (CONTEXT)->ra, align it to 64-bytes |
| to get the beginning of the signal frame, and then check offsets 0, 4 |
| and 5 to see if we found the beginning of the trampoline. This will |
| tell us how to locate the sigcontext structure. |
| |
| Note that with a 2.4 64-bit kernel, the signal context is not properly |
| passed back to userspace so the unwind will not work correctly. */ |
| |
| #define MD_FALLBACK_FRAME_STATE_FOR pa32_fallback_frame_state |
| |
| static _Unwind_Reason_Code |
| pa32_fallback_frame_state (struct _Unwind_Context *context, |
| _Unwind_FrameState *fs) |
| { |
| unsigned long sp = (unsigned long)context->ra & ~63; |
| unsigned int *pc = (unsigned int *)sp; |
| unsigned long off; |
| _Unwind_Ptr new_cfa; |
| int i; |
| struct sigcontext *sc; |
| struct rt_sigframe { |
| struct siginfo info; |
| struct ucontext uc; |
| } *frame; |
| |
| /* rt_sigreturn trampoline: |
| 3419000x ldi 0, %r25 or ldi 1, %r25 (x = 0 or 2) |
| 3414015a ldi __NR_rt_sigreturn, %r20 |
| e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31 |
| 08000240 nop */ |
| |
| if (pc[0] == 0x34190000 || pc[0] == 0x34190002) |
| off = 4*4; |
| else if (pc[4] == 0x34190000 || pc[4] == 0x34190002) |
| { |
| pc += 4; |
| off = 10 * 4; |
| } |
| else if (pc[5] == 0x34190000 || pc[5] == 0x34190002) |
| { |
| pc += 5; |
| off = 10 * 4; |
| } |
| else |
| { |
| /* We may have to unwind through an alternate signal stack. |
| We assume that the alignment of the alternate signal stack |
| is BIGGEST_ALIGNMENT (i.e., that it has been allocated using |
| malloc). As a result, we can't distinguish trampolines |
| used prior to 2.6.5-rc2-pa4. However after 2.6.5-rc2-pa4, |
| the return address of a signal trampoline will be on an odd |
| word boundary and we can then determine the frame offset. */ |
| sp = (unsigned long)context->ra; |
| pc = (unsigned int *)sp; |
| if ((pc[0] == 0x34190000 || pc[0] == 0x34190002) && (sp & 4)) |
| off = 5 * 4; |
| else |
| return _URC_END_OF_STACK; |
| } |
| |
| if (pc[1] != 0x3414015a |
| || pc[2] != 0xe4008200 |
| || pc[3] != 0x08000240) |
| return _URC_END_OF_STACK; |
| |
| frame = (struct rt_sigframe *)(sp + off); |
| sc = &frame->uc.uc_mcontext; |
| |
| new_cfa = sc->sc_gr[30]; |
| fs->cfa_how = CFA_REG_OFFSET; |
| fs->cfa_reg = 30; |
| fs->cfa_offset = new_cfa - (long) context->cfa; |
| for (i = 1; i <= 31; i++) |
| { |
| fs->regs.reg[i].how = REG_SAVED_OFFSET; |
| fs->regs.reg[i].loc.offset = (long)&sc->sc_gr[i] - new_cfa; |
| } |
| for (i = 4; i <= 31; i++) |
| { |
| /* FP regs have left and right halves */ |
| fs->regs.reg[2*i+24].how = REG_SAVED_OFFSET; |
| fs->regs.reg[2*i+24].loc.offset |
| = (long)&sc->sc_fr[i] - new_cfa; |
| fs->regs.reg[2*i+24+1].how = REG_SAVED_OFFSET; |
| fs->regs.reg[2*i+24+1].loc.offset |
| = (long)&sc->sc_fr[i] + 4 - new_cfa; |
| } |
| fs->regs.reg[88].how = REG_SAVED_OFFSET; |
| fs->regs.reg[88].loc.offset = (long) &sc->sc_sar - new_cfa; |
| fs->regs.reg[2].how = REG_SAVED_OFFSET; |
| fs->regs.reg[2].loc.offset = (long) &sc->sc_iaoq[0] - new_cfa; |
| fs->retaddr_column = 2; |
| return _URC_NO_REASON; |
| } |