309 lines
11 KiB
C++
309 lines
11 KiB
C++
/* DWARF2 EH unwinding support for IA64 VMS.
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Copyright (C) 2005-2020 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 __NEW_STARLET
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#include <libicb.h>
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#include <chfdef.h>
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#include <lib_c/chfctxdef.h>
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#include <lib_c/intstkdef.h>
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#include <stdio.h>
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#include <string.h>
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#define UNW_IVMS_MODE(HEADER) (((HEADER) >> 44) & 0x3L)
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#define MD_UNW_COMPATIBLE_PERSONALITY_P(HEADER) (!UNW_IVMS_MODE (HEADER))
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#define DYN$C_SSENTRY 66
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/* ??? would rather get the proper header file. */
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#define MD_FALLBACK_FRAME_STATE_FOR ia64_vms_fallback_frame_state
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extern INVO_CONTEXT_BLK * LIB$I64_CREATE_INVO_CONTEXT (void);
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extern int LIB$I64_IS_EXC_DISPATCH_FRAME (void *);
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extern int LIB$I64_IS_AST_DISPATCH_FRAME (void *);
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extern int LIB$I64_INIT_INVO_CONTEXT (INVO_CONTEXT_BLK *, int, int);
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extern int LIB$I64_GET_CURR_INVO_CONTEXT (INVO_CONTEXT_BLK *);
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extern int LIB$I64_GET_PREV_INVO_CONTEXT (INVO_CONTEXT_BLK *);
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typedef unsigned int uint;
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typedef unsigned __int64 uw_reg;
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typedef uw_reg * uw_loc;
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typedef char fp_reg[16];
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#define DENOTES_VMS_DISPATCHER_FRAME(icb) \
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(LIB$I64_IS_EXC_DISPATCH_FRAME (&(icb)->libicb$ih_pc))
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#define DENOTES_BOTTOM_OF_STACK(icb) ((icb)->libicb$v_bottom_of_stack)
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#define FAIL_IF(COND) \
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do { if (COND) { context->rp = 0; return _URC_END_OF_STACK; } } while (0)
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/* Clearing context->rp is required to prevent the ia64 gcc unwinder from
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attempting to keep on walking the call chain. */
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static int
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ia64_vms_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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int i, status;
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INVO_CONTEXT_BLK local_icb;
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INVO_CONTEXT_BLK *icb = &local_icb;
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CHFCTX * chfctx;
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CHF$MECH_ARRAY * chfmech;
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CHF64$SIGNAL_ARRAY *chfsig64;
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INTSTK * intstk;
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static int eh_debug = -1;
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int try_bs_copy = 0;
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/* Non zero to attempt copy of alternate backing store contents for
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dirty partition in interrupted context. ??? Alpha code, only activated
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on specific request via specific bit in EH_DEBUG. */
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if (eh_debug == -1)
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{
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char * EH_DEBUG = getenv ("EH_DEBUG");
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const uint try_bs_copy_mask = (1 << 16);
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eh_debug = EH_DEBUG ? atoi (EH_DEBUG) : 0;
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/* Fetch and clear the try_bs_copy bit. */
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try_bs_copy = (uint)eh_debug & try_bs_copy_mask;
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eh_debug &= ~try_bs_copy_mask;
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}
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/* We're called to attempt unwinding through a frame for which no unwind
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info is available, typical of an operating system exception dispatcher
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frame. The code below knows how to handle this case, and only this one,
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returning a failure code if it finds it is not in this situation.
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Note that we're called from deep down in the exception propagation call
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chain, possibly below an exception dispatcher but for a frame above it
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like some os entry point. */
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if (eh_debug)
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printf ("FALLBACK - ctxt->rp=0x%lx, sp=0x%lx, psp=0x%lx, bsp=0x%lx\n",
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context->rp, context->sp, context->psp, context->bsp);
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/* Step 0 :
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-------------------------------------------------------------------------
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VMS-unwind up until we reach a VMS dispatcher frame corresponding to the
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context we are trying to unwind through. Fail if get past this context or
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if we reach the bottom of stack along the way.
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-------------------------------------------------------------------------
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*/
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status = LIB$I64_INIT_INVO_CONTEXT (icb, LIBICB$K_INVO_CONTEXT_VERSION, 0);
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FAIL_IF (status == 0);
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status = LIB$I64_GET_CURR_INVO_CONTEXT (icb);
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/* Beware: we might be unwinding through nested condition handlers, so the
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dispatcher frame we seek might not be the first one on the way up. Loop
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thus. */
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do {
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/* Seek the next dispatcher frame up the "current" point. Stop if we
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either get past the target context or hit the bottom-of-stack along
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the way. */
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status = LIB$I64_GET_PREV_INVO_CONTEXT (icb);
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FAIL_IF (status == 0);
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FAIL_IF ((uw_reg)icb->libicb$ih_sp > (uw_reg)context->psp
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|| DENOTES_BOTTOM_OF_STACK (icb));
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if (eh_debug)
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printf ("frame%s sp @ 0x%llx, pc @ 0x%llx bsp=0x%llx\n",
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DENOTES_VMS_DISPATCHER_FRAME (icb) ? " (dispatcher)" : "",
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icb->libicb$ih_sp, icb->libicb$ih_pc, icb->libicb$ih_bsp);
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/* Continue until the target frame is found. */
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} while ((uw_reg)icb->libicb$ih_bsp != (uw_reg)context->bsp);
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/* If this is not a dispatcher frame, this is certainly a frame for a leaf
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subprogram. Use default unwind information. */
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if (! DENOTES_VMS_DISPATCHER_FRAME (icb))
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return _URC_END_OF_STACK;
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/* At this point, we know we are really trying to unwind past an exception
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dispatcher frame, and have it described in ICB. Proceed. */
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/* Step 1 :
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------------------------------------------------------------------------
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We have the VMS dispatcher frame ICB handy and know we are trying to
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unwind past it. Fetch pointers to useful datastructures from there, then
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unwind one step further up to the interrupted user context from which
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some required values will be easily accessible.
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------------------------------------------------------------------------
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*/
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chfctx = icb->libicb$ph_chfctx_addr;
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FAIL_IF (chfctx == 0);
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chfmech = (CHF$MECH_ARRAY *)chfctx->chfctx$q_mcharglst;
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FAIL_IF (chfmech == 0);
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chfsig64 = (CHF64$SIGNAL_ARRAY *)chfmech->chf$ph_mch_sig64_addr;
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FAIL_IF (chfsig64 == 0);
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intstk = (INTSTK *)chfmech->chf$q_mch_esf_addr;
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FAIL_IF (intstk == 0 || intstk->intstk$b_subtype == DYN$C_SSENTRY);
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status = LIB$I64_GET_PREV_INVO_CONTEXT (icb);
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FAIL_IF (status == 0);
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if (eh_debug)
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printf ("User frame, "
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"chfmech @ 0x%p, chfsig64 @ 0x%p, intstk @ 0x%p\n",
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chfmech, chfsig64, intstk);
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/* Step 2 :
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------------------------------------------------------------------------
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Point the GCC context locations/values required for further unwinding at
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their corresponding locations/values in the datastructures at hand.
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------------------------------------------------------------------------
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*/
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/* Static General Register locations, including scratch registers in case
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the unwinder needs to refer to a value stored in one of them. */
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{
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uw_reg * ctxregs = (uw_reg *)&intstk->intstk$q_regbase;
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for (i = 2; i <= 3; i++)
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context->ireg[i - 2].loc = (uw_loc)&ctxregs[i];
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for (i = 8; i <= 11; i++)
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context->ireg[i - 2].loc = (uw_loc)&ctxregs[i];
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for (i = 14; i <= 31; i++)
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context->ireg[i - 2].loc = (uw_loc)&ctxregs[i];
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}
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/* Static Floating Point Register locations, as available from the
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mechargs array, which happens to include all the to be preserved
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ones + others. */
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{
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fp_reg * ctxregs;
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ctxregs = (fp_reg *)&chfmech->chf$fh_mch_savf2;
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for (i = 2; i <= 5 ; i++)
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context->fr_loc[i - 2] = (uw_loc)&ctxregs[i - 2];
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ctxregs = (fp_reg *)&chfmech->chf$fh_mch_savf12;
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for (i = 12; i <= 31 ; i++)
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context->fr_loc[i - 2] = (uw_loc)&ctxregs[i - 12];
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}
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/* Relevant application register locations. */
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context->fpsr_loc = (uw_loc)&intstk->intstk$q_fpsr;
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context->lc_loc = (uw_loc)&intstk->intstk$q_lc;
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context->unat_loc = (uw_loc)&intstk->intstk$q_unat;
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/* Branch register locations. */
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{
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uw_reg * ctxregs = (uw_reg *)&intstk->intstk$q_b0;
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for (i = 0; i < 8; i++)
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context->br_loc[i] = (uw_loc)&ctxregs[i];
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}
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/* Necessary register values. */
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/* ??? Still unclear if we need to account for possible flushes to an
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alternate backing store (maybe the unwinding performed above did the
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trick already) and how this would be handled. Blind alpha tentative
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below for experimentation purposes in malfunctioning cases. */
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{
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uw_reg q_bsp = (uw_reg) intstk->intstk$q_bsp;
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uw_reg q_bspstore = (uw_reg) intstk->intstk$q_bspstore;
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uw_reg q_bspbase = (uw_reg) intstk->intstk$q_bspbase;
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uw_reg ih_bspbase = (uw_reg) icb->libicb$ih_bspbase;
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if (eh_debug)
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printf ("q_bspstore = 0x%lx, q_bsp = 0x%lx, q_bspbase = 0x%lx\n"
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"ih_bspbase = 0x%lx\n",
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q_bspstore, q_bsp, q_bspbase, ih_bspbase);
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/* We witness many situations where q_bspbase is set while ih_bspbase is
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null, and every attempt made with q_bspbase badly failed while doing
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nothing resulted in proper behavior. */
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if (q_bspstore < q_bsp && ih_bspbase && try_bs_copy)
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{
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uw_reg dirty_size = q_bsp - q_bspstore;
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uw_reg q_rnat = (uw_reg) intstk->intstk$q_rnat;
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if (eh_debug)
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printf ("Attempting an alternate backing store copy ...\n");
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ia64_copy_rbs
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(context, q_bspstore, ih_bspbase, dirty_size, q_rnat);
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/* Not clear if these are the proper arguments here. This is what
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looked the closest to what is performed in the Linux case. */
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}
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}
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context->bsp = (uw_reg)intstk->intstk$q_bsp;
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fs->no_reg_stack_frame = 1;
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context->pr = (uw_reg)intstk->intstk$q_preds;
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context->gp = (uw_reg)intstk->intstk$q_gp;
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/* We're directly setting up the "context" for a VMS exception handler.
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The "previous SP" for it is the SP upon the handler's entry, that is
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the SP at the condition/interruption/exception point. */
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context->psp = (uw_reg)icb->libicb$ih_sp;
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/* Previous Frame State location. What eventually ends up in pfs_loc is
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installed with ar.pfs = pfs_loc; br.ret; so setup to target intstk->q_ifs
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to have the interrupted context restored and not that of its caller if
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we happen to have a handler in the interrupted context itself. */
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fs->curr.reg[UNW_REG_PFS].where = UNW_WHERE_PSPREL;
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fs->curr.reg[UNW_REG_PFS].val
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= (uw_reg)&intstk->intstk$q_ifs - (uw_reg)context->psp;
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fs->curr.reg[UNW_REG_PFS].when = -1;
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/* If we need to unwind further up, past the interrupted context, we need to
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hand out the interrupted context's pfs, still. */
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context->signal_pfs_loc = (uw_loc) &intstk->intstk$q_pfs;
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/* Finally, rules for RP . */
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{
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uw_reg * post_sigarray
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= (uw_reg *)chfsig64 + 1 + chfsig64->chf64$l_sig_args;
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uw_reg * ih_pc_loc = post_sigarray - 2;
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fs->curr.reg[UNW_REG_RP].where = UNW_WHERE_PSPREL;
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fs->curr.reg[UNW_REG_RP].val
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= (uw_reg)ih_pc_loc - (uw_reg)context->psp;
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fs->curr.reg[UNW_REG_RP].when = -1;
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}
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return _URC_NO_REASON;
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}
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