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77 lines
2.3 KiB
77 lines
2.3 KiB
4 months ago
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/* Get previous frame state for an existing frame state.
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Copyright (C) 2017 Red Hat, Inc.
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This file is part of elfutils.
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This file is free software; you can redistribute it and/or modify
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it under the terms of either
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at
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your option) any later version
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at
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your option) any later version
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or both in parallel, as here.
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elfutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see <http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#define BACKEND ppc64_
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#define LR_REG 65 /* Not 108, see ppc_dwarf_to_regno. */
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#define SP_REG 1
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#define LR_OFFSET 16
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#include "libebl_CPU.h"
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/* Simplistic fallback frame unwinder. SP points to the backchain (contains
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address of previous stack pointer). At SP offset 16 is the LR save area
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(contains the value of the previous LR). */
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bool
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EBLHOOK(unwind) (Ebl *ebl __attribute__ ((unused)),
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Dwarf_Addr pc __attribute__ ((unused)),
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ebl_tid_registers_t *setfunc, ebl_tid_registers_get_t *getfunc,
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ebl_pid_memory_read_t *readfunc, void *arg,
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bool *signal_framep __attribute__ ((unused)))
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{
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Dwarf_Word sp, newSp, lr, newLr;
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/* Stack pointer points to the backchain which contains the previous sp. */
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if (! getfunc (SP_REG, 1, &sp, arg))
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sp = 0;
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/* Link register contains previous program counter. */
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if (! getfunc (LR_REG, 1, &lr, arg)
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|| lr == 0
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|| ! setfunc (-1, 1, &lr, arg))
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return false;
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if (! readfunc(sp, &newSp, arg))
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newSp = 0;
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if (! readfunc(newSp + LR_OFFSET, &newLr, arg))
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newLr = 0;
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setfunc(SP_REG, 1, &newSp, arg);
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setfunc(LR_REG, 1, &newLr, arg);
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/* Sanity check the stack grows down. */
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return newSp > sp;
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}
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