106 lines
3.3 KiB
C
106 lines
3.3 KiB
C
/* DWARF2 EH unwinding support for Nios II Linux.
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Copyright (C) 2008-2020 Free Software Foundation, Inc.
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This file 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 by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.
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This file 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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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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#ifndef inhibit_libc
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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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The corresponding bits in the Linux kernel are in
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arch/nios2/kernel/signal.c. */
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#include <signal.h>
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#include <asm/unistd.h>
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/* Exactly the same layout as the kernel structures, unique names. */
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struct nios2_mcontext {
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int version;
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int gregs[32];
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};
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struct nios2_ucontext {
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unsigned long uc_flags;
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ucontext_t *uc_link;
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stack_t uc_stack;
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struct nios2_mcontext uc_mcontext;
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sigset_t uc_sigmask; /* mask last for extensibility */
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};
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#define MD_FALLBACK_FRAME_STATE_FOR nios2_fallback_frame_state
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static _Unwind_Reason_Code
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nios2_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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u_int32_t *pc = (u_int32_t *) context->ra;
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_Unwind_Ptr new_cfa;
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/* The expected sequence of instructions is:
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movi r2,(rt_sigreturn)
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trap
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Check for the trap first. */
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if (pc[1] != 0x003b683a)
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return _URC_END_OF_STACK;
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#define NIOS2_REG(NUM,NAME) \
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(fs->regs.reg[NUM].how = REG_SAVED_OFFSET, \
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fs->regs.reg[NUM].loc.offset = (_Unwind_Ptr)&(regs->NAME) - new_cfa)
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if (pc[0] == (0x00800004 | (__NR_rt_sigreturn << 6)))
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{
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struct rt_sigframe {
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siginfo_t info;
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struct nios2_ucontext uc;
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} *rt_ = context->cfa;
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struct nios2_mcontext *regs = &rt_->uc.uc_mcontext;
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int i;
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/* MCONTEXT_VERSION is defined to 2 in the kernel. */
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if (regs->version != 2)
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return _URC_END_OF_STACK;
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/* The CFA is the user's incoming stack pointer value. */
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new_cfa = (_Unwind_Ptr)regs->gregs[28];
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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 - (_Unwind_Ptr) context->cfa;
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/* The sequential registers. */
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for (i = 1; i < 24; i++)
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NIOS2_REG (i, gregs[i-1]);
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/* The random registers. The kernel stores these in a funny order
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in the gregs array. */
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NIOS2_REG (RA_REGNO, gregs[23]);
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NIOS2_REG (FP_REGNO, gregs[24]);
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NIOS2_REG (GP_REGNO, gregs[25]);
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NIOS2_REG (EA_REGNO, gregs[27]);
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fs->retaddr_column = EA_REGNO;
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fs->signal_frame = 1;
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return _URC_NO_REASON;
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}
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#undef NIOS2_REG
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return _URC_END_OF_STACK;
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}
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#endif
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