dc76aa0e4d
This patch is implemented according to the RISC-V CFI specification. It supports the generation of shadow stack instructions in the prologue, epilogue, non-local gotos, and unwinding. RISC-V CFI SPEC: https://github.com/riscv/riscv-cfi gcc/ChangeLog: * common/config/riscv/riscv-common.cc: Add ZICFISS ISA string. * config/riscv/predicates.md: New predicate x1x5_operand. * config/riscv/riscv.cc (riscv_expand_prologue): Insert shadow stack instructions. (riscv_expand_epilogue): Likewise. (riscv_for_each_saved_reg): Assign t0 or ra register for sspopchk instruction. (need_shadow_stack_push_pop_p): New function. Omit shadow stack operation on leaf function. * config/riscv/riscv.h (need_shadow_stack_push_pop_p): Define. * config/riscv/riscv.md: Add shadow stack patterns. (save_stack_nonlocal): Add shadow stack instructions for setjump. (restore_stack_nonlocal): Add shadow stack instructions for longjump. * config/riscv/riscv.opt (TARGET_ZICFISS): Define. libgcc/ChangeLog: * config/riscv/linux-unwind.h: Include shadow-stack-unwind.h. * config/riscv/shadow-stack-unwind.h (_Unwind_Frames_Extra): Define. (_Unwind_Frames_Increment): Define. gcc/testsuite/ChangeLog: * gcc.target/riscv/ssp-1.c: New test. * gcc.target/riscv/ssp-2.c: New test. Co-Developed-by: Greg McGary <gkm@rivosinc.com>, Kito Cheng <kito.cheng@gmail.com>
74 lines
2.3 KiB
C
74 lines
2.3 KiB
C
/* _Unwind_Frames_Extra with shadow stack.
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Copyright (C) 2016-2025 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
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU 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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#define LIBGCC2_UNITS_PER_WORD (__riscv_xlen / 8)
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/* Unwind the shadow stack for EH. */
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#undef _Unwind_Frames_Extra
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#define _Unwind_Frames_Extra(x) \
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do \
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{ \
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_Unwind_Word ssp = 0; \
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asm volatile ("ssrdp %0" : "=r"(ssp)); \
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if (ssp != 0) \
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{ \
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_Unwind_Word tmp = (x); \
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tmp = tmp * LIBGCC2_UNITS_PER_WORD; \
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while (tmp > 4096) \
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{ \
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ssp += 4096; \
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tmp -= 4096; \
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asm volatile ("csrw ssp, %0" :: "r"(ssp)); \
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asm volatile ("sspush x5\n" \
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"sspopchk x5" : : : "x5"); \
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} \
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\
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if (tmp > 0) \
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{ \
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ssp += tmp; \
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asm volatile ("csrw ssp, %0" :: "r"(ssp)); \
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} \
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} \
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} \
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while (0)
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#undef _Unwind_Frames_Increment
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#define _Unwind_Frames_Increment(exc, context, frames) \
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{ \
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frames++; \
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if (exc->exception_class != 0 \
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&& _Unwind_GetIP (context) != 0 \
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&& !_Unwind_IsSignalFrame (context)) \
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{ \
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_Unwind_Word ssp; \
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asm volatile ("ssrdp %0" : "=r"(ssp)); \
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if (ssp != 0) \
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{ \
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ssp += LIBGCC2_UNITS_PER_WORD * frames; \
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_Unwind_Word ra = *(_Unwind_Word *) ssp; \
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if (ra != _Unwind_GetIP (context)) \
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return _URC_FATAL_PHASE2_ERROR; \
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} \
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} \
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}
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