On 11/15/24 3:53 AM, Monk Chiang wrote:
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.
* gcc/config/riscv/predicates.md: New predicate x1x5_operand.
* gcc/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.
* gcc/config/riscv/riscv.h
(need_shadow_stack_push_pop_p): Define.
* gcc/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.
libgcc/ChangeLog:
* gcc/config/riscv/riscv.opt (TARGET_ZICFISS): Define.
* libgcc/config/riscv/linux-unwind.h: Include shadow-stack-unwind.h.
* libgcc/config/riscv/shadow-stack-unwind.h
(_Unwind_Frames_Extra): Define.
(_Unwind_Frames_Increment): Define.
gcc/testsuite/ChangeLog:
* gcc/testsuite/gcc.target/riscv/ssp-1.c: New test.
* gcc/testsuite/gcc.target/riscv/ssp-2.c: New test.
Just a note. Kito has a far better understanding of the needs of this
stuff than I do. So I'm explicitly deferring review of this series to him.
jeff
