Messages in this thread | | | From | Sami Tolvanen <> | Date | Thu, 11 Apr 2024 17:05:38 +0000 | Subject | Re: [RFC PATCH 08/12] riscv: dynamic (zicfiss) shadow call stack support |
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Hi Deepak,
Thanks for the patches!
On Tue, Apr 9, 2024 at 6:12 AM Deepak Gupta <debug@rivosinc.com> wrote: > > Adding support for dynamic shadow call stack on riscv. zicfiss ISA extn. > enables protection for shadow stack against stray writes. This patch > enables scs_* macros to use zicfiss shadow stack pointer (CSR_SSP) instead > of relying on `gp`.
CONFIG_DYNAMIC_SCS implies that runtime patching is used to select between software SCS and an alternative hardware implementation (in arm64's case, PAC instead of hardware shadow stacks). I understand this series is still an RFC, but I didn't see runtime patching support. Are you planning on implementing this later?
If there's no plan to actually patch between Zicfiss and SCS at runtime, CONFIG_DYNAMIC_SCS doesn't seem like the appropriate choice and we might need a separate config option that still allows you to reuse most of the software SCS code.
Sami
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