Messages in this thread | | | Date | Wed, 21 Feb 2024 16:39:57 -0800 | From | Deepak Gupta <> | Subject | Re: [RFC PATCH v1 11/28] riscv: Implementing "PROT_SHADOWSTACK" on riscv |
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On Fri, Feb 09, 2024 at 08:44:35PM +0000, Edgecombe, Rick P wrote: >On Wed, 2024-01-24 at 22:21 -0800, debug@rivosinc.com wrote: >> + /* >> + * PROT_SHADOWSTACK is a kernel only protection flag on risc- >> v. >> + * mmap doesn't expect PROT_SHADOWSTACK to be set by user >> space. >> + * User space can rely on `map_shadow_stack` syscall to >> create >> + * shadow stack pages. >> + */ >> + if (unlikely(prot & PROT_SHADOWSTACK)) >> + return -EINVAL; > >Are you sure you need PROT_SHADOWSTACK? Since you are passing >VM_SHADOW_STACK into do_mmap() directly.
Sorry for (very) late response. In this patch series since VM_SHADOW_STACK was an alias to VM_WRITE. And that's why I needed PROT_SHADOWSTACK to disambiguate.
I am updating my patches and going with ARCH_5 bit (and thus only 64bit support). So x86, aarch64 and risc-v will be using same bit position.
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