On Wed, Dec 27, 2023 at 2:24 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, 27 Dec 2023 14:20:36 -0800 Deepak Gupta <debug@xxxxxxxxxxxx> wrote: > > > On Wed, Dec 27, 2023 at 1:45 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Fri, 22 Dec 2023 15:51:04 -0800 Deepak Gupta <debug@xxxxxxxxxxxx> wrote: > > > > > > > x86 has used VM_SHADOW_STACK (alias to VM_HIGH_ARCH_5) to encode shadow > > > > stack VMA. VM_SHADOW_STACK is thus not possible on 32bit. Some arches may > > > > need a way to encode shadow stack on 32bit and 64bit both and they may > > > > encode this information differently in VMAs. > > > > > > Is such a patch in the pipeline? Otherwise we're making a change that > > > serves no purpose. > > > > Yes I do have patches in the pipeline for riscv. > > On riscv, presence of only `VM_WRITE` (i.e. (flags & (VM_READ | > > VM_WRITE | VM_EXEC)) > > == VM_WRITE) would mean a shadow stack. > > And yes there would be relevant patches to ensure that existing consumers using > > `PROT_WRITE` gets translated to (VM_WRITE | VM_READ) > > OK, please plan to carry this patch in whatever tree contains the above. > > ACK. Thanks
