Messages in this thread | | | From | Sami Tolvanen <> | Date | Mon, 24 Oct 2022 10:15:59 -0700 | Subject | Re: [PATCH] x86/ibt: Implement FineIBT |
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On Sat, Oct 22, 2022 at 8:03 AM Peter Zijlstra <peterz@infradead.org> wrote: > > On Fri, Oct 21, 2022 at 04:08:59PM -0700, Josh Poimboeuf wrote: > > On Tue, Oct 18, 2022 at 03:35:50PM +0200, Peter Zijlstra wrote: > > > +#ifdef CONFIG_FINEIBT > > > +/* > > > + * kCFI FineIBT > > > + * > > > + * __cfi_\func: __cfi_\func: > > > + * movl $0x12345678,%eax endbr64 // 4 > > > + * nop subl $0x12345678,%r10d // 7 > > > + * nop jz 1f // 2 > > > + * nop ud2 // 2 > > > + * nop 1: nop // 1 > > > + * nop > > > + * nop > > > + * nop > > > + * nop > > > + * nop > > > + * nop > > > + * nop > > > > All the "CFI" naming everywhere is very unfortunate. We already have > > "call frame information" in both the toolchain and objtool. > > > > The feature is called "kCFI" anyway, can Clang call the symbols > > '__kcfi_*'? > > I think the compiler patch is already merged in clang, not sure that's > still an option, Sami?
Yes, the compiler patch is already in, but if the cfi/kcfi confusion is a big concern, it's still possible to rename the symbol before Clang 16 is released. However, I thought we picked the __cfi prefix earlier to make things less confusing with FineIBT? Joao, are you still planning on adding FineIBT to Clang as well?
Sami
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