Commit 628a15e0 authored Sep 03, 2025 by Kees Cook Committed by Peter Zijlstra Sep 04, 2025

x86/traps: Clarify KCFI instruction layout



Just a nit-picky change to the KCFI indirect call check instruction
documentation. The addl offset isn't always -4 (it depends on patchable
function entry configuration).

Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250904034656.3670313-2-kees@kernel.org

parent 038c7dc6

arch/x86/kernel/cfi.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -27,7 +27,7 @@ static bool decode_cfi_insn(struct pt_regs regs, unsigned long target,
		* for indirect call checks:
		*
		* movl -<id>, %r10d ; 6 bytes
		* addl -4(%reg), %r10d ; 4 bytes
		* addl -<pos>(%reg), %r10d; 4 bytes
		* je .Ltmp1 ; 2 bytes
		* ud2 ; <- regs->ip
		* .Ltmp1: