Commit e9d13b9d authored Dec 15, 2023 by Peter Zijlstra Committed by Alexei Starovoitov Dec 15, 2023

cfi: Add CFI_NOSEAL()

Add a CFI_NOSEAL() helper to mark functions that need to retain their
CFI information, despite not otherwise leaking their address.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231215092707.669401084@infradead.org

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent 2cd3e377

arch/x86/include/asm/cfi.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -8,6 +8,7 @@
		* Copyright (C) 2022 Google LLC
		*/
		#include <linux/bug.h>
		#include <asm/ibt.h>

		/*
		* An overview of the various calling conventions...
		@@ -138,4 +139,8 @@ static inline u32 cfi_get_func_hash(void *func)
		}
		#endif /* CONFIG_CFI_CLANG */

		#if HAS_KERNEL_IBT == 1
		#define CFI_NOSEAL(x) asm(IBT_NOSEAL(__stringify(x)))
		#endif

		#endif /* _ASM_X86_CFI_H */

include/linux/cfi.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -46,4 +46,8 @@ static inline void module_cfi_finalize(const Elf_Ehdr *hdr,
		#endif /* CONFIG_ARCH_USES_CFI_TRAPS */
		#endif /* CONFIG_MODULES */

		#ifndef CFI_NOSEAL
		#define CFI_NOSEAL(x)
		#endif

		#endif /* _LINUX_CFI_H */