linux-stable/include/linux/cfi.h
Peter Zijlstra cb9010f87d x86/ibt: Ensure module init/exit points have references
Since the references to the module init/exit points only have external
references, a module LTO run will consider them 'unused' and seal
them, leading to an immediate fail on module load.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.113767246@infradead.org
2022-03-15 10:32:42 +01:00

50 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Clang Control Flow Integrity (CFI) support.
*
* Copyright (C) 2021 Google LLC
*/
#ifndef _LINUX_CFI_H
#define _LINUX_CFI_H
#ifdef CONFIG_CFI_CLANG
typedef void (*cfi_check_fn)(uint64_t id, void *ptr, void *diag);
/* Compiler-generated function in each module, and the kernel */
extern void __cfi_check(uint64_t id, void *ptr, void *diag);
/*
* Force the compiler to generate a CFI jump table entry for a function
* and store the jump table address to __cfi_jt_<function>.
*/
#define __CFI_ADDRESSABLE(fn, __attr) \
const void *__cfi_jt_ ## fn __visible __attr = (void *)&fn
#ifdef CONFIG_CFI_CLANG_SHADOW
extern void cfi_module_add(struct module *mod, unsigned long base_addr);
extern void cfi_module_remove(struct module *mod, unsigned long base_addr);
#else
static inline void cfi_module_add(struct module *mod, unsigned long base_addr) {}
static inline void cfi_module_remove(struct module *mod, unsigned long base_addr) {}
#endif /* CONFIG_CFI_CLANG_SHADOW */
#else /* !CONFIG_CFI_CLANG */
#ifdef CONFIG_X86_KERNEL_IBT
#define __CFI_ADDRESSABLE(fn, __attr) \
const void *__cfi_jt_ ## fn __visible __attr = (void *)&fn
#endif /* CONFIG_X86_KERNEL_IBT */
#endif /* CONFIG_CFI_CLANG */
#ifndef __CFI_ADDRESSABLE
#define __CFI_ADDRESSABLE(fn, __attr)
#endif
#endif /* _LINUX_CFI_H */