Messages in this thread Patch in this message | | | From | Mark Rutland <> | Subject | [PATCH] CFI: Move function_nocfi() into compiler.h | Date | Wed, 2 Jun 2021 16:37:01 +0100 |
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Currently the common definition of function_nocfi() is provided by <linux/mm.h>, and architectures are expected to provide a definition in <asm/memory.h>. Due to header dependencies, this can make it hard to use function_nocfi() in low-level headers.
As function_nocfi() has no dependency on any mm code, nor on any memory definitions, it doesn't need to live in <linux/mm.h> or <asm/memory.h>. Generally, it would make more sense for it to live in <linux/compiler.h>, where an architecture can override it in <asm/compiler.h>.
Move the definitions accordingly.
Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/compiler.h | 16 ++++++++++++++++ arch/arm64/include/asm/memory.h | 16 ---------------- include/linux/compiler.h | 10 ++++++++++ include/linux/mm.h | 10 ---------- 4 files changed, 26 insertions(+), 26 deletions(-)
diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h index 6fb2e6bcc392..dc3ea4080e2e 100644 --- a/arch/arm64/include/asm/compiler.h +++ b/arch/arm64/include/asm/compiler.h @@ -23,4 +23,20 @@ #define __builtin_return_address(val) \ (void *)(ptrauth_clear_pac((unsigned long)__builtin_return_address(val))) +#ifdef CONFIG_CFI_CLANG +/* + * With CONFIG_CFI_CLANG, the compiler replaces function address + * references with the address of the function's CFI jump table + * entry. The function_nocfi macro always returns the address of the + * actual function instead. + */ +#define function_nocfi(x) ({ \ + void *addr; \ + asm("adrp %0, " __stringify(x) "\n\t" \ + "add %0, %0, :lo12:" __stringify(x) \ + : "=r" (addr)); \ + addr; \ +}) +#endif + #endif /* __ASM_COMPILER_H */ diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 7b360960cc35..1a35a4473598 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -321,22 +321,6 @@ static inline void *phys_to_virt(phys_addr_t x) #define virt_to_pfn(x) __phys_to_pfn(__virt_to_phys((unsigned long)(x))) #define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x)) -#ifdef CONFIG_CFI_CLANG -/* - * With CONFIG_CFI_CLANG, the compiler replaces function address - * references with the address of the function's CFI jump table - * entry. The function_nocfi macro always returns the address of the - * actual function instead. - */ -#define function_nocfi(x) ({ \ - void *addr; \ - asm("adrp %0, " __stringify(x) "\n\t" \ - "add %0, %0, :lo12:" __stringify(x) \ - : "=r" (addr)); \ - addr; \ -}) -#endif - /* * virt_to_page(x) convert a _valid_ virtual address to struct page * * virt_addr_valid(x) indicates whether a virtual address is valid diff --git a/include/linux/compiler.h b/include/linux/compiler.h index df5b405e6305..099e529a5d25 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -213,6 +213,16 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, __v; \ }) +/* + * With CONFIG_CFI_CLANG, the compiler replaces function addresses in + * instrumented C code with jump table addresses. Architectures that + * support CFI can define this macro to return the actual function address + * when needed. + */ +#ifndef function_nocfi +#define function_nocfi(x) (x) +#endif + #endif /* __KERNEL__ */ /* diff --git a/include/linux/mm.h b/include/linux/mm.h index c274f75efcf9..b8c28b10f25d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -125,16 +125,6 @@ extern int mmap_rnd_compat_bits __read_mostly; #endif /* - * With CONFIG_CFI_CLANG, the compiler replaces function addresses in - * instrumented C code with jump table addresses. Architectures that - * support CFI can define this macro to return the actual function address - * when needed. - */ -#ifndef function_nocfi -#define function_nocfi(x) (x) -#endif - -/* * To prevent common memory management code establishing * a zero page mapping on a read fault. * This macro should be defined within <asm/pgtable.h>. -- 2.11.0
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