| Message ID | 20220401201916.1487500-4-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cfi: Use __builtin_function_start | expand |
On Fri, Apr 01, 2022 at 01:19:16PM -0700, Sami Tolvanen wrote: > Drop the inline assembly version of function_nocfi() now that > CONFIG_CFI_CLANG depends on __builtin_function_start(), which allows > this macro to be implemented more cleanly and in a way that works also > with static initializers. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > --- > arch/arm64/include/asm/compiler.h | 16 ---------------- > 1 file changed, 16 deletions(-) > > diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h > index dc3ea4080e2e..6fb2e6bcc392 100644 > --- a/arch/arm64/include/asm/compiler.h > +++ b/arch/arm64/include/asm/compiler.h > @@ -23,20 +23,4 @@ > #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 */ Acked-by: Will Deacon <will@kernel.org> Will
On Fri, Apr 01, 2022 at 01:19:16PM -0700, Sami Tolvanen wrote: > Drop the inline assembly version of function_nocfi() now that > CONFIG_CFI_CLANG depends on __builtin_function_start(), which allows > this macro to be implemented more cleanly and in a way that works also > with static initializers. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > --- > arch/arm64/include/asm/compiler.h | 16 ---------------- > 1 file changed, 16 deletions(-) It's very nice to see the asm go here! I grabbed the LLVM 14.0.0 binary release from llvm.org and gave this a spin. I tested with ThinLTO and CFI_CLANG, and verified that CPU hotplug and ftrace worked as expected (given those rely on function_nocfi()), and that the LKDTM CFI_FORWARD_PROTO caught the mismatched prototype as expected. FWIW: Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> As noted on patch 2 I think we should squash the series together, but those tags apply either way. Thanks, Mark. > > diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h > index dc3ea4080e2e..6fb2e6bcc392 100644 > --- a/arch/arm64/include/asm/compiler.h > +++ b/arch/arm64/include/asm/compiler.h > @@ -23,20 +23,4 @@ > #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 */ > -- > 2.35.0 >
diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h index dc3ea4080e2e..6fb2e6bcc392 100644 --- a/arch/arm64/include/asm/compiler.h +++ b/arch/arm64/include/asm/compiler.h @@ -23,20 +23,4 @@ #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 */
Drop the inline assembly version of function_nocfi() now that CONFIG_CFI_CLANG depends on __builtin_function_start(), which allows this macro to be implemented more cleanly and in a way that works also with static initializers. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- arch/arm64/include/asm/compiler.h | 16 ---------------- 1 file changed, 16 deletions(-)