From 29efbc6aea9d9bd9aa9870a9afc1882046303cf9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 30 Aug 2018 19:07:27 +0200 Subject: Compiler Attributes: remove unused attributes __optimize and __deprecate_for_modules are unused in the whole kernel tree. Simply drop them. Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7 Reviewed-by: Nick Desaulniers Reviewed-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda --- include/linux/compiler-gcc.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 4d36b27214fd..1302b425e625 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -81,8 +81,6 @@ #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) -#define __optimize(level) __attribute__((__optimize__(level))) - #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) #ifndef __CHECKER__ -- cgit v1.2.3 From 5c67a52f3da0f0d22764f2daec417702695a8112 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 30 Aug 2018 19:13:37 +0200 Subject: Compiler Attributes: always use the extra-underscores syntax The attribute syntax optionally allows to surround attribute names with "__" in order to avoid collisions with macros of the same name (see https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html). This homogenizes all attributes to use the syntax with underscores. While there are currently only a handful of cases of some TUs defining macros like "error" which may collide with the attributes, this should prevent futures surprises. This has been done only for "standard" attributes supported by the major compilers. In other words, those of third-party tools (e.g. sparse, plugins...) have not been changed for the moment. Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7 Reviewed-by: Nick Desaulniers Reviewed-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda --- include/linux/compiler-gcc.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 1302b425e625..7a1de7683df5 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -76,7 +76,7 @@ #endif #ifdef RETPOLINE -#define __noretpoline __attribute__((indirect_branch("keep"))) +#define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) @@ -84,8 +84,8 @@ #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) #ifndef __CHECKER__ -#define __compiletime_warning(message) __attribute__((warning(message))) -#define __compiletime_error(message) __attribute__((error(message))) +#define __compiletime_warning(message) __attribute__((__warning__(message))) +#define __compiletime_error(message) __attribute__((__error__(message))) #ifdef LATENT_ENTROPY_PLUGIN #define __latent_entropy __attribute__((latent_entropy)) @@ -134,7 +134,7 @@ * optimizer that something else uses this function or variable, thus preventing * this. */ -#define __visible __attribute__((externally_visible)) +#define __visible __attribute__((__externally_visible__)) /* gcc version specific checks */ @@ -191,7 +191,7 @@ * should not be applied to that function. * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 */ -#define __no_sanitize_address __attribute__((no_sanitize_address)) +#define __no_sanitize_address __attribute__((__no_sanitize_address__)) #endif #if GCC_VERSION >= 50100 @@ -199,7 +199,7 @@ * Mark structures as requiring designated initializers. * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html */ -#define __designated_init __attribute__((designated_init)) +#define __designated_init __attribute__((__designated_init__)) #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif -- cgit v1.2.3 From ec0bbef66f867854691d5af18c2231d746958e0e Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 30 Aug 2018 19:25:14 +0200 Subject: Compiler Attributes: homogenize __must_be_array Different definitions of __must_be_array: * gcc: disabled for __CHECKER__ * clang: same definition as gcc's, but without __CHECKER__ * intel: the comment claims __builtin_types_compatible_p() is unsupported; but icc seems to support it since 13.0.1 (released in 2012). See https://godbolt.org/z/S0l6QQ Therefore, we can remove all of them and have a single definition in compiler.h Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7 Reviewed-by: Nick Desaulniers Reviewed-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda --- include/linux/compiler-gcc.h | 7 ------- 1 file changed, 7 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 7a1de7683df5..3b32bbfa5a49 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -68,13 +68,6 @@ */ #define uninitialized_var(x) x = x -#ifdef __CHECKER__ -#define __must_be_array(a) 0 -#else -/* &a[0] degrades to a pointer: a different type from an array */ -#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) -#endif - #ifdef RETPOLINE #define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif -- cgit v1.2.3 From 989bd5000f36052df604888ed12bb6ef390786b7 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Fri, 31 Aug 2018 18:00:16 +0200 Subject: Compiler Attributes: remove unneeded sparse (__CHECKER__) tests Sparse knows about a few more attributes now, so we can remove the __CHECKER__ conditions from them (which, in turn, allow us to move some of them later on to compiler_attributes.h). * assume_aligned: since sparse's commit ffc860b ("sparse: ignore __assume_aligned__ attribute"), included in 0.5.1 * error: since sparse's commit 0a04210 ("sparse: Add 'error' to ignored attributes"), included in 0.5.0 * hotpatch: since sparse's commit 6043210 ("sparse/parse.c: ignore hotpatch attribute"), included in 0.5.1 * warning: since sparse's commit 977365d ("Avoid "attribute 'warning': unknown attribute" warning"), included in 0.4.2 On top of that, __must_be_array does not need it either because: * Even ancient versions of sparse do not have a problem * BUILD_BUG_ON_ZERO() is currently disabled for __CHECKER__ Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7 Reviewed-by: Nick Desaulniers Reviewed-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda --- include/linux/compiler-gcc.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 3b32bbfa5a49..1ca6a51cfaa9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -76,14 +76,12 @@ #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) -#ifndef __CHECKER__ #define __compiletime_warning(message) __attribute__((__warning__(message))) #define __compiletime_error(message) __attribute__((__error__(message))) -#ifdef LATENT_ENTROPY_PLUGIN +#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) #define __latent_entropy __attribute__((latent_entropy)) #endif -#endif /* __CHECKER__ */ /* * calling noreturn functions, __builtin_unreachable() and __builtin_trap() @@ -131,7 +129,7 @@ /* gcc version specific checks */ -#if GCC_VERSION >= 40900 && !defined(__CHECKER__) +#if GCC_VERSION >= 40900 /* * __assume_aligned(n, k): Tell the optimizer that the returned * pointer can be assumed to be k modulo n. The second argument is -- cgit v1.2.3 From a3f8a30f3f0079c7edfc72e329eee8594fb3e3cb Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 30 Aug 2018 20:36:59 +0200 Subject: Compiler Attributes: use feature checks instead of version checks Instead of using version checks per-compiler to define (or not) each attribute, use __has_attribute to test for them, following the cleanup started with commit 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive"), which is supported on gcc >= 5, clang >= 2.9 and icc >= 17. In the meantime, to support 4.6 <= gcc < 5, we implement __has_attribute by hand. All the attributes that can be unconditionally defined and directly map to compiler attribute(s) (even if optional) have been moved to a new file include/linux/compiler_attributes.h In an effort to make the file as regular as possible, comments stating the purpose of attributes have been removed. Instead, links to the compiler docs have been added (i.e. to gcc and, if available, to clang as well). In addition, they have been sorted. Finally, if an attribute is optional (i.e. if it is guarded by __has_attribute), the reason has been stated for future reference. Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7 Reviewed-by: Nick Desaulniers Reviewed-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda --- include/linux/compiler-gcc.h | 51 -------------------------------------------- 1 file changed, 51 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 1ca6a51cfaa9..cfac027e1625 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -108,9 +108,6 @@ __builtin_unreachable(); \ } while (0) -/* Mark a function definition as prohibited from being cloned. */ -#define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) - #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__) #define __randomize_layout __attribute__((randomize_layout)) #define __no_randomize_layout __attribute__((no_randomize_layout)) @@ -119,32 +116,6 @@ #define randomized_struct_fields_end } __randomize_layout; #endif -/* - * When used with Link Time Optimization, gcc can optimize away C functions or - * variables which are referenced only from assembly code. __visible tells the - * optimizer that something else uses this function or variable, thus preventing - * this. - */ -#define __visible __attribute__((__externally_visible__)) - -/* gcc version specific checks */ - -#if GCC_VERSION >= 40900 -/* - * __assume_aligned(n, k): Tell the optimizer that the returned - * pointer can be assumed to be k modulo n. The second argument is - * optional (default 0), so we use a variadic macro to make the - * shorthand. - * - * Beware: Do not apply this to functions which may return - * ERR_PTRs. Also, it is probably unwise to apply it to functions - * returning extra information in the low bits (but in that case the - * compiler should see some alignment anyway, when the return value is - * massaged by 'flags = ptr & 3; ptr &= ~3;'). - */ -#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) -#endif - /* * GCC 'asm goto' miscompiles certain code sequences: * @@ -176,32 +147,10 @@ #define KASAN_ABI_VERSION 3 #endif -#if GCC_VERSION >= 40902 -/* - * Tell the compiler that address safety instrumentation (KASAN) - * should not be applied to that function. - * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 - */ -#define __no_sanitize_address __attribute__((__no_sanitize_address__)) -#endif - #if GCC_VERSION >= 50100 -/* - * Mark structures as requiring designated initializers. - * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html - */ -#define __designated_init __attribute__((__designated_init__)) #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif -#if !defined(__noclone) -#define __noclone /* not needed */ -#endif - -#if !defined(__no_sanitize_address) -#define __no_sanitize_address -#endif - /* * Turn individual warnings and errors on and off locally, depending * on version. -- cgit v1.2.3 From dde709d1361ab50d3b9f2824f72b4374f5582e84 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Mon, 20 Nov 2017 11:16:14 +0100 Subject: compiler: introduce __no_sanitize_address_or_inline Due to conflict between kasan instrumentation and inlining https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 functions which are defined as inline could not be called from functions defined with __no_sanitize_address. Introduce __no_sanitize_address_or_inline which would expand to __no_sanitize_address when the kernel is built with kasan support and to inline otherwise. This helps to avoid disabling kasan instrumentation for entire files. Reviewed-by: Martin Schwidefsky Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky --- include/linux/compiler-gcc.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 763bbad1e258..997ade08a79d 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -208,6 +208,12 @@ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 */ #define __no_sanitize_address __attribute__((no_sanitize_address)) +#ifdef CONFIG_KASAN +#define __no_sanitize_address_or_inline \ + __no_sanitize_address __maybe_unused notrace +#else +#define __no_sanitize_address_or_inline inline +#endif #endif #if GCC_VERSION >= 50100 @@ -225,6 +231,7 @@ #if !defined(__no_sanitize_address) #define __no_sanitize_address +#define __no_sanitize_address_or_inline inline #endif /* -- cgit v1.2.3 From 1ff2fea5e30ca15752777441ecb64a169fe22e9e Mon Sep 17 00:00:00 2001 From: "ndesaulniers@google.com" Date: Mon, 15 Oct 2018 14:24:27 -0700 Subject: compiler-gcc: remove comment about gcc 4.5 from unreachable() Remove the comment about being unable to detect __builtin_unreachable. __builtin_unreachable was implemented in the GCC 4.5 timeframe. The kernel's minimum supported version of GCC is 4.6 since commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6"). Commit cb984d101b30 ("compiler-gcc: integrate the various compiler-gcc[345].h files") shows that unreachable() had different guards based on GCC version. Suggested-by: Miguel Ojeda Signed-off-by: Nick Desaulniers Signed-off-by: Miguel Ojeda --- include/linux/compiler-gcc.h | 4 ---- 1 file changed, 4 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index cfac027e1625..2010493e1040 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -96,10 +96,6 @@ * Mark a position in code as unreachable. This can be used to * suppress control flow warnings after asm blocks that transfer * control elsewhere. - * - * Early snapshots of gcc 4.5 don't support this and we can't detect - * this in the preprocessor, but we can live with this because they're - * unreleased. Really, we need to have autoconf for the kernel. */ #define unreachable() \ do { \ -- cgit v1.2.3 From 163c8d54a997153ee1a1e07fcac087492ad85b37 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 5 Nov 2018 07:36:28 +0100 Subject: compiler: remove __no_sanitize_address_or_inline again The __no_sanitize_address_or_inline and __no_kasan_or_inline defines are almost identical. The only difference is that __no_kasan_or_inline does not have the 'notrace' attribute. To be able to replace __no_sanitize_address_or_inline with the older definition, add 'notrace' to __no_kasan_or_inline and change to two users of __no_sanitize_address_or_inline in the s390 code. The 'notrace' option is necessary for e.g. the __load_psw_mask function in arch/s390/include/asm/processor.h. Without the option it is possible to trace __load_psw_mask which leads to kernel stack overflow. Signed-off-by: Martin Schwidefsky Pointed-out-by: Andrey Ryabinin Acked-by: Steven Rostedt (VMware) Signed-off-by: Linus Torvalds --- include/linux/compiler-gcc.h | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index c0f5db3a9621..2010493e1040 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -143,18 +143,6 @@ #define KASAN_ABI_VERSION 3 #endif -/* - * Because __no_sanitize_address conflicts with inlining: - * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 - * we do one or the other. - */ -#ifdef CONFIG_KASAN -#define __no_sanitize_address_or_inline \ - __no_sanitize_address __maybe_unused notrace -#else -#define __no_sanitize_address_or_inline inline -#endif - #if GCC_VERSION >= 50100 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif -- cgit v1.2.3