From 8793bb7f4a9dd1396575d2e9337d331662cb7555 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 19 Jun 2018 13:14:56 -0700 Subject: kbuild: add macro for controlling warnings to linux/compiler.h I have occasionally run into a situation where it would make sense to control a compiler warning from a source file rather than doing so from a Makefile using the $(cc-disable-warning, ...) or $(cc-option, ...) helpers. The approach here is similar to what glibc uses, using __diag() and related macros to encapsulate a _Pragma("GCC diagnostic ...") statement that gets turned into the respective "#pragma GCC diagnostic ..." by the preprocessor when the macro gets expanded. Like glibc, I also have an argument to pass the affected compiler version, but decided to actually evaluate that one. For now, this supports GCC_4_6, GCC_4_7, GCC_4_8, GCC_4_9, GCC_5, GCC_6, GCC_7, GCC_8 and GCC_9. Adding support for CLANG_5 and other interesting versions is straightforward here. GNU compilers starting with gcc-4.2 could support it in principle, but "#pragma GCC diagnostic push" was only added in gcc-4.6, so it seems simpler to not deal with those at all. The same versions show a large number of warnings already, so it seems easier to just leave it at that and not do a more fine-grained control for them. The use cases I found so far include: - turning off the gcc-8 -Wattribute-alias warning inside of the SYSCALL_DEFINEx() macro without having to do it globally. - Reducing the build time for a simple re-make after a change, once we move the warnings from ./Makefile and ./scripts/Makefile.extrawarn into linux/compiler.h - More control over the warnings based on other configurations, using preprocessor syntax instead of Makefile syntax. This should make it easier for the average developer to understand and change things. - Adding an easy way to turn the W=1 option on unconditionally for a subdirectory or a specific file. This has been requested by several developers in the past that want to have their subsystems W=1 clean. - Integrating clang better into the build systems. Clang supports more warnings than GCC, and we probably want to classify them as default, W=1, W=2 etc, but there are cases in which the warnings should be classified differently due to excessive false positives from one or the other compiler. - Adding a way to turn the default warnings into errors (e.g. using a new "make E=0" tag) while not also turning the W=1 warnings into errors. This patch for now just adds the minimal infrastructure in order to do the first of the list above. As the #pragma GCC diagnostic takes precedence over command line options, the next step would be to convert a lot of the individual Makefiles that set nonstandard options to use __diag() instead. [paul.burton@mips.com: - Rebase atop current master. - Add __diag_GCC, or more generally __diag_, abstraction to avoid code outside of linux/compiler-gcc.h needing to duplicate knowledge about different GCC versions. - Add a comment argument to __diag_{ignore,warn,error} which isn't used in the expansion of the macros but serves to push people to document the reason for using them - per feedback from Kees Cook. - Translate severity to GCC-specific pragmas in linux/compiler-gcc.h rather than using GCC-specific in linux/compiler_types.h. - Drop all but GCC 8 macros, since we only need to define macros for versions that we need to introduce pragmas for, and as of this series that's just GCC 8. - Capitalize comments in linux/compiler-gcc.h to match the style of the rest of the file. - Line up macro definitions with tabs in linux/compiler-gcc.h.] Signed-off-by: Arnd Bergmann Signed-off-by: Paul Burton Tested-by: Christophe Leroy Tested-by: Stafford Horne Signed-off-by: Masahiro Yamada --- include/linux/compiler-gcc.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index f1a7492a5cc8..fd282c7d3e5e 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -347,3 +347,28 @@ #if GCC_VERSION >= 50100 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif + +/* + * Turn individual warnings and errors on and off locally, depending + * on version. + */ +#define __diag_GCC(version, severity, s) \ + __diag_GCC_ ## version(__diag_GCC_ ## severity s) + +/* Severity used in pragma directives */ +#define __diag_GCC_ignore ignored +#define __diag_GCC_warn warning +#define __diag_GCC_error error + +/* Compilers before gcc-4.6 do not understand "#pragma GCC diagnostic push" */ +#if GCC_VERSION >= 40600 +#define __diag_str1(s) #s +#define __diag_str(s) __diag_str1(s) +#define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) +#endif + +#if GCC_VERSION >= 80000 +#define __diag_GCC_8(s) __diag(s) +#else +#define __diag_GCC_8(s) +#endif -- cgit From d03db2bc26f0e4a6849ad649a09c9c73fccdc656 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Thu, 21 Jun 2018 09:23:22 -0700 Subject: compiler-gcc.h: Add __attribute__((gnu_inline)) to all inline declarations Functions marked extern inline do not emit an externally visible function when the gnu89 C standard is used. Some KBUILD Makefiles overwrite KBUILD_CFLAGS. This is an issue for GCC 5.1+ users as without an explicit C standard specified, the default is gnu11. Since c99, the semantics of extern inline have changed such that an externally visible function is always emitted. This can lead to multiple definition errors of extern inline functions at link time of compilation units whose build files have removed an explicit C standard compiler flag for users of GCC 5.1+ or Clang. Suggested-by: Arnd Bergmann Suggested-by: H. Peter Anvin Suggested-by: Joe Perches Signed-off-by: Nick Desaulniers Acked-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: acme@redhat.com Cc: akataria@vmware.com Cc: akpm@linux-foundation.org Cc: andrea.parri@amarulasolutions.com Cc: ard.biesheuvel@linaro.org Cc: aryabinin@virtuozzo.com Cc: astrachan@google.com Cc: boris.ostrovsky@oracle.com Cc: brijesh.singh@amd.com Cc: caoj.fnst@cn.fujitsu.com Cc: geert@linux-m68k.org Cc: ghackmann@google.com Cc: gregkh@linuxfoundation.org Cc: jan.kiszka@siemens.com Cc: jarkko.sakkinen@linux.intel.com Cc: jpoimboe@redhat.com Cc: keescook@google.com Cc: kirill.shutemov@linux.intel.com Cc: kstewart@linuxfoundation.org Cc: linux-efi@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: manojgupta@google.com Cc: mawilcox@microsoft.com Cc: michal.lkml@markovi.net Cc: mjg59@google.com Cc: mka@chromium.org Cc: pombredanne@nexb.com Cc: rientjes@google.com Cc: rostedt@goodmis.org Cc: sedat.dilek@gmail.com Cc: thomas.lendacky@amd.com Cc: tstellar@redhat.com Cc: tweek@google.com Cc: virtualization@lists.linux-foundation.org Cc: will.deacon@arm.com Cc: yamada.masahiro@socionext.com Link: http://lkml.kernel.org/r/20180621162324.36656-2-ndesaulniers@google.com Signed-off-by: Ingo Molnar --- include/linux/compiler-gcc.h | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index fd282c7d3e5e..573f5a7d42d4 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -65,6 +65,18 @@ #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) #endif +/* + * Feature detection for gnu_inline (gnu89 extern inline semantics). Either + * __GNUC_STDC_INLINE__ is defined (not using gnu89 extern inline semantics, + * and we opt in to the gnu89 semantics), or __GNUC_STDC_INLINE__ is not + * defined so the gnu89 semantics are the default. + */ +#ifdef __GNUC_STDC_INLINE__ +# define __gnu_inline __attribute__((gnu_inline)) +#else +# define __gnu_inline +#endif + /* * Force always-inline if the user requests it so via the .config, * or if gcc is too old. @@ -72,19 +84,22 @@ * -Wunused-function. This turns out to avoid the need for complex #ifdef * directives. Suppress the warning in clang as well by using "unused" * function attribute, which is redundant but not harmful for gcc. + * Prefer gnu_inline, so that extern inline functions do not emit an + * externally visible function. This makes extern inline behave as per gnu89 + * semantics rather than c99. This prevents multiple symbol definition errors + * of extern inline functions at link time. + * A lot of inline functions can cause havoc with function tracing. */ #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) -#define inline inline __attribute__((always_inline,unused)) notrace -#define __inline__ __inline__ __attribute__((always_inline,unused)) notrace -#define __inline __inline __attribute__((always_inline,unused)) notrace +#define inline \ + inline __attribute__((always_inline, unused)) notrace __gnu_inline #else -/* A lot of inline functions can cause havoc with function tracing */ -#define inline inline __attribute__((unused)) notrace -#define __inline__ __inline__ __attribute__((unused)) notrace -#define __inline __inline __attribute__((unused)) notrace +#define inline inline __attribute__((unused)) notrace __gnu_inline #endif +#define __inline__ inline +#define __inline inline #define __always_inline inline __attribute__((always_inline)) #define noinline __attribute__((noinline)) -- cgit From 771c035372a036f83353eef46dbb829780330234 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 18 Aug 2018 12:19:56 -0700 Subject: deprecate the '__deprecated' attribute warnings entirely and for good We haven't had lots of deprecation warnings lately, but the rdma use of it made them flare up again. They are not useful. They annoy everybody, and nobody ever does anything about them, because it's always "somebody elses problem". And when people start thinking that warnings are normal, they stop looking at them, and the real warnings that mean something go unnoticed. If you want to get rid of a function, just get rid of it. Convert every user to the new world order. And if you can't do that, then don't annoy everybody else with your marking that says "I couldn't be bothered to fix this, so I'll just spam everybody elses build logs with warnings about my laziness". Make a kernelnewbies wiki page about things that could be cleaned up, write a blog post about it, or talk to people on the mailing lists. But don't add warnings to the kernel build about cleanup that you think should happen but you aren't doing yourself. Don't. Just don't. Signed-off-by: Linus Torvalds --- include/linux/compiler-gcc.h | 1 - include/linux/compiler_types.h | 21 ++------------------- lib/Kconfig.debug | 8 -------- 3 files changed, 2 insertions(+), 28 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 573f5a7d42d4..3e70b7d4e9ed 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -103,7 +103,6 @@ #define __always_inline inline __attribute__((always_inline)) #define noinline __attribute__((noinline)) -#define __deprecated __attribute__((deprecated)) #define __packed __attribute__((packed)) #define __weak __attribute__((weak)) #define __alias(symbol) __attribute__((alias(#symbol))) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index a8ba6b04152c..fbf337933fd8 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -111,21 +111,10 @@ struct ftrace_likely_data { #endif /* __ASSEMBLY__ */ #ifdef __KERNEL__ -/* - * Allow us to mark functions as 'deprecated' and have gcc emit a nice - * warning for each use, in hopes of speeding the functions removal. - * Usage is: - * int __deprecated foo(void) - */ -#ifndef __deprecated -# define __deprecated /* unimplemented */ -#endif -#ifdef MODULE -#define __deprecated_for_modules __deprecated -#else +/* Don't. Just don't. */ +#define __deprecated #define __deprecated_for_modules -#endif #ifndef __must_check #define __must_check @@ -135,12 +124,6 @@ struct ftrace_likely_data { #undef __must_check #define __must_check #endif -#ifndef CONFIG_ENABLE_WARN_DEPRECATED -#undef __deprecated -#undef __deprecated_for_modules -#define __deprecated -#define __deprecated_for_modules -#endif #ifndef __malloc #define __malloc diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c6e73904c5a5..ab1b599202bc 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -211,14 +211,6 @@ config GDB_SCRIPTS instance. See Documentation/dev-tools/gdb-kernel-debugging.rst for further details. -config ENABLE_WARN_DEPRECATED - bool "Enable __deprecated logic" - default y - help - Enable the __deprecated logic in the kernel build. - Disable this to suppress the "warning: 'foo' is deprecated - (declared at kernel/power/somefile.c:1234)" messages. - config ENABLE_MUST_CHECK bool "Enable __must_check logic" default y -- cgit From cafa0010cd51fb711fdcb50fc55f394c5f167a0a Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 20 Aug 2018 13:15:26 -0700 Subject: Raise the minimum required gcc version to 4.6 Various architectures fail to build properly with older versions of the gcc compiler. An example from Guenter Roeck in thread [1]: > > In file included from ./include/linux/mm.h:17:0, > from ./include/linux/pid_namespace.h:7, > from ./include/linux/ptrace.h:10, > from arch/openrisc/kernel/asm-offsets.c:32: > ./include/linux/mm_types.h:497:16: error: flexible array member in otherwise empty struct > > This is just an example with gcc 4.5.1 for or32. I have seen the problem > with gcc 4.4 (for unicore32) as well. So update the minimum required version of gcc to 4.6. [1] https://lore.kernel.org/lkml/20180814170904.GA12768@roeck-us.net/ Miscellanea: - Update Documentation/process/changes.rst - Remove and consolidate version test blocks in compiler-gcc.h for versions lower than 4.6 Signed-off-by: Joe Perches Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Linus Torvalds --- Documentation/process/changes.rst | 2 +- include/linux/compiler-gcc.h | 86 ++++++++------------------------------- 2 files changed, 19 insertions(+), 69 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index 7a92a06f90de..61f918b10a0c 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -29,7 +29,7 @@ you probably needn't concern yourself with isdn4k-utils. ====================== =============== ======================================== Program Minimal version Command to check the version ====================== =============== ======================================== -GNU C 3.2 gcc --version +GNU C 4.6 gcc --version GNU make 3.81 make --version binutils 2.20 ld -v flex 2.5.35 flex --version diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 3e70b7d4e9ed..250b9b7cfd60 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -10,6 +10,10 @@ + __GNUC_MINOR__ * 100 \ + __GNUC_PATCHLEVEL__) +#if GCC_VERSION < 40600 +# error Sorry, your compiler is too old - please upgrade it. +#endif + /* Optimization barrier */ /* The "volatile" is due to gcc bugs */ @@ -58,6 +62,12 @@ #define OPTIMIZER_HIDE_VAR(var) \ __asm__ ("" : "=r" (var) : "0" (var)) +/* + * A trick to suppress uninitialized variable warning without generating any + * code + */ +#define uninitialized_var(x) x = x + #ifdef __CHECKER__ #define __must_be_array(a) 0 #else @@ -91,7 +101,7 @@ * A lot of inline functions can cause havoc with function tracing. */ #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ - !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) + !defined(CONFIG_OPTIMIZE_INLINING) #define inline \ inline __attribute__((always_inline, unused)) notrace __gnu_inline #else @@ -147,47 +157,13 @@ #define __always_unused __attribute__((unused)) #define __mode(x) __attribute__((mode(x))) -/* gcc version specific checks */ - -#if GCC_VERSION < 30200 -# error Sorry, your compiler is too old - please upgrade it. -#endif - -#if GCC_VERSION < 30300 -# define __used __attribute__((__unused__)) -#else -# define __used __attribute__((__used__)) -#endif - -#ifdef CONFIG_GCOV_KERNEL -# if GCC_VERSION < 30400 -# error "GCOV profiling support for gcc versions below 3.4 not included" -# endif /* __GNUC_MINOR__ */ -#endif /* CONFIG_GCOV_KERNEL */ - -#if GCC_VERSION >= 30400 #define __must_check __attribute__((warn_unused_result)) #define __malloc __attribute__((__malloc__)) -#endif - -#if GCC_VERSION >= 40000 - -/* GCC 4.1.[01] miscompiles __weak */ -#ifdef __KERNEL__ -# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 -# error Your version of gcc miscompiles the __weak directive -# endif -#endif #define __used __attribute__((__used__)) #define __compiler_offsetof(a, b) \ __builtin_offsetof(a, b) -#if GCC_VERSION >= 40100 -# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) -#endif - -#if GCC_VERSION >= 40300 /* Mark functions as cold. gcc will assume any path leading to a call * to them will be unlikely. This means a lot of manual unlikely()s * are unnecessary now for any paths leading to the usual suspects @@ -206,24 +182,19 @@ #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) -#ifndef __CHECKER__ -# define __compiletime_warning(message) __attribute__((warning(message))) -# define __compiletime_error(message) __attribute__((error(message))) -#endif /* __CHECKER__ */ -#endif /* GCC_VERSION >= 40300 */ - -#if GCC_VERSION >= 40400 #define __optimize(level) __attribute__((__optimize__(level))) #define __nostackprotector __optimize("no-stack-protector") -#endif /* GCC_VERSION >= 40400 */ -#if GCC_VERSION >= 40500 +#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 #define __latent_entropy __attribute__((latent_entropy)) #endif -#endif +#endif /* __CHECKER__ */ /* * calling noreturn functions, __builtin_unreachable() and __builtin_trap() @@ -261,10 +232,6 @@ #define randomized_struct_fields_end } __randomize_layout; #endif -#endif /* GCC_VERSION >= 40500 */ - -#if GCC_VERSION >= 40600 - /* * When used with Link Time Optimization, gcc can optimize away C functions or * variables which are referenced only from assembly code. __visible tells the @@ -273,8 +240,7 @@ */ #define __visible __attribute__((externally_visible)) -#endif /* GCC_VERSION >= 40600 */ - +/* gcc version specific checks */ #if GCC_VERSION >= 40900 && !defined(__CHECKER__) /* @@ -308,10 +274,8 @@ * folding in __builtin_bswap*() (yet), so don't set these for it. */ #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) -#if GCC_VERSION >= 40400 #define __HAVE_BUILTIN_BSWAP32__ #define __HAVE_BUILTIN_BSWAP64__ -#endif #if GCC_VERSION >= 40800 #define __HAVE_BUILTIN_BSWAP16__ #endif @@ -340,10 +304,9 @@ * https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html */ #define __designated_init __attribute__((designated_init)) +#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif -#endif /* gcc version >= 40000 specific checks */ - #if !defined(__noclone) #define __noclone /* not needed */ #endif @@ -352,16 +315,6 @@ #define __no_sanitize_address #endif -/* - * A trick to suppress uninitialized variable warning without generating any - * code - */ -#define uninitialized_var(x) x = x - -#if GCC_VERSION >= 50100 -#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 -#endif - /* * Turn individual warnings and errors on and off locally, depending * on version. @@ -374,12 +327,9 @@ #define __diag_GCC_warn warning #define __diag_GCC_error error -/* Compilers before gcc-4.6 do not understand "#pragma GCC diagnostic push" */ -#if GCC_VERSION >= 40600 #define __diag_str1(s) #s #define __diag_str(s) __diag_str1(s) #define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) -#endif #if GCC_VERSION >= 80000 #define __diag_GCC_8(s) __diag(s) -- cgit From 815f0ddb346c196018d4d8f8f55c12b83da1de3f Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Wed, 22 Aug 2018 16:37:24 -0700 Subject: include/linux/compiler*.h: make compiler-*.h mutually exclusive Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") recently exposed a brittle part of the build for supporting non-gcc compilers. Both Clang and ICC define __GNUC__, __GNUC_MINOR__, and __GNUC_PATCHLEVEL__ for quick compatibility with code bases that haven't added compiler specific checks for __clang__ or __INTEL_COMPILER. This is brittle, as they happened to get compatibility by posing as a certain version of GCC. This broke when upgrading the minimal version of GCC required to build the kernel, to a version above what ICC and Clang claim to be. Rather than always including compiler-gcc.h then undefining or redefining macros in compiler-intel.h or compiler-clang.h, let's separate out the compiler specific macro definitions into mutually exclusive headers, do more proper compiler detection, and keep shared definitions in compiler_types.h. Fixes: cafa0010cd51 ("Raise the minimum required gcc version to 4.6") Reported-by: Masahiro Yamada Suggested-by: Eli Friedman Suggested-by: Joe Perches Signed-off-by: Nick Desaulniers Signed-off-by: Linus Torvalds --- arch/arm/kernel/asm-offsets.c | 13 +-- drivers/gpu/drm/i915/i915_utils.h | 2 +- drivers/watchdog/kempld_wdt.c | 5 - include/linux/compiler-clang.h | 20 ++-- include/linux/compiler-gcc.h | 88 -------------- include/linux/compiler-intel.h | 13 +-- include/linux/compiler_types.h | 238 ++++++++++++++++++-------------------- mm/ksm.c | 4 +- mm/migrate.c | 3 +- 9 files changed, 133 insertions(+), 253 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 974d8d7d1bcd..3968d6c22455 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -38,25 +38,14 @@ #error Sorry, your compiler targets APCS-26 but this kernel requires APCS-32 #endif /* - * GCC 3.0, 3.1: general bad code generation. - * GCC 3.2.0: incorrect function argument offset calculation. - * GCC 3.2.x: miscompiles NEW_AUX_ENT in fs/binfmt_elf.c - * (http://gcc.gnu.org/PR8896) and incorrect structure - * initialisation in fs/jffs2/erase.c * GCC 4.8.0-4.8.2: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58854 * miscompiles find_get_entry(), and can result in EXT3 and EXT4 * filesystem corruption (possibly other FS too). */ -#ifdef __GNUC__ -#if (__GNUC__ == 3 && __GNUC_MINOR__ < 3) -#error Your compiler is too buggy; it is known to miscompile kernels. -#error Known good compilers: 3.3, 4.x -#endif -#if GCC_VERSION >= 40800 && GCC_VERSION < 40803 +#if defined(GCC_VERSION) && GCC_VERSION >= 40800 && GCC_VERSION < 40803 #error Your compiler is too buggy; it is known to miscompile kernels #error and result in filesystem corruption and oopses. #endif -#endif int main(void) { diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index 00165ad55fb3..395dd2511568 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -43,7 +43,7 @@ #define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \ __stringify(x), (long)(x)) -#if GCC_VERSION >= 70000 +#if defined(GCC_VERSION) && GCC_VERSION >= 70000 #define add_overflows(A, B) \ __builtin_add_overflow_p((A), (B), (typeof((A) + (B)))0) #else diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c index 2f3b049ea301..e268add43010 100644 --- a/drivers/watchdog/kempld_wdt.c +++ b/drivers/watchdog/kempld_wdt.c @@ -146,12 +146,7 @@ static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data, u32 remainder; u8 stage_cfg; -#if GCC_VERSION < 40400 - /* work around a bug compiling do_div() */ - prescaler = READ_ONCE(kempld_prescaler[PRESCALER_21]); -#else prescaler = kempld_prescaler[PRESCALER_21]; -#endif if (!stage) return -EINVAL; diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 7087446c24c8..b1ce500fe8b3 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -6,11 +6,7 @@ /* Some compiler specific definitions are overwritten here * for Clang compiler */ - -#ifdef uninitialized_var -#undef uninitialized_var #define uninitialized_var(x) x = *(&(x)) -#endif /* same as gcc, this was present in clang-2.6 so we can assume it works * with any version that can compile the kernel @@ -25,14 +21,8 @@ #define __SANITIZE_ADDRESS__ #endif -#undef __no_sanitize_address #define __no_sanitize_address __attribute__((no_sanitize("address"))) -/* Clang doesn't have a way to turn it off per-function, yet. */ -#ifdef __noretpoline -#undef __noretpoline -#endif - /* * Not all versions of clang implement the the type-generic versions * of the builtin overflow checkers. Fortunately, clang implements @@ -40,9 +30,17 @@ * checks. Unfortunately, we don't know which version of gcc clang * pretends to be, so the macro may or may not be defined. */ -#undef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW #if __has_builtin(__builtin_mul_overflow) && \ __has_builtin(__builtin_add_overflow) && \ __has_builtin(__builtin_sub_overflow) #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif + +/* The following are for compatibility with GCC, from compiler-gcc.h, + * and may be redefined here because they should not be shared with other + * compilers, like ICC. + */ +#define barrier() __asm__ __volatile__("" : : : "memory") +#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) +#define __assume_aligned(a, ...) \ + __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 250b9b7cfd60..763bbad1e258 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -75,48 +75,6 @@ #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) #endif -/* - * Feature detection for gnu_inline (gnu89 extern inline semantics). Either - * __GNUC_STDC_INLINE__ is defined (not using gnu89 extern inline semantics, - * and we opt in to the gnu89 semantics), or __GNUC_STDC_INLINE__ is not - * defined so the gnu89 semantics are the default. - */ -#ifdef __GNUC_STDC_INLINE__ -# define __gnu_inline __attribute__((gnu_inline)) -#else -# define __gnu_inline -#endif - -/* - * Force always-inline if the user requests it so via the .config, - * or if gcc is too old. - * GCC does not warn about unused static inline functions for - * -Wunused-function. This turns out to avoid the need for complex #ifdef - * directives. Suppress the warning in clang as well by using "unused" - * function attribute, which is redundant but not harmful for gcc. - * Prefer gnu_inline, so that extern inline functions do not emit an - * externally visible function. This makes extern inline behave as per gnu89 - * semantics rather than c99. This prevents multiple symbol definition errors - * of extern inline functions at link time. - * A lot of inline functions can cause havoc with function tracing. - */ -#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ - !defined(CONFIG_OPTIMIZE_INLINING) -#define inline \ - inline __attribute__((always_inline, unused)) notrace __gnu_inline -#else -#define inline inline __attribute__((unused)) notrace __gnu_inline -#endif - -#define __inline__ inline -#define __inline inline -#define __always_inline inline __attribute__((always_inline)) -#define noinline __attribute__((noinline)) - -#define __packed __attribute__((packed)) -#define __weak __attribute__((weak)) -#define __alias(symbol) __attribute__((alias(#symbol))) - #ifdef RETPOLINE #define __noretpoline __attribute__((indirect_branch("keep"))) #endif @@ -135,55 +93,9 @@ */ #define __naked __attribute__((naked)) noinline __noclone notrace -#define __noreturn __attribute__((noreturn)) - -/* - * From the GCC manual: - * - * Many functions have no effects except the return value and their - * return value depends only on the parameters and/or global - * variables. Such a function can be subject to common subexpression - * elimination and loop optimization just as an arithmetic operator - * would be. - * [...] - */ -#define __pure __attribute__((pure)) -#define __aligned(x) __attribute__((aligned(x))) -#define __aligned_largest __attribute__((aligned)) -#define __printf(a, b) __attribute__((format(printf, a, b))) -#define __scanf(a, b) __attribute__((format(scanf, a, b))) -#define __attribute_const__ __attribute__((__const__)) -#define __maybe_unused __attribute__((unused)) -#define __always_unused __attribute__((unused)) -#define __mode(x) __attribute__((mode(x))) - -#define __must_check __attribute__((warn_unused_result)) -#define __malloc __attribute__((__malloc__)) - -#define __used __attribute__((__used__)) -#define __compiler_offsetof(a, b) \ - __builtin_offsetof(a, b) - -/* Mark functions as cold. gcc will assume any path leading to a call - * to them will be unlikely. This means a lot of manual unlikely()s - * are unnecessary now for any paths leading to the usual suspects - * like BUG(), printk(), panic() etc. [but let's keep them for now for - * older compilers] - * - * Early snapshots of gcc 4.3 don't support this and we can't detect this - * in the preprocessor, but we can live with this because they're unreleased. - * Maketime probing would be overkill here. - * - * gcc also has a __attribute__((__hot__)) to move hot functions into - * a special section, but I don't see any sense in this right now in - * the kernel context - */ -#define __cold __attribute__((__cold__)) - #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) #define __optimize(level) __attribute__((__optimize__(level))) -#define __nostackprotector __optimize("no-stack-protector") #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h index 547cdc920a3c..4c7f9befa9f6 100644 --- a/include/linux/compiler-intel.h +++ b/include/linux/compiler-intel.h @@ -14,10 +14,6 @@ /* Intel ECC compiler doesn't support gcc specific asm stmts. * It uses intrinsics to do the equivalent things. */ -#undef barrier -#undef barrier_data -#undef RELOC_HIDE -#undef OPTIMIZER_HIDE_VAR #define barrier() __memory_barrier() #define barrier_data(ptr) barrier() @@ -38,13 +34,12 @@ #endif -#ifndef __HAVE_BUILTIN_BSWAP16__ /* icc has this, but it's called _bswap16 */ #define __HAVE_BUILTIN_BSWAP16__ #define __builtin_bswap16 _bswap16 -#endif -/* - * icc defines __GNUC__, but does not implement the builtin overflow checkers. +/* The following are for compatibility with GCC, from compiler-gcc.h, + * and may be redefined here because they should not be shared with other + * compilers, like clang. */ -#undef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW +#define __visible __attribute__((externally_visible)) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index fbf337933fd8..90479a0f3986 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -54,32 +54,20 @@ extern void __chk_io_ptr(const volatile void __iomem *); #ifdef __KERNEL__ -#ifdef __GNUC__ -#include -#endif - -#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__) -#define notrace __attribute__((hotpatch(0,0))) -#else -#define notrace __attribute__((no_instrument_function)) -#endif - -/* Intel compiler defines __GNUC__. So we will overwrite implementations - * coming from above header files here - */ -#ifdef __INTEL_COMPILER -# include -#endif - -/* Clang compiler defines __GNUC__. So we will overwrite implementations - * coming from above header files here - */ +/* Compiler specific macros. */ #ifdef __clang__ #include +#elif defined(__INTEL_COMPILER) +#include +#elif defined(__GNUC__) +/* The above compilers also define __GNUC__, so order is important here. */ +#include +#else +#error "Unknown compiler" #endif /* - * Generic compiler-dependent macros required for kernel + * Generic compiler-independent macros required for kernel * build go below this comment. Actual compiler/compiler version * specific implementations come from the above header files */ @@ -106,93 +94,19 @@ struct ftrace_likely_data { unsigned long constant; }; -#endif /* __KERNEL__ */ - -#endif /* __ASSEMBLY__ */ - -#ifdef __KERNEL__ - /* Don't. Just don't. */ #define __deprecated #define __deprecated_for_modules -#ifndef __must_check -#define __must_check -#endif - -#ifndef CONFIG_ENABLE_MUST_CHECK -#undef __must_check -#define __must_check -#endif - -#ifndef __malloc -#define __malloc -#endif - -/* - * Allow us to avoid 'defined but not used' warnings on functions and data, - * as well as force them to be emitted to the assembly file. - * - * As of gcc 3.4, static functions that are not marked with attribute((used)) - * may be elided from the assembly file. As of gcc 3.4, static data not so - * marked will not be elided, but this may change in a future gcc version. - * - * NOTE: Because distributions shipped with a backported unit-at-a-time - * compiler in gcc 3.3, we must define __used to be __attribute__((used)) - * for gcc >=3.3 instead of 3.4. - * - * In prior versions of gcc, such functions and data would be emitted, but - * would be warned about except with attribute((unused)). - * - * Mark functions that are referenced only in inline assembly as __used so - * the code is emitted even though it appears to be unreferenced. - */ -#ifndef __used -# define __used /* unimplemented */ -#endif - -#ifndef __maybe_unused -# define __maybe_unused /* unimplemented */ -#endif - -#ifndef __always_unused -# define __always_unused /* unimplemented */ -#endif - -#ifndef noinline -#define noinline -#endif - -/* - * Rather then using noinline to prevent stack consumption, use - * noinline_for_stack instead. For documentation reasons. - */ -#define noinline_for_stack noinline - -#ifndef __always_inline -#define __always_inline inline -#endif - #endif /* __KERNEL__ */ +#endif /* __ASSEMBLY__ */ + /* - * From the GCC manual: - * - * Many functions do not examine any values except their arguments, - * and have no effects except the return value. Basically this is - * just slightly more strict class than the `pure' attribute above, - * since function is not allowed to read global memory. - * - * Note that a function that has pointer arguments and examines the - * data pointed to must _not_ be declared `const'. Likewise, a - * function that calls a non-`const' function usually must not be - * `const'. It does not make sense for a `const' function to return - * `void'. + * The below symbols may be defined for one or more, but not ALL, of the above + * compilers. We don't consider that to be an error, so set them to nothing. + * For example, some of them are for compiler specific plugins. */ -#ifndef __attribute_const__ -# define __attribute_const__ /* unimplemented */ -#endif - #ifndef __designated_init # define __designated_init #endif @@ -214,28 +128,10 @@ struct ftrace_likely_data { # define randomized_struct_fields_end #endif -/* - * Tell gcc if a function is cold. The compiler will assume any path - * directly leading to the call is unlikely. - */ - -#ifndef __cold -#define __cold -#endif - -/* Simple shorthand for a section definition */ -#ifndef __section -# define __section(S) __attribute__ ((__section__(#S))) -#endif - #ifndef __visible #define __visible #endif -#ifndef __nostackprotector -# define __nostackprotector -#endif - /* * Assume alignment of return value. */ @@ -243,17 +139,23 @@ struct ftrace_likely_data { #define __assume_aligned(a, ...) #endif - /* Are two types/vars the same type (ignoring qualifiers)? */ -#ifndef __same_type -# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) -#endif +#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) /* Is this type a native word size -- useful for atomic operations */ -#ifndef __native_word -# define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) +#define __native_word(t) \ + (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \ + sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) + +#ifndef __attribute_const__ +#define __attribute_const__ __attribute__((__const__)) #endif +#ifndef __noclone +#define __noclone +#endif + +/* Helpers for emitting diagnostics in pragmas. */ #ifndef __diag #define __diag(string) #endif @@ -272,4 +174,92 @@ struct ftrace_likely_data { #define __diag_error(compiler, version, option, comment) \ __diag_ ## compiler(version, error, option) +/* + * From the GCC manual: + * + * Many functions have no effects except the return value and their + * return value depends only on the parameters and/or global + * variables. Such a function can be subject to common subexpression + * elimination and loop optimization just as an arithmetic operator + * would be. + * [...] + */ +#define __pure __attribute__((pure)) +#define __aligned(x) __attribute__((aligned(x))) +#define __aligned_largest __attribute__((aligned)) +#define __printf(a, b) __attribute__((format(printf, a, b))) +#define __scanf(a, b) __attribute__((format(scanf, a, b))) +#define __maybe_unused __attribute__((unused)) +#define __always_unused __attribute__((unused)) +#define __mode(x) __attribute__((mode(x))) +#define __malloc __attribute__((__malloc__)) +#define __used __attribute__((__used__)) +#define __noreturn __attribute__((noreturn)) +#define __packed __attribute__((packed)) +#define __weak __attribute__((weak)) +#define __alias(symbol) __attribute__((alias(#symbol))) +#define __cold __attribute__((cold)) +#define __section(S) __attribute__((__section__(#S))) + + +#ifdef CONFIG_ENABLE_MUST_CHECK +#define __must_check __attribute__((warn_unused_result)) +#else +#define __must_check +#endif + +#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__) +#define notrace __attribute__((hotpatch(0, 0))) +#else +#define notrace __attribute__((no_instrument_function)) +#endif + +#define __compiler_offsetof(a, b) __builtin_offsetof(a, b) + +/* + * Feature detection for gnu_inline (gnu89 extern inline semantics). Either + * __GNUC_STDC_INLINE__ is defined (not using gnu89 extern inline semantics, + * and we opt in to the gnu89 semantics), or __GNUC_STDC_INLINE__ is not + * defined so the gnu89 semantics are the default. + */ +#ifdef __GNUC_STDC_INLINE__ +# define __gnu_inline __attribute__((gnu_inline)) +#else +# define __gnu_inline +#endif + +/* + * Force always-inline if the user requests it so via the .config. + * GCC does not warn about unused static inline functions for + * -Wunused-function. This turns out to avoid the need for complex #ifdef + * directives. Suppress the warning in clang as well by using "unused" + * function attribute, which is redundant but not harmful for gcc. + * Prefer gnu_inline, so that extern inline functions do not emit an + * externally visible function. This makes extern inline behave as per gnu89 + * semantics rather than c99. This prevents multiple symbol definition errors + * of extern inline functions at link time. + * A lot of inline functions can cause havoc with function tracing. + */ +#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ + !defined(CONFIG_OPTIMIZE_INLINING) +#define inline \ + inline __attribute__((always_inline, unused)) notrace __gnu_inline +#else +#define inline inline __attribute__((unused)) notrace __gnu_inline +#endif + +#define __inline__ inline +#define __inline inline +#define noinline __attribute__((noinline)) + +#ifndef __always_inline +#define __always_inline inline __attribute__((always_inline)) +#endif + +/* + * Rather then using noinline to prevent stack consumption, use + * noinline_for_stack instead. For documentation reasons. + */ +#define noinline_for_stack noinline + #endif /* __LINUX_COMPILER_TYPES_H */ diff --git a/mm/ksm.c b/mm/ksm.c index 1bd514c9e5d0..5b0894b45ee5 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -652,9 +652,9 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node) * list_head to stay clear from the rb_parent_color union * (aligned and different than any node) and also different * from &migrate_nodes. This will verify that future list.h changes - * don't break STABLE_NODE_DUP_HEAD. + * don't break STABLE_NODE_DUP_HEAD. Only recent gcc can handle it. */ -#if GCC_VERSION >= 40903 /* only recent gcc can handle it */ +#if defined(GCC_VERSION) && GCC_VERSION >= 40903 BUILD_BUG_ON(STABLE_NODE_DUP_HEAD <= &migrate_nodes); BUILD_BUG_ON(STABLE_NODE_DUP_HEAD >= &migrate_nodes + 1); #endif diff --git a/mm/migrate.c b/mm/migrate.c index 4a83268e23c2..c27e97b5b69d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1131,7 +1131,8 @@ out: * gcc 4.7 and 4.8 on arm get an ICEs when inlining unmap_and_move(). Work * around it. */ -#if (GCC_VERSION >= 40700 && GCC_VERSION < 40900) && defined(CONFIG_ARM) +#if defined(CONFIG_ARM) && \ + defined(GCC_VERSION) && GCC_VERSION < 40900 && GCC_VERSION >= 40700 #define ICE_noinline noinline #else #define ICE_noinline -- cgit From d124b44f09cab67fc6da4a4513417e3e54b01efc Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Tue, 18 Sep 2018 18:55:41 +0200 Subject: Compiler Attributes: naked was fixed in gcc 4.6 Commit 9c695203a7dd ("compiler-gcc.h: gcc-4.5 needs noclone and noinline on __naked functions") added noinline and noclone as a workaround for a gcc 4.5 bug, which was resolved in 4.6.0. Since now the minimum gcc supported version is 4.6, we can clean it up. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44290 and https://godbolt.org/z/h6NMIL Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") Cc: Rasmus Villemoes Cc: Eli Friedman Cc: Christopher Li Cc: Kees Cook Cc: Ingo Molnar Cc: Geert Uytterhoeven Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Masahiro Yamada Cc: Joe Perches Cc: Dominique Martinet Cc: Linus Torvalds Cc: linux-sparse@vger.kernel.org Tested-by: Stefan Agner Reviewed-by: Stefan Agner Reviewed-by: Luc Van Oostenryck Reviewed-by: Nick Desaulniers Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman --- include/linux/compiler-gcc.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 763bbad1e258..25d3dd6b2702 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -84,14 +84,8 @@ * to trace naked functions because then mcount is called without * stack and frame pointer being set up and there is no chance to * restore the lr register to the value before mcount was called. - * - * The asm() bodies of naked functions often depend on standard calling - * conventions, therefore they must be noinline and noclone. - * - * GCC 4.[56] currently fail to enforce this, so we must do so ourselves. - * See GCC PR44290. */ -#define __naked __attribute__((naked)) noinline __noclone notrace +#define __naked __attribute__((naked)) notrace #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) -- cgit From ae596de1a0c8c2c924dc99d23c026259372ab234 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Tue, 18 Sep 2018 18:55:42 +0200 Subject: Compiler Attributes: naked can be shared The naked attribute is supported by at least gcc >= 4.6 (for ARM, which is the only current user), gcc >= 8 (for x86), clang >= 3.1 and icc >= 13. See https://godbolt.org/z/350Dyc Therefore, move it out of compiler-gcc.h so that the definition is shared by all compilers. This also fixes Clang support for ARM32 --- 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive"). Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") Cc: Rasmus Villemoes Cc: Eli Friedman Cc: Christopher Li Cc: Kees Cook Cc: Ingo Molnar Cc: Geert Uytterhoeven Cc: Greg Kroah-Hartman Cc: Masahiro Yamada Cc: Joe Perches Cc: Dominique Martinet Cc: Linus Torvalds Cc: linux-sparse@vger.kernel.org Suggested-by: Arnd Bergmann Tested-by: Stefan Agner Reviewed-by: Stefan Agner Reviewed-by: Luc Van Oostenryck Reviewed-by: Nick Desaulniers Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman --- include/linux/compiler-gcc.h | 8 -------- include/linux/compiler_types.h | 8 ++++++++ 2 files changed, 8 insertions(+), 8 deletions(-) (limited to 'include/linux/compiler-gcc.h') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 25d3dd6b2702..4d36b27214fd 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -79,14 +79,6 @@ #define __noretpoline __attribute__((indirect_branch("keep"))) #endif -/* - * it doesn't make sense on ARM (currently the only user of __naked) - * to trace naked functions because then mcount is called without - * stack and frame pointer being set up and there is no chance to - * restore the lr register to the value before mcount was called. - */ -#define __naked __attribute__((naked)) notrace - #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) #define __optimize(level) __attribute__((__optimize__(level))) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 3525c179698c..db192becfec4 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -226,6 +226,14 @@ struct ftrace_likely_data { #define notrace __attribute__((no_instrument_function)) #endif +/* + * it doesn't make sense on ARM (currently the only user of __naked) + * to trace naked functions because then mcount is called without + * stack and frame pointer being set up and there is no chance to + * restore the lr register to the value before mcount was called. + */ +#define __naked __attribute__((naked)) notrace + #define __compiler_offsetof(a, b) __builtin_offsetof(a, b) /* -- cgit