| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef __LINUX_COMPILER_TYPES_H |
| #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." |
| #endif |
| |
| /* |
| * Common definitions for all gcc versions go here. |
| */ |
| #define GCC_VERSION (__GNUC__ * 10000 \ |
| + __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 */ |
| #define barrier() __asm__ __volatile__("": : :"memory") |
| /* |
| * This version is i.e. to prevent dead stores elimination on @ptr |
| * where gcc and llvm may behave differently when otherwise using |
| * normal barrier(): while gcc behavior gets along with a normal |
| * barrier(), llvm needs an explicit input variable to be assumed |
| * clobbered. The issue is as follows: while the inline asm might |
| * access any memory it wants, the compiler could have fit all of |
| * @ptr into memory registers instead, and since @ptr never escaped |
| * from that, it proved that the inline asm wasn't touching any of |
| * it. This version works well with both compilers, i.e. we're telling |
| * the compiler that the inline asm absolutely may see the contents |
| * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 |
| */ |
| #define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") |
| |
| /* |
| * This macro obfuscates arithmetic on a variable address so that gcc |
| * shouldn't recognize the original var, and make assumptions about it. |
| * |
| * This is needed because the C standard makes it undefined to do |
| * pointer arithmetic on "objects" outside their boundaries and the |
| * gcc optimizers assume this is the case. In particular they |
| * assume such arithmetic does not wrap. |
| * |
| * A miscompilation has been observed because of this on PPC. |
| * To work around it we hide the relationship of the pointer and the object |
| * using this macro. |
| * |
| * Versions of the ppc64 compiler before 4.1 had a bug where use of |
| * RELOC_HIDE could trash r30. The bug can be worked around by changing |
| * the inline assembly constraint from =g to =r, in this particular |
| * case either is valid. |
| */ |
| #define RELOC_HIDE(ptr, off) \ |
| ({ \ |
| unsigned long __ptr; \ |
| __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ |
| (typeof(ptr)) (__ptr + (off)); \ |
| }) |
| |
| /* Make the optimizer believe the variable can be manipulated arbitrarily. */ |
| #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 |
| /* &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 |
| |
| #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__ |
| #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 /* __CHECKER__ */ |
| |
| /* |
| * calling noreturn functions, __builtin_unreachable() and __builtin_trap() |
| * confuse the stack allocation in gcc, leading to overly large stack |
| * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 |
| * |
| * Adding an empty inline assembly before it works around the problem |
| */ |
| #define barrier_before_unreachable() asm volatile("") |
| |
| /* |
| * 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 { \ |
| annotate_unreachable(); \ |
| barrier_before_unreachable(); \ |
| __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)) |
| /* This anon struct can add padding, so only enable it under randstruct. */ |
| #define randomized_struct_fields_start struct { |
| #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 && !defined(__CHECKER__) |
| /* |
| * __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: |
| * |
| * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 |
| * |
| * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. |
| * |
| * (asm goto is automatically volatile - the naming reflects this.) |
| */ |
| #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) |
| |
| /* |
| * sparse (__CHECKER__) pretends to be gcc, but can't do constant |
| * folding in __builtin_bswap*() (yet), so don't set these for it. |
| */ |
| #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__) |
| #define __HAVE_BUILTIN_BSWAP32__ |
| #define __HAVE_BUILTIN_BSWAP64__ |
| #if GCC_VERSION >= 40800 |
| #define __HAVE_BUILTIN_BSWAP16__ |
| #endif |
| #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */ |
| |
| #if GCC_VERSION >= 70000 |
| #define KASAN_ABI_VERSION 5 |
| #elif GCC_VERSION >= 50000 |
| #define KASAN_ABI_VERSION 4 |
| #elif GCC_VERSION >= 40902 |
| #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. |
| */ |
| #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 |
| |
| #define __diag_str1(s) #s |
| #define __diag_str(s) __diag_str1(s) |
| #define __diag(s) _Pragma(__diag_str(GCC diagnostic s)) |
| |
| #if GCC_VERSION >= 80000 |
| #define __diag_GCC_8(s) __diag(s) |
| #else |
| #define __diag_GCC_8(s) |
| #endif |