| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _TOOLS_LINUX_COMPILER_H_ |
| #define _TOOLS_LINUX_COMPILER_H_ |
| |
| #include <linux/compiler_types.h> |
| |
| #ifndef __compiletime_error |
| # define __compiletime_error(message) |
| #endif |
| |
| #ifdef __OPTIMIZE__ |
| # define __compiletime_assert(condition, msg, prefix, suffix) \ |
| do { \ |
| extern void prefix ## suffix(void) __compiletime_error(msg); \ |
| if (!(condition)) \ |
| prefix ## suffix(); \ |
| } while (0) |
| #else |
| # define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0) |
| #endif |
| |
| #define _compiletime_assert(condition, msg, prefix, suffix) \ |
| __compiletime_assert(condition, msg, prefix, suffix) |
| |
| /** |
| * compiletime_assert - break build and emit msg if condition is false |
| * @condition: a compile-time constant condition to check |
| * @msg: a message to emit if condition is false |
| * |
| * In tradition of POSIX assert, this macro will break the build if the |
| * supplied condition is *false*, emitting the supplied error message if the |
| * compiler has support to do so. |
| */ |
| #define compiletime_assert(condition, msg) \ |
| _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) |
| |
| /* Optimization barrier */ |
| /* The "volatile" is due to gcc bugs */ |
| #define barrier() __asm__ __volatile__("": : :"memory") |
| |
| #ifndef __always_inline |
| # define __always_inline inline __attribute__((always_inline)) |
| #endif |
| |
| #ifndef noinline |
| #define noinline |
| #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 |
| |
| #ifdef __ANDROID__ |
| /* |
| * FIXME: Big hammer to get rid of tons of: |
| * "warning: always_inline function might not be inlinable" |
| * |
| * At least on android-ndk-r12/platforms/android-24/arch-arm |
| */ |
| #undef __always_inline |
| #define __always_inline inline |
| #endif |
| |
| #define __user |
| #define __rcu |
| #define __read_mostly |
| |
| #ifndef __attribute_const__ |
| # define __attribute_const__ |
| #endif |
| |
| #ifndef __maybe_unused |
| # define __maybe_unused __attribute__((unused)) |
| #endif |
| |
| #ifndef __used |
| # define __used __attribute__((__unused__)) |
| #endif |
| |
| #ifndef __packed |
| # define __packed __attribute__((__packed__)) |
| #endif |
| |
| #ifndef __force |
| # define __force |
| #endif |
| |
| #ifndef __weak |
| # define __weak __attribute__((weak)) |
| #endif |
| |
| #ifndef likely |
| # define likely(x) __builtin_expect(!!(x), 1) |
| #endif |
| |
| #ifndef unlikely |
| # define unlikely(x) __builtin_expect(!!(x), 0) |
| #endif |
| |
| #ifndef __init |
| # define __init |
| #endif |
| |
| #include <linux/types.h> |
| |
| /* |
| * Following functions are taken from kernel sources and |
| * break aliasing rules in their original form. |
| * |
| * While kernel is compiled with -fno-strict-aliasing, |
| * perf uses -Wstrict-aliasing=3 which makes build fail |
| * under gcc 4.4. |
| * |
| * Using extra __may_alias__ type to allow aliasing |
| * in this case. |
| */ |
| typedef __u8 __attribute__((__may_alias__)) __u8_alias_t; |
| typedef __u16 __attribute__((__may_alias__)) __u16_alias_t; |
| typedef __u32 __attribute__((__may_alias__)) __u32_alias_t; |
| typedef __u64 __attribute__((__may_alias__)) __u64_alias_t; |
| |
| static __always_inline void __read_once_size(const volatile void *p, void *res, int size) |
| { |
| switch (size) { |
| case 1: *(__u8_alias_t *) res = *(volatile __u8_alias_t *) p; break; |
| case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break; |
| case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break; |
| case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break; |
| default: |
| barrier(); |
| __builtin_memcpy((void *)res, (const void *)p, size); |
| barrier(); |
| } |
| } |
| |
| static __always_inline void __write_once_size(volatile void *p, void *res, int size) |
| { |
| switch (size) { |
| case 1: *(volatile __u8_alias_t *) p = *(__u8_alias_t *) res; break; |
| case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break; |
| case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break; |
| case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) res; break; |
| default: |
| barrier(); |
| __builtin_memcpy((void *)p, (const void *)res, size); |
| barrier(); |
| } |
| } |
| |
| /* |
| * Prevent the compiler from merging or refetching reads or writes. The |
| * compiler is also forbidden from reordering successive instances of |
| * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some |
| * particular ordering. One way to make the compiler aware of ordering is to |
| * put the two invocations of READ_ONCE or WRITE_ONCE in different C |
| * statements. |
| * |
| * These two macros will also work on aggregate data types like structs or |
| * unions. If the size of the accessed data type exceeds the word size of |
| * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will |
| * fall back to memcpy and print a compile-time warning. |
| * |
| * Their two major use cases are: (1) Mediating communication between |
| * process-level code and irq/NMI handlers, all running on the same CPU, |
| * and (2) Ensuring that the compiler does not fold, spindle, or otherwise |
| * mutilate accesses that either do not require ordering or that interact |
| * with an explicit memory barrier or atomic instruction that provides the |
| * required ordering. |
| */ |
| |
| #define READ_ONCE(x) \ |
| ({ \ |
| union { typeof(x) __val; char __c[1]; } __u = \ |
| { .__c = { 0 } }; \ |
| __read_once_size(&(x), __u.__c, sizeof(x)); \ |
| __u.__val; \ |
| }) |
| |
| #define WRITE_ONCE(x, val) \ |
| ({ \ |
| union { typeof(x) __val; char __c[1]; } __u = \ |
| { .__val = (val) }; \ |
| __write_once_size(&(x), __u.__c, sizeof(x)); \ |
| __u.__val; \ |
| }) |
| |
| |
| #ifndef __fallthrough |
| # define __fallthrough |
| #endif |
| |
| /* Indirect macros required for expanded argument pasting, eg. __LINE__. */ |
| #define ___PASTE(a, b) a##b |
| #define __PASTE(a, b) ___PASTE(a, b) |
| |
| #endif /* _TOOLS_LINUX_COMPILER_H */ |