175db11786Clang recently added support for -Wattribute-alias [1], which results in the same warnings that necessitated commitbee2003177("disable -Wattribute-alias warning for SYSCALL_DEFINEx()") for GCC. kernel/time/itimer.c:325:1: error: alias and aliasee have different types 'long (unsigned int)' and 'long (typeof (__builtin_choose_expr((__builtin_types_compatible_p(typeof ((unsigned int)0), typeof (0LL)) || __builtin_types_compatible_p(typeof ((unsigned int)0), typeof (0ULL))), 0LL, 0L)))' (aka 'long (long)') [-Werror,-Wattribute-alias] 325 | SYSCALL_DEFINE1(alarm, unsigned int, seconds) | ^ include/linux/syscalls.h:225:36: note: expanded from macro 'SYSCALL_DEFINE1' 225 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__) | ^ include/linux/syscalls.h:236:2: note: expanded from macro 'SYSCALL_DEFINEx' 236 | __SYSCALL_DEFINEx(x, sname, __VA_ARGS__) | ^ include/linux/syscalls.h:251:18: note: expanded from macro '__SYSCALL_DEFINEx' 251 | __attribute__((alias(__stringify(__se_sys##name)))); \ | ^ kernel/time/itimer.c:325:1: note: aliasee is declared here include/linux/syscalls.h:225:36: note: expanded from macro 'SYSCALL_DEFINE1' 225 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__) | ^ include/linux/syscalls.h:236:2: note: expanded from macro 'SYSCALL_DEFINEx' 236 | __SYSCALL_DEFINEx(x, sname, __VA_ARGS__) | ^ include/linux/syscalls.h:255:18: note: expanded from macro '__SYSCALL_DEFINEx' 255 | asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ | ^ <scratch space>:16:1: note: expanded from here 16 | __se_sys_alarm | ^ Disable the warnings in the same way for clang-23 and newer. Disable the warning about unknown warning options to avoid breaking the build for versions of clang-23 that do not have -Wattribute-alias, such as ones deployed by vendors like Android or CI systems or when bisecting LLVM between llvmorg-23-init and release/23.x. Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2163 Link:40da6920a0[1] Link: https://patch.msgid.link/20260515-syscall-disable-attribute-alias-for-clang-v1-1-9a9d95d41df6@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org>
162 lines
5.2 KiB
C
162 lines
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_COMPILER_TYPES_H
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#error "Please do not include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
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#endif
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/* Compiler specific definitions for Clang compiler */
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/*
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* Clang prior to 17 is being silly and considers many __cleanup() variables
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* as unused (because they are, their sole purpose is to go out of scope).
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*
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* https://github.com/llvm/llvm-project/commit/877210faa447f4cc7db87812f8ed80e398fedd61
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*/
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#undef __cleanup
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#define __cleanup(func) __maybe_unused __attribute__((__cleanup__(func)))
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/* all clang versions usable with the kernel support KASAN ABI version 5 */
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#define KASAN_ABI_VERSION 5
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/*
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* Clang 22 added preprocessor macros to match GCC, in hopes of eventually
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* dropping __has_feature support for sanitizers:
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* https://github.com/llvm/llvm-project/commit/568c23bbd3303518c5056d7f03444dae4fdc8a9c
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* Create these macros for older versions of clang so that it is easy to clean
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* up once the minimum supported version of LLVM for building the kernel always
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* creates these macros.
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*
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* Note: Checking __has_feature(*_sanitizer) is only true if the feature is
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* enabled. Therefore it is not required to additionally check defined(CONFIG_*)
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* to avoid adding redundant attributes in other configurations.
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*/
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#if __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
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#define __SANITIZE_ADDRESS__
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#endif
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#if __has_feature(hwaddress_sanitizer) && !defined(__SANITIZE_HWADDRESS__)
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#define __SANITIZE_HWADDRESS__
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#endif
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#if __has_feature(thread_sanitizer) && !defined(__SANITIZE_THREAD__)
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#define __SANITIZE_THREAD__
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#endif
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/*
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* Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel.
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*/
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#ifdef __SANITIZE_HWADDRESS__
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#define __SANITIZE_ADDRESS__
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#endif
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#ifdef __SANITIZE_ADDRESS__
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#define __no_sanitize_address \
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__attribute__((no_sanitize("address", "hwaddress")))
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#else
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#define __no_sanitize_address
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#endif
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#ifdef __SANITIZE_THREAD__
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#define __no_sanitize_thread \
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__attribute__((no_sanitize("thread")))
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#else
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#define __no_sanitize_thread
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#endif
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#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
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#define __HAVE_BUILTIN_BSWAP32__
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#define __HAVE_BUILTIN_BSWAP64__
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#define __HAVE_BUILTIN_BSWAP16__
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#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
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#if __has_feature(undefined_behavior_sanitizer)
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/* GCC does not have __SANITIZE_UNDEFINED__ */
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#define __no_sanitize_undefined \
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__attribute__((no_sanitize("undefined")))
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#else
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#define __no_sanitize_undefined
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#endif
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#if __has_feature(memory_sanitizer)
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#define __SANITIZE_MEMORY__
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/*
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* Unlike other sanitizers, KMSAN still inserts code into functions marked with
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* no_sanitize("kernel-memory"). Using disable_sanitizer_instrumentation
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* provides the behavior consistent with other __no_sanitize_ attributes,
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* guaranteeing that __no_sanitize_memory functions remain uninstrumented.
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*/
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#define __no_sanitize_memory __disable_sanitizer_instrumentation
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/*
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* The __no_kmsan_checks attribute ensures that a function does not produce
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* false positive reports by:
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* - initializing all local variables and memory stores in this function;
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* - skipping all shadow checks;
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* - passing initialized arguments to this function's callees.
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*/
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#define __no_kmsan_checks __attribute__((no_sanitize("kernel-memory")))
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#else
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#define __no_sanitize_memory
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#define __no_kmsan_checks
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#endif
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/*
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* Support for __has_feature(coverage_sanitizer) was added in Clang 13 together
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* with no_sanitize("coverage"). Prior versions of Clang support coverage
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* instrumentation, but cannot be queried for support by the preprocessor.
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*/
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#if __has_feature(coverage_sanitizer)
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#define __no_sanitize_coverage __attribute__((no_sanitize("coverage")))
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#else
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#define __no_sanitize_coverage
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#endif
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/* Only Clang needs to disable the coverage sanitizer for kstack_erase. */
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#define __no_kstack_erase __no_sanitize_coverage
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#if __has_feature(shadow_call_stack)
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# define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
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#endif
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/*
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* Turn individual warnings and errors on and off locally, depending
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* on version.
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*/
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#define __diag_clang(version, severity, s) \
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__diag_clang_ ## version(__diag_clang_ ## severity s)
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/* Severity used in pragma directives */
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#define __diag_clang_ignore ignored
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#define __diag_clang_warn warning
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#define __diag_clang_error error
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#define __diag_str1(s) #s
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#define __diag_str(s) __diag_str1(s)
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#define __diag(s) _Pragma(__diag_str(clang diagnostic s))
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#if CONFIG_CLANG_VERSION >= 230000
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#define __diag_clang_23(s) __diag(s)
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#else
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#define __diag_clang_23(s)
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#endif
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#define __diag_clang_13(s) __diag(s)
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#define __diag_ignore_all(option, comment) \
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__diag_clang(13, ignore, option)
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/*
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* clang has horrible behavior with "g" or "rm" constraints for asm
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* inputs, turning them into something worse than "m". Avoid using
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* constraints with multiple possible uses (but "ir" seems to be ok):
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*
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* https://github.com/llvm/llvm-project/issues/20571
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*/
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#define ASM_INPUT_G "ir"
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#define ASM_INPUT_RM "r"
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#define ASM_OUTPUT_RM "=r"
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/*
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* Declare compiler support for __typeof_unqual__() operator.
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*
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* Bindgen uses LLVM even if our C compiler is GCC, so we cannot
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* rely on the auto-detected CONFIG_CC_HAS_TYPEOF_UNQUAL.
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*/
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#define CC_HAS_TYPEOF_UNQUAL (__clang_major__ > 19 || (__clang_major__ == 19 && __clang_minor__ > 0))
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