189863162d
commit dca5244d2f5b94f1809f0c02a549edf41ccd5493 upstream. GCC versions >= 4.9 and < 5.1 have been shown to emit memory references beyond the stack pointer, resulting in memory corruption if an interrupt is taken after the stack pointer has been adjusted but before the reference has been executed. This leads to subtle, infrequent data corruption such as the EXT4 problems reported by Russell King at the link below. Life is too short for buggy compilers, so raise the minimum GCC version required by arm64 to 5.1. Reported-by: Russell King <linux@armlinux.org.uk> Suggested-by: Arnd Bergmann <arnd@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Florian Weimer <fweimer@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20210105154726.GD1551@shell.armlinux.org.uk Link: https://lore.kernel.org/r/20210112224832.10980-1-will@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> [will: backport to 4.19.y/5.4.y] Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
224 lines
7.1 KiB
C
224 lines
7.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_COMPILER_TYPES_H
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#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
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#endif
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/*
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* Common definitions for all gcc versions go here.
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*/
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#define GCC_VERSION (__GNUC__ * 10000 \
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+ __GNUC_MINOR__ * 100 \
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+ __GNUC_PATCHLEVEL__)
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#if GCC_VERSION < 40600
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# error Sorry, your compiler is too old - please upgrade it.
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#elif defined(CONFIG_ARM64) && GCC_VERSION < 50100
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/*
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* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
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* https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
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*/
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# error Sorry, your version of GCC is too old - please use 5.1 or newer.
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#endif
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/*
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* This macro obfuscates arithmetic on a variable address so that gcc
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* shouldn't recognize the original var, and make assumptions about it.
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*
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* This is needed because the C standard makes it undefined to do
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* pointer arithmetic on "objects" outside their boundaries and the
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* gcc optimizers assume this is the case. In particular they
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* assume such arithmetic does not wrap.
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*
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* A miscompilation has been observed because of this on PPC.
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* To work around it we hide the relationship of the pointer and the object
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* using this macro.
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*
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* Versions of the ppc64 compiler before 4.1 had a bug where use of
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* RELOC_HIDE could trash r30. The bug can be worked around by changing
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* the inline assembly constraint from =g to =r, in this particular
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* case either is valid.
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*/
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#define RELOC_HIDE(ptr, off) \
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({ \
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unsigned long __ptr; \
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__asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
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(typeof(ptr)) (__ptr + (off)); \
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})
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/*
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* A trick to suppress uninitialized variable warning without generating any
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* code
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*/
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#define uninitialized_var(x) x = x
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#ifdef __CHECKER__
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#define __must_be_array(a) 0
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#else
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/* &a[0] degrades to a pointer: a different type from an array */
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#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
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#endif
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#ifdef CONFIG_RETPOLINE
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#define __noretpoline __attribute__((indirect_branch("keep")))
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#endif
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#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
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#define __optimize(level) __attribute__((__optimize__(level)))
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#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
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#ifndef __CHECKER__
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#define __compiletime_warning(message) __attribute__((warning(message)))
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#define __compiletime_error(message) __attribute__((error(message)))
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#ifdef LATENT_ENTROPY_PLUGIN
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#define __latent_entropy __attribute__((latent_entropy))
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#endif
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#endif /* __CHECKER__ */
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/*
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* calling noreturn functions, __builtin_unreachable() and __builtin_trap()
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* confuse the stack allocation in gcc, leading to overly large stack
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* frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
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*
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* Adding an empty inline assembly before it works around the problem
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*/
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#define barrier_before_unreachable() asm volatile("")
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/*
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* Mark a position in code as unreachable. This can be used to
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* suppress control flow warnings after asm blocks that transfer
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* control elsewhere.
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*
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* Early snapshots of gcc 4.5 don't support this and we can't detect
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* this in the preprocessor, but we can live with this because they're
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* unreleased. Really, we need to have autoconf for the kernel.
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*/
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#define unreachable() \
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do { \
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annotate_unreachable(); \
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barrier_before_unreachable(); \
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__builtin_unreachable(); \
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} while (0)
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/* Mark a function definition as prohibited from being cloned. */
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#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
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#if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
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#define __randomize_layout __attribute__((randomize_layout))
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#define __no_randomize_layout __attribute__((no_randomize_layout))
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/* This anon struct can add padding, so only enable it under randstruct. */
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#define randomized_struct_fields_start struct {
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#define randomized_struct_fields_end } __randomize_layout;
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#endif
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/*
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* When used with Link Time Optimization, gcc can optimize away C functions or
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* variables which are referenced only from assembly code. __visible tells the
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* optimizer that something else uses this function or variable, thus preventing
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* this.
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*/
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#define __visible __attribute__((externally_visible))
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/* gcc version specific checks */
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#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
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/*
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* __assume_aligned(n, k): Tell the optimizer that the returned
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* pointer can be assumed to be k modulo n. The second argument is
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* optional (default 0), so we use a variadic macro to make the
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* shorthand.
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*
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* Beware: Do not apply this to functions which may return
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* ERR_PTRs. Also, it is probably unwise to apply it to functions
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* returning extra information in the low bits (but in that case the
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* compiler should see some alignment anyway, when the return value is
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* massaged by 'flags = ptr & 3; ptr &= ~3;').
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*/
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#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
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#endif
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/*
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* GCC 'asm goto' miscompiles certain code sequences:
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*
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* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
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*
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* Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
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*
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* (asm goto is automatically volatile - the naming reflects this.)
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*/
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#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
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/*
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* sparse (__CHECKER__) pretends to be gcc, but can't do constant
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* folding in __builtin_bswap*() (yet), so don't set these for it.
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*/
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#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
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#define __HAVE_BUILTIN_BSWAP32__
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#define __HAVE_BUILTIN_BSWAP64__
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#if GCC_VERSION >= 40800
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#define __HAVE_BUILTIN_BSWAP16__
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#endif
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#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
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#if GCC_VERSION >= 70000
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#define KASAN_ABI_VERSION 5
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#elif GCC_VERSION >= 50000
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#define KASAN_ABI_VERSION 4
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#elif GCC_VERSION >= 40902
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#define KASAN_ABI_VERSION 3
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#endif
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#if GCC_VERSION >= 40902
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/*
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* Tell the compiler that address safety instrumentation (KASAN)
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* should not be applied to that function.
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* Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
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*/
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#define __no_sanitize_address __attribute__((no_sanitize_address))
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#endif
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#if GCC_VERSION >= 50100
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/*
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* Mark structures as requiring designated initializers.
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* https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html
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*/
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#define __designated_init __attribute__((designated_init))
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#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
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#endif
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#if GCC_VERSION >= 90100
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#define __copy(symbol) __attribute__((__copy__(symbol)))
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#endif
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#if !defined(__noclone)
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#define __noclone /* not needed */
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#endif
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#if !defined(__no_sanitize_address)
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#define __no_sanitize_address
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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_GCC(version, severity, s) \
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__diag_GCC_ ## version(__diag_GCC_ ## severity s)
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/* Severity used in pragma directives */
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#define __diag_GCC_ignore ignored
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#define __diag_GCC_warn warning
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#define __diag_GCC_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(GCC diagnostic s))
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#if GCC_VERSION >= 80000
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#define __diag_GCC_8(s) __diag(s)
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#else
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#define __diag_GCC_8(s)
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#endif
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