linux/arch/arm64/include/asm/vdso/compat_barrier.h
Vincenzo Frascino 0df2c90eba arm64: vdso32: Detect binutils support for dmb ishld
Older versions of binutils (prior to 2.24) do not support the "ISHLD"
option for memory barrier instructions, which leads to a build failure
when assembling the vdso32 library.

Add a compilation time mechanism that detects if binutils supports those
instructions and configure the kernel accordingly.

Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
2019-10-07 11:07:16 +01:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2018 ARM Limited
*/
#ifndef __COMPAT_BARRIER_H
#define __COMPAT_BARRIER_H
#ifndef __ASSEMBLY__
/*
* Warning: This code is meant to be used with
* ENABLE_COMPAT_VDSO only.
*/
#ifndef ENABLE_COMPAT_VDSO
#error This header is meant to be used with ENABLE_COMPAT_VDSO only
#endif
#ifdef dmb
#undef dmb
#endif
#define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory")
#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD)
#define aarch32_smp_mb() dmb(ish)
#define aarch32_smp_rmb() dmb(ishld)
#define aarch32_smp_wmb() dmb(ishst)
#else
#define aarch32_smp_mb() dmb(ish)
#define aarch32_smp_rmb() aarch32_smp_mb()
#define aarch32_smp_wmb() dmb(ishst)
#endif
#undef smp_mb
#undef smp_rmb
#undef smp_wmb
#define smp_mb() aarch32_smp_mb()
#define smp_rmb() aarch32_smp_rmb()
#define smp_wmb() aarch32_smp_wmb()
#endif /* !__ASSEMBLY__ */
#endif /* __COMPAT_BARRIER_H */