a5cd290599
commit 015d98149b326e0f1f02e44413112ca8b4330543 upstream.
A change in clang 13 results in the __lwsync macro being defined as
__builtin_ppc_lwsync, which emits 'lwsync' or 'msync' depending on what
the target supports. This breaks the build because of -Werror in
arch/powerpc, along with thousands of warnings:
In file included from arch/powerpc/kernel/pmc.c:12:
In file included from include/linux/bug.h:5:
In file included from arch/powerpc/include/asm/bug.h:109:
In file included from include/asm-generic/bug.h:20:
In file included from include/linux/kernel.h:12:
In file included from include/linux/bitops.h:32:
In file included from arch/powerpc/include/asm/bitops.h:62:
arch/powerpc/include/asm/barrier.h:49:9: error: '__lwsync' macro redefined [-Werror,-Wmacro-redefined]
#define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory")
^
<built-in>:308:9: note: previous definition is here
#define __lwsync __builtin_ppc_lwsync
^
1 error generated.
Undefine this macro so that the runtime patching introduced by
commit 2d1b202762 ("powerpc: Fixup lwsync at runtime") continues to
work properly with clang and the build no longer breaks.
Cc: stable@vger.kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/1386
Link: 62b5df7fe2
Link: https://lore.kernel.org/r/20210528182752.1852002-1-nathan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
107 lines
3.6 KiB
C
107 lines
3.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
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*/
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#ifndef _ASM_POWERPC_BARRIER_H
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#define _ASM_POWERPC_BARRIER_H
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#include <asm/asm-const.h>
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/*
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* Memory barrier.
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* The sync instruction guarantees that all memory accesses initiated
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* by this processor have been performed (with respect to all other
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* mechanisms that access memory). The eieio instruction is a barrier
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* providing an ordering (separately) for (a) cacheable stores and (b)
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* loads and stores to non-cacheable memory (e.g. I/O devices).
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*
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* mb() prevents loads and stores being reordered across this point.
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* rmb() prevents loads being reordered across this point.
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* wmb() prevents stores being reordered across this point.
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* read_barrier_depends() prevents data-dependent loads being reordered
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* across this point (nop on PPC).
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*
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* *mb() variants without smp_ prefix must order all types of memory
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* operations with one another. sync is the only instruction sufficient
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* to do this.
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*
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* For the smp_ barriers, ordering is for cacheable memory operations
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* only. We have to use the sync instruction for smp_mb(), since lwsync
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* doesn't order loads with respect to previous stores. Lwsync can be
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* used for smp_rmb() and smp_wmb().
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*
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* However, on CPUs that don't support lwsync, lwsync actually maps to a
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* heavy-weight sync, so smp_wmb() can be a lighter-weight eieio.
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*/
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#define mb() __asm__ __volatile__ ("sync" : : : "memory")
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#define rmb() __asm__ __volatile__ ("sync" : : : "memory")
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#define wmb() __asm__ __volatile__ ("sync" : : : "memory")
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/* The sub-arch has lwsync */
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#if defined(__powerpc64__) || defined(CONFIG_PPC_E500MC)
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# define SMPWMB LWSYNC
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#else
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# define SMPWMB eieio
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#endif
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/* clang defines this macro for a builtin, which will not work with runtime patching */
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#undef __lwsync
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#define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory")
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#define dma_rmb() __lwsync()
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#define dma_wmb() __asm__ __volatile__ (stringify_in_c(SMPWMB) : : :"memory")
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#define __smp_lwsync() __lwsync()
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#define __smp_mb() mb()
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#define __smp_rmb() __lwsync()
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#define __smp_wmb() __asm__ __volatile__ (stringify_in_c(SMPWMB) : : :"memory")
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/*
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* This is a barrier which prevents following instructions from being
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* started until the value of the argument x is known. For example, if
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* x is a variable loaded from memory, this prevents following
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* instructions from being executed until the load has been performed.
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*/
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#define data_barrier(x) \
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asm volatile("twi 0,%0,0; isync" : : "r" (x) : "memory");
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#define __smp_store_release(p, v) \
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do { \
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compiletime_assert_atomic_type(*p); \
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__smp_lwsync(); \
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WRITE_ONCE(*p, v); \
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} while (0)
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#define __smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1 = READ_ONCE(*p); \
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compiletime_assert_atomic_type(*p); \
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__smp_lwsync(); \
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___p1; \
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})
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#ifdef CONFIG_PPC_BOOK3S_64
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#define NOSPEC_BARRIER_SLOT nop
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#elif defined(CONFIG_PPC_FSL_BOOK3E)
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#define NOSPEC_BARRIER_SLOT nop; nop
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#endif
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#ifdef CONFIG_PPC_BARRIER_NOSPEC
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/*
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* Prevent execution of subsequent instructions until preceding branches have
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* been fully resolved and are no longer executing speculatively.
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*/
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#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; NOSPEC_BARRIER_SLOT
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// This also acts as a compiler barrier due to the memory clobber.
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#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
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#else /* !CONFIG_PPC_BARRIER_NOSPEC */
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#define barrier_nospec_asm
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#define barrier_nospec()
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#endif /* CONFIG_PPC_BARRIER_NOSPEC */
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#include <asm-generic/barrier.h>
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#endif /* _ASM_POWERPC_BARRIER_H */
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