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From:   Arnd Bergmann <arnd@arndb.de>
To:     Catalin Marinas <catalin.marinas@arm.com>,
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        Mark Rutland <mark.rutland@arm.com>,
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        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
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Subject: [PATCH] arm64: disable patchable function entry on big-endian clang builds
Date:   Tue,  5 May 2020 16:12:36 +0200
Message-Id: <20200505141257.707945-1-arnd@arndb.de>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Clang only supports the patchable_function_entry attribute on
little-endian arm64 builds, but not on big-endian:

include/linux/kasan-checks.h:16:8: error: unknown attribute 'patchable_function_entry' ignored [-Werror,-Wunknown-attributes]

Disable that configuration with another dependency. Unfortunately
the existing check is not enough, as $(cc-option) at this point does
not pass the -mbig-endian flag.

Fixes: 3b23e4991fb6 ("arm64: implement ftrace with regs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm64/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4b256fa6db7a..a33d6402b934 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -151,7 +151,7 @@ config ARM64
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS \
-		if $(cc-option,-fpatchable-function-entry=2)
+		if $(cc-option,-fpatchable-function-entry=2) && !(CC_IS_CLANG && CPU_BIG_ENDIAN)
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_FAST_GUP
 	select HAVE_FTRACE_MCOUNT_RECORD
-- 
2.26.0