Thread (15 messages) flat view 15 messages, 4 authors, 2017-11-30

[PATCH 3/3] arm64: use -mno-implicit-float instead of -mgeneral-regs-only

From: Ard Biesheuvel <hidden>
Date: 2017-11-29 12:15:17
Also in: linux-kbuild, lkml

On 29 November 2017 at 00:00, Sami Tolvanen [off-list ref] wrote:
From: Greg Hackmann <redacted>

LLVM bug 30792 causes clang's AArch64 backend to crash compiling
arch/arm64/crypto/aes-ce-cipher.c.  Replacing -mgeneral-regs-only with
-mno-implicit-float is the suggested workaround.
Do we still need these patches now that the AES code has been fixed?
quoted hunk ↗ jump to hunk
Signed-off-by: Greg Hackmann <redacted>
Cc: Matthias Kaehlcke <mka@chromium.org>
[added clang-ifversion to enable the workaround only for clang <6.0]
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index b35788c909f1..d2efb5a0212f 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -49,7 +49,10 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable)
   endif
 endif

-KBUILD_CFLAGS  += -mgeneral-regs-only $(lseinstr) $(brokengasinst)
+# This is a workaround for https://bugs.llvm.org/show_bug.cgi?id=30792.
+KBUILD_CFLAGS  += $(call clang-ifversion, -lt, 0600, -mno-implicit-float, -mgeneral-regs-only)
+
+KBUILD_CFLAGS  += $(lseinstr) $(brokengasinst)
 KBUILD_CFLAGS  += -fno-asynchronous-unwind-tables
 KBUILD_CFLAGS  += $(call cc-option, -mpc-relative-literal-loads)
 KBUILD_AFLAGS  += $(lseinstr) $(brokengasinst)
--
2.15.0.417.g466bffb3ac-goog
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