From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 2/9] powerpc/64s: Disable pcrel code model on Clang
Date: Wed, 26 Apr 2023 15:58:39 +1000 [thread overview]
Message-ID: <20230426055848.402993-3-npiggin@gmail.com> (raw)
In-Reply-To: <20230426055848.402993-1-npiggin@gmail.com>
Clang has a bug that casues the pcrel code model not to be used when any of
-msoft-float, -mno-altivec, or -mno-vsx are set. Leaving these off causes
FP/vector instructions to be generated, causing crashes. So disable pcrel
for clang for now.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/Kconfig | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 7a0f25a09759..261e9453b43c 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -8,7 +8,12 @@ config CC_HAS_PREFIXED
def_bool PPC64 && $(cc-option, -mcpu=power10 -mprefixed)
config CC_HAS_PCREL
- def_bool PPC64 && $(cc-option, -mcpu=power10 -mpcrel)
+ # Clang has a bug (https://github.com/llvm/llvm-project/issues/62372)
+ # where pcrel code is not generated if -msoft-float, -mno-altivec, or
+ # -mno-vsx options are also given. Without these options, fp/vec
+ # instructions are generated from regular kernel code. So Clang can't
+ # do pcrel yet.
+ def_bool PPC64 && CC_IS_GCC && $(cc-option, -mcpu=power10 -mpcrel)
config 32BIT
bool
--
2.40.0
next prev parent reply other threads:[~2023-04-26 6:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-26 5:58 [PATCH 0/9] powerpc: Build fixes Nicholas Piggin
2023-04-26 5:58 ` [PATCH 1/9] powerpc: Fix merge conflict between pcrel and copy_thread changes Nicholas Piggin
2023-04-26 5:58 ` Nicholas Piggin [this message]
2023-04-26 5:58 ` [PATCH 3/9] powerpc/boot: Seperate target flags from BOOTCFLAGS Nicholas Piggin
2023-04-26 5:58 ` [PATCH 4/9] powerpc/boot: Seperate CPP " Nicholas Piggin
2023-04-26 5:58 ` [PATCH 5/9] powerpc/boot: Separate BOOTCFLAGS from BOOTASFLAGS Nicholas Piggin
2023-04-26 15:11 ` Linus Torvalds
2023-04-26 5:58 ` [PATCH 6/9] powerpc/boot: Clean up Makefile after cflags and asflags separation Nicholas Piggin
2023-04-26 5:58 ` [PATCH 6/9] powerpc/boot: clean up Makefile flags Nicholas Piggin
2023-04-26 5:58 ` [PATCH 7/9] powerpc/build: Remove -pipe from compilation flags Nicholas Piggin
2023-04-26 5:58 ` [PATCH 8/9] powerpc/64s: Permit d-form memops in asm when building with prefix on clang Nicholas Piggin
2023-04-26 5:58 ` [PATCH 9/9] powerpc/64s: Work around llvm-as not recognising pla Nicholas Piggin
2023-04-26 12:01 ` (subset) [PATCH 0/9] powerpc: Build fixes Michael Ellerman
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