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| author | Huacai Chen <chenhuacai@loongson.cn> | 2023-02-25 15:52:56 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2023-02-25 22:12:16 +0800 |
| commit | 41596803302d83a67a80dc1efef4e51ac46acabb (patch) | |
| tree | 91fb727f636ae6d72b1f0653567edd861c1afa9e /arch/loongarch/Makefile | |
| parent | bb7a78e343468873bf00b2b181fcfd3c02d8cb56 (diff) | |
| download | linux-stable-41596803302d83a67a80dc1efef4e51ac46acabb.tar.gz linux-stable-41596803302d83a67a80dc1efef4e51ac46acabb.tar.bz2 linux-stable-41596803302d83a67a80dc1efef4e51ac46acabb.zip | |
LoongArch: Make -mstrict-align configurable
Introduce Kconfig option ARCH_STRICT_ALIGN to make -mstrict-align be
configurable.
Not all LoongArch cores support h/w unaligned access, we can use the
-mstrict-align build parameter to prevent unaligned accesses.
CPUs with h/w unaligned access support:
Loongson-2K2000/2K3000/3A5000/3C5000/3D5000.
CPUs without h/w unaligned access support:
Loongson-2K500/2K1000.
This option is enabled by default to make the kernel be able to run on
all LoongArch systems. But you can disable it manually if you want to
run kernel only on systems with h/w unaligned access support in order to
optimise for performance.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/Makefile')
| -rw-r--r-- | arch/loongarch/Makefile | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile index 4402387d2755..6e1c931a8507 100644 --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -91,10 +91,15 @@ KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y) # instead of .eh_frame so we don't discard them. KBUILD_CFLAGS += -fno-asynchronous-unwind-tables +ifdef CONFIG_ARCH_STRICT_ALIGN # Don't emit unaligned accesses. # Not all LoongArch cores support unaligned access, and as kernel we can't # rely on others to provide emulation for these accesses. KBUILD_CFLAGS += $(call cc-option,-mstrict-align) +else +# Optimise for performance on hardware supports unaligned access. +KBUILD_CFLAGS += $(call cc-option,-mno-strict-align) +endif KBUILD_CFLAGS += -isystem $(shell $(CC) -print-file-name=include) |