diff options
| author | Aurelien Jarno <aurelien@aurel32.net> | 2021-01-09 20:30:47 +0100 |
|---|---|---|
| committer | Thomas Bogendoerfer <tsbogend@alpha.franken.de> | 2021-01-15 15:34:20 +0100 |
| commit | 5373ae67c3aad1ab306cc722b5a80b831eb4d4d1 (patch) | |
| tree | f8b46e8326f9ef4efde53cea2dd97d84dd28c608 /arch/mips/Makefile | |
| parent | 8790ccf8daf1a8c53b6cb8ce0c9a109274bd3fa8 (diff) | |
MIPS: Support binutils configured with --enable-mips-fix-loongson3-llsc=yes
From version 2.35, binutils can be configured with
--enable-mips-fix-loongson3-llsc=yes, which means it defaults to
-mfix-loongson3-llsc. This breaks labels which might then point at the
wrong instruction.
The workaround to explicitly pass -mno-fix-loongson3-llsc has been
added in Linux version 5.1, but is only enabled when building a Loongson
64 kernel. As vendors might use a common toolchain for building Loongson
and non-Loongson kernels, just move that workaround to
arch/mips/Makefile. At the same time update the comments to reflect the
current status.
Cc: stable@vger.kernel.org # 5.1+
Cc: YunQiang Su <syq@debian.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips/Makefile')
| -rw-r--r-- | arch/mips/Makefile | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index cd4343edeb11..5ffdd67093bc 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -136,6 +136,25 @@ cflags-$(CONFIG_SB1XXX_CORELIS) += $(call cc-option,-mno-sched-prolog) \ # cflags-y += -fno-stack-check +# binutils from v2.35 when built with --enable-mips-fix-loongson3-llsc=yes, +# supports an -mfix-loongson3-llsc flag which emits a sync prior to each ll +# instruction to work around a CPU bug (see __SYNC_loongson3_war in asm/sync.h +# for a description). +# +# We disable this in order to prevent the assembler meddling with the +# instruction that labels refer to, ie. if we label an ll instruction: +# +# 1: ll v0, 0(a0) +# +# ...then with the assembler fix applied the label may actually point at a sync +# instruction inserted by the assembler, and if we were using the label in an +# exception table the table would no longer contain the address of the ll +# instruction. +# +# Avoid this by explicitly disabling that assembler behaviour. +# +cflags-y += $(call as-option,-Wa$(comma)-mno-fix-loongson3-llsc,) + # # CPU-dependent compiler/assembler options for optimization. # |