diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/Makefile | 19 | ||||
| -rw-r--r-- | arch/mips/loongson64/Platform | 22 |
2 files changed, 19 insertions, 22 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. # diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform index ec42c5085905..e2354e128d9a 100644 --- a/arch/mips/loongson64/Platform +++ b/arch/mips/loongson64/Platform @@ -6,28 +6,6 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap # -# Some versions of binutils, not currently mainline as of 2019/02/04, support -# an -mfix-loongson3-llsc flag which emits a sync prior to each ll instruction -# to work around a CPU bug (see __SYNC_loongson3_war in asm/sync.h for a -# description). -# -# We disable this in order to prevent the assembler meddling with the -# instruction that labels refer to, ie. if we label an ll instruction: -# -# 1: ll v0, 0(a0) -# -# ...then with the assembler fix applied the label may actually point at a sync -# instruction inserted by the assembler, and if we were using the label in an -# exception table the table would no longer contain the address of the ll -# instruction. -# -# Avoid this by explicitly disabling that assembler behaviour. If upstream -# binutils does not merge support for the flag then we can revisit & remove -# this later - for now it ensures vendor toolchains don't cause problems. -# -cflags-$(CONFIG_CPU_LOONGSON64) += $(call as-option,-Wa$(comma)-mno-fix-loongson3-llsc,) - -# # binutils from v2.25 on and gcc starting from v4.9.0 treat -march=loongson3a # as MIPS64 R2; older versions as just R1. This leaves the possibility open # that GCC might generate R2 code for -march=loongson3a which then is rejected |