| Message ID | 20220120214001.1879469-1-nathan@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/2] MIPS: Loongson64: Clean up use of cc-ifversion | expand |
On Thu, Jan 20, 2022 at 1:40 PM Nathan Chancellor <nathan@kernel.org> wrote: > > This Makefile checks that GCC is 4.9 or newer, which is redundant after > commit 76ae847497bc ("Documentation: raise minimum supported version of > GCC to 5.1"), so cc-option can be removed. > > Clang does not support -march=loongson3a so it needs to continue to use > -march=mips64r2, along with binutils less than 2.25, so check that both > GCC and binutils 2.25 or newer are being used before using > -march=loongson3a. These flags do not need to be checked with cc-option > anymore because all GCC versions support -march=loongson3a and > -march=mips64r2 and all clang versions support -march=mips64r2. > > Signed-off-by: Nathan Chancellor <nathan@kernel.org> Thanks for the patch. I wonder why `_MIPS_ISA` only seems to be set at all for `-march=loongson3a` AFAICT, though that question is orthogonal to this patch. Perhaps the Loongson or MIPS maintainers know more? Otherwise seems like most uses of _MIPS_ISA can either be deleted or simplified now. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > arch/mips/loongson64/Platform | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform > index 3e660d6d3c2b..981d3abc150e 100644 > --- a/arch/mips/loongson64/Platform > +++ b/arch/mips/loongson64/Platform > @@ -12,17 +12,10 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap > # by GAS. The cc-option can't probe for this behaviour so -march=loongson3a > # can't easily be used safely within the kbuild framework. > # > -ifeq ($(call cc-ifversion, -ge, 0409, y), y) > - ifeq ($(call ld-ifversion, -ge, 22500, y), y) > - cflags-$(CONFIG_CPU_LOONGSON64) += \ > - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > - else > - cflags-$(CONFIG_CPU_LOONGSON64) += \ > - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > - endif > +ifeq ($(CONFIG_CC_IS_GCC)$(call ld-ifversion, -ge, 22500, y), yy) > + cflags-$(CONFIG_CPU_LOONGSON64) += -march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64 > else > - cflags-$(CONFIG_CPU_LOONGSON64) += \ > - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > + cflags-$(CONFIG_CPU_LOONGSON64) += -march=mips64r2 > endif > > # Some -march= flags enable MMI instructions, and GCC complains about that > > base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39 > -- > 2.34.1 >
在2022年1月24日一月 下午8:31，Nick Desaulniers写道： > On Thu, Jan 20, 2022 at 1:40 PM Nathan Chancellor <nathan@kernel.org> wrote: >> >> This Makefile checks that GCC is 4.9 or newer, which is redundant after >> commit 76ae847497bc ("Documentation: raise minimum supported version of >> GCC to 5.1"), so cc-option can be removed. >> >> Clang does not support -march=loongson3a so it needs to continue to use >> -march=mips64r2, along with binutils less than 2.25, so check that both >> GCC and binutils 2.25 or newer are being used before using >> -march=loongson3a. These flags do not need to be checked with cc-option >> anymore because all GCC versions support -march=loongson3a and >> -march=mips64r2 and all clang versions support -march=mips64r2. >> >> Signed-off-by: Nathan Chancellor <nathan@kernel.org> > > Thanks for the patch. I wonder why `_MIPS_ISA` only seems to be set at > all for `-march=loongson3a` AFAICT, though that question is orthogonal > to this patch. Perhaps the Loongson or MIPS maintainers know more? > Otherwise seems like most uses of _MIPS_ISA can either be deleted or > simplified now. This is because earlier GCC mistakenly set loongson3a to MIPS64 not MIPS64R2. But given that it's earlier than the minimal requirement GCC of kernel today, I think it should be safe to just move the whole logic. Thanks. > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > >> --- >> arch/mips/loongson64/Platform | 13 +++---------- >> 1 file changed, 3 insertions(+), 10 deletions(-) >> >> diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform >> index 3e660d6d3c2b..981d3abc150e 100644 >> --- a/arch/mips/loongson64/Platform >> +++ b/arch/mips/loongson64/Platform >> @@ -12,17 +12,10 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap >> # by GAS. The cc-option can't probe for this behaviour so -march=loongson3a >> # can't easily be used safely within the kbuild framework. >> # >> -ifeq ($(call cc-ifversion, -ge, 0409, y), y) >> - ifeq ($(call ld-ifversion, -ge, 22500, y), y) >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ >> - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) >> - else >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) >> - endif >> +ifeq ($(CONFIG_CC_IS_GCC)$(call ld-ifversion, -ge, 22500, y), yy) >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64 >> else >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=mips64r2 >> endif >> >> # Some -march= flags enable MMI instructions, and GCC complains about that >> >> base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39 >> -- >> 2.34.1 >> > > > -- > Thanks, > ~Nick Desaulniers
On Tue, Jan 25, 2022 at 12:03:32AM +0000, Jiaxun Yang wrote: > > > 在2022年1月24日一月 下午8:31，Nick Desaulniers写道： > > On Thu, Jan 20, 2022 at 1:40 PM Nathan Chancellor <nathan@kernel.org> wrote: > >> > >> This Makefile checks that GCC is 4.9 or newer, which is redundant after > >> commit 76ae847497bc ("Documentation: raise minimum supported version of > >> GCC to 5.1"), so cc-option can be removed. > >> > >> Clang does not support -march=loongson3a so it needs to continue to use > >> -march=mips64r2, along with binutils less than 2.25, so check that both > >> GCC and binutils 2.25 or newer are being used before using > >> -march=loongson3a. These flags do not need to be checked with cc-option > >> anymore because all GCC versions support -march=loongson3a and > >> -march=mips64r2 and all clang versions support -march=mips64r2. > >> > >> Signed-off-by: Nathan Chancellor <nathan@kernel.org> > > > > Thanks for the patch. I wonder why `_MIPS_ISA` only seems to be set at > > all for `-march=loongson3a` AFAICT, though that question is orthogonal > > to this patch. Perhaps the Loongson or MIPS maintainers know more? > > Otherwise seems like most uses of _MIPS_ISA can either be deleted or > > simplified now. > > This is because earlier GCC mistakenly set loongson3a to MIPS64 not MIPS64R2. > > But given that it's earlier than the minimal requirement GCC of kernel today, I think it should be safe to just move the whole logic. > > Thanks. So something like this (completely untested)? diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform index 3e660d6d3c2b..36ab2fe00835 100644 --- a/arch/mips/loongson64/Platform +++ b/arch/mips/loongson64/Platform @@ -5,24 +5,9 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -# -# binutils from v2.25 on and gcc starting from v4.9.0 treat -march=loongson3a -# as MIPS64 R2; older versions as just R1. This leaves the possibility open -# that GCC might generate R2 code for -march=loongson3a which then is rejected -# by GAS. The cc-option can't probe for this behaviour so -march=loongson3a -# can't easily be used safely within the kbuild framework. -# -ifeq ($(call cc-ifversion, -ge, 0409, y), y) - ifeq ($(call ld-ifversion, -ge, 22500, y), y) - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) - else - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) - endif -else - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) +ifdef CONFIG_CPU_LOONGSON64 +cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 +cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a endif # Some -march= flags enable MMI instructions, and GCC complains about that > > > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > > >> --- > >> arch/mips/loongson64/Platform | 13 +++---------- > >> 1 file changed, 3 insertions(+), 10 deletions(-) > >> > >> diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform > >> index 3e660d6d3c2b..981d3abc150e 100644 > >> --- a/arch/mips/loongson64/Platform > >> +++ b/arch/mips/loongson64/Platform > >> @@ -12,17 +12,10 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap > >> # by GAS. The cc-option can't probe for this behaviour so -march=loongson3a > >> # can't easily be used safely within the kbuild framework. > >> # > >> -ifeq ($(call cc-ifversion, -ge, 0409, y), y) > >> - ifeq ($(call ld-ifversion, -ge, 22500, y), y) > >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ > >> - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > >> - else > >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ > >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > >> - endif > >> +ifeq ($(CONFIG_CC_IS_GCC)$(call ld-ifversion, -ge, 22500, y), yy) > >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64 > >> else > >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ > >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) > >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=mips64r2 > >> endif > >> > >> # Some -march= flags enable MMI instructions, and GCC complains about that > >> > >> base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39 > >> -- > >> 2.34.1 > >> > > > > > > -- > > Thanks, > > ~Nick Desaulniers > > -- > - Jiaxun
在2022年1月25日一月 上午1:25，Nathan Chancellor写道： [...] > > So something like this (completely untested)? Yep, tested with multiple GCC toolchains and it works :-) Thanks. > > diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform > index 3e660d6d3c2b..36ab2fe00835 100644 > --- a/arch/mips/loongson64/Platform > +++ b/arch/mips/loongson64/Platform > @@ -5,24 +5,9 @@ > > cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap > > -# > -# binutils from v2.25 on and gcc starting from v4.9.0 treat > -march=loongson3a > -# as MIPS64 R2; older versions as just R1. This leaves the > possibility open > -# that GCC might generate R2 code for -march=loongson3a which then is > rejected > -# by GAS. The cc-option can't probe for this behaviour so > -march=loongson3a > -# can't easily be used safely within the kbuild framework. > -# > -ifeq ($(call cc-ifversion, -ge, 0409, y), y) > - ifeq ($(call ld-ifversion, -ge, 22500, y), y) > - cflags-$(CONFIG_CPU_LOONGSON64) += \ > - $(call cc-option,-march=loongson3a -U_MIPS_ISA > -D_MIPS_ISA=_MIPS_ISA_MIPS64) > - else > - cflags-$(CONFIG_CPU_LOONGSON64) += \ > - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA > -D_MIPS_ISA=_MIPS_ISA_MIPS64) > - endif > -else > - cflags-$(CONFIG_CPU_LOONGSON64) += \ > - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA > -D_MIPS_ISA=_MIPS_ISA_MIPS64) > +ifdef CONFIG_CPU_LOONGSON64 > +cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 > +cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a > endif > > # Some -march= flags enable MMI instructions, and GCC complains about that > >> > >> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> >> > >> >> --- >> >> arch/mips/loongson64/Platform | 13 +++---------- >> >> 1 file changed, 3 insertions(+), 10 deletions(-) >> >> >> >> diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform >> >> index 3e660d6d3c2b..981d3abc150e 100644 >> >> --- a/arch/mips/loongson64/Platform >> >> +++ b/arch/mips/loongson64/Platform >> >> @@ -12,17 +12,10 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap >> >> # by GAS. The cc-option can't probe for this behaviour so -march=loongson3a >> >> # can't easily be used safely within the kbuild framework. >> >> # >> >> -ifeq ($(call cc-ifversion, -ge, 0409, y), y) >> >> - ifeq ($(call ld-ifversion, -ge, 22500, y), y) >> >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ >> >> - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) >> >> - else >> >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ >> >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) >> >> - endif >> >> +ifeq ($(CONFIG_CC_IS_GCC)$(call ld-ifversion, -ge, 22500, y), yy) >> >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64 >> >> else >> >> - cflags-$(CONFIG_CPU_LOONGSON64) += \ >> >> - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) >> >> + cflags-$(CONFIG_CPU_LOONGSON64) += -march=mips64r2 >> >> endif >> >> >> >> # Some -march= flags enable MMI instructions, and GCC complains about that >> >> >> >> base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39 >> >> -- >> >> 2.34.1 >> >> >> > >> > >> > -- >> > Thanks, >> > ~Nick Desaulniers >> >> -- >> - Jiaxun
diff --git a/arch/mips/loongson64/Platform b/arch/mips/loongson64/Platform index 3e660d6d3c2b..981d3abc150e 100644 --- a/arch/mips/loongson64/Platform +++ b/arch/mips/loongson64/Platform @@ -12,17 +12,10 @@ cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap # by GAS. The cc-option can't probe for this behaviour so -march=loongson3a # can't easily be used safely within the kbuild framework. # -ifeq ($(call cc-ifversion, -ge, 0409, y), y) - ifeq ($(call ld-ifversion, -ge, 22500, y), y) - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) - else - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) - endif +ifeq ($(CONFIG_CC_IS_GCC)$(call ld-ifversion, -ge, 22500, y), yy) + cflags-$(CONFIG_CPU_LOONGSON64) += -march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64 else - cflags-$(CONFIG_CPU_LOONGSON64) += \ - $(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64) + cflags-$(CONFIG_CPU_LOONGSON64) += -march=mips64r2 endif # Some -march= flags enable MMI instructions, and GCC complains about that
This Makefile checks that GCC is 4.9 or newer, which is redundant after commit 76ae847497bc ("Documentation: raise minimum supported version of GCC to 5.1"), so cc-option can be removed. Clang does not support -march=loongson3a so it needs to continue to use -march=mips64r2, along with binutils less than 2.25, so check that both GCC and binutils 2.25 or newer are being used before using -march=loongson3a. These flags do not need to be checked with cc-option anymore because all GCC versions support -march=loongson3a and -march=mips64r2 and all clang versions support -march=mips64r2. Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- arch/mips/loongson64/Platform | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39