After commit 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") we get a build error when make modules_install:
cc1: error: '-mloongson-mmi' must be used with '-mhard-float'
The reason is when make modules_install, 'call cc-option' doesn't work in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi applied and -march=loongson3a enable MMI instructions.
Fix this by partially reverting to the old logic, use 'call cc-option' to conditionally apply -march=loongson3a and -march=mips64r2.
Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") Cc: stable@vger.kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn --- arch/mips/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..7fb76d12829e 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -186,11 +186,8 @@ cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap # Some -march= flags enable MMI instructions, and GCC complains about that # support being enabled alongside -msoft-float. Thus explicitly disable MMI. cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi) -ifdef CONFIG_CPU_LOONGSON64 cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a -cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 -endif +cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2) cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,)
On Mon, Jun 26, 2023 at 03:50:47PM +0800, Huacai Chen wrote:
After commit 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") we get a build error when make modules_install:
cc1: error: '-mloongson-mmi' must be used with '-mhard-float'
The reason is when make modules_install, 'call cc-option' doesn't work in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi applied and -march=loongson3a enable MMI instructions.
The first sentence does not make much sense to me, specifically "in $(KBUILD_CFLAGS) of 'CHECKFLAGS'". What configuration and build command reproduces this? I do not see how '-mno-loongson-mmi' would fail to get added to cflags-y after 0e96ea5c3eb5, which should have had no functional change... I don't want to hang this change up since there is real breakage but I want to make sure we fully understand why 0e96ea5c3eb5 broke things and why this patch resolves it.
Fix this by partially reverting to the old logic, use 'call cc-option' to conditionally apply -march=loongson3a and -march=mips64r2.
Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") Cc: stable@vger.kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/mips/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..7fb76d12829e 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -186,11 +186,8 @@ cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap # Some -march= flags enable MMI instructions, and GCC complains about that # support being enabled alongside -msoft-float. Thus explicitly disable MMI. cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi) -ifdef CONFIG_CPU_LOONGSON64 cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a -cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 -endif +cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2) cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi) cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,) -- 2.39.3
Hi, Nathan,
On Tue, Jun 27, 2023 at 12:07 AM Nathan Chancellor nathan@kernel.org wrote:
On Mon, Jun 26, 2023 at 03:50:47PM +0800, Huacai Chen wrote:
After commit 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") we get a build error when make modules_install:
cc1: error: '-mloongson-mmi' must be used with '-mhard-float'
The reason is when make modules_install, 'call cc-option' doesn't work in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi applied and -march=loongson3a enable MMI instructions.
The first sentence does not make much sense to me, specifically "in $(KBUILD_CFLAGS) of 'CHECKFLAGS'". What configuration and build command reproduces this? I do not see how '-mno-loongson-mmi' would fail to get added to cflags-y after 0e96ea5c3eb5, which should have had no functional change... I don't want to hang this change up since there is real breakage but I want to make sure we fully understand why 0e96ea5c3eb5 broke things and why this patch resolves it.
Please use loongson3_defconfig to build a loongson kernel with toolchains from here [1]: 'make' will succeed, but there is a build error when 'make modules_install'. And you should be careful because 'make modules_install' doesn't stop when the error occurs.
[1] https://mirrors.edge.kernel.org/pub/tools/crosstool/
Huacai
Fix this by partially reverting to the old logic, use 'call cc-option' to conditionally apply -march=loongson3a and -march=mips64r2.
Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") Cc: stable@vger.kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/mips/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..7fb76d12829e 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -186,11 +186,8 @@ cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap # Some -march= flags enable MMI instructions, and GCC complains about that # support being enabled alongside -msoft-float. Thus explicitly disable MMI. cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi) -ifdef CONFIG_CPU_LOONGSON64 cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a -cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 -endif +cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2) cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,)
2.39.3
Hi Huacai,
+ Masahiro
On Tue, Jun 27, 2023 at 11:11:27AM +0800, Huacai Chen wrote:
Hi, Nathan,
On Tue, Jun 27, 2023 at 12:07 AM Nathan Chancellor nathan@kernel.org wrote:
On Mon, Jun 26, 2023 at 03:50:47PM +0800, Huacai Chen wrote:
After commit 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") we get a build error when make modules_install:
cc1: error: '-mloongson-mmi' must be used with '-mhard-float'
The reason is when make modules_install, 'call cc-option' doesn't work in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi applied and -march=loongson3a enable MMI instructions.
The first sentence does not make much sense to me, specifically "in $(KBUILD_CFLAGS) of 'CHECKFLAGS'". What configuration and build command reproduces this? I do not see how '-mno-loongson-mmi' would fail to get added to cflags-y after 0e96ea5c3eb5, which should have had no functional change... I don't want to hang this change up since there is real breakage but I want to make sure we fully understand why 0e96ea5c3eb5 broke things and why this patch resolves it.
Please use loongson3_defconfig to build a loongson kernel with toolchains from here [1]: 'make' will succeed, but there is a build error when 'make modules_install'. And you should be careful because 'make modules_install' doesn't stop when the error occurs.
Excellent, thank you! I understand what is going on here and your patch should work to resolve it (although I think the commit message should be flushed out a little more with the following details) but I am curious if Masahiro has any thoughts around this.
As you note, the error message comes from the CHECKFLAGS invocation of $(CC) but it has no impact on the final result of modules_install, it is purely a cosmetic issue from what I can tell. The error occurs because cc-option is defined in scripts/Makefile.compiler, which is not included in Makefile when running modules_install, as install targets are not supposed to require the compiler; see commit 805b2e1d427a ("kbuild: include Makefile.compiler only when compiler is needed"). As a result, the call to check for '-mno-loongson-mmi' just never happens.
It would nice if '-mno-loongson-mmi' could be added unconditionally when using GCC but I can see that the flag has only existed since 9.x, so we do need to keep the cc-option call.
I am fine with your change as long as it includes some of the above information (basically noting that while the original change should have been equivalent, the requirement of '-mno-loongson-mmi' when using certain Loongson '-march=' values with '-msoft-float' means that those Loongson '-march=' values need to be called with cc-option as well), even if clang will incur two more cc-option calls as a result (not the end of the world).
Additionally, it seems like the same issue will occur when running modules_install when CONFIG_CPU_LOONGSON2E or CONFIG_CPU_LOONGSON2F are enabled, which I guess I also broke in commit 13ceb48bc19c ("MIPS: Loongson2ef: Remove unnecessary {as,cc}-option calls") :/
Sorry again for the breakage and thanks for the fix!
Cheers, Nathan
Fix this by partially reverting to the old logic, use 'call cc-option' to conditionally apply -march=loongson3a and -march=mips64r2.
Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") Cc: stable@vger.kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/mips/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..7fb76d12829e 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -186,11 +186,8 @@ cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap # Some -march= flags enable MMI instructions, and GCC complains about that # support being enabled alongside -msoft-float. Thus explicitly disable MMI. cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi) -ifdef CONFIG_CPU_LOONGSON64 cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a -cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 -endif +cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2) cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,)
2.39.3
Hi, Nathan,
On Wed, Jun 28, 2023 at 5:28 AM Nathan Chancellor nathan@kernel.org wrote:
Hi Huacai,
- Masahiro
On Tue, Jun 27, 2023 at 11:11:27AM +0800, Huacai Chen wrote:
Hi, Nathan,
On Tue, Jun 27, 2023 at 12:07 AM Nathan Chancellor nathan@kernel.org wrote:
On Mon, Jun 26, 2023 at 03:50:47PM +0800, Huacai Chen wrote:
After commit 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") we get a build error when make modules_install:
cc1: error: '-mloongson-mmi' must be used with '-mhard-float'
The reason is when make modules_install, 'call cc-option' doesn't work in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi applied and -march=loongson3a enable MMI instructions.
The first sentence does not make much sense to me, specifically "in $(KBUILD_CFLAGS) of 'CHECKFLAGS'". What configuration and build command reproduces this? I do not see how '-mno-loongson-mmi' would fail to get added to cflags-y after 0e96ea5c3eb5, which should have had no functional change... I don't want to hang this change up since there is real breakage but I want to make sure we fully understand why 0e96ea5c3eb5 broke things and why this patch resolves it.
Please use loongson3_defconfig to build a loongson kernel with toolchains from here [1]: 'make' will succeed, but there is a build error when 'make modules_install'. And you should be careful because 'make modules_install' doesn't stop when the error occurs.
Excellent, thank you! I understand what is going on here and your patch should work to resolve it (although I think the commit message should be flushed out a little more with the following details) but I am curious if Masahiro has any thoughts around this.
As you note, the error message comes from the CHECKFLAGS invocation of $(CC) but it has no impact on the final result of modules_install, it is purely a cosmetic issue from what I can tell. The error occurs because cc-option is defined in scripts/Makefile.compiler, which is not included in Makefile when running modules_install, as install targets are not supposed to require the compiler; see commit 805b2e1d427a ("kbuild: include Makefile.compiler only when compiler is needed"). As a result, the call to check for '-mno-loongson-mmi' just never happens.
It would nice if '-mno-loongson-mmi' could be added unconditionally when using GCC but I can see that the flag has only existed since 9.x, so we do need to keep the cc-option call.
I am fine with your change as long as it includes some of the above information (basically noting that while the original change should have been equivalent, the requirement of '-mno-loongson-mmi' when using certain Loongson '-march=' values with '-msoft-float' means that those Loongson '-march=' values need to be called with cc-option as well), even if clang will incur two more cc-option calls as a result (not the end of the world).
Additionally, it seems like the same issue will occur when running modules_install when CONFIG_CPU_LOONGSON2E or CONFIG_CPU_LOONGSON2F are enabled, which I guess I also broke in commit 13ceb48bc19c ("MIPS: Loongson2ef: Remove unnecessary {as,cc}-option calls") :/
Sorry again for the breakage and thanks for the fix!
OK, I will update the commit message and fix for LOONGSON2EF together.
Huacai
Cheers, Nathan
Fix this by partially reverting to the old logic, use 'call cc-option' to conditionally apply -march=loongson3a and -march=mips64r2.
Fixes: 0e96ea5c3eb5904e5dc2f ("MIPS: Loongson64: Clean up use of cc-ifversion") Cc: stable@vger.kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/mips/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index a7a4ee66a9d3..7fb76d12829e 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -186,11 +186,8 @@ cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap # Some -march= flags enable MMI instructions, and GCC complains about that # support being enabled alongside -msoft-float. Thus explicitly disable MMI. cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi) -ifdef CONFIG_CPU_LOONGSON64 cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap -cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a -cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2 -endif +cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2) cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
cflags-$(CONFIG_CPU_R4000_WORKAROUNDS) += $(call cc-option,-mfix-r4000,)
2.39.3
linux-stable-mirror@lists.linaro.org
-
Huacai Chen -
Huacai Chen -
Nathan Chancellor