* [PATCH 0/3] Fix cross compiling x86 with clang
@ 2021-03-26 0:04 Nathan Chancellor
2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor
` (3 more replies)
0 siblings, 4 replies; 10+ messages in thread
From: Nathan Chancellor @ 2021-03-26 0:04 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86, Ard Biesheuvel
Cc: Nick Desaulniers, linux-efi, linux-kernel, clang-built-linux,
Nathan Chancellor
Hi all,
This series fixes cross compiling x86 with clang, which was initially
brought up by John here:
https://lore.kernel.org/r/cceb074c-861c-d716-5e19-834a8492f245@gmail.com/
I have picked up that patch and added the same fix in a couple of other
places where it is needed.
I have tested this on an ARM based server with both defconfig and
allmodconfig, where the build now passes.
Please let me know if there are any problems.
Cheers,
Nathan
John Millikin (1):
x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS)
Nathan Chancellor (2):
x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS
efi/libstub: Add $(CLANG_FLAGS) to x86 flags
arch/x86/Makefile | 1 +
arch/x86/boot/compressed/Makefile | 1 +
drivers/firmware/efi/libstub/Makefile | 3 ++-
3 files changed, 4 insertions(+), 1 deletion(-)
base-commit: 0d02ec6b3136c73c09e7859f0d0e4e2c4c07b49b
--
2.31.0
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) 2021-03-26 0:04 [PATCH 0/3] Fix cross compiling x86 with clang Nathan Chancellor @ 2021-03-26 0:04 ` Nathan Chancellor 2021-03-26 8:42 ` Sedat Dilek ` (2 more replies) 2021-03-26 0:04 ` [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS Nathan Chancellor ` (2 subsequent siblings) 3 siblings, 3 replies; 10+ messages in thread From: Nathan Chancellor @ 2021-03-26 0:04 UTC (permalink / raw) To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86, Ard Biesheuvel Cc: Nick Desaulniers, linux-efi, linux-kernel, clang-built-linux, John Millikin, Sedat Dilek, Nathan Chancellor From: John Millikin <john@john-millikin.com> When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable contains additional flags needed to build C and assembly sources for the target platform. Normally this variable is automatically included in `$(KBUILD_CFLAGS)' by via the top-level Makefile. The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a plain assignment and therefore drops the Clang flags. This causes Clang to not recognize x86-specific assembler directives: arch/x86/realmode/rm/header.S:36:1: error: unknown directive .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header ^ Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)', which is inherited by real-mode make rules, fixes cross-compilation with Clang for x86 targets. Relevant flags: * `--target' sets the target architecture when cross-compiling. This flag must be set for both compilation and assembly (`KBUILD_AFLAGS') to support architecture-specific assembler directives. * `-no-integrated-as' tells clang to assemble with GNU Assembler instead of its built-in LLVM assembler. This flag is set by default unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet parse certain GNU extensions. Signed-off-by: John Millikin <john@john-millikin.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- arch/x86/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 2d6d5a28c3bf..9a73e0cea19c 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -33,6 +33,7 @@ REALMODE_CFLAGS += -ffreestanding REALMODE_CFLAGS += -fno-stack-protector REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) +REALMODE_CFLAGS += $(CLANG_FLAGS) export REALMODE_CFLAGS # BITS is used as extension for files which are available in a 32 bit -- 2.31.0 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) 2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor @ 2021-03-26 8:42 ` Sedat Dilek 2021-03-26 13:13 ` [tip: x86/build] x86/build: " tip-bot2 for John Millikin 2021-03-26 13:38 ` [PATCH 1/3] x86: " John Millikin 2 siblings, 0 replies; 10+ messages in thread From: Sedat Dilek @ 2021-03-26 8:42 UTC (permalink / raw) To: Nathan Chancellor Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86, Ard Biesheuvel, Nick Desaulniers, linux-efi, linux-kernel, Clang-Built-Linux ML, John Millikin On Fri, Mar 26, 2021 at 1:04 AM Nathan Chancellor <nathan@kernel.org> wrote: > > From: John Millikin <john@john-millikin.com> > > When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable > contains additional flags needed to build C and assembly sources > for the target platform. Normally this variable is automatically > included in `$(KBUILD_CFLAGS)' by via the top-level Makefile. > > The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a > plain assignment and therefore drops the Clang flags. This causes > Clang to not recognize x86-specific assembler directives: > > arch/x86/realmode/rm/header.S:36:1: error: unknown directive > .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header > ^ > > Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)', > which is inherited by real-mode make rules, fixes cross-compilation > with Clang for x86 targets. > > Relevant flags: > > * `--target' sets the target architecture when cross-compiling. This > flag must be set for both compilation and assembly (`KBUILD_AFLAGS') > to support architecture-specific assembler directives. > > * `-no-integrated-as' tells clang to assemble with GNU Assembler > instead of its built-in LLVM assembler. This flag is set by default > unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet > parse certain GNU extensions. > > Signed-off-by: John Millikin <john@john-millikin.com> > Tested-by: Sedat Dilek <sedat.dilek@gmail.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> I had John's v2 of this patch in my custom 5.11 patchset. Thanks for bringing this up again, Nathan. Later, I will test the triple patchset series. Feel free to add for this one: Tested-by: Sedat Dilek <sedat.dilek@gmail.com> - Sedat - > --- > arch/x86/Makefile | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index 2d6d5a28c3bf..9a73e0cea19c 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -33,6 +33,7 @@ REALMODE_CFLAGS += -ffreestanding > REALMODE_CFLAGS += -fno-stack-protector > REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) > REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) > +REALMODE_CFLAGS += $(CLANG_FLAGS) > export REALMODE_CFLAGS > > # BITS is used as extension for files which are available in a 32 bit > -- > 2.31.0 > ^ permalink raw reply [flat|nested] 10+ messages in thread
* [tip: x86/build] x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) 2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor 2021-03-26 8:42 ` Sedat Dilek @ 2021-03-26 13:13 ` tip-bot2 for John Millikin 2021-03-26 13:38 ` [PATCH 1/3] x86: " John Millikin 2 siblings, 0 replies; 10+ messages in thread From: tip-bot2 for John Millikin @ 2021-03-26 13:13 UTC (permalink / raw) To: linux-tip-commits Cc: John Millikin, Nathan Chancellor, Borislav Petkov, Ard Biesheuvel, Sedat Dilek, x86, linux-kernel The following commit has been merged into the x86/build branch of tip: Commit-ID: 8abe7fc26ad8f28bfdf78adbed56acd1fa93f82d Gitweb: https://git.kernel.org/tip/8abe7fc26ad8f28bfdf78adbed56acd1fa93f82d Author: John Millikin <john@john-millikin.com> AuthorDate: Thu, 25 Mar 2021 17:04:33 -07:00 Committer: Borislav Petkov <bp@suse.de> CommitterDate: Fri, 26 Mar 2021 11:32:47 +01:00 x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable contains additional flags needed to build C and assembly sources for the target platform. Normally this variable is automatically included in `$(KBUILD_CFLAGS)' via the top-level Makefile. The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a plain assignment and therefore drops the Clang flags. This causes Clang to not recognize x86-specific assembler directives: arch/x86/realmode/rm/header.S:36:1: error: unknown directive .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header ^ Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)', which is inherited by real-mode make rules, fixes cross-compilation with Clang for x86 targets. Relevant flags: * `--target' sets the target architecture when cross-compiling. This flag must be set for both compilation and assembly (`KBUILD_AFLAGS') to support architecture-specific assembler directives. * `-no-integrated-as' tells clang to assemble with GNU Assembler instead of its built-in LLVM assembler. This flag is set by default unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet parse certain GNU extensions. Signed-off-by: John Millikin <john@john-millikin.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Link: https://lkml.kernel.org/r/20210326000435.4785-2-nathan@kernel.org --- arch/x86/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 2d6d5a2..9a73e0c 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -33,6 +33,7 @@ REALMODE_CFLAGS += -ffreestanding REALMODE_CFLAGS += -fno-stack-protector REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) +REALMODE_CFLAGS += $(CLANG_FLAGS) export REALMODE_CFLAGS # BITS is used as extension for files which are available in a 32 bit ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) 2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor 2021-03-26 8:42 ` Sedat Dilek 2021-03-26 13:13 ` [tip: x86/build] x86/build: " tip-bot2 for John Millikin @ 2021-03-26 13:38 ` John Millikin 2 siblings, 0 replies; 10+ messages in thread From: John Millikin @ 2021-03-26 13:38 UTC (permalink / raw) To: Nathan Chancellor, Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86, Ard Biesheuvel Cc: Nick Desaulniers, linux-efi, linux-kernel, clang-built-linux, Sedat Dilek On 3/26/21 09:04, Nathan Chancellor wrote: > From: John Millikin <john@john-millikin.com> > > When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable > contains additional flags needed to build C and assembly sources > for the target platform. Normally this variable is automatically > included in `$(KBUILD_CFLAGS)' by via the top-level Makefile. > > The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a > plain assignment and therefore drops the Clang flags. This causes > Clang to not recognize x86-specific assembler directives: > > arch/x86/realmode/rm/header.S:36:1: error: unknown directive > .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header > ^ > > Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)', > which is inherited by real-mode make rules, fixes cross-compilation > with Clang for x86 targets. > > Relevant flags: > > * `--target' sets the target architecture when cross-compiling. This > flag must be set for both compilation and assembly (`KBUILD_AFLAGS') > to support architecture-specific assembler directives. > > * `-no-integrated-as' tells clang to assemble with GNU Assembler > instead of its built-in LLVM assembler. This flag is set by default > unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet > parse certain GNU extensions. > > Signed-off-by: John Millikin <john@john-millikin.com> > Tested-by: Sedat Dilek <sedat.dilek@gmail.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > arch/x86/Makefile | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index 2d6d5a28c3bf..9a73e0cea19c 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -33,6 +33,7 @@ REALMODE_CFLAGS += -ffreestanding > REALMODE_CFLAGS += -fno-stack-protector > REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) > REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) > +REALMODE_CFLAGS += $(CLANG_FLAGS) > export REALMODE_CFLAGS > > # BITS is used as extension for files which are available in a 32 bit > Just wanted to say "thank you" for picking this up -- I ran into some real-life situations and didn't have time to debug why my patch was failing the Git validity check (presumed to be an email client misconfiguration). ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS 2021-03-26 0:04 [PATCH 0/3] Fix cross compiling x86 with clang Nathan Chancellor 2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor @ 2021-03-26 0:04 ` Nathan Chancellor 2021-03-26 13:13 ` [tip: x86/build] " tip-bot2 for Nathan Chancellor 2021-03-26 0:04 ` [PATCH 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags Nathan Chancellor 2021-03-26 8:43 ` [PATCH 0/3] Fix cross compiling x86 with clang Ard Biesheuvel 3 siblings, 1 reply; 10+ messages in thread From: Nathan Chancellor @ 2021-03-26 0:04 UTC (permalink / raw) To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86, Ard Biesheuvel Cc: Nick Desaulniers, linux-efi, linux-kernel, clang-built-linux, Nathan Chancellor When cross compiling x86 on an ARM machine with clang, there are several errors along the lines of: arch/x86/include/asm/string_64.h:27:10: error: invalid output constraint '=&c' in asm This happens because the compressed boot Makefile reassigns KBUILD_CFLAGS and drops the clang flags that set the target architecture ('--target=') and the path to the GNU cross tools ('--prefix='), meaning that the host architecture is targeted. These flags are available as $(CLANG_FLAGS) from the main Makefile so add them to the compressed boot folder's KBUILD_CFLAGS so that cross compiling works as expected. Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- arch/x86/boot/compressed/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index e0bc3988c3fa..6e5522aebbbd 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -46,6 +46,7 @@ KBUILD_CFLAGS += -D__DISABLE_EXPORTS # Disable relocation relaxation in case the link is not PIE. KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no) KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h +KBUILD_CFLAGS += $(CLANG_FLAGS) # sev-es.c indirectly inludes inat-table.h which is generated during # compilation and stored in $(objtree). Add the directory to the includes so -- 2.31.0 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [tip: x86/build] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS 2021-03-26 0:04 ` [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS Nathan Chancellor @ 2021-03-26 13:13 ` tip-bot2 for Nathan Chancellor 0 siblings, 0 replies; 10+ messages in thread From: tip-bot2 for Nathan Chancellor @ 2021-03-26 13:13 UTC (permalink / raw) To: linux-tip-commits Cc: Nathan Chancellor, Borislav Petkov, Ard Biesheuvel, x86, linux-kernel The following commit has been merged into the x86/build branch of tip: Commit-ID: d5cbd80e302dfea59726c44c56ab7957f822409f Gitweb: https://git.kernel.org/tip/d5cbd80e302dfea59726c44c56ab7957f822409f Author: Nathan Chancellor <nathan@kernel.org> AuthorDate: Thu, 25 Mar 2021 17:04:34 -07:00 Committer: Borislav Petkov <bp@suse.de> CommitterDate: Fri, 26 Mar 2021 11:32:55 +01:00 x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS When cross compiling x86 on an ARM machine with clang, there are several errors along the lines of: arch/x86/include/asm/string_64.h:27:10: error: invalid output constraint '=&c' in asm This happens because the compressed boot Makefile reassigns KBUILD_CFLAGS and drops the clang flags that set the target architecture ('--target=') and the path to the GNU cross tools ('--prefix='), meaning that the host architecture is targeted. These flags are available as $(CLANG_FLAGS) from the main Makefile so add them to the compressed boot folder's KBUILD_CFLAGS so that cross compiling works as expected. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lkml.kernel.org/r/20210326000435.4785-3-nathan@kernel.org --- arch/x86/boot/compressed/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index e0bc398..6e5522a 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -46,6 +46,7 @@ KBUILD_CFLAGS += -D__DISABLE_EXPORTS # Disable relocation relaxation in case the link is not PIE. KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no) KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h +KBUILD_CFLAGS += $(CLANG_FLAGS) # sev-es.c indirectly inludes inat-table.h which is generated during # compilation and stored in $(objtree). Add the directory to the includes so ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags 2021-03-26 0:04 [PATCH 0/3] Fix cross compiling x86 with clang Nathan Chancellor 2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor 2021-03-26 0:04 ` [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS Nathan Chancellor @ 2021-03-26 0:04 ` Nathan Chancellor 2021-03-26 13:13 ` [tip: x86/build] " tip-bot2 for Nathan Chancellor 2021-03-26 8:43 ` [PATCH 0/3] Fix cross compiling x86 with clang Ard Biesheuvel 3 siblings, 1 reply; 10+ messages in thread From: Nathan Chancellor @ 2021-03-26 0:04 UTC (permalink / raw) To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86, Ard Biesheuvel Cc: Nick Desaulniers, linux-efi, linux-kernel, clang-built-linux, Nathan Chancellor When cross compiling x86 on an ARM machine with clang, there are several errors along the lines of: arch/x86/include/asm/page_64.h:52:7: error: invalid output constraint '=D' in asm This happens because the x86 flags in the EFI stub are not derived from KBUILD_CFLAGS like the other architectures are and the clang flags that set the target architecture ('--target=') and the path to the GNU cross tools ('--prefix=') are not present, meaning that the host architecture is targeted. These flags are available as $(CLANG_FLAGS) from the main Makefile so add them to the cflags for x86 so that cross compiling works as expected. Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- drivers/firmware/efi/libstub/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index c23466e05e60..d0537573501e 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -13,7 +13,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ -Wno-pointer-sign \ $(call cc-disable-warning, address-of-packed-member) \ $(call cc-disable-warning, gnu) \ - -fno-asynchronous-unwind-tables + -fno-asynchronous-unwind-tables \ + $(CLANG_FLAGS) # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly # disable the stackleak plugin -- 2.31.0 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [tip: x86/build] efi/libstub: Add $(CLANG_FLAGS) to x86 flags 2021-03-26 0:04 ` [PATCH 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags Nathan Chancellor @ 2021-03-26 13:13 ` tip-bot2 for Nathan Chancellor 0 siblings, 0 replies; 10+ messages in thread From: tip-bot2 for Nathan Chancellor @ 2021-03-26 13:13 UTC (permalink / raw) To: linux-tip-commits Cc: Nathan Chancellor, Borislav Petkov, Ard Biesheuvel, x86, linux-kernel The following commit has been merged into the x86/build branch of tip: Commit-ID: 58d746c119dfa28e72fc35aacaf3d2a3ac625cd0 Gitweb: https://git.kernel.org/tip/58d746c119dfa28e72fc35aacaf3d2a3ac625cd0 Author: Nathan Chancellor <nathan@kernel.org> AuthorDate: Thu, 25 Mar 2021 17:04:35 -07:00 Committer: Borislav Petkov <bp@suse.de> CommitterDate: Fri, 26 Mar 2021 11:34:58 +01:00 efi/libstub: Add $(CLANG_FLAGS) to x86 flags When cross compiling x86 on an ARM machine with clang, there are several errors along the lines of: arch/x86/include/asm/page_64.h:52:7: error: invalid output constraint '=D' in asm This happens because the x86 flags in the EFI stub are not derived from KBUILD_CFLAGS like the other architectures are and the clang flags that set the target architecture ('--target=') and the path to the GNU cross tools ('--prefix=') are not present, meaning that the host architecture is targeted. These flags are available as $(CLANG_FLAGS) from the main Makefile so add them to the cflags for x86 so that cross compiling works as expected. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lkml.kernel.org/r/20210326000435.4785-4-nathan@kernel.org --- drivers/firmware/efi/libstub/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index c23466e..d053757 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -13,7 +13,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ -Wno-pointer-sign \ $(call cc-disable-warning, address-of-packed-member) \ $(call cc-disable-warning, gnu) \ - -fno-asynchronous-unwind-tables + -fno-asynchronous-unwind-tables \ + $(CLANG_FLAGS) # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly # disable the stackleak plugin ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] Fix cross compiling x86 with clang 2021-03-26 0:04 [PATCH 0/3] Fix cross compiling x86 with clang Nathan Chancellor ` (2 preceding siblings ...) 2021-03-26 0:04 ` [PATCH 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags Nathan Chancellor @ 2021-03-26 8:43 ` Ard Biesheuvel 3 siblings, 0 replies; 10+ messages in thread From: Ard Biesheuvel @ 2021-03-26 8:43 UTC (permalink / raw) To: Nathan Chancellor Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, X86 ML, Nick Desaulniers, linux-efi, Linux Kernel Mailing List, clang-built-linux On Fri, 26 Mar 2021 at 01:04, Nathan Chancellor <nathan@kernel.org> wrote: > > Hi all, > > This series fixes cross compiling x86 with clang, which was initially > brought up by John here: > > https://lore.kernel.org/r/cceb074c-861c-d716-5e19-834a8492f245@gmail.com/ > > I have picked up that patch and added the same fix in a couple of other > places where it is needed. > > I have tested this on an ARM based server with both defconfig and > allmodconfig, where the build now passes. > > Please let me know if there are any problems. > > Cheers, > Nathan > > John Millikin (1): > x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) > > Nathan Chancellor (2): > x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS > efi/libstub: Add $(CLANG_FLAGS) to x86 flags > Acked-by: Ard Biesheuvel <ardb@kernel.org> > arch/x86/Makefile | 1 + > arch/x86/boot/compressed/Makefile | 1 + > drivers/firmware/efi/libstub/Makefile | 3 ++- > 3 files changed, 4 insertions(+), 1 deletion(-) > > > base-commit: 0d02ec6b3136c73c09e7859f0d0e4e2c4c07b49b > -- > 2.31.0 > ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2021-03-26 13:39 UTC | newest] Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-03-26 0:04 [PATCH 0/3] Fix cross compiling x86 with clang Nathan Chancellor 2021-03-26 0:04 ` [PATCH 1/3] x86: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS) Nathan Chancellor 2021-03-26 8:42 ` Sedat Dilek 2021-03-26 13:13 ` [tip: x86/build] x86/build: " tip-bot2 for John Millikin 2021-03-26 13:38 ` [PATCH 1/3] x86: " John Millikin 2021-03-26 0:04 ` [PATCH 2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS Nathan Chancellor 2021-03-26 13:13 ` [tip: x86/build] " tip-bot2 for Nathan Chancellor 2021-03-26 0:04 ` [PATCH 3/3] efi/libstub: Add $(CLANG_FLAGS) to x86 flags Nathan Chancellor 2021-03-26 13:13 ` [tip: x86/build] " tip-bot2 for Nathan Chancellor 2021-03-26 8:43 ` [PATCH 0/3] Fix cross compiling x86 with clang Ard Biesheuvel
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