From: Alistair Strachan <astrachan@xxxxxxxxxx>
(commit 41f1c48420709470c51ee0e54b6fb28b956bb4e0 upstream)
When building with CONFIG_EFI and CONFIG_EFI_STUB on ARM, the libstub
Makefile would use -mno-single-pic-base without checking it was
supported by the compiler. As the ARM (32-bit) clang backend does not
support this flag, the build would fail.
This changes the Makefile to check the compiler's support for
-mno-single-pic-base before using it, similar to c1c386681bd7 ("ARM:
8767/1: add support for building ARM kernel with clang").
Signed-off-by: Alistair Strachan <astrachan@xxxxxxxxxx>
Reviewed-by: Stefan Agner <stefan@xxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
Please land in 4.19, 4.18. I'm preparing backports for 4.9 and 4.4 I
will send today or tomorrow. This is for building the Linux kernel for
arm32 with Clang.
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 14c40a7750d1..c51627660dbb 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -16,7 +16,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -O2 \
cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS)) -fpie \
$(DISABLE_STACKLEAK_PLUGIN)
cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \
- -fno-builtin -fpic -mno-single-pic-base
+ -fno-builtin -fpic \
+ $(call cc-option,-mno-single-pic-base)
cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
--
2.20.0.rc0.387.gc7a69e6b6c-goog
