4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alistair Strachan astrachan@google.com
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@google.com Reviewed-by: Stefan Agner stefan@agner.ch Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/firmware/efi/libstub/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -16,7 +16,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__K 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