efi: efistub: Convert into static library
This patch changes both x86 and arm64 efistub implementations
from #including shared .c files under drivers/firmware/efi to
building shared code as a static library.
The x86 code uses a stub built into the boot executable which
uncompresses the kernel at boot time. In this case, the library is
linked into the decompressor.
In the arm64 case, the stub is part of the kernel proper so the library
is linked into the kernel proper as well.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 588dc47..f712d47 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -57,6 +57,9 @@
config EFI_RUNTIME_WRAPPERS
bool
+config EFI_ARMSTUB
+ bool
+
endmenu
config UEFI_CPER
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index e109653..a204d14 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -7,3 +7,4 @@
obj-$(CONFIG_UEFI_CPER) += cper.o
obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o
+obj-$(CONFIG_EFI_STUB) += libstub/
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
new file mode 100644
index 0000000..b14bc2b
--- /dev/null
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -0,0 +1,26 @@
+#
+# The stub may be linked into the kernel proper or into a separate boot binary,
+# but in either case, it executes before the kernel does (with MMU disabled) so
+# things like ftrace and stack-protector are likely to cause trouble if left
+# enabled, even if doing so doesn't break the build.
+#
+cflags-$(CONFIG_X86_32) := -march=i386
+cflags-$(CONFIG_X86_64) := -mcmodel=small
+cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2 \
+ -fPIC -fno-strict-aliasing -mno-red-zone \
+ -mno-mmx -mno-sse -DDISABLE_BRANCH_PROFILING
+
+cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS))
+cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \
+ -fno-builtin -fpic -mno-single-pic-base
+
+KBUILD_CFLAGS := $(cflags-y) \
+ $(call cc-option,-ffreestanding) \
+ $(call cc-option,-fno-stack-protector)
+
+GCOV_PROFILE := n
+
+lib-y := efi-stub-helper.o
+lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o
+
+CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/
diff --git a/drivers/firmware/efi/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
similarity index 100%
rename from drivers/firmware/efi/arm-stub.c
rename to drivers/firmware/efi/libstub/arm-stub.c
diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
similarity index 100%
rename from drivers/firmware/efi/efi-stub-helper.c
rename to drivers/firmware/efi/libstub/efi-stub-helper.c
diff --git a/drivers/firmware/efi/efistub.h b/drivers/firmware/efi/libstub/efistub.h
similarity index 100%
rename from drivers/firmware/efi/efistub.h
rename to drivers/firmware/efi/libstub/efistub.h
diff --git a/drivers/firmware/efi/fdt.c b/drivers/firmware/efi/libstub/fdt.c
similarity index 100%
rename from drivers/firmware/efi/fdt.c
rename to drivers/firmware/efi/libstub/fdt.c