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# SPDX-License-Identifier: GPL-2.0
java.lang.NullPointerException
# 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.
java.lang.NullPointerException

# non-x86 reuses KBUILD_CFLAGS, x86 does not
cflags-y   := $(KBUILD_CFLAGS)

cflags-$(CONFIG_X86_32)  := -march=i386
cflags-$(CONFIG_X86_64)  := -mcmodel=small
cflags-$(CONFIG_X86)  += -m$(BITS) -D__KERNEL__ -std=gnu11 \
       -fPIC -fno-strict-aliasing -mno-red-zone \
       -mno-mmx -mno-sse -fshort-wchar \
       -Wno-pointer-sign \
       $(call cc-disable-warning, address-of-packed-member) \
       $(call cc-disable-warning, gnu) \
       -fno-asynchronous-unwind-tables \
       $(CLANG_FLAGS)

# arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
# disable the stackleak plugin
cflags-$(CONFIG_ARM64)  += -fpie $(DISABLE_KSTACK_ERASE) \
       -fno-unwind-tables -fno-asynchronous-unwind-tables
cflags-$(CONFIG_ARM)  += -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \
       -DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \
       -DEFI_HAVE_STRCMP -fno-builtin -fpic \
       $(call cc-option,-mno-single-pic-base) \
       $(DISABLE_KSTACK_ERASE)
cflags-$(CONFIG_RISCV)  += -fpic -DNO_ALTERNATIVE -mno-relax \
       $(DISABLE_KSTACK_ERASE)
cflags-$(CONFIG_LOONGARCH) += -fpie $(DISABLE_KSTACK_ERASE)

cflags-$(CONFIG_EFI_PARAMS_FROM_FDT) += -I$(srctree)/scripts/dtc/libfdt

KBUILD_CFLAGS   := $(subst $(CC_FLAGS_FTRACE),,$(cflags-y)) \
       -Os -DDISABLE_BRANCH_PROFILING \
       -include $(srctree)/include/linux/hidden.h \
       -D__NO_FORTIFY \
       -ffreestanding \
       -fno-stack-protector \
       $(call cc-option,-fno-addrsig) \
       -D__DISABLE_EXPORTS

java.lang.NullPointerException
# struct randomization only makes sense for Linux internal types, which the EFI
# stub code never touches, so let's turn off struct randomization for the stub
# altogether
java.lang.NullPointerException
KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS), $(KBUILD_CFLAGS))

# remove SCS flags from all objects in this directory
KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
# disable CFI
KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_CFI), $(KBUILD_CFLAGS))
# disable LTO
KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))

# The .data section would be renamed to .data.efistub, therefore, remove
# `-fdata-sections` flag from KBUILD_CFLAGS_KERNEL
KBUILD_CFLAGS_KERNEL := $(filter-out -fdata-sections, $(KBUILD_CFLAGS_KERNEL))

KBUILD_AFLAGS   := $(KBUILD_CFLAGS) -D__ASSEMBLY__

lib-y    := efi-stub-helper.o gop.o secureboot.o tpm.o \
       file.o mem.o random.o randomalloc.o pci.o \
       skip_spaces.o lib-cmdline.o lib-ctype.o \
       alignedmem.o relocate.o printk.o vsprintf.o

# include the stub's libfdt dependencies from lib/ when needed
libfdt-deps   := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c \
       fdt_empty_tree.c fdt_sw.c

lib-$(CONFIG_EFI_PARAMS_FROM_FDT) += fdt.o \
         $(patsubst %.c,lib-%.o,$(libfdt-deps))

$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
 $(call if_changed_rule,cc_o_c)

lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o \
       screen_info.o efi-stub-entry.o

lib-$(CONFIG_ARM)  += arm32-stub.o
lib-$(CONFIG_ARM64)  += kaslr.o arm64.o arm64-stub.o smbios.o
lib-$(CONFIG_X86)  += x86-stub.o smbios.o
lib-$(CONFIG_X86_64)  += x86-5lvl.o
lib-$(CONFIG_RISCV)  += kaslr.o riscv.o riscv-stub.o
lib-$(CONFIG_LOONGARCH)  += loongarch.o loongarch-stub.o

CFLAGS_arm32-stub.o  := -DTEXT_OFFSET=$(TEXT_OFFSET)

zboot-obj-y   := zboot-decompress-gzip.o
CFLAGS_zboot-decompress-gzip.o += -I$(srctree)/lib/zlib_inflate
zboot-obj-$(CONFIG_KERNEL_ZSTD) := zboot-decompress-zstd.o lib-xxhash.o
CFLAGS_zboot-decompress-zstd.o += -I$(srctree)/lib/zstd

zboot-obj-$(CONFIG_RISCV) += lib-clz_ctz.o lib-ashldi3.o
lib-$(CONFIG_EFI_ZBOOT)  += zboot.o $(zboot-obj-y)

lib-$(CONFIG_UNACCEPTED_MEMORY) += unaccepted_memory.o bitmap.o find.o

targets    := $(lib-y)
lib-y    := $(patsubst %.o,%.stub.o,$(lib-y))

# Even when -mbranch-protection=none is set, Clang will generate a
# .note.gnu.property for code-less object files (like lib/ctype.c),
# so work around this by explicitly removing the unwanted section.
# https://llvm.org/pr46480
STUBCOPY_FLAGS-y  += --remove-section=.note.gnu.property

STUBCOPY_RELOC-$(CONFIG_X86_32) := R_386_32
STUBCOPY_RELOC-$(CONFIG_X86_64) := R_X86_64_64

java.lang.NullPointerException
# ARM discards the .data section because it disallows r/w data in the
# decompressor. So move our .data to .data.efistub and .bss to .bss.efistub,
# which are preserved explicitly by the decompressor linker script.
java.lang.NullPointerException
STUBCOPY_FLAGS-$(CONFIG_ARM) += --rename-section .data=.data.efistub \
       --rename-section .bss=.bss.efistub,load,alloc
STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS

java.lang.NullPointerException
# arm64 puts the stub in the kernel proper, which will unnecessarily retain all
# code indefinitely unless it is annotated as __init/__initdata/__initconst etc.
# So let's apply the __init annotations at the section level, by prefixing
# the section names directly. This will ensure that even all the inline string
# literals are covered.
# The fact that the stub and the kernel proper are essentially the same binary
# also means that we need to be extra careful to make sure that the stub does
# not rely on any absolute symbol references, considering that the virtual
# kernel mapping that the linker uses is not active yet when the stub is
# executing. So build all C dependencies of the EFI stub into libstub, and do
# a verification pass to see if any absolute relocations exist in any of the
# object files.
java.lang.NullPointerException
STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
       --prefix-symbols=__efistub_
STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS

# For RISC-V, we don't need anything special other than arm64. Keep all the
# symbols in .init section and make sure that no absolute symbols references
# exist.
STUBCOPY_FLAGS-$(CONFIG_RISCV) += --prefix-alloc-sections=.init \
       --prefix-symbols=__efistub_
STUBCOPY_RELOC-$(CONFIG_RISCV) := -E R_RISCV_HI20\|R_RISCV_$(BITS)\|R_RISCV_RELAX

# For LoongArch, keep all the symbols in .init section and make sure that no
# absolute symbols references exist.
STUBCOPY_FLAGS-$(CONFIG_LOONGARCH) += --prefix-alloc-sections=.init \
        --prefix-symbols=__efistub_
STUBCOPY_RELOC-$(CONFIG_LOONGARCH) := R_LARCH_MARK_LA

$(obj)/%.stub.o: $(obj)/%.o FORCE
 $(call if_changed,stubcopy)

java.lang.NullPointerException
# Strip debug sections and some other sections that may legally contain
# absolute relocations, so that we can inspect the remaining sections for
# such relocations. If none are found, regenerate the output object, but
# this time, use objcopy and leave all sections in place.
java.lang.NullPointerException
quiet_cmd_stubcopy = STUBCPY $@
      cmd_stubcopy =       \
 $(STRIP) --strip-debug -o $@ $<;    \
 if $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y); then  \
  echo "$@: absolute symbol references not allowed in the EFI stub" >&2; \
  /bin/false;      \
 fi;        \
 $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@