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a1b87d54f4
The bare metal decompressor code was never really intended to run in a hosted environment such as the EFI boot services, and does a few things that are becoming problematic in the context of EFI boot now that the logo requirements are getting tighter: EFI executables will no longer be allowed to consist of a single executable section that is mapped with read, write and execute permissions if they are intended for use in a context where Secure Boot is enabled (and where Microsoft's set of certificates is used, i.e., every x86 PC built to run Windows). To avoid stepping on reserved memory before having inspected the E820 tables, and to ensure the correct placement when running a kernel build that is non-relocatable, the bare metal decompressor moves its own executable image to the end of the allocation that was reserved for it, in order to perform the decompression in place. This means the region in question requires both write and execute permissions, which either need to be given upfront (which EFI will no longer permit), or need to be applied on demand using the existing page fault handling framework. However, the physical placement of the kernel is usually randomized anyway, and even if it isn't, a dedicated decompression output buffer can be allocated anywhere in memory using EFI APIs when still running in the boot services, given that EFI support already implies a relocatable kernel. This means that decompression in place is never necessary, nor is moving the compressed image from one end to the other. Since EFI already maps all of memory 1:1, it is also unnecessary to create new page tables or handle page faults when decompressing the kernel. That means there is also no need to replace the special exception handlers for SEV. Generally, there is little need to do any of the things that the decompressor does beyond - initialize SEV encryption, if needed, - perform the 4/5 level paging switch, if needed, - decompress the kernel - relocate the kernel So do all of this from the EFI stub code, and avoid the bare metal decompressor altogether. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230807162720.545787-24-ardb@kernel.org
166 lines
5.9 KiB
Makefile
166 lines
5.9 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# linux/arch/x86/boot/compressed/Makefile
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#
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# create a compressed vmlinux image from the original vmlinux
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#
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# vmlinuz is:
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# decompression code (*.o)
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# asm globals (piggy.S), including:
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# vmlinux.bin.(gz|bz2|lzma|...)
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#
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# vmlinux.bin is:
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# vmlinux stripped of debugging and comments
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# vmlinux.bin.all is:
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# vmlinux.bin + vmlinux.relocs
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# vmlinux.bin.(gz|bz2|lzma|...) is:
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# (see scripts/Makefile.lib size_append)
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# compressed vmlinux.bin.all + u32 size of vmlinux.bin.all
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# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
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KASAN_SANITIZE := n
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KCSAN_SANITIZE := n
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KMSAN_SANITIZE := n
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OBJECT_FILES_NON_STANDARD := y
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# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
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KCOV_INSTRUMENT := n
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targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
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vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 vmlinux.bin.zst
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# CLANG_FLAGS must come before any cc-disable-warning or cc-option calls in
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# case of cross compiling, as it has the '--target=' flag, which is needed to
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# avoid errors with '-march=i386', and future flags may depend on the target to
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# be valid.
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KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS)
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KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
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KBUILD_CFLAGS += -Wundef
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KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
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cflags-$(CONFIG_X86_32) := -march=i386
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cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone
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KBUILD_CFLAGS += $(cflags-y)
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KBUILD_CFLAGS += -mno-mmx -mno-sse
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KBUILD_CFLAGS += -ffreestanding -fshort-wchar
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KBUILD_CFLAGS += -fno-stack-protector
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KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
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KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
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KBUILD_CFLAGS += -Wno-pointer-sign
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KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
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KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
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KBUILD_CFLAGS += -D__DISABLE_EXPORTS
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# Disable relocation relaxation in case the link is not PIE.
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KBUILD_CFLAGS += $(call cc-option,-Wa$(comma)-mrelax-relocations=no)
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KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h
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# sev.c indirectly inludes inat-table.h which is generated during
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# compilation and stored in $(objtree). Add the directory to the includes so
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# that the compiler finds it even with out-of-tree builds (make O=/some/path).
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CFLAGS_sev.o += -I$(objtree)/arch/x86/lib/
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KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
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GCOV_PROFILE := n
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UBSAN_SANITIZE :=n
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KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
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KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
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# Compressed kernel should be built as PIE since it may be loaded at any
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# address by the bootloader.
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LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)
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ifdef CONFIG_LD_ORPHAN_WARN
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LDFLAGS_vmlinux += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
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endif
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LDFLAGS_vmlinux += -z noexecstack
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ifeq ($(CONFIG_LD_IS_BFD),y)
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LDFLAGS_vmlinux += $(call ld-option,--no-warn-rwx-segments)
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endif
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ifeq ($(CONFIG_EFI_STUB),y)
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# ensure that the static EFI stub library will be pulled in, even if it is
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# never referenced explicitly from the startup code
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LDFLAGS_vmlinux += -u efi_pe_entry
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endif
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LDFLAGS_vmlinux += -T
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hostprogs := mkpiggy
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include
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sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p'
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quiet_cmd_voffset = VOFFSET $@
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cmd_voffset = $(NM) $< | sed -n $(sed-voffset) > $@
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targets += ../voffset.h
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$(obj)/../voffset.h: vmlinux FORCE
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$(call if_changed,voffset)
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$(obj)/misc.o: $(obj)/../voffset.h
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vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/kernel_info.o $(obj)/head_$(BITS).o \
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$(obj)/misc.o $(obj)/string.o $(obj)/cmdline.o $(obj)/error.o \
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$(obj)/piggy.o $(obj)/cpuflags.o
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vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o
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vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr.o
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ifdef CONFIG_X86_64
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vmlinux-objs-y += $(obj)/ident_map_64.o
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vmlinux-objs-y += $(obj)/idt_64.o $(obj)/idt_handlers_64.o
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vmlinux-objs-$(CONFIG_AMD_MEM_ENCRYPT) += $(obj)/mem_encrypt.o
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vmlinux-objs-y += $(obj)/pgtable_64.o
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vmlinux-objs-$(CONFIG_AMD_MEM_ENCRYPT) += $(obj)/sev.o
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endif
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vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
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vmlinux-objs-$(CONFIG_INTEL_TDX_GUEST) += $(obj)/tdx.o $(obj)/tdcall.o $(obj)/tdx-shared.o
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vmlinux-objs-$(CONFIG_UNACCEPTED_MEMORY) += $(obj)/mem.o
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vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o
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vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_mixed.o
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vmlinux-objs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
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$(obj)/vmlinux: $(vmlinux-objs-y) FORCE
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$(call if_changed,ld)
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OBJCOPYFLAGS_vmlinux.bin := -R .comment -S
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$(obj)/vmlinux.bin: vmlinux FORCE
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$(call if_changed,objcopy)
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targets += $(patsubst $(obj)/%,%,$(vmlinux-objs-y)) vmlinux.bin.all vmlinux.relocs
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# vmlinux.relocs is created by the vmlinux postlink step.
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$(obj)/vmlinux.relocs: vmlinux
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@true
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vmlinux.bin.all-y := $(obj)/vmlinux.bin
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vmlinux.bin.all-$(CONFIG_X86_NEED_RELOCS) += $(obj)/vmlinux.relocs
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$(obj)/vmlinux.bin.gz: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,gzip)
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$(obj)/vmlinux.bin.bz2: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,bzip2_with_size)
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$(obj)/vmlinux.bin.lzma: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,lzma_with_size)
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$(obj)/vmlinux.bin.xz: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,xzkern_with_size)
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$(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,lzo_with_size)
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$(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,lz4_with_size)
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$(obj)/vmlinux.bin.zst: $(vmlinux.bin.all-y) FORCE
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$(call if_changed,zstd22_with_size)
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suffix-$(CONFIG_KERNEL_GZIP) := gz
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suffix-$(CONFIG_KERNEL_BZIP2) := bz2
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suffix-$(CONFIG_KERNEL_LZMA) := lzma
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suffix-$(CONFIG_KERNEL_XZ) := xz
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suffix-$(CONFIG_KERNEL_LZO) := lzo
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suffix-$(CONFIG_KERNEL_LZ4) := lz4
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suffix-$(CONFIG_KERNEL_ZSTD) := zst
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quiet_cmd_mkpiggy = MKPIGGY $@
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cmd_mkpiggy = $(obj)/mkpiggy $< > $@
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targets += piggy.S
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$(obj)/piggy.S: $(obj)/vmlinux.bin.$(suffix-y) $(obj)/mkpiggy FORCE
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$(call if_changed,mkpiggy)
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