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41cd96fa14
The EFI stubloader for ARM starts out by allocating a 32 MB window at the base of RAM, in order to ensure that the decompressor (which blindly copies the uncompressed kernel into that window) does not overwrite other allocations that are made while running in the context of the EFI firmware. In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is causing boot failures because this initial allocation conflicts with a page of reserved memory at the base of RAM that contains the SMP spin tables and other pieces of firmware data and which was put there by the bootloader under the assumption that the TEXT_OFFSET window right below the kernel is only used partially during early boot, and will be left alone once the memory reservations are processed and taken into account. So let's permit reserved memory regions to exist in the region starting at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is the window below the kernel that is not touched by the early boot code. Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Chester Lin <clin@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
104 lines
4.0 KiB
Makefile
104 lines
4.0 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# The stub may be linked into the kernel proper or into a separate boot binary,
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# but in either case, it executes before the kernel does (with MMU disabled) so
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# things like ftrace and stack-protector are likely to cause trouble if left
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# enabled, even if doing so doesn't break the build.
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#
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cflags-$(CONFIG_X86_32) := -march=i386
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cflags-$(CONFIG_X86_64) := -mcmodel=small
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cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -O2 \
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-fPIC -fno-strict-aliasing -mno-red-zone \
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-mno-mmx -mno-sse -fshort-wchar \
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-Wno-pointer-sign \
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$(call cc-disable-warning, address-of-packed-member) \
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$(call cc-disable-warning, gnu)
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# arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
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# disable the stackleak plugin
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cflags-$(CONFIG_ARM64) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
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-fpie $(DISABLE_STACKLEAK_PLUGIN)
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cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
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-fno-builtin -fpic \
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$(call cc-option,-mno-single-pic-base)
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cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
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KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
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-D__NO_FORTIFY \
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$(call cc-option,-ffreestanding) \
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$(call cc-option,-fno-stack-protector) \
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-D__DISABLE_EXPORTS
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GCOV_PROFILE := n
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KASAN_SANITIZE := n
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UBSAN_SANITIZE := n
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OBJECT_FILES_NON_STANDARD := y
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# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
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KCOV_INSTRUMENT := n
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lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o
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# include the stub's generic dependencies from lib/ when building for ARM/arm64
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arm-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c
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arm-deps-$(CONFIG_ARM64) += sort.c
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$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
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$(call if_changed_rule,cc_o_c)
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lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o random.o \
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$(patsubst %.c,lib-%.o,$(arm-deps-y))
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lib-$(CONFIG_ARM) += arm32-stub.o
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lib-$(CONFIG_ARM64) += arm64-stub.o
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CFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
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CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
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#
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# arm64 puts the stub in the kernel proper, which will unnecessarily retain all
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# code indefinitely unless it is annotated as __init/__initdata/__initconst etc.
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# So let's apply the __init annotations at the section level, by prefixing
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# the section names directly. This will ensure that even all the inline string
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# literals are covered.
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# The fact that the stub and the kernel proper are essentially the same binary
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# also means that we need to be extra careful to make sure that the stub does
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# not rely on any absolute symbol references, considering that the virtual
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# kernel mapping that the linker uses is not active yet when the stub is
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# executing. So build all C dependencies of the EFI stub into libstub, and do
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# a verification pass to see if any absolute relocations exist in any of the
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# object files.
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#
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extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
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lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
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STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
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--prefix-symbols=__efistub_
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STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
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$(obj)/%.stub.o: $(obj)/%.o FORCE
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$(call if_changed,stubcopy)
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#
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# Strip debug sections and some other sections that may legally contain
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# absolute relocations, so that we can inspect the remaining sections for
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# such relocations. If none are found, regenerate the output object, but
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# this time, use objcopy and leave all sections in place.
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#
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quiet_cmd_stubcopy = STUBCPY $@
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cmd_stubcopy = \
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$(STRIP) --strip-debug -o $@ $<; \
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if $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y); then \
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echo "$@: absolute symbol references not allowed in the EFI stub" >&2; \
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/bin/false; \
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fi; \
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$(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@
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#
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# ARM discards the .data section because it disallows r/w data in the
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# decompressor. So move our .data to .data.efistub, which is preserved
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# explicitly by the decompressor linker script.
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#
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STUBCOPY_FLAGS-$(CONFIG_ARM) += --rename-section .data=.data.efistub
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STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS
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