From e8f3010f7326c00368dbc057bd052bec80dfc072 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 8 Oct 2015 20:02:04 +0100 Subject: arm64/efi: isolate EFI stub from the kernel proper Since arm64 does not use a builtin decompressor, the EFI stub is built into the kernel proper. So far, this has been working fine, but actually, since the stub is in fact a PE/COFF relocatable binary that is executed at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we should not be seamlessly sharing code with the kernel proper, which is a position dependent executable linked at a high virtual offset. So instead, separate the contents of libstub and its dependencies, by putting them into their own namespace by prefixing all of its symbols with __efistub. This way, we have tight control over what parts of the kernel proper are referenced by the stub. Signed-off-by: Ard Biesheuvel Reviewed-by: Matt Fleming Signed-off-by: Catalin Marinas --- arch/arm64/kernel/Makefile | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'arch/arm64/kernel/Makefile') diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 22dc9bc781be..7b17f6245f1e 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -20,6 +20,14 @@ arm64-obj-y := debug-monitors.o entry.o irq.o fpsimd.o \ cpufeature.o alternative.o cacheinfo.o \ smp.o smp_spin_table.o topology.o +stub-obj := efi-stub.o efi-entry.o +extra-y := $(stub-obj) +stub-obj := $(patsubst %.o,%.stub.o,$(stub-obj)) + +OBJCOPYFLAGS := --prefix-symbols=__efistub_ +$(obj)/%.stub.o: $(obj)/%.o FORCE + $(call if_changed,objcopy) + arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \ sys_compat.o entry32.o \ ../../arm/kernel/opcodes.o @@ -32,7 +40,7 @@ arm64-obj-$(CONFIG_CPU_PM) += sleep.o suspend.o arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o arm64-obj-$(CONFIG_KGDB) += kgdb.o -arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o +arm64-obj-$(CONFIG_EFI) += efi.o $(stub-obj) arm64-obj-$(CONFIG_PCI) += pci.o arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o arm64-obj-$(CONFIG_ACPI) += acpi.o @@ -40,7 +48,7 @@ arm64-obj-$(CONFIG_ACPI) += acpi.o obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) head-y := head.o -extra-y := $(head-y) vmlinux.lds +extra-y += $(head-y) vmlinux.lds # vDSO - this must be built first to generate the symbol offsets $(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h -- cgit v1.2.3