@@ -52,6 +52,7 @@ SECTIONS
_data = . ;
*(.data)
*(.data.*)
+ *(.bss.efistub)
_edata = . ;
}
. = ALIGN(L1_CACHE_BYTES);
@@ -73,13 +73,32 @@ CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
# a verification pass to see if any absolute relocations exist in any of the
# object files.
#
-extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
-lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
+extra-y := $(lib-y)
+lib-y := $(patsubst %.o,%.stub.o,$(lib-y))
STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
--prefix-symbols=__efistub_
STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
+#
+# 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.
+#
+STUBCOPY_FLAGS-$(CONFIG_ARM) += --rename-section .data=.data.efistub \
+ --rename-section .bss=.bss.efistub,load,alloc
+STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS
+
+#
+# For x86, bootloaders like systemd-boot or grub-efi do not zero-initialize the
+# .bss section, so the .bss section of the EFI stub needs to be included in the
+# .data section of the compressed kernel to ensure initialization. Rename the
+# .bss section here so it's easy to pick out in the linker script.
+#
+STUBCOPY_FLAGS-$(CONFIG_X86) += --rename-section .bss=.bss.efistub,load,alloc
+STUBCOPY_RELOC-$(CONFIG_X86_32) := R_386_32
+STUBCOPY_RELOC-$(CONFIG_X86_64) := R_X86_64_64
+
$(obj)/%.stub.o: $(obj)/%.o FORCE
$(call if_changed,stubcopy)
@@ -97,12 +116,3 @@ quiet_cmd_stubcopy = STUBCPY $@
/bin/false; \
fi; \
$(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@
-
-#
-# ARM discards the .data section because it disallows r/w data in the
-# decompressor. So move our .data to .data.efistub and .bss to .bss.efistub,
-# which are preserved explicitly by the decompressor linker script.
-#
-STUBCOPY_FLAGS-$(CONFIG_ARM) += --rename-section .data=.data.efistub \
- --rename-section .bss=.bss.efistub,load,alloc
-STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS
@@ -25,11 +25,7 @@
#define EFI_ALLOC_ALIGN EFI_PAGE_SIZE
#endif
-#if defined(CONFIG_X86)
-#define __efistub_global __section(.data)
-#else
#define __efistub_global
-#endif
extern bool __pure nochunk(void);
extern bool __pure nokaslr(void);
Instead of using __efistub_global to force variables into the .data section, leave them in the .bss but pull the EFI stub's .bss section into .data in the linker script for the compressed kernel. Add relocation checking for x86 as well to catch non-PC-relative relocations that require runtime processing, since the EFI stub does not do any runtime relocation processing. This will catch, for example, data relocations created by static initializers of pointers. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> --- arch/x86/boot/compressed/vmlinux.lds.S | 1 + drivers/firmware/efi/libstub/Makefile | 32 +++++++++++++++++--------- drivers/firmware/efi/libstub/efistub.h | 4 ---- 3 files changed, 22 insertions(+), 15 deletions(-)