linux/arch/arm/boot/compressed/Makefile
Nicolas Pitre 8d7e4cc2c8 ARM: zImage: make sure no GOTOFF relocs are used with .bss symbols
To be able to relocate the .bss section at run time independently from
the rest of the code, we must make sure that no GOTOFF relocations are
used with .bss symbols.  This usually means that no global variables can
be marked static unless they're also const.

To enforce this, suffice to fail the build whenever a private symbol
is allocated to .bss and list those symbols for convenience.

The user_stack and user_stack_end labels in head.S were converted into
non exported symbols to remove false positives.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Tony Lindgren <tony@atomide.com>
2011-05-07 00:08:03 -04:00

153 lines
3.9 KiB
Makefile

#
# linux/arch/arm/boot/compressed/Makefile
#
# create a compressed vmlinuz image from the original vmlinux
#
OBJS =
# Ensure that mmcif loader code appears early in the image
# to minimise that number of bocks that have to be read in
# order to load it.
ifeq ($(CONFIG_ZBOOT_ROM_MMCIF),y)
ifeq ($(CONFIG_ARCH_SH7372),y)
OBJS += mmcif-sh7372.o
endif
endif
AFLAGS_head.o += -DTEXT_OFFSET=$(TEXT_OFFSET)
HEAD = head.o
OBJS += misc.o decompress.o
FONTC = $(srctree)/drivers/video/console/font_acorn_8x8.c
#
# Architecture dependencies
#
ifeq ($(CONFIG_ARCH_ACORN),y)
OBJS += ll_char_wr.o font.o
endif
ifeq ($(CONFIG_ARCH_SHARK),y)
OBJS += head-shark.o ofw-shark.o
endif
ifeq ($(CONFIG_ARCH_P720T),y)
# Borrow this code from SA1100
OBJS += head-sa1100.o
endif
ifeq ($(CONFIG_ARCH_SA1100),y)
OBJS += head-sa1100.o
endif
ifeq ($(CONFIG_ARCH_VT8500),y)
OBJS += head-vt8500.o
endif
ifeq ($(CONFIG_CPU_XSCALE),y)
OBJS += head-xscale.o
endif
ifeq ($(CONFIG_PXA_SHARPSL_DETECT_MACH_ID),y)
OBJS += head-sharpsl.o
endif
ifeq ($(CONFIG_CPU_ENDIAN_BE32),y)
ifeq ($(CONFIG_CPU_CP15),y)
OBJS += big-endian.o
else
# The endian should be set by h/w design.
endif
endif
ifeq ($(CONFIG_ARCH_SHMOBILE),y)
OBJS += head-shmobile.o
endif
#
# We now have a PIC decompressor implementation. Decompressors running
# from RAM should not define ZTEXTADDR. Decompressors running directly
# from ROM or Flash must define ZTEXTADDR (preferably via the config)
# FIXME: Previous assignment to ztextaddr-y is lost here. See SHARK
ifeq ($(CONFIG_ZBOOT_ROM),y)
ZTEXTADDR := $(CONFIG_ZBOOT_ROM_TEXT)
ZBSSADDR := $(CONFIG_ZBOOT_ROM_BSS)
else
ZTEXTADDR := 0
ZBSSADDR := ALIGN(8)
endif
SEDFLAGS = s/TEXT_START/$(ZTEXTADDR)/;s/BSS_START/$(ZBSSADDR)/
suffix_$(CONFIG_KERNEL_GZIP) = gzip
suffix_$(CONFIG_KERNEL_LZO) = lzo
suffix_$(CONFIG_KERNEL_LZMA) = lzma
targets := vmlinux vmlinux.lds \
piggy.$(suffix_y) piggy.$(suffix_y).o \
font.o font.c head.o misc.o $(OBJS)
# Make sure files are removed during clean
extra-y += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S
ifeq ($(CONFIG_FUNCTION_TRACER),y)
ORIG_CFLAGS := $(KBUILD_CFLAGS)
KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
endif
ccflags-y := -fpic -fno-builtin
asflags-y := -Wa,-march=all
# Supply ZRELADDR to the decompressor via a linker symbol.
ifneq ($(CONFIG_AUTO_ZRELADDR),y)
LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR)
endif
ifeq ($(CONFIG_CPU_ENDIAN_BE8),y)
LDFLAGS_vmlinux += --be8
endif
# ?
LDFLAGS_vmlinux += -p
# Report unresolved symbol references
LDFLAGS_vmlinux += --no-undefined
# Delete all temporary local symbols
LDFLAGS_vmlinux += -X
# Next argument is a linker script
LDFLAGS_vmlinux += -T
# For __aeabi_uidivmod
lib1funcs = $(obj)/lib1funcs.o
$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
$(call cmd,shipped)
# We need to prevent any GOTOFF relocs being used with references
# to symbols in the .bss section since we cannot relocate them
# independently from the rest at run time. This can be achieved by
# ensuring that no private .bss symbols exist, as global symbols
# always have a GOT entry which is what we need.
# The .data section is already discarded by the linker script so no need
# to bother about it here.
check_for_bad_syms = \
bad_syms=$$($(CROSS_COMPILE)nm $@ | sed -n 's/^.\{8\} [bc] \(.*\)/\1/p') && \
[ -z "$$bad_syms" ] || \
( echo "following symbols must have non local/private scope:" >&2; \
echo "$$bad_syms" >&2; rm -f $@; false )
$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
$(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
$(call if_changed,ld)
@$(check_for_bad_syms)
$(obj)/piggy.$(suffix_y): $(obj)/../Image FORCE
$(call if_changed,$(suffix_y))
$(obj)/piggy.$(suffix_y).o: $(obj)/piggy.$(suffix_y) FORCE
CFLAGS_font.o := -Dstatic=
$(obj)/font.c: $(FONTC)
$(call cmd,shipped)
$(obj)/vmlinux.lds: $(obj)/vmlinux.lds.in arch/arm/boot/Makefile $(KCONFIG_CONFIG)
@sed "$(SEDFLAGS)" < $< > $@