a0f97e06a4
The variable CFLAGS is a wellknown variable and the usage by kbuild may result in unexpected behaviour. On top of that several people over time has asked for a way to pass in additional flags to gcc. This patch replace use of CFLAGS with KBUILD_CFLAGS all over the tree and enabling one to use: make CFLAGS=... to specify additional gcc commandline options. One usecase is when trying to find gcc bugs but other use cases has been requested too. Patch was tested on following architectures: alpha, arm, i386, x86_64, mips, sparc, sparc64, ia64, m68k Test was simple to do a defconfig build, apply the patch and check that nothing got rebuild. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
50 lines
1.5 KiB
Makefile
50 lines
1.5 KiB
Makefile
#
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# x86-64 vDSO.
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#
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# files to link into the vdso
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# vdso-start.o has to be first
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vobjs-y := vdso-start.o vdso-note.o vclock_gettime.o vgetcpu.o vvar.o
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# files to link into kernel
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obj-y := vma.o vdso.o vdso-syms.o
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vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
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$(obj)/vdso.o: $(obj)/vdso.so
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targets += vdso.so vdso.lds $(vobjs-y) vdso-syms.o
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# The DSO images are built using a special linker script.
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quiet_cmd_syscall = SYSCALL $@
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cmd_syscall = $(CC) -m elf_x86_64 -nostdlib $(SYSCFLAGS_$(@F)) \
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-Wl,-T,$(filter-out FORCE,$^) -o $@
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export CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
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vdso-flags = -fPIC -shared -Wl,-soname=linux-vdso.so.1 \
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$(call ld-option, -Wl$(comma)--hash-style=sysv) \
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-Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
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SYSCFLAGS_vdso.so = $(vdso-flags)
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$(obj)/vdso.o: $(src)/vdso.S $(obj)/vdso.so
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$(obj)/vdso.so: $(src)/vdso.lds $(vobjs) FORCE
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$(call if_changed,syscall)
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CFL := $(PROFILING) -mcmodel=small -fPIC -g0 -O2 -fasynchronous-unwind-tables -m64
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$(obj)/vclock_gettime.o: KBUILD_CFLAGS = $(CFL)
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$(obj)/vgetcpu.o: KBUILD_CFLAGS = $(CFL)
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# We also create a special relocatable object that should mirror the symbol
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# table and layout of the linked DSO. With ld -R we can then refer to
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# these symbols in the kernel code rather than hand-coded addresses.
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extra-y += vdso-syms.o
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$(obj)/built-in.o: $(obj)/vdso-syms.o
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$(obj)/built-in.o: ld_flags += -R $(obj)/vdso-syms.o
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SYSCFLAGS_vdso-syms.o = -r -d
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$(obj)/vdso-syms.o: $(src)/vdso.lds $(vobjs) FORCE
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$(call if_changed,syscall)
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