x86 vDSO: vdso32 build
This builds the 32-bit vDSO images in the arch/x86/vdso subdirectory. Nothing uses the images yet, but this paves the way for consolidating the vDSO build logic all in one place. The new images use a linker script sharing the layout parts from vdso-layout.lds.S with the 64-bit vDSO. A new vdso32-syms.lds is generated in the style of vdso-syms.lds. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath
Ingo Molnar
parent
0c2f51a7d2
commit
0249c9c1e7
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@ -1,7 +1,15 @@
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#
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# x86-64 vDSO.
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# Building vDSO images for x86.
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#
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VDSO64-$(CONFIG_X86_64) := y
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VDSO32-$(CONFIG_X86_32) := y
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VDSO32-$(CONFIG_COMPAT) := y
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vdso-install-$(VDSO64-y) += vdso.so
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vdso-install-$(VDSO32-y) += $(vdso32-y:=.so)
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# files to link into the vdso
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vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vvar.o
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@ -57,10 +65,74 @@ quiet_cmd_vdsosym = VDSOSYM $@
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$(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
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$(call if_changed,vdsosym)
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#
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# Build multiple 32-bit vDSO images to choose from at boot time.
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#
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vdso32.so-$(CONFIG_X86_32) += int80
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vdso32.so-$(VDSO32-y) += sysenter
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CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
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VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -Wl,-soname=linux-gate.so.1
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# This makes sure the $(obj) subdirectory exists even though vdso32/
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# is not a kbuild sub-make subdirectory.
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override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
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targets += vdso32/vdso32.lds
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targets += $(vdso32.so-y:%=vdso32-%.so.dbg) $(vdso32.so-y:%=vdso32-%.so)
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targets += vdso32/note.o $(vdso32.so-y:%=vdso32/%.o)
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extra-y += $(vdso32.so-y:%=vdso32-%.so)
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KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
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$(vdso32.so-y:%=$(obj)/vdso32-%.so.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
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$(vdso32.so-y:%=$(obj)/vdso32-%.so.dbg): asflags-$(CONFIG_X86_64) += -m32
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$(vdso32.so-y:%=$(obj)/vdso32-%.so.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
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$(obj)/vdso32/vdso32.lds \
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$(obj)/vdso32/note.o \
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$(obj)/vdso32/%.o
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$(call if_changed,vdso)
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# Make vdso32-*-syms.lds from each image, and then make sure they match.
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# The only difference should be that some do not define VDSO32_SYSENTER_RETURN.
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targets += vdso32-syms.lds $(vdso32.so-y:%=vdso32-%-syms.lds)
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quiet_cmd_vdso32sym = VDSOSYM $@
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define cmd_vdso32sym
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if LC_ALL=C sort -u $(filter-out FORCE,$^) > $(@D)/.tmp_$(@F) && \
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$(foreach H,$(filter-out FORCE,$^),\
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if grep -q VDSO32_SYSENTER_RETURN $H; \
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then diff -u $(@D)/.tmp_$(@F) $H; \
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else sed /VDSO32_SYSENTER_RETURN/d $(@D)/.tmp_$(@F) | \
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diff -u - $H; fi &&) : ;\
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then mv -f $(@D)/.tmp_$(@F) $@; \
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else rm -f $(@D)/.tmp_$(@F); exit 1; \
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fi
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endef
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$(obj)/vdso32-syms.lds: $(vdso32.so-y:%=$(obj)/vdso32-%-syms.lds) FORCE
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$(call if_changed,vdso32sym)
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#
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# The DSO images are built using a special linker script.
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#
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quiet_cmd_vdso = VDSO $@
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cmd_vdso = $(CC) -nostdlib -o $@ \
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$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
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-Wl,-T,$(filter %.lds,$^) $(filter %.o,$^)
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VDSO_LDFLAGS = -fPIC -shared $(call ld-option, -Wl$(comma)--hash-style=sysv)
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#
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# Install the unstripped copy of vdso*.so listed in $(vdso-install-y).
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#
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quiet_cmd_vdso_install = INSTALL $@
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cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
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vdso.so:
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$(vdso-install-y): %.so: $(obj)/%.so.dbg FORCE
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@mkdir -p $(MODLIB)/vdso
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$(call cmd,vdso_install)
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vdso_install: vdso.so
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PHONY += vdso_install $(vdso-install-y)
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vdso_install: $(vdso-install-y)
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@ -0,0 +1,37 @@
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/*
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* Linker script for 32-bit vDSO.
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* We #include the file to define the layout details.
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* Here we only choose the prelinked virtual address.
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*
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* This file defines the version script giving the user-exported symbols in
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* the DSO. We can define local symbols here called VDSO* to make their
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* values visible using the asm-x86/vdso.h macros from the kernel proper.
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*/
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#define VDSO_PRELINK 0
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#include "../vdso-layout.lds.S"
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/* The ELF entry point can be used to set the AT_SYSINFO value. */
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ENTRY(__kernel_vsyscall);
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/*
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* This controls what userland symbols we export from the vDSO.
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*/
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VERSION
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{
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LINUX_2.5 {
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global:
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__kernel_vsyscall;
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__kernel_sigreturn;
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__kernel_rt_sigreturn;
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local: *;
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};
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}
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/*
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* Symbols we define here called VDSO* get their values into vdso32-syms.h.
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*/
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VDSO32_PRELINK = VDSO_PRELINK;
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VDSO32_vsyscall = __kernel_vsyscall;
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VDSO32_sigreturn = __kernel_sigreturn;
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VDSO32_rt_sigreturn = __kernel_rt_sigreturn;
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