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linux-next/arch/powerpc/kernel/vdso32/Makefile
Anton Blanchard 18ad51dd34 powerpc: Add VDSO version of getcpu
We have a request for a fast method of getting CPU and NUMA node IDs
from userspace. This patch implements a getcpu VDSO function,
similar to x86.

Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be
modified by a KVM guest, so we save the SPRG3 value in the paca and
restore it when transitioning from the guest to the host.

I have a glibc patch that implements sched_getcpu on top of this.
Testing on a POWER7:

baseline: 538 cycles
vdso:      30 cycles

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-11 14:18:40 +10:00

59 lines
1.5 KiB
Makefile

# List of files in the vdso, has to be asm only for now
obj-vdso32-$(CONFIG_PPC64) = getcpu.o
obj-vdso32 = sigtramp.o gettimeofday.o datapage.o cacheflush.o note.o \
$(obj-vdso32-y)
# Build rules
ifeq ($(CONFIG_PPC32),y)
CROSS32CC := $(CC)
endif
targets := $(obj-vdso32) vdso32.so vdso32.so.dbg
obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
GCOV_PROFILE := n
ccflags-y := -shared -fno-common -fno-builtin
ccflags-y += -nostdlib -Wl,-soname=linux-vdso32.so.1 \
$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
asflags-y := -D__VDSO32__ -s
obj-y += vdso32_wrapper.o
extra-y += vdso32.lds
CPPFLAGS_vdso32.lds += -P -C -Upowerpc
# Force dependency (incbin is bad)
$(obj)/vdso32_wrapper.o : $(obj)/vdso32.so
# link rule for the .so file, .lds has to be first
$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32)
$(call if_changed,vdso32ld)
# strip rule for the .so file
$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg FORCE
$(call if_changed,objcopy)
# assembly rules for the .S files
$(obj-vdso32): %.o: %.S
$(call if_changed_dep,vdso32as)
# actual build commands
quiet_cmd_vdso32ld = VDSO32L $@
cmd_vdso32ld = $(CROSS32CC) $(c_flags) -Wl,-T $^ -o $@
quiet_cmd_vdso32as = VDSO32A $@
cmd_vdso32as = $(CROSS32CC) $(a_flags) -c -o $@ $<
# install commands for the unstripped file
quiet_cmd_vdso_install = INSTALL $@
cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
vdso32.so: $(obj)/vdso32.so.dbg
@mkdir -p $(MODLIB)/vdso
$(call cmd,vdso_install)
vdso_install: vdso32.so