powerpc/32: Add VDSO version of getcpu on non SMP (902137ba) · Commits · 戴 / test

Commit ("powerpc: Add VDSO version of getcpu") added getcpu() for PPC64 only, by making use of a user readable general purpose SPR. PPC32 doesn't have any such SPR. For non SMP, just return CPU id 0 from the VDSO directly. PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0. Before the patch, vdsotest reported: getcpu: syscall: 1572 nsec/call getcpu: libc: 1787 nsec/call getcpu: vdso: not tested Now, vdsotest reports: getcpu: syscall: 1582 nsec/call getcpu: libc: 502 nsec/call getcpu: vdso: 187 nsec/call Signed-off-by:

Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/eaac4b6494ecff1811220fccc895bf282aab884a.1575273217.git.christophe.leroy@c-s.fr

arch/powerpc/kernel/vdso32/Makefile

+1 −3

Original line number	Diff line number	Diff line
		@@ -2,9 +2,7 @@

		# 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)
		obj-vdso32 = sigtramp.o gettimeofday.o datapage.o cacheflush.o note.o getcpu.o

		# Build rules

arch/powerpc/kernel/vdso32/getcpu.S

+17 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@
		* int __kernel_getcpu(unsigned cpu, unsigned node);
		*
		*/
		#if defined(CONFIG_PPC64)
		V_FUNCTION_BEGIN(__kernel_getcpu)
		.cfi_startproc
		mfspr r5,SPRN_SPRG_VDSO_READ
		@@ -31,3 +32,19 @@ V_FUNCTION_BEGIN(__kernel_getcpu)
		blr
		.cfi_endproc
		V_FUNCTION_END(__kernel_getcpu)
		#elif !defined(CONFIG_SMP)
		V_FUNCTION_BEGIN(__kernel_getcpu)
		.cfi_startproc
		cmpwi cr0, r3, 0
		cmpwi cr1, r4, 0
		li r5, 0
		beq cr0, 1f
		stw r5, 0(r3)
		1: li r3, 0 /* always success */
		crclr cr0*4+so
		beqlr cr1
		stw r5, 0(r4)
		blr
		.cfi_endproc
		V_FUNCTION_END(__kernel_getcpu)
		#endif

arch/powerpc/kernel/vdso32/vdso32.lds.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -155,7 +155,7 @@ VERSION
		__kernel_sync_dicache_p5;
		__kernel_sigtramp32;
		__kernel_sigtramp_rt32;
		#ifdef CONFIG_PPC64
		#if defined(CONFIG_PPC64) \|\| !defined(CONFIG_SMP)
		__kernel_getcpu;
		#endif

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