s390/vdso: optimize getcpu system call (249c543b) · Commits · 戴 / test

arch/s390/include/asm/vdso.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,8 @@ struct vdso_data {
		struct vdso_per_cpu_data {
		__u64 ectg_timer_base;
		__u64 ectg_user_time;
		__u32 cpu_nr;
		__u32 node_id;
		};

		extern struct vdso_data *vdso_data;

+2 −0

Original line number	Diff line number	Diff line
		@@ -80,6 +80,8 @@ int main(void)
		OFFSET(__VDSO_TK_SHIFT, vdso_data, tk_shift);
		OFFSET(__VDSO_ECTG_BASE, vdso_per_cpu_data, ectg_timer_base);
		OFFSET(__VDSO_ECTG_USER, vdso_per_cpu_data, ectg_user_time);
		OFFSET(__VDSO_CPU_NR, vdso_per_cpu_data, cpu_nr);
		OFFSET(__VDSO_NODE_ID, vdso_per_cpu_data, node_id);
		BLANK();
		/* constants used by the vdso */
		DEFINE(__CLOCK_REALTIME, CLOCK_REALTIME);

+8 −1

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		@@ -80,7 +80,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
		/*
		* Setup vdso data page.
		*/
		static void vdso_init_data(struct vdso_data *vd)
		static void __init vdso_init_data(struct vdso_data *vd)
		{
		vd->ectg_available = test_facility(31);
		}
		@@ -93,6 +93,7 @@ static void vdso_init_data(struct vdso_data *vd)
		int vdso_alloc_per_cpu(struct lowcore *lowcore)
		{
		unsigned long segment_table, page_table, page_frame;
		struct vdso_per_cpu_data *vd;
		u32 psal, aste;
		int i;

		@@ -107,6 +108,12 @@ int vdso_alloc_per_cpu(struct lowcore *lowcore)
		if (!segment_table \|\| !page_table \|\| !page_frame)
		goto out;

		/* Initialize per-cpu vdso data page */
		vd = (struct vdso_per_cpu_data *) page_frame;
		vd->cpu_nr = lowcore->cpu_nr;
		vd->node_id = cpu_to_node(vd->cpu_nr);

		/* Set up access register mode page table */
		clear_table((unsigned long *) segment_table, _SEGMENT_ENTRY_EMPTY,
		PAGE_SIZE << SEGMENT_ORDER);
		clear_table((unsigned long *) page_table, _PAGE_INVALID,

+1 −1

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		# List of files in the vdso, has to be asm only for now

		obj-vdso32 = gettimeofday.o clock_getres.o clock_gettime.o note.o
		obj-vdso32 = gettimeofday.o clock_getres.o clock_gettime.o note.o getcpu.o

		# Build rules

0 → 100644

+43 −0

Original line number	Diff line number	Diff line
		/*
		* Userland implementation of getcpu() for 32 bits processes in a
		* s390 kernel for use in the vDSO
		*
		* Copyright IBM Corp. 2016
		* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
		*/
		#include <asm/vdso.h>
		#include <asm/asm-offsets.h>

		.text
		.align 4
		.globl __kernel_getcpu
		.type __kernel_getcpu,@function
		__kernel_getcpu:
		.cfi_startproc
		ear %r1,%a4
		lhi %r4,1
		sll %r4,24
		sar %a4,%r4
		la %r4,0
		epsw %r0,0
		sacf 512
		l %r5,__VDSO_CPU_NR(%r4)
		l %r4,__VDSO_NODE_ID(%r4)
		tml %r0,0x4000
		jo 1f
		tml %r0,0x8000
		jno 0f
		sacf 256
		j 1f
		0: sacf 0
		1: sar %a4,%r1
		ltr %r2,%r2
		jz 2f
		st %r5,0(%r2)
		2: ltr %r3,%r3
		jz 3f
		st %r4,0(%r3)
		3: lhi %r2,0
		br %r14
		.cfi_endproc
		.size __kernel_getcpu,.-__kernel_getcpu