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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-01-05 15:29:38 +0300
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-01-11 15:01:24 +0300
commit249c543b97e1409b13fb9539b2f880e58ddd87cf (patch)
tree956a0719238b56b8dffa3877d3fe3eb5c27df9f4 /arch/s390
parent0dab3e0e59ac3692e2f95cb37ba17d5dfb3d1e5f (diff)
downloadlinux-249c543b97e1409b13fb9539b2f880e58ddd87cf.tar.xz
s390/vdso: optimize getcpu system call
Add the CPU number to the per-cpu vdso data page and add the __kernel_getcpu function to the vdso object to retrieve the CPU number in user space. Suggested-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/vdso.h2
-rw-r--r--arch/s390/kernel/asm-offsets.c2
-rw-r--r--arch/s390/kernel/vdso.c9
-rw-r--r--arch/s390/kernel/vdso32/Makefile2
-rw-r--r--arch/s390/kernel/vdso32/getcpu.S43
-rw-r--r--arch/s390/kernel/vdso32/vdso32.lds.S1
-rw-r--r--arch/s390/kernel/vdso64/Makefile2
-rw-r--r--arch/s390/kernel/vdso64/getcpu.S42
-rw-r--r--arch/s390/kernel/vdso64/vdso64.lds.S1
9 files changed, 101 insertions, 3 deletions
diff --git a/arch/s390/include/asm/vdso.h b/arch/s390/include/asm/vdso.h
index f9b02d300d60..d0a2dbf2433d 100644
--- a/arch/s390/include/asm/vdso.h
+++ b/arch/s390/include/asm/vdso.h
@@ -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;
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index d5916ef9c619..53bbc9e8b281 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -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);
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 604f4a68b524..94495cac8be3 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -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,
diff --git a/arch/s390/kernel/vdso32/Makefile b/arch/s390/kernel/vdso32/Makefile
index ee8a18e50a25..f9c459586649 100644
--- a/arch/s390/kernel/vdso32/Makefile
+++ b/arch/s390/kernel/vdso32/Makefile
@@ -1,6 +1,6 @@
# 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
diff --git a/arch/s390/kernel/vdso32/getcpu.S b/arch/s390/kernel/vdso32/getcpu.S
new file mode 100644
index 000000000000..c1ed0b72030f
--- /dev/null
+++ b/arch/s390/kernel/vdso32/getcpu.S
@@ -0,0 +1,43 @@
+/*
+ * 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
diff --git a/arch/s390/kernel/vdso32/vdso32.lds.S b/arch/s390/kernel/vdso32/vdso32.lds.S
index a8c379fa1247..8f048c2d6d13 100644
--- a/arch/s390/kernel/vdso32/vdso32.lds.S
+++ b/arch/s390/kernel/vdso32/vdso32.lds.S
@@ -132,6 +132,7 @@ VERSION
__kernel_gettimeofday;
__kernel_clock_gettime;
__kernel_clock_getres;
+ __kernel_getcpu;
local: *;
};
diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile
index c4b03f9ed228..058659c1b8cf 100644
--- a/arch/s390/kernel/vdso64/Makefile
+++ b/arch/s390/kernel/vdso64/Makefile
@@ -1,6 +1,6 @@
# List of files in the vdso, has to be asm only for now
-obj-vdso64 = gettimeofday.o clock_getres.o clock_gettime.o note.o
+obj-vdso64 = gettimeofday.o clock_getres.o clock_gettime.o note.o getcpu.o
# Build rules
diff --git a/arch/s390/kernel/vdso64/getcpu.S b/arch/s390/kernel/vdso64/getcpu.S
new file mode 100644
index 000000000000..4cbe98291931
--- /dev/null
+++ b/arch/s390/kernel/vdso64/getcpu.S
@@ -0,0 +1,42 @@
+/*
+ * Userland implementation of getcpu() for 64 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
+ llilh %r4,0x0100
+ 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
+ ltgr %r2,%r2
+ jz 2f
+ st %r5,0(%r2)
+2: ltgr %r3,%r3
+ jz 3f
+ st %r4,0(%r3)
+3: lghi %r2,0
+ br %r14
+ .cfi_endproc
+ .size __kernel_getcpu,.-__kernel_getcpu
diff --git a/arch/s390/kernel/vdso64/vdso64.lds.S b/arch/s390/kernel/vdso64/vdso64.lds.S
index 9f5979d102a9..f35455d497fe 100644
--- a/arch/s390/kernel/vdso64/vdso64.lds.S
+++ b/arch/s390/kernel/vdso64/vdso64.lds.S
@@ -132,6 +132,7 @@ VERSION
__kernel_gettimeofday;
__kernel_clock_gettime;
__kernel_clock_getres;
+ __kernel_getcpu;
local: *;
};