mirror of
https://github.com/torvalds/linux.git
synced 2024-12-14 15:13:52 +00:00
249c543b97
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>
44 lines
730 B
ArmAsm
44 lines
730 B
ArmAsm
/*
|
|
* 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
|