diff options
Diffstat (limited to 'arch/s390/kernel/vdso64/getcpu.S')
| -rw-r--r-- | arch/s390/kernel/vdso64/getcpu.S | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/s390/kernel/vdso64/getcpu.S b/arch/s390/kernel/vdso64/getcpu.S new file mode 100644 index 000000000..2446e9dac --- /dev/null +++ b/arch/s390/kernel/vdso64/getcpu.S @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * 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> +#include <asm/dwarf.h> + + .text + .align 4 + .globl __kernel_getcpu + .type __kernel_getcpu,@function +__kernel_getcpu: + CFI_STARTPROC + la %r4,0 + sacf 256 + l %r5,__VDSO_CPU_NR(%r4) + l %r4,__VDSO_NODE_ID(%r4) + sacf 0 + 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 |