diff options
Diffstat (limited to 'arch/s390/kernel/switch_cpu.S')
| -rw-r--r-- | arch/s390/kernel/switch_cpu.S | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/s390/kernel/switch_cpu.S b/arch/s390/kernel/switch_cpu.S new file mode 100644 index 000000000000..c05ee6c221d8 --- /dev/null +++ b/arch/s390/kernel/switch_cpu.S @@ -0,0 +1,59 @@ +/* + * 31-bit switch cpu code + * + * Copyright IBM Corp. 2009 + * + */ + +#include <asm/asm-offsets.h> +#include <asm/lowcore.h> +#include <asm/ptrace.h> + +# smp_switch_to_cpu switches to destination cpu and executes the passed function +# Parameter: %r2 - function to call +# %r3 - function parameter +# %r4 - stack poiner +# %r5 - current cpu +# %r6 - destination cpu + + .section .text + .align 4 + .globl smp_switch_to_cpu +smp_switch_to_cpu: + stm %r6,%r15,__SF_GPRS(%r15) + lr %r1,%r15 + ahi %r15,-STACK_FRAME_OVERHEAD + st %r1,__SF_BACKCHAIN(%r15) + basr %r13,0 +0: la %r1,.gprregs_addr-0b(%r13) + l %r1,0(%r1) + stm %r0,%r15,0(%r1) +1: sigp %r0,%r6,__SIGP_RESTART /* start destination CPU */ + brc 2,1b /* busy, try again */ +2: sigp %r0,%r5,__SIGP_STOP /* stop current CPU */ + brc 2,2b /* busy, try again */ +3: j 3b + + .globl smp_restart_cpu +smp_restart_cpu: + basr %r13,0 +0: la %r1,.gprregs_addr-0b(%r13) + l %r1,0(%r1) + lm %r0,%r15,0(%r1) +1: sigp %r0,%r5,__SIGP_SENSE /* Wait for calling CPU */ + brc 10,1b /* busy, accepted (status 0), running */ + tmll %r0,0x40 /* Test if calling CPU is stopped */ + jz 1b + ltr %r4,%r4 /* New stack ? */ + jz 1f + lr %r15,%r4 +1: basr %r14,%r2 + +.gprregs_addr: + .long .gprregs + + .section .data,"aw",@progbits +.gprregs: + .rept 16 + .long 0 + .endr |