s390/vtimer: rework virtual timer interface
The current virtual timer interface is inherently per-cpu and hard to
use. The sole user of the interface is appldata which uses it to execute
a function after a specific amount of cputime has been used over all cpus.
Rework the virtual timer interface to hook into the cputime accounting.
This makes the interface independent from the CPU timer interrupts, and
makes the virtual timers global as opposed to per-cpu.
Overall the code is greatly simplified. The downside is that the accuracy
is not as good as the original implementation, but it is still good enough
for appldata.
Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 2c0eff4..870bad6 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -616,17 +616,13 @@
* Load idle PSW. The second "half" of this function is in cleanup_idle.
*/
ENTRY(psw_idle)
- st %r4,__SF_EMPTY(%r15)
+ st %r3,__SF_EMPTY(%r15)
basr %r1,0
la %r1,psw_idle_lpsw+4-.(%r1)
st %r1,__SF_EMPTY+4(%r15)
oi __SF_EMPTY+4(%r15),0x80
- la %r1,.Lvtimer_max-psw_idle_lpsw-4(%r1)
- stck __IDLE_ENTER(%r2)
- ltr %r5,%r5
- stpt __VQ_IDLE_ENTER(%r3)
- jz psw_idle_lpsw
- spt 0(%r1)
+ stck __CLOCK_IDLE_ENTER(%r2)
+ stpt __TIMER_IDLE_ENTER(%r2)
psw_idle_lpsw:
lpsw __SF_EMPTY(%r15)
br %r14
@@ -885,33 +881,28 @@
cleanup_idle:
# copy interrupt clock & cpu timer
- mvc __IDLE_EXIT(8,%r2),__LC_INT_CLOCK
- mvc __VQ_IDLE_EXIT(8,%r3),__LC_ASYNC_ENTER_TIMER
+ mvc __CLOCK_IDLE_EXIT(8,%r2),__LC_INT_CLOCK
+ mvc __TIMER_IDLE_EXIT(8,%r2),__LC_ASYNC_ENTER_TIMER
chi %r11,__LC_SAVE_AREA_ASYNC
je 0f
- mvc __IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
- mvc __VQ_IDLE_EXIT(8,%r3),__LC_MCCK_ENTER_TIMER
+ mvc __CLOCK_IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
+ mvc __TIMER_IDLE_EXIT(8,%r2),__LC_MCCK_ENTER_TIMER
0: # check if stck has been executed
cl %r9,BASED(cleanup_idle_insn)
jhe 1f
- mvc __IDLE_ENTER(8,%r2),__IDLE_EXIT(%r2)
- mvc __VQ_IDLE_ENTER(8,%r3),__VQ_IDLE_EXIT(%r3)
- j 2f
-1: # check if the cpu timer has been reprogrammed
- ltr %r5,%r5
- jz 2f
- spt __VQ_IDLE_ENTER(%r3)
-2: # account system time going idle
+ mvc __CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
+ mvc __TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r3)
+1: # account system time going idle
lm %r9,%r10,__LC_STEAL_TIMER
- ADD64 %r9,%r10,__IDLE_ENTER(%r2)
+ ADD64 %r9,%r10,__CLOCK_IDLE_ENTER(%r2)
SUB64 %r9,%r10,__LC_LAST_UPDATE_CLOCK
stm %r9,%r10,__LC_STEAL_TIMER
- mvc __LC_LAST_UPDATE_CLOCK(8),__IDLE_EXIT(%r2)
+ mvc __LC_LAST_UPDATE_CLOCK(8),__CLOCK_IDLE_EXIT(%r2)
lm %r9,%r10,__LC_SYSTEM_TIMER
ADD64 %r9,%r10,__LC_LAST_UPDATE_TIMER
- SUB64 %r9,%r10,__VQ_IDLE_ENTER(%r3)
+ SUB64 %r9,%r10,__TIMER_IDLE_ENTER(%r2)
stm %r9,%r10,__LC_SYSTEM_TIMER
- mvc __LC_LAST_UPDATE_TIMER(8),__VQ_IDLE_EXIT(%r3)
+ mvc __LC_LAST_UPDATE_TIMER(8),__TIMER_IDLE_EXIT(%r2)
# prepare return psw
n %r8,BASED(cleanup_idle_wait) # clear wait state bit
l %r9,24(%r11) # return from psw_idle