redonkable/alistair23-linux
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[S390] system call optimization.

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After the in-kernel system call has been remove the system call path
can be optimized. The problem state bit of the old psw is always set
between system_call and sysc_do_svc. SAVE_ALL_SVC uses this information
to avoid two instructions.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2007-07-10 11:24:18 +02:00
parent 3d62149f02
commit 987ad70a4d
2 changed files with 12 additions and 2 deletions
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7
arch/s390/kernel/entry.S
View file

@ -107,6 +107,11 @@ STACK_SIZE = 1 << STACK_SHIFT
l %r13,__LC_SVC_NEW_PSW+4 # load &system_call to %r13
.endm
.macro SAVE_ALL_SVC psworg,savearea
la %r12,\psworg
l %r15,__LC_KERNEL_STACK # problem state -> load ksp
.endm
.macro SAVE_ALL_SYNC psworg,savearea
la %r12,\psworg
tm \psworg+1,0x01 # test problem state bit
@ -218,7 +223,7 @@ system_call:
STORE_TIMER __LC_SYNC_ENTER_TIMER
sysc_saveall:
SAVE_ALL_BASE __LC_SAVE_AREA
SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
lh %r7,0x8a # get svc number from lowcore
#ifdef CONFIG_VIRT_CPU_ACCOUNTING

7
arch/s390/kernel/entry64.S
View file

@ -99,6 +99,11 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK | _TIF_NEED_RESCHED | \
larl %r13,system_call
.endm
.macro SAVE_ALL_SVC psworg,savearea
la %r12,\psworg
lg %r15,__LC_KERNEL_STACK # problem state -> load ksp
.endm
.macro SAVE_ALL_SYNC psworg,savearea
la %r12,\psworg
tm \psworg+1,0x01 # test problem state bit
@ -207,7 +212,7 @@ system_call:
STORE_TIMER __LC_SYNC_ENTER_TIMER
sysc_saveall:
SAVE_ALL_BASE __LC_SAVE_AREA
SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
llgh %r7,__LC_SVC_INT_CODE # get svc number from lowcore
#ifdef CONFIG_VIRT_CPU_ACCOUNTING