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s390: system call path micro optimization

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Add a pointer to the system call table to the thread_info structure.
The TIF_31BIT bit is set or cleared by SET_PERSONALITY exactly once
for the lifetime of a process. With the pointer to the correct system
call table in thread_info the system call code in entry64.S path can
drop the check for TIF_31BIT which saves a couple of instructions.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2013-04-24 12:58:39 +02:00
parent dc7ee00d47
commit 616498813b
6 changed files with 24 additions and 13 deletions
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1
arch/s390/kernel/asm-offsets.c
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@@ -35,6 +35,7 @@ int main(void)
DEFINE(__TI_task, offsetof(struct thread_info, task));
DEFINE(__TI_domain, offsetof(struct thread_info, exec_domain));
DEFINE(__TI_flags, offsetof(struct thread_info, flags));
DEFINE(__TI_sysc_table, offsetof(struct thread_info, sys_call_table));
DEFINE(__TI_cpu, offsetof(struct thread_info, cpu));
DEFINE(__TI_precount, offsetof(struct thread_info, preempt_count));
DEFINE(__TI_user_timer, offsetof(struct thread_info, user_timer));