diff options
| author |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-12-03 14:57:18 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-12-16 14:37:45 +0100 |
| commit | c63badebfebacdba827ab1cc1d420fc81bd8d818 (patch) | |
| tree | 6bc09659dd889c7d85b09e7d1283cfecf08859a8 /arch | |
| parent | s390/ptrace: simplify enable/disable single step (diff) | |
| download | linux-dev-c63badebfebacdba827ab1cc1d420fc81bd8d818.tar.xz linux-dev-c63badebfebacdba827ab1cc1d420fc81bd8d818.zip | |
s390: optimize control register update
It is less expensive to update control registers 0 and 2 with two
individual stctg/lctlg instructions as with a single one that spans
control register 0, 1 and 2.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/ptrace.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index c369a26d1d56..f6be6087a0e9 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -56,25 +56,26 @@ void update_cr_regs(struct task_struct *task) #ifdef CONFIG_64BIT /* Take care of the enable/disable of transactional execution. */ if (MACHINE_HAS_TE) { - unsigned long cr[3], cr_new[3]; + unsigned long cr, cr_new; - __ctl_store(cr, 0, 2); - cr_new[1] = cr[1]; + __ctl_store(cr, 0, 0); /* Set or clear transaction execution TXC bit 8. */ + cr_new = cr | (1UL << 55); if (task->thread.per_flags & PER_FLAG_NO_TE) - cr_new[0] = cr[0] & ~(1UL << 55); - else - cr_new[0] = cr[0] | (1UL << 55); + cr_new &= ~(1UL << 55); + if (cr_new != cr) + __ctl_load(cr, 0, 0); /* Set or clear transaction execution TDC bits 62 and 63. */ - cr_new[2] = cr[2] & ~3UL; + __ctl_store(cr, 2, 2); + cr_new = cr & ~3UL; if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) { if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND) - cr_new[2] |= 1UL; + cr_new |= 1UL; else - cr_new[2] |= 2UL; + cr_new |= 2UL; } - if (memcmp(&cr_new, &cr, sizeof(cr))) - __ctl_load(cr_new, 0, 2); + if (cr_new != cr) + __ctl_load(cr_new, 2, 2); } #endif /* Copy user specified PER registers */ |