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| author | Kyle McMartin <kyle@parisc-linux.org> | 2006-03-24 21:24:21 -0700 |
|---|---|---|
| committer | Kyle McMartin <kyle@hera.kernel.org> | 2006-03-30 17:48:54 +0000 |
| commit | 50a34dbd612925f2ec55b1781632835ef36b97d5 (patch) | |
| tree | 1624f33bdbdd367efb8fadebe80da7db275ea1e6 /arch | |
| parent | bc8846c522264d2522b0082321ec8c2051a4536f (diff) | |
| download | lwn-50a34dbd612925f2ec55b1781632835ef36b97d5.tar.gz lwn-50a34dbd612925f2ec55b1781632835ef36b97d5.zip | |
[PARISC] Add PREEMPT support
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/parisc/Kconfig | 6 | ||||
| -rw-r--r-- | arch/parisc/kernel/entry.S | 39 |
2 files changed, 37 insertions, 8 deletions
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 6b3c50964ca9..2fdf21989dc2 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -177,14 +177,10 @@ config ARCH_DISCONTIGMEM_DEFAULT def_bool y depends on ARCH_DISCONTIGMEM_ENABLE +source "kernel/Kconfig.preempt" source "kernel/Kconfig.hz" source "mm/Kconfig" -config PREEMPT - bool -# bool "Preemptible Kernel" - default n - config COMPAT def_bool y depends on 64BIT diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index 6d17c0a3431b..7c95d7663c29 100644 --- a/arch/parisc/kernel/entry.S +++ b/arch/parisc/kernel/entry.S @@ -1014,14 +1014,21 @@ intr_restore: nop nop +#ifndef CONFIG_PREEMPT +# define intr_do_preempt intr_restore +#endif /* !CONFIG_PREEMPT */ + .import schedule,code intr_do_resched: - /* Only do reschedule if we are returning to user space */ + /* Only call schedule on return to userspace. If we're returning + * to kernel space, we may schedule if CONFIG_PREEMPT, otherwise + * we jump back to intr_restore. + */ LDREG PT_IASQ0(%r16), %r20 - CMPIB= 0,%r20,intr_restore /* backward */ + CMPIB= 0, %r20, intr_do_preempt nop LDREG PT_IASQ1(%r16), %r20 - CMPIB= 0,%r20,intr_restore /* backward */ + CMPIB= 0, %r20, intr_do_preempt nop #ifdef CONFIG_64BIT @@ -1037,6 +1044,32 @@ intr_do_resched: #endif ldo R%intr_check_sig(%r2), %r2 + /* preempt the current task on returning to kernel + * mode from an interrupt, iff need_resched is set, + * and preempt_count is 0. otherwise, we continue on + * our merry way back to the current running task. + */ +#ifdef CONFIG_PREEMPT + .import preempt_schedule_irq,code +intr_do_preempt: + rsm PSW_SM_I, %r0 /* disable interrupts */ + + /* current_thread_info()->preempt_count */ + mfctl %cr30, %r1 + LDREG TI_PRE_COUNT(%r1), %r19 + CMPIB<> 0, %r19, intr_restore /* if preempt_count > 0 */ + nop /* prev insn branched backwards */ + + /* check if we interrupted a critical path */ + LDREG PT_PSW(%r16), %r20 + bb,<,n %r20, 31 - PSW_SM_I, intr_restore + nop + + BL preempt_schedule_irq, %r2 + nop + + b intr_restore /* ssm PSW_SM_I done by intr_restore */ +#endif /* CONFIG_PREEMPT */ .import do_signal,code intr_do_signal: |