Date: Fri, 16 Mar 2007 20:52:28 GMT From: Oleksandr Tymoshenko <gonzo@FreeBSD.org> To: Perforce Change Reviews <perforce@FreeBSD.org> Subject: PERFORCE change 116002 for review Message-ID: <200703162052.l2GKqS9E017466@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=116002 Change 116002 by gonzo@gonzo_jeeves on 2007/03/16 20:51:48 o Clearly define places where to enable interrupts and where not to: - Interrupts must not be enabled in cpu_throw, so we does not set IE bit in status register in PCB. That's because we have sched_lock aquired right before fork_exit - so no interrupts. - Interrupts must be enabled on sched_lock unlocking in spinlock_exit routine. So we set IE bit and unmask IRQ5(timer) in md_saved_sr field. Affected files ... .. //depot/projects/mips2/src/sys/mips/mips/vm_machdep.c#13 edit Differences ... ==== //depot/projects/mips2/src/sys/mips/mips/vm_machdep.c#13 (text+ko) ==== @@ -100,6 +100,13 @@ */ td2->td_pcb->pcb_regs[PCB_REG_SP] = sp; + /* + * DO NOT ENABLE ANY INTERRUPTS HERE: + * after cpu_throw we're supposed to be with sched_lock locked + * and this means - no interrupts enabled. + */ + td2->td_pcb->pcb_regs[PCB_REG_SR] = 0; + /* * Return values for fork syscall for child: * v0 == 0 -> actual return value @@ -110,9 +117,13 @@ td2->td_frame->tf_regs[TF_V1] = 1; td2->td_frame->tf_regs[TF_A3] = 0; - /* Setup to release sched_lock in fork_exit(). */ + /* + * Setup to release sched_lock in fork_exit(). By unlocking + * sched_lock we'll enable interrupts and unmask timer + * interrupt (HW IRQ5) + */ td2->td_md.md_spinlock_count = 1; - td2->td_md.md_saved_sr = td2->td_pcb->pcb_regs[PCB_REG_SR]; + td2->td_md.md_saved_sr = MIPS_SR_INT_IE | (((1 << 5) << 8) << 2); /* * Now cpu_switch() can schedule the new process. @@ -215,11 +226,6 @@ + (KSTACK_PAGES - 1) * PAGE_SIZE) - 1; td->td_frame = (struct trapframe *)td->td_pcb - 1; - /* - * Enable interrupts and unmask timer interrupt (HW IRQ5) - */ - td->td_pcb->pcb_regs[PCB_REG_SR] = MIPS_SR_INT_IE | - (((1 << 5) << 8) << 2); /* Stack pointer. Should be double-word aligned due to EABI */ td->td_pcb->pcb_regs[PCB_REG_SP] =
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