#include <linux/ptrace.h>
#include <linux/random.h>
#include <linux/personality.h>
+#include <linux/tick.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/cpu.h>
+#include <asm/pda.h>
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
*/
void default_idle(void)
{
- local_irq_enable();
-
if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
current_thread_info()->status &= ~TS_POLLING;
- smp_mb__after_clear_bit();
- while (!need_resched()) {
- local_irq_disable();
- if (!need_resched())
- safe_halt();
- else
- local_irq_enable();
- }
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+
+ local_irq_disable();
+ if (!need_resched())
+ safe_halt(); /* enables interrupts racelessly */
+ else
+ local_irq_enable();
current_thread_info()->status |= TS_POLLING;
} else {
- while (!need_resched())
- cpu_relax();
+ /* loop is done by the caller */
+ cpu_relax();
}
}
#ifdef CONFIG_APM_MODULE
*/
static void poll_idle (void)
{
- local_irq_enable();
-
- asm volatile(
- "2:"
- "testl %0, %1;"
- "rep; nop;"
- "je 2b;"
- : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
+ cpu_relax();
}
#ifdef CONFIG_HOTPLUG_CPU
/* endless idle loop with no priority at all */
while (1) {
+ tick_nohz_stop_sched_tick();
while (!need_resched()) {
void (*idle)(void);
__get_cpu_var(irq_stat).idle_timestamp = jiffies;
idle();
}
+ tick_nohz_restart_sched_tick();
preempt_enable_no_resched();
schedule();
preempt_disable();
static void mwait_idle(void)
{
local_irq_enable();
- while (!need_resched())
- mwait_idle_with_hints(0, 0);
+ mwait_idle_with_hints(0, 0);
}
void __devinit select_idle_routine(const struct cpuinfo_x86 *c)
regs->eax,regs->ebx,regs->ecx,regs->edx);
printk("ESI: %08lx EDI: %08lx EBP: %08lx",
regs->esi, regs->edi, regs->ebp);
- printk(" DS: %04x ES: %04x\n",
- 0xffff & regs->xds,0xffff & regs->xes);
+ printk(" DS: %04x ES: %04x FS: %04x\n",
+ 0xffff & regs->xds,0xffff & regs->xes, 0xffff & regs->xfs);
cr0 = read_cr0();
cr2 = read_cr2();
regs.xds = __USER_DS;
regs.xes = __USER_DS;
+ regs.xfs = __KERNEL_PDA;
regs.orig_eax = -1;
regs.eip = (unsigned long) kernel_thread_helper;
regs.xcs = __KERNEL_CS | get_kernel_rpl();
p->thread.eip = (unsigned long) ret_from_fork;
- savesegment(fs,p->thread.fs);
savesegment(gs,p->thread.gs);
tsk = current;
dump->regs.eax = regs->eax;
dump->regs.ds = regs->xds;
dump->regs.es = regs->xes;
- savesegment(fs,dump->regs.fs);
+ dump->regs.fs = regs->xfs;
savesegment(gs,dump->regs.gs);
dump->regs.orig_eax = regs->orig_eax;
dump->regs.eip = regs->eip;
__unlazy_fpu(prev_p);
+
+ /* we're going to use this soon, after a few expensive things */
+ if (next_p->fpu_counter > 5)
+ prefetch(&next->i387.fxsave);
+
/*
* Reload esp0.
*/
load_esp0(tss, next);
/*
- * Save away %fs and %gs. No need to save %es and %ds, as
- * those are always kernel segments while inside the kernel.
- * Doing this before setting the new TLS descriptors avoids
- * the situation where we temporarily have non-reloadable
- * segments in %fs and %gs. This could be an issue if the
- * NMI handler ever used %fs or %gs (it does not today), or
- * if the kernel is running inside of a hypervisor layer.
+ * Save away %gs. No need to save %fs, as it was saved on the
+ * stack on entry. No need to save %es and %ds, as those are
+ * always kernel segments while inside the kernel. Doing this
+ * before setting the new TLS descriptors avoids the situation
+ * where we temporarily have non-reloadable segments in %fs
+ * and %gs. This could be an issue if the NMI handler ever
+ * used %fs or %gs (it does not today), or if the kernel is
+ * running inside of a hypervisor layer.
*/
- savesegment(fs, prev->fs);
savesegment(gs, prev->gs);
/*
load_TLS(next, cpu);
/*
- * Restore %fs and %gs if needed.
- *
- * Glibc normally makes %fs be zero, and %gs is one of
- * the TLS segments.
- */
- if (unlikely(prev->fs | next->fs))
- loadsegment(fs, next->fs);
-
- if (prev->gs | next->gs)
- loadsegment(gs, next->gs);
-
- /*
- * Restore IOPL if needed.
+ * Restore IOPL if needed. In normal use, the flags restore
+ * in the switch assembly will handle this. But if the kernel
+ * is running virtualized at a non-zero CPL, the popf will
+ * not restore flags, so it must be done in a separate step.
*/
- if (unlikely(prev->iopl != next->iopl))
+ if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl))
set_iopl_mask(next->iopl);
/*
disable_tsc(prev_p, next_p);
+ /*
+ * Leave lazy mode, flushing any hypercalls made here.
+ * This must be done before restoring TLS segments so
+ * the GDT and LDT are properly updated, and must be
+ * done before math_state_restore, so the TS bit is up
+ * to date.
+ */
+ arch_leave_lazy_cpu_mode();
+
+ /* If the task has used fpu the last 5 timeslices, just do a full
+ * restore of the math state immediately to avoid the trap; the
+ * chances of needing FPU soon are obviously high now
+ */
+ if (next_p->fpu_counter > 5)
+ math_state_restore();
+
+ /*
+ * Restore %gs if needed (which is common)
+ */
+ if (prev->gs | next->gs)
+ loadsegment(gs, next->gs);
+
+ write_pda(pcurrent, next_p);
+
return prev_p;
}
git.openpandora.org / pandora-kernel.git / blobdiff