#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/tick.h>
+#include <linux/prctl.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
* test NEED_RESCHED:
*/
smp_mb();
- local_irq_disable();
- if (!need_resched()) {
- ktime_t t0, t1;
- u64 t0n, t1n;
-
- t0 = ktime_get();
- t0n = ktime_to_ns(t0);
+ if (!need_resched())
safe_halt(); /* enables interrupts racelessly */
- local_irq_disable();
- t1 = ktime_get();
- t1n = ktime_to_ns(t1);
- sched_clock_idle_wakeup_event(t1n - t0n);
- }
- local_irq_enable();
+ else
+ local_irq_enable();
current_thread_info()->status |= TS_POLLING;
}
-/*
- * On SMP it's slightly faster (but much more power-consuming!)
- * to poll the ->need_resched flag instead of waiting for the
- * cross-CPU IPI to arrive. Use this option with caution.
- */
-static void poll_idle(void)
-{
- local_irq_enable();
- cpu_relax();
-}
-
#ifdef CONFIG_HOTPLUG_CPU
DECLARE_PER_CPU(int, cpu_state);
}
}
-static void do_nothing(void *unused)
-{
-}
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
- smp_mb();
- /* kick all the CPUs so that they exit out of pm_idle */
- smp_call_function(do_nothing, NULL, 0, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
-
-/*
- * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
- * which can obviate IPI to trigger checking of need_resched.
- * We execute MONITOR against need_resched and enter optimized wait state
- * through MWAIT. Whenever someone changes need_resched, we would be woken
- * up from MWAIT (without an IPI).
- *
- * New with Core Duo processors, MWAIT can take some hints based on CPU
- * capability.
- */
-void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
-{
- if (!need_resched()) {
- __monitor((void *)¤t_thread_info()->flags, 0, 0);
- smp_mb();
- if (!need_resched())
- __mwait(ax, cx);
- }
-}
-
-/* Default MONITOR/MWAIT with no hints, used for default C1 state */
-static void mwait_idle(void)
-{
- if (!need_resched()) {
- __monitor((void *)¤t_thread_info()->flags, 0, 0);
- smp_mb();
- if (!need_resched())
- __sti_mwait(0, 0);
- else
- local_irq_enable();
- } else {
- local_irq_enable();
- }
-}
-
-
-static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
-{
- if (force_mwait)
- return 1;
- /* Any C1 states supported? */
- return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0;
-}
-
-void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
-{
- static int selected;
-
- if (selected)
- return;
-#ifdef CONFIG_X86_SMP
- if (pm_idle == poll_idle && smp_num_siblings > 1) {
- printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
- " performance may degrade.\n");
- }
-#endif
- if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
- /*
- * Skip, if setup has overridden idle.
- * One CPU supports mwait => All CPUs supports mwait
- */
- if (!pm_idle) {
- printk(KERN_INFO "using mwait in idle threads.\n");
- pm_idle = mwait_idle;
- }
- }
- selected = 1;
-}
-
-static int __init idle_setup(char *str)
-{
- if (!strcmp(str, "poll")) {
- printk("using polling idle threads.\n");
- pm_idle = poll_idle;
- } else if (!strcmp(str, "mwait"))
- force_mwait = 1;
- else
- return -1;
-
- boot_option_idle_override = 1;
- return 0;
-}
-early_param("idle", idle_setup);
-
/* Prints also some state that isn't saved in the pt_regs */
void __show_regs(struct pt_regs * regs)
{
return err;
}
+void
+start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
+{
+ asm volatile("movl %0, %%fs; movl %0, %%es; movl %0, %%ds" :: "r"(0));
+ load_gs_index(0);
+ regs->ip = new_ip;
+ regs->sp = new_sp;
+ write_pda(oldrsp, new_sp);
+ regs->cs = __USER_CS;
+ regs->ss = __USER_DS;
+ regs->flags = 0x200;
+ set_fs(USER_DS);
+ /*
+ * Free the old FP and other extended state
+ */
+ free_thread_xstate(current);
+}
+EXPORT_SYMBOL_GPL(start_thread);
+
+static void hard_disable_TSC(void)
+{
+ write_cr4(read_cr4() | X86_CR4_TSD);
+}
+
+void disable_TSC(void)
+{
+ preempt_disable();
+ if (!test_and_set_thread_flag(TIF_NOTSC))
+ /*
+ * Must flip the CPU state synchronously with
+ * TIF_NOTSC in the current running context.
+ */
+ hard_disable_TSC();
+ preempt_enable();
+}
+
+static void hard_enable_TSC(void)
+{
+ write_cr4(read_cr4() & ~X86_CR4_TSD);
+}
+
+static void enable_TSC(void)
+{
+ preempt_disable();
+ if (test_and_clear_thread_flag(TIF_NOTSC))
+ /*
+ * Must flip the CPU state synchronously with
+ * TIF_NOTSC in the current running context.
+ */
+ hard_enable_TSC();
+ preempt_enable();
+}
+
+int get_tsc_mode(unsigned long adr)
+{
+ unsigned int val;
+
+ if (test_thread_flag(TIF_NOTSC))
+ val = PR_TSC_SIGSEGV;
+ else
+ val = PR_TSC_ENABLE;
+
+ return put_user(val, (unsigned int __user *)adr);
+}
+
+int set_tsc_mode(unsigned int val)
+{
+ if (val == PR_TSC_SIGSEGV)
+ disable_TSC();
+ else if (val == PR_TSC_ENABLE)
+ enable_TSC();
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
/*
* This special macro can be used to load a debugging register
*/
/* we clear debugctl to make sure DS
* is not in use when we change it */
debugctl = 0;
- wrmsrl(MSR_IA32_DEBUGCTLMSR, 0);
+ update_debugctlmsr(0);
wrmsrl(MSR_IA32_DS_AREA, next->ds_area_msr);
}
if (next->debugctlmsr != debugctl)
- wrmsrl(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr);
+ update_debugctlmsr(next->debugctlmsr);
if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
loaddebug(next, 0);
loaddebug(next, 7);
}
+ if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
+ test_tsk_thread_flag(next_p, TIF_NOTSC)) {
+ /* prev and next are different */
+ if (test_tsk_thread_flag(next_p, TIF_NOTSC))
+ hard_disable_TSC();
+ else
+ hard_enable_TSC();
+ }
+
if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
/*
* Copy the relevant range of the IO bitmap.
/* we're going to use this soon, after a few expensive things */
if (next_p->fpu_counter>5)
- prefetch(&next->i387.fxsave);
+ prefetch(next->xstate);
/*
* Reload esp0, LDT and the page table pointer:
/* 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
+ *
+ * tsk_used_math() checks prevent calling math_state_restore(),
+ * which can sleep in the case of !tsk_used_math()
*/
- if (next_p->fpu_counter>5)
+ if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
math_state_restore();
return prev_p;
}