diff options
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r-- | arch/x86/kernel/process_64.c | 146 |
1 files changed, 69 insertions, 77 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index e2319f39988..e8a8e1b9981 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -56,15 +56,6 @@ asmlinkage extern void ret_from_fork(void); unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED; -unsigned long boot_option_idle_override = 0; -EXPORT_SYMBOL(boot_option_idle_override); - -/* - * Powermanagement idle function, if any.. - */ -void (*pm_idle)(void); -EXPORT_SYMBOL(pm_idle); - static ATOMIC_NOTIFIER_HEAD(idle_notifier); void idle_notifier_register(struct notifier_block *n) @@ -94,25 +85,6 @@ void exit_idle(void) __exit_idle(); } -/* - * We use this if we don't have any better - * idle routine.. - */ -void default_idle(void) -{ - current_thread_info()->status &= ~TS_POLLING; - /* - * TS_POLLING-cleared state must be visible before we - * test NEED_RESCHED: - */ - smp_mb(); - if (!need_resched()) - safe_halt(); /* enables interrupts racelessly */ - else - local_irq_enable(); - current_thread_info()->status |= TS_POLLING; -} - #ifdef CONFIG_HOTPLUG_CPU DECLARE_PER_CPU(int, cpu_state); @@ -150,12 +122,9 @@ void cpu_idle(void) while (1) { tick_nohz_stop_sched_tick(); while (!need_resched()) { - void (*idle)(void); rmb(); - idle = pm_idle; - if (!idle) - idle = default_idle; + if (cpu_is_offline(smp_processor_id())) play_dead(); /* @@ -165,7 +134,10 @@ void cpu_idle(void) */ local_irq_disable(); enter_idle(); - idle(); + /* Don't trace irqs off for idle */ + stop_critical_timings(); + pm_idle(); + start_critical_timings(); /* In many cases the interrupt that ended idle has already called exit_idle. But some idle loops can be woken up without interrupt. */ @@ -294,6 +266,7 @@ void flush_thread(void) /* * Forget coprocessor state.. */ + tsk->fpu_counter = 0; clear_fpu(tsk); clear_used_math(); } @@ -365,10 +338,10 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp, p->thread.fs = me->thread.fs; p->thread.gs = me->thread.gs; - asm("mov %%gs,%0" : "=m" (p->thread.gsindex)); - asm("mov %%fs,%0" : "=m" (p->thread.fsindex)); - asm("mov %%es,%0" : "=m" (p->thread.es)); - asm("mov %%ds,%0" : "=m" (p->thread.ds)); + savesegment(gs, p->thread.gsindex); + savesegment(fs, p->thread.fsindex); + savesegment(es, p->thread.es); + savesegment(ds, p->thread.ds); if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); @@ -407,7 +380,9 @@ out: 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)); + loadsegment(fs, 0); + loadsegment(es, 0); + loadsegment(ds, 0); load_gs_index(0); regs->ip = new_ip; regs->sp = new_sp; @@ -562,10 +537,11 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) { - struct thread_struct *prev = &prev_p->thread, - *next = &next_p->thread; + struct thread_struct *prev = &prev_p->thread; + struct thread_struct *next = &next_p->thread; int cpu = smp_processor_id(); struct tss_struct *tss = &per_cpu(init_tss, cpu); + unsigned fsindex, gsindex; /* we're going to use this soon, after a few expensive things */ if (next_p->fpu_counter>5) @@ -580,52 +556,64 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) * Switch DS and ES. * This won't pick up thread selector changes, but I guess that is ok. */ - asm volatile("mov %%es,%0" : "=m" (prev->es)); + savesegment(es, prev->es); if (unlikely(next->es | prev->es)) loadsegment(es, next->es); - - asm volatile ("mov %%ds,%0" : "=m" (prev->ds)); + + savesegment(ds, prev->ds); if (unlikely(next->ds | prev->ds)) loadsegment(ds, next->ds); + + /* We must save %fs and %gs before load_TLS() because + * %fs and %gs may be cleared by load_TLS(). + * + * (e.g. xen_load_tls()) + */ + savesegment(fs, fsindex); + savesegment(gs, gsindex); + load_TLS(next, cpu); + /* + * 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(); + /* * Switch FS and GS. + * + * Segment register != 0 always requires a reload. Also + * reload when it has changed. When prev process used 64bit + * base always reload to avoid an information leak. */ - { - unsigned fsindex; - asm volatile("movl %%fs,%0" : "=r" (fsindex)); - /* segment register != 0 always requires a reload. - also reload when it has changed. - when prev process used 64bit base always reload - to avoid an information leak. */ - if (unlikely(fsindex | next->fsindex | prev->fs)) { - loadsegment(fs, next->fsindex); - /* check if the user used a selector != 0 - * if yes clear 64bit base, since overloaded base - * is always mapped to the Null selector - */ - if (fsindex) + if (unlikely(fsindex | next->fsindex | prev->fs)) { + loadsegment(fs, next->fsindex); + /* + * Check if the user used a selector != 0; if yes + * clear 64bit base, since overloaded base is always + * mapped to the Null selector + */ + if (fsindex) prev->fs = 0; - } - /* when next process has a 64bit base use it */ - if (next->fs) - wrmsrl(MSR_FS_BASE, next->fs); - prev->fsindex = fsindex; } - { - unsigned gsindex; - asm volatile("movl %%gs,%0" : "=r" (gsindex)); - if (unlikely(gsindex | next->gsindex | prev->gs)) { - load_gs_index(next->gsindex); - if (gsindex) + /* when next process has a 64bit base use it */ + if (next->fs) + wrmsrl(MSR_FS_BASE, next->fs); + prev->fsindex = fsindex; + + if (unlikely(gsindex | next->gsindex | prev->gs)) { + load_gs_index(next->gsindex); + if (gsindex) prev->gs = 0; - } - if (next->gs) - wrmsrl(MSR_KERNEL_GS_BASE, next->gs); - prev->gsindex = gsindex; } + if (next->gs) + wrmsrl(MSR_KERNEL_GS_BASE, next->gs); + prev->gsindex = gsindex; /* Must be after DS reload */ unlazy_fpu(prev_p); @@ -638,7 +626,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) write_pda(pcurrent, next_p); write_pda(kernelstack, - (unsigned long)task_stack_page(next_p) + THREAD_SIZE - PDA_STACKOFFSET); + (unsigned long)task_stack_page(next_p) + + THREAD_SIZE - PDA_STACKOFFSET); #ifdef CONFIG_CC_STACKPROTECTOR write_pda(stack_canary, next_p->stack_canary); /* @@ -658,8 +647,11 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) /* 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; } @@ -794,7 +786,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) set_32bit_tls(task, FS_TLS, addr); if (doit) { load_TLS(&task->thread, cpu); - asm volatile("movl %0,%%fs" :: "r"(FS_TLS_SEL)); + loadsegment(fs, FS_TLS_SEL); } task->thread.fsindex = FS_TLS_SEL; task->thread.fs = 0; @@ -804,7 +796,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) if (doit) { /* set the selector to 0 to not confuse __switch_to */ - asm volatile("movl %0,%%fs" :: "r" (0)); + loadsegment(fs, 0); ret = checking_wrmsrl(MSR_FS_BASE, addr); } } @@ -827,7 +819,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) if (task->thread.gsindex == GS_TLS_SEL) base = read_32bit_tls(task, GS_TLS); else if (doit) { - asm("movl %%gs,%0" : "=r" (gsindex)); + savesegment(gs, gsindex); if (gsindex) rdmsrl(MSR_KERNEL_GS_BASE, base); else |