diff options
Diffstat (limited to 'arch/x86/kernel/process.c')
| -rw-r--r-- | arch/x86/kernel/process.c | 73 |
1 files changed, 38 insertions, 35 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 1d92a5ab6e8b..735279e54e59 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -27,6 +27,15 @@ #include <asm/debugreg.h> #include <asm/nmi.h> +/* + * per-CPU TSS segments. Threads are completely 'soft' on Linux, + * no more per-task TSS's. The TSS size is kept cacheline-aligned + * so they are allowed to end up in the .data..cacheline_aligned + * section. Since TSS's are completely CPU-local, we want them + * on exact cacheline boundaries, to eliminate cacheline ping-pong. + */ +DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS; + #ifdef CONFIG_X86_64 static DEFINE_PER_CPU(unsigned char, is_idle); static ATOMIC_NOTIFIER_HEAD(idle_notifier); @@ -47,10 +56,16 @@ EXPORT_SYMBOL_GPL(idle_notifier_unregister); struct kmem_cache *task_xstate_cachep; EXPORT_SYMBOL_GPL(task_xstate_cachep); +/* + * this gets called so that we can store lazy state into memory and copy the + * current task into the new thread. + */ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { int ret; + unlazy_fpu(src); + *dst = *src; if (fpu_allocated(&src->thread.fpu)) { memset(&dst->thread.fpu, 0, sizeof(dst->thread.fpu)); @@ -67,10 +82,9 @@ void free_thread_xstate(struct task_struct *tsk) fpu_free(&tsk->thread.fpu); } -void free_thread_info(struct thread_info *ti) +void arch_release_task_struct(struct task_struct *tsk) { - free_thread_xstate(ti->task); - free_pages((unsigned long)ti, THREAD_ORDER); + free_thread_xstate(tsk); } void arch_task_cache_init(void) @@ -81,6 +95,16 @@ void arch_task_cache_init(void) SLAB_PANIC | SLAB_NOTRACK, NULL); } +static inline void drop_fpu(struct task_struct *tsk) +{ + /* + * Forget coprocessor state.. + */ + tsk->fpu_counter = 0; + clear_fpu(tsk); + clear_used_math(); +} + /* * Free current thread data structures etc.. */ @@ -103,12 +127,8 @@ void exit_thread(void) put_cpu(); kfree(bp); } -} -void show_regs(struct pt_regs *regs) -{ - show_registers(regs); - show_trace(NULL, regs, (unsigned long *)kernel_stack_pointer(regs), 0); + drop_fpu(me); } void show_regs_common(void) @@ -143,12 +163,7 @@ void flush_thread(void) flush_ptrace_hw_breakpoint(tsk); memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); - /* - * Forget coprocessor state.. - */ - tsk->fpu_counter = 0; - clear_fpu(tsk); - clear_used_math(); + drop_fpu(tsk); } static void hard_disable_TSC(void) @@ -377,7 +392,7 @@ static inline void play_dead(void) #ifdef CONFIG_X86_64 void enter_idle(void) { - percpu_write(is_idle, 1); + this_cpu_write(is_idle, 1); atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL); } @@ -516,26 +531,6 @@ void stop_this_cpu(void *dummy) } } -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, 1); -} -EXPORT_SYMBOL_GPL(cpu_idle_wait); - /* Default MONITOR/MWAIT with no hints, used for default C1 state */ static void mwait_idle(void) { @@ -594,9 +589,17 @@ int mwait_usable(const struct cpuinfo_x86 *c) { u32 eax, ebx, ecx, edx; + /* Use mwait if idle=mwait boot option is given */ if (boot_option_idle_override == IDLE_FORCE_MWAIT) return 1; + /* + * Any idle= boot option other than idle=mwait means that we must not + * use mwait. Eg: idle=halt or idle=poll or idle=nomwait + */ + if (boot_option_idle_override != IDLE_NO_OVERRIDE) + return 0; + if (c->cpuid_level < MWAIT_INFO) return 0; |