diff options
Diffstat (limited to 'arch/x86/kernel/process.c')
| -rw-r--r-- | arch/x86/kernel/process.c | 106 |
1 files changed, 89 insertions, 17 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 046e2d620bbe..8213da62b1b7 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -9,7 +9,7 @@ #include <linux/sched.h> #include <linux/module.h> #include <linux/pm.h> -#include <linux/clockchips.h> +#include <linux/tick.h> #include <linux/random.h> #include <linux/user-return-notifier.h> #include <linux/dmi.h> @@ -24,6 +24,7 @@ #include <asm/syscalls.h> #include <asm/idle.h> #include <asm/uaccess.h> +#include <asm/mwait.h> #include <asm/i387.h> #include <asm/fpu-internal.h> #include <asm/debugreg.h> @@ -37,7 +38,26 @@ * section. Since TSS's are completely CPU-local, we want them * on exact cacheline boundaries, to eliminate cacheline ping-pong. */ -__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS; +__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = { + .x86_tss = { + .sp0 = TOP_OF_INIT_STACK, +#ifdef CONFIG_X86_32 + .ss0 = __KERNEL_DS, + .ss1 = __KERNEL_CS, + .io_bitmap_base = INVALID_IO_BITMAP_OFFSET, +#endif + }, +#ifdef CONFIG_X86_32 + /* + * Note that the .io_bitmap member must be extra-big. This is because + * the CPU will access an additional byte beyond the end of the IO + * permission bitmap. The extra byte must be all 1 bits, and must + * be within the limit. + */ + .io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 }, +#endif +}; +EXPORT_PER_CPU_SYMBOL_GPL(cpu_tss); #ifdef CONFIG_X86_64 static DEFINE_PER_CPU(unsigned char, is_idle); @@ -69,8 +89,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) dst->thread.fpu_counter = 0; dst->thread.fpu.has_fpu = 0; - dst->thread.fpu.last_cpu = ~0; dst->thread.fpu.state = NULL; + task_disable_lazy_fpu_restore(dst); if (tsk_used_math(src)) { int err = fpu_alloc(&dst->thread.fpu); if (err) @@ -109,7 +129,7 @@ void exit_thread(void) unsigned long *bp = t->io_bitmap_ptr; if (bp) { - struct tss_struct *tss = &per_cpu(init_tss, get_cpu()); + struct tss_struct *tss = &per_cpu(cpu_tss, get_cpu()); t->io_bitmap_ptr = NULL; clear_thread_flag(TIF_IO_BITMAP); @@ -131,13 +151,18 @@ void flush_thread(void) flush_ptrace_hw_breakpoint(tsk); memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); - drop_init_fpu(tsk); - /* - * Free the FPU state for non xsave platforms. They get reallocated - * lazily at the first use. - */ - if (!use_eager_fpu()) + + if (!use_eager_fpu()) { + /* FPU state will be reallocated lazily at the first use. */ + drop_fpu(tsk); free_thread_xstate(tsk); + } else if (!used_math()) { + /* kthread execs. TODO: cleanup this horror. */ + if (WARN_ON(init_fpu(tsk))) + force_sig(SIGKILL, tsk); + user_fpu_begin(); + restore_init_xstate(); + } } static void hard_disable_TSC(void) @@ -377,14 +402,11 @@ static void amd_e400_idle(void) if (!cpumask_test_cpu(cpu, amd_e400_c1e_mask)) { cpumask_set_cpu(cpu, amd_e400_c1e_mask); - /* - * Force broadcast so ACPI can not interfere. - */ - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE, - &cpu); + /* Force broadcast so ACPI can not interfere. */ + tick_broadcast_force(); pr_info("Switch to broadcast mode on CPU%d\n", cpu); } - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); + tick_broadcast_enter(); default_idle(); @@ -393,12 +415,59 @@ static void amd_e400_idle(void) * called with interrupts disabled. */ local_irq_disable(); - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); + tick_broadcast_exit(); local_irq_enable(); } else default_idle(); } +/* + * Intel Core2 and older machines prefer MWAIT over HALT for C1. + * We can't rely on cpuidle installing MWAIT, because it will not load + * on systems that support only C1 -- so the boot default must be MWAIT. + * + * Some AMD machines are the opposite, they depend on using HALT. + * + * So for default C1, which is used during boot until cpuidle loads, + * use MWAIT-C1 on Intel HW that has it, else use HALT. + */ +static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c) +{ + if (c->x86_vendor != X86_VENDOR_INTEL) + return 0; + + if (!cpu_has(c, X86_FEATURE_MWAIT)) + return 0; + + return 1; +} + +/* + * MONITOR/MWAIT with no hints, used for default default C1 state. + * This invokes MWAIT with interrutps enabled and no flags, + * which is backwards compatible with the original MWAIT implementation. + */ + +static void mwait_idle(void) +{ + if (!current_set_polling_and_test()) { + if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) { + smp_mb(); /* quirk */ + clflush((void *)¤t_thread_info()->flags); + smp_mb(); /* quirk */ + } + + __monitor((void *)¤t_thread_info()->flags, 0, 0); + if (!need_resched()) + __sti_mwait(0, 0); + else + local_irq_enable(); + } else { + local_irq_enable(); + } + __current_clr_polling(); +} + void select_idle_routine(const struct cpuinfo_x86 *c) { #ifdef CONFIG_SMP @@ -412,6 +481,9 @@ void select_idle_routine(const struct cpuinfo_x86 *c) /* E400: APIC timer interrupt does not wake up CPU from C1e */ pr_info("using AMD E400 aware idle routine\n"); x86_idle = amd_e400_idle; + } else if (prefer_mwait_c1_over_halt(c)) { + pr_info("using mwait in idle threads\n"); + x86_idle = mwait_idle; } else x86_idle = default_idle; } |