diff options
Diffstat (limited to 'arch/x86/kernel/process_32.c')
| -rw-r--r-- | arch/x86/kernel/process_32.c | 170 |
1 files changed, 60 insertions, 110 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 96586c3cbbb..7bc86bbe748 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -9,7 +9,6 @@ * This file handles the architecture-dependent parts of process handling.. */ -#include <linux/stackprotector.h> #include <linux/cpu.h> #include <linux/errno.h> #include <linux/sched.h> @@ -25,13 +24,11 @@ #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/reboot.h> -#include <linux/init.h> #include <linux/mc146818rtc.h> #include <linux/module.h> #include <linux/kallsyms.h> #include <linux/ptrace.h> #include <linux/personality.h> -#include <linux/tick.h> #include <linux/percpu.h> #include <linux/prctl.h> #include <linux/ftrace.h> @@ -40,10 +37,10 @@ #include <linux/kdebug.h> #include <asm/pgtable.h> -#include <asm/system.h> #include <asm/ldt.h> #include <asm/processor.h> #include <asm/i387.h> +#include <asm/fpu-internal.h> #include <asm/desc.h> #ifdef CONFIG_MATH_EMULATION #include <asm/math_emu.h> @@ -56,10 +53,10 @@ #include <asm/idle.h> #include <asm/syscalls.h> #include <asm/debugreg.h> - -#include <trace/events/power.h> +#include <asm/switch_to.h> asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); +asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread"); /* * Return saved PC of a blocked thread. @@ -69,60 +66,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk) return ((unsigned long *)tsk->thread.sp)[3]; } -#ifndef CONFIG_SMP -static inline void play_dead(void) -{ - BUG(); -} -#endif - -/* - * The idle thread. There's no useful work to be - * done, so just try to conserve power and have a - * low exit latency (ie sit in a loop waiting for - * somebody to say that they'd like to reschedule) - */ -void cpu_idle(void) -{ - int cpu = smp_processor_id(); - - /* - * If we're the non-boot CPU, nothing set the stack canary up - * for us. CPU0 already has it initialized but no harm in - * doing it again. This is a good place for updating it, as - * we wont ever return from this function (so the invalid - * canaries already on the stack wont ever trigger). - */ - boot_init_stack_canary(); - - current_thread_info()->status |= TS_POLLING; - - /* endless idle loop with no priority at all */ - while (1) { - tick_nohz_stop_sched_tick(1); - while (!need_resched()) { - - check_pgt_cache(); - rmb(); - - if (cpu_is_offline(cpu)) - play_dead(); - - local_irq_disable(); - /* Don't trace irqs off for idle */ - stop_critical_timings(); - pm_idle(); - start_critical_timings(); - - trace_power_end(smp_processor_id()); - } - tick_nohz_restart_sched_tick(); - preempt_enable_no_resched(); - schedule(); - preempt_disable(); - } -} - void __show_regs(struct pt_regs *regs, int all) { unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; @@ -140,8 +83,6 @@ void __show_regs(struct pt_regs *regs, int all) savesegment(gs, gs); } - show_regs_common(); - printk(KERN_DEFAULT "EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n", (u16)regs->cs, regs->ip, regs->flags, smp_processor_id()); @@ -168,11 +109,16 @@ void __show_regs(struct pt_regs *regs, int all) get_debugreg(d1, 1); get_debugreg(d2, 2); get_debugreg(d3, 3); - printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", - d0, d1, d2, d3); - get_debugreg(d6, 6); get_debugreg(d7, 7); + + /* Only print out debug registers if they are in their non-default state. */ + if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && + (d6 == DR6_RESERVED) && (d7 == 0x400)) + return; + + printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", + d0, d1, d2, d3); printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n", d6, d7); } @@ -183,35 +129,43 @@ void release_thread(struct task_struct *dead_task) release_vm86_irqs(dead_task); } -/* - * This gets called before we allocate a new thread and copy - * the current task into it. - */ -void prepare_to_copy(struct task_struct *tsk) -{ - unlazy_fpu(tsk); -} - int copy_thread(unsigned long clone_flags, unsigned long sp, - unsigned long unused, - struct task_struct *p, struct pt_regs *regs) + unsigned long arg, struct task_struct *p) { - struct pt_regs *childregs; + struct pt_regs *childregs = task_pt_regs(p); struct task_struct *tsk; int err; - childregs = task_pt_regs(p); - *childregs = *regs; - childregs->ax = 0; - childregs->sp = sp; - p->thread.sp = (unsigned long) childregs; p->thread.sp0 = (unsigned long) (childregs+1); - p->thread.ip = (unsigned long) ret_from_fork; + if (unlikely(p->flags & PF_KTHREAD)) { + /* kernel thread */ + memset(childregs, 0, sizeof(struct pt_regs)); + p->thread.ip = (unsigned long) ret_from_kernel_thread; + task_user_gs(p) = __KERNEL_STACK_CANARY; + childregs->ds = __USER_DS; + childregs->es = __USER_DS; + childregs->fs = __KERNEL_PERCPU; + childregs->bx = sp; /* function */ + childregs->bp = arg; + childregs->orig_ax = -1; + childregs->cs = __KERNEL_CS | get_kernel_rpl(); + childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED; + p->thread.fpu_counter = 0; + p->thread.io_bitmap_ptr = NULL; + memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); + return 0; + } + *childregs = *current_pt_regs(); + childregs->ax = 0; + if (sp) + childregs->sp = sp; - task_user_gs(p) = get_user_gs(regs); + p->thread.ip = (unsigned long) ret_from_fork; + task_user_gs(p) = get_user_gs(current_pt_regs()); + p->thread.fpu_counter = 0; p->thread.io_bitmap_ptr = NULL; tsk = current; err = -ENOMEM; @@ -249,23 +203,24 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) { set_user_gs(regs, 0); regs->fs = 0; - set_fs(USER_DS); regs->ds = __USER_DS; regs->es = __USER_DS; regs->ss = __USER_DS; regs->cs = __USER_CS; regs->ip = new_ip; regs->sp = new_sp; + regs->flags = X86_EFLAGS_IF; /* - * Free the old FP and other extended state + * force it to the iret return path by making it look as if there was + * some work pending. */ - free_thread_xstate(current); + set_thread_flag(TIF_NOTIFY_RESUME); } EXPORT_SYMBOL_GPL(start_thread); /* - * switch_to(x,yn) should switch tasks from x to y. + * switch_to(x,y) should switch tasks from x to y. * * We fsave/fwait so that an exception goes off at the right time * (as a call from the fsave or fwait in effect) rather than to @@ -291,29 +246,18 @@ EXPORT_SYMBOL_GPL(start_thread); * the task-switch, and shows up in ret_from_fork in entry.S, * for example. */ -__notrace_funcgraph struct task_struct * +__visible __notrace_funcgraph 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; int cpu = smp_processor_id(); struct tss_struct *tss = &per_cpu(init_tss, cpu); - bool preload_fpu; + fpu_switch_t fpu; /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ - /* - * 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 - */ - preload_fpu = tsk_used_math(next_p) && next_p->fpu_counter > 5; - - __unlazy_fpu(prev_p); - - /* we're going to use this soon, after a few expensive things */ - if (preload_fpu) - prefetch(next->fpu.state); + fpu = switch_fpu_prepare(prev_p, next_p, cpu); /* * Reload esp0. @@ -347,17 +291,20 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) set_iopl_mask(next->iopl); /* + * If it were not for PREEMPT_ACTIVE we could guarantee that the + * preempt_count of all tasks was equal here and this would not be + * needed. + */ + task_thread_info(prev_p)->saved_preempt_count = this_cpu_read(__preempt_count); + this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count); + + /* * Now maybe handle debug registers and/or IO bitmaps */ if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV || task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT)) __switch_to_xtra(prev_p, next_p, tss); - /* If we're going to preload the fpu context, make sure clts - is run while we're batching the cpu state updates. */ - if (preload_fpu) - clts(); - /* * Leave lazy mode, flushing any hypercalls made here. * This must be done before restoring TLS segments so @@ -367,8 +314,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) */ arch_end_context_switch(next_p); - if (preload_fpu) - __math_state_restore(); + this_cpu_write(kernel_stack, + (unsigned long)task_stack_page(next_p) + + THREAD_SIZE - KERNEL_STACK_OFFSET); /* * Restore %gs if needed (which is common) @@ -376,7 +324,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) if (prev->gs | next->gs) lazy_load_gs(next->gs); - percpu_write(current_task, next_p); + switch_fpu_finish(next_p, fpu); + + this_cpu_write(current_task, next_p); return prev_p; } |