Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[safe/jmp/linux-2.6] / arch / x86 / kernel / process_64.c
index 4e65ae8..ebefb54 100644 (file)
@@ -14,8 +14,7 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <stdarg.h>
-
+#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
 #include <linux/slab.h>
 #include <linux/user.h>
-#include <linux/a.out.h>
 #include <linux/interrupt.h>
 #include <linux/utsname.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/ptrace.h>
-#include <linux/random.h>
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
 #include <linux/tick.h>
+#include <linux/prctl.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/ftrace.h>
+#include <linux/dmi.h>
 
-#include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
-#include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/i387.h>
 #include <asm/mmu_context.h>
-#include <asm/pda.h>
 #include <asm/prctl.h>
 #include <asm/desc.h>
 #include <asm/proto.h>
 #include <asm/ia32.h>
 #include <asm/idle.h>
+#include <asm/syscalls.h>
+#include <asm/ds.h>
 
 asmlinkage extern void ret_from_fork(void);
 
-unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
+DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
+EXPORT_PER_CPU_SYMBOL(current_task);
 
-unsigned long boot_option_idle_override = 0;
-EXPORT_SYMBOL(boot_option_idle_override);
+DEFINE_PER_CPU(unsigned long, old_rsp);
+static DEFINE_PER_CPU(unsigned char, is_idle);
 
-/*
- * Powermanagement idle function, if any..
- */
-void (*pm_idle)(void);
-EXPORT_SYMBOL(pm_idle);
-static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
+unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
 
@@ -72,16 +69,23 @@ void idle_notifier_register(struct notifier_block *n)
 {
        atomic_notifier_chain_register(&idle_notifier, n);
 }
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+       atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
 
 void enter_idle(void)
 {
-       write_pda(isidle, 1);
+       percpu_write(is_idle, 1);
        atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
 }
 
 static void __exit_idle(void)
 {
-       if (test_and_clear_bit_pda(0, isidle) == 0)
+       if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
                return;
        atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
 }
@@ -95,69 +99,12 @@ 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();
-       local_irq_disable();
-       if (!need_resched()) {
-               ktime_t t0, t1;
-               u64 t0n, t1n;
-
-               t0 = ktime_get();
-               t0n = ktime_to_ns(t0);
-               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();
-       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);
-
-#include <asm/nmi.h>
-/* We halt the CPU with physical CPU hotplug */
-static inline void play_dead(void)
-{
-       idle_task_exit();
-       wbinvd();
-       mb();
-       /* Ack it */
-       __get_cpu_var(cpu_state) = CPU_DEAD;
-
-       local_irq_disable();
-       while (1)
-               halt();
-}
-#else
+#ifndef CONFIG_SMP
 static inline void play_dead(void)
 {
        BUG();
 }
-#endif /* CONFIG_HOTPLUG_CPU */
+#endif
 
 /*
  * The idle thread. There's no useful work to be
@@ -168,19 +115,23 @@ static inline void play_dead(void)
 void cpu_idle(void)
 {
        current_thread_info()->status |= TS_POLLING;
+
+       /*
+        * 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();
+
        /* endless idle loop with no priority at all */
        while (1) {
-               tick_nohz_stop_sched_tick();
+               tick_nohz_stop_sched_tick(1);
                while (!need_resched()) {
-                       void (*idle)(void);
-
-                       if (__get_cpu_var(cpu_idle_state))
-                               __get_cpu_var(cpu_idle_state) = 0;
 
                        rmb();
-                       idle = pm_idle;
-                       if (!idle)
-                               idle = default_idle;
+
                        if (cpu_is_offline(smp_processor_id()))
                                play_dead();
                        /*
@@ -190,7 +141,10 @@ 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. */
@@ -204,234 +158,82 @@ void cpu_idle(void)
        }
 }
 
-static void do_nothing(void *unused)
-{
-}
-
-void cpu_idle_wait(void)
-{
-       unsigned int cpu, this_cpu = get_cpu();
-       cpumask_t map, tmp = current->cpus_allowed;
-
-       set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
-       put_cpu();
-
-       cpus_clear(map);
-       for_each_online_cpu(cpu) {
-               per_cpu(cpu_idle_state, cpu) = 1;
-               cpu_set(cpu, map);
-       }
-
-       __get_cpu_var(cpu_idle_state) = 0;
-
-       wmb();
-       do {
-               ssleep(1);
-               for_each_online_cpu(cpu) {
-                       if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))
-                               cpu_clear(cpu, map);
-               }
-               cpus_and(map, map, cpu_online_map);
-               /*
-                * We waited 1 sec, if a CPU still did not call idle
-                * it may be because it is in idle and not waking up
-                * because it has nothing to do.
-                * Give all the remaining CPUS a kick.
-                */
-               smp_call_function_mask(map, do_nothing, 0, 0);
-       } while (!cpus_empty(map));
-
-       set_cpus_allowed(current, tmp);
-}
-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 *)&current_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 *)&current_thread_info()->flags, 0, 0);
-               smp_mb();
-               if (!need_resched())
-                       __sti_mwait(0, 0);
-               else
-                       local_irq_enable();
-       } else {
-               local_irq_enable();
-       }
-}
-
-void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
-{
-       static int printed;
-       if (cpu_has(c, X86_FEATURE_MWAIT)) {
-               /*
-                * Skip, if setup has overridden idle.
-                * One CPU supports mwait => All CPUs supports mwait
-                */
-               if (!pm_idle) {
-                       if (!printed) {
-                               printk(KERN_INFO "using mwait in idle threads.\n");
-                               printed = 1;
-                       }
-                       pm_idle = mwait_idle;
-               }
-       }
-}
-
-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)
+void __show_regs(struct pt_regs *regs, int all)
 {
        unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
        unsigned long d0, d1, d2, d3, d6, d7;
        unsigned int fsindex, gsindex;
        unsigned int ds, cs, es;
+       const char *board;
 
        printk("\n");
        print_modules();
-       printk("Pid: %d, comm: %.20s %s %s %.*s\n",
+       board = dmi_get_system_info(DMI_PRODUCT_NAME);
+       if (!board)
+               board = "";
+       printk(KERN_INFO "Pid: %d, comm: %.20s %s %s %.*s %s\n",
                current->pid, current->comm, print_tainted(),
                init_utsname()->release,
                (int)strcspn(init_utsname()->version, " "),
-               init_utsname()->version);
-       printk("RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
+               init_utsname()->version, board);
+       printk(KERN_INFO "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
        printk_address(regs->ip, 1);
-       printk("RSP: %04lx:%016lx  EFLAGS: %08lx\n", regs->ss, regs->sp,
-               regs->flags);
-       printk("RAX: %016lx RBX: %016lx RCX: %016lx\n",
+       printk(KERN_INFO "RSP: %04lx:%016lx  EFLAGS: %08lx\n", regs->ss,
+                       regs->sp, regs->flags);
+       printk(KERN_INFO "RAX: %016lx RBX: %016lx RCX: %016lx\n",
               regs->ax, regs->bx, regs->cx);
-       printk("RDX: %016lx RSI: %016lx RDI: %016lx\n",
+       printk(KERN_INFO "RDX: %016lx RSI: %016lx RDI: %016lx\n",
               regs->dx, regs->si, regs->di);
-       printk("RBP: %016lx R08: %016lx R09: %016lx\n",
+       printk(KERN_INFO "RBP: %016lx R08: %016lx R09: %016lx\n",
               regs->bp, regs->r8, regs->r9);
-       printk("R10: %016lx R11: %016lx R12: %016lx\n",
-              regs->r10, regs->r11, regs->r12); 
-       printk("R13: %016lx R14: %016lx R15: %016lx\n",
-              regs->r13, regs->r14, regs->r15); 
-
-       asm("movl %%ds,%0" : "=r" (ds)); 
-       asm("movl %%cs,%0" : "=r" (cs)); 
-       asm("movl %%es,%0" : "=r" (es)); 
+       printk(KERN_INFO "R10: %016lx R11: %016lx R12: %016lx\n",
+              regs->r10, regs->r11, regs->r12);
+       printk(KERN_INFO "R13: %016lx R14: %016lx R15: %016lx\n",
+              regs->r13, regs->r14, regs->r15);
+
+       asm("movl %%ds,%0" : "=r" (ds));
+       asm("movl %%cs,%0" : "=r" (cs));
+       asm("movl %%es,%0" : "=r" (es));
        asm("movl %%fs,%0" : "=r" (fsindex));
        asm("movl %%gs,%0" : "=r" (gsindex));
 
        rdmsrl(MSR_FS_BASE, fs);
-       rdmsrl(MSR_GS_BASE, gs); 
-       rdmsrl(MSR_KERNEL_GS_BASE, shadowgs); 
+       rdmsrl(MSR_GS_BASE, gs);
+       rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
+
+       if (!all)
+               return;
 
        cr0 = read_cr0();
        cr2 = read_cr2();
        cr3 = read_cr3();
        cr4 = read_cr4();
 
-       printk("FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n", 
-              fs,fsindex,gs,gsindex,shadowgs); 
-       printk("CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds, es, cr0); 
-       printk("CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3, cr4);
+       printk(KERN_INFO "FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
+              fs, fsindex, gs, gsindex, shadowgs);
+       printk(KERN_INFO "CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
+                       es, cr0);
+       printk(KERN_INFO "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
+                       cr4);
 
        get_debugreg(d0, 0);
        get_debugreg(d1, 1);
        get_debugreg(d2, 2);
-       printk("DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
+       printk(KERN_INFO "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
        get_debugreg(d3, 3);
        get_debugreg(d6, 6);
        get_debugreg(d7, 7);
-       printk("DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
+       printk(KERN_INFO "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
 }
 
 void show_regs(struct pt_regs *regs)
 {
-       printk("CPU %d:", smp_processor_id());
-       __show_regs(regs);
+       printk(KERN_INFO "CPU %d:", smp_processor_id());
+       __show_regs(regs, 1);
        show_trace(NULL, regs, (void *)(regs + 1), regs->bp);
 }
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-       struct task_struct *me = current;
-       struct thread_struct *t = &me->thread;
-
-       if (me->thread.io_bitmap_ptr) {
-               struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
-
-               kfree(t->io_bitmap_ptr);
-               t->io_bitmap_ptr = NULL;
-               clear_thread_flag(TIF_IO_BITMAP);
-               /*
-                * Careful, clear this in the TSS too:
-                */
-               memset(tss->io_bitmap, 0xff, t->io_bitmap_max);
-               t->io_bitmap_max = 0;
-               put_cpu();
-       }
-}
-
-void flush_thread(void)
-{
-       struct task_struct *tsk = current;
-
-       if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {
-               clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);
-               if (test_tsk_thread_flag(tsk, TIF_IA32)) {
-                       clear_tsk_thread_flag(tsk, TIF_IA32);
-               } else {
-                       set_tsk_thread_flag(tsk, TIF_IA32);
-                       current_thread_info()->status |= TS_COMPAT;
-               }
-       }
-       clear_tsk_thread_flag(tsk, TIF_DEBUG);
-
-       tsk->thread.debugreg0 = 0;
-       tsk->thread.debugreg1 = 0;
-       tsk->thread.debugreg2 = 0;
-       tsk->thread.debugreg3 = 0;
-       tsk->thread.debugreg6 = 0;
-       tsk->thread.debugreg7 = 0;
-       memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
-       /*
-        * Forget coprocessor state..
-        */
-       clear_fpu(tsk);
-       clear_used_math();
-}
-
 void release_thread(struct task_struct *dead_task)
 {
        if (dead_task->mm) {
@@ -454,7 +256,7 @@ static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
                .limit_in_pages = 1,
                .useable = 1,
        };
-       struct desc_struct *desc = (void *)t->thread.tls_array;
+       struct desc_struct *desc = t->thread.tls_array;
        desc += tls;
        fill_ldt(desc, &ud);
 }
@@ -473,12 +275,12 @@ void prepare_to_copy(struct task_struct *tsk)
        unlazy_fpu(tsk);
 }
 
-int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
+int copy_thread(unsigned long clone_flags, unsigned long sp,
                unsigned long unused,
-       struct task_struct * p, struct pt_regs * regs)
+       struct task_struct *p, struct pt_regs *regs)
 {
        int err;
-       struct pt_regs * childregs;
+       struct pt_regs *childregs;
        struct task_struct *me = current;
 
        childregs = ((struct pt_regs *)
@@ -499,10 +301,10 @@ 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);
@@ -523,12 +325,19 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
                if (test_thread_flag(TIF_IA32))
                        err = do_set_thread_area(p, -1,
                                (struct user_desc __user *)childregs->si, 0);
-               else                    
-#endif  
-                       err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8); 
-               if (err) 
+               else
+#endif
+                       err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
+               if (err)
                        goto out;
        }
+
+       clear_tsk_thread_flag(p, TIF_DS_AREA_MSR);
+       p->thread.ds_ctx = NULL;
+
+       clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
+       p->thread.debugctlmsr = 0;
+
        err = 0;
 out:
        if (err && p->thread.io_bitmap_ptr) {
@@ -538,63 +347,26 @@ out:
        return err;
 }
 
-/*
- * This special macro can be used to load a debugging register
- */
-#define loaddebug(thread, r) set_debugreg(thread->debugreg ## r, r)
-
-static inline void __switch_to_xtra(struct task_struct *prev_p,
-                                   struct task_struct *next_p,
-                                   struct tss_struct *tss)
-{
-       struct thread_struct *prev, *next;
-       unsigned long debugctl;
-
-       prev = &prev_p->thread,
-       next = &next_p->thread;
-
-       debugctl = prev->debugctlmsr;
-       if (next->ds_area_msr != prev->ds_area_msr) {
-               /* we clear debugctl to make sure DS
-                * is not in use when we change it */
-               debugctl = 0;
-               wrmsrl(MSR_IA32_DEBUGCTLMSR, 0);
-               wrmsrl(MSR_IA32_DS_AREA, next->ds_area_msr);
-       }
-
-       if (next->debugctlmsr != debugctl)
-               wrmsrl(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr);
-
-       if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
-               loaddebug(next, 0);
-               loaddebug(next, 1);
-               loaddebug(next, 2);
-               loaddebug(next, 3);
-               /* no 4 and 5 */
-               loaddebug(next, 6);
-               loaddebug(next, 7);
-       }
-
-       if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
-               /*
-                * Copy the relevant range of the IO bitmap.
-                * Normally this is 128 bytes or less:
-                */
-               memcpy(tss->io_bitmap, next->io_bitmap_ptr,
-                      max(prev->io_bitmap_max, next->io_bitmap_max));
-       } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
-               /*
-                * Clear any possible leftover bits:
-                */
-               memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
-       }
-
-       if (test_tsk_thread_flag(prev_p, TIF_BTS_TRACE_TS))
-               ptrace_bts_take_timestamp(prev_p, BTS_TASK_DEPARTS);
-
-       if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS))
-               ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES);
+void
+start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
+{
+       loadsegment(fs, 0);
+       loadsegment(es, 0);
+       loadsegment(ds, 0);
+       load_gs_index(0);
+       regs->ip                = new_ip;
+       regs->sp                = new_sp;
+       percpu_write(old_rsp, 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);
 
 /*
  *     switch_to(x,y) should switch tasks from x to y.
@@ -604,95 +376,102 @@ static inline void __switch_to_xtra(struct task_struct *prev_p,
  * - could test fs/gs bitsliced
  *
  * Kprobes not supported here. Set the probe on schedule instead.
+ * Function graph tracer not supported too.
  */
-struct task_struct *
+__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;
+       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)
-               prefetch(&next->i387.fxsave);
+       if (next_p->fpu_counter > 5)
+               prefetch(next->xstate);
 
        /*
         * Reload esp0, LDT and the page table pointer:
         */
        load_sp0(tss, next);
 
-       /* 
+       /*
         * 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));
+               loadsegment(es, next->es);
+
+       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_end_context_switch(next_p);
+
+       /*
         * 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)
-                       prev->fs = 0;                           
-               }
-               /* when next process has a 64bit base use it */
-               if (next->fs) 
-                       wrmsrl(MSR_FS_BASE, next->fs); 
-               prev->fsindex = 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;
        }
-       { 
-               unsigned gsindex;
-               asm volatile("movl %%gs,%0" : "=r" (gsindex)); 
-               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;
+       /* 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;
 
        /* Must be after DS reload */
        unlazy_fpu(prev_p);
 
-       /* 
-        * Switch the PDA and FPU contexts.
-        */
-       prev->usersp = read_pda(oldrsp);
-       write_pda(oldrsp, next->usersp);
-       write_pda(pcurrent, next_p); 
-
-       write_pda(kernelstack,
-       (unsigned long)task_stack_page(next_p) + THREAD_SIZE - PDA_STACKOFFSET);
-#ifdef CONFIG_CC_STACKPROTECTOR
-       write_pda(stack_canary, next_p->stack_canary);
        /*
-        * Build time only check to make sure the stack_canary is at
-        * offset 40 in the pda; this is a gcc ABI requirement
+        * Switch the PDA and FPU contexts.
         */
-       BUILD_BUG_ON(offsetof(struct x8664_pda, stack_canary) != 40);
-#endif
+       prev->usersp = percpu_read(old_rsp);
+       percpu_write(old_rsp, next->usersp);
+       percpu_write(current_task, next_p);
+
+       percpu_write(kernel_stack,
+                 (unsigned long)task_stack_page(next_p) +
+                 THREAD_SIZE - KERNEL_STACK_OFFSET);
 
        /*
         * Now maybe reload the debug registers and handle I/O bitmaps
@@ -704,8 +483,11 @@ __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;
 }
@@ -715,16 +497,16 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
  */
 asmlinkage
 long sys_execve(char __user *name, char __user * __user *argv,
-               char __user * __user *envp, struct pt_regs regs)
+               char __user * __user *envp, struct pt_regs *regs)
 {
        long error;
-       char * filename;
+       char *filename;
 
        filename = getname(name);
        error = PTR_ERR(filename);
-       if (IS_ERR(filename)) 
+       if (IS_ERR(filename))
                return error;
-       error = do_execve(filename, argv, envp, &regs); 
+       error = do_execve(filename, argv, envp, regs);
        putname(filename);
        return error;
 }
@@ -743,11 +525,6 @@ void set_personality_64bit(void)
        current->personality &= ~READ_IMPLIES_EXEC;
 }
 
-asmlinkage long sys_fork(struct pt_regs *regs)
-{
-       return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
 asmlinkage long
 sys_clone(unsigned long clone_flags, unsigned long newsp,
          void __user *parent_tid, void __user *child_tid, struct pt_regs *regs)
@@ -757,74 +534,58 @@ sys_clone(unsigned long clone_flags, unsigned long newsp,
        return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
 }
 
-/*
- * This is trivial, and on the face of it looks like it
- * could equally well be done in user mode.
- *
- * Not so, for quite unobvious reasons - register pressure.
- * In user mode vfork() cannot have a stack frame, and if
- * done by calling the "clone()" system call directly, you
- * do not have enough call-clobbered registers to hold all
- * the information you need.
- */
-asmlinkage long sys_vfork(struct pt_regs *regs)
-{
-       return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,
-                   NULL, NULL);
-}
-
 unsigned long get_wchan(struct task_struct *p)
 {
        unsigned long stack;
-       u64 fp,ip;
+       u64 fp, ip;
        int count = 0;
 
-       if (!p || p == current || p->state==TASK_RUNNING)
-               return 0; 
+       if (!p || p == current || p->state == TASK_RUNNING)
+               return 0;
        stack = (unsigned long)task_stack_page(p);
-       if (p->thread.sp < stack || p->thread.sp > stack+THREAD_SIZE)
+       if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE)
                return 0;
        fp = *(u64 *)(p->thread.sp);
-       do { 
+       do {
                if (fp < (unsigned long)stack ||
-                   fp > (unsigned long)stack+THREAD_SIZE)
-                       return 0; 
+                   fp >= (unsigned long)stack+THREAD_SIZE)
+                       return 0;
                ip = *(u64 *)(fp+8);
                if (!in_sched_functions(ip))
                        return ip;
-               fp = *(u64 *)fp; 
-       } while (count++ < 16); 
+               fp = *(u64 *)fp;
+       } while (count++ < 16);
        return 0;
 }
 
 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
-{ 
-       int ret = 0; 
+{
+       int ret = 0;
        int doit = task == current;
        int cpu;
 
-       switch (code) { 
+       switch (code) {
        case ARCH_SET_GS:
                if (addr >= TASK_SIZE_OF(task))
-                       return -EPERM; 
+                       return -EPERM;
                cpu = get_cpu();
-               /* handle small bases via the GDT because that's faster to 
+               /* handle small bases via the GDT because that's faster to
                   switch. */
-               if (addr <= 0xffffffff) {  
-                       set_32bit_tls(task, GS_TLS, addr); 
-                       if (doit) { 
+               if (addr <= 0xffffffff) {
+                       set_32bit_tls(task, GS_TLS, addr);
+                       if (doit) {
                                load_TLS(&task->thread, cpu);
-                               load_gs_index(GS_TLS_SEL); 
+                               load_gs_index(GS_TLS_SEL);
                        }
-                       task->thread.gsindex = GS_TLS_SEL; 
+                       task->thread.gsindex = GS_TLS_SEL;
                        task->thread.gs = 0;
-               } else { 
+               } else {
                        task->thread.gsindex = 0;
                        task->thread.gs = addr;
                        if (doit) {
                                load_gs_index(0);
                                ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr);
-                       } 
+                       }
                }
                put_cpu();
                break;
@@ -840,7 +601,7 @@ 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;
@@ -850,7 +611,7 @@ 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);
                        }
                }
@@ -873,13 +634,12 @@ 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
                                base = task->thread.gs;
-               }
-               else
+               } else
                        base = task->thread.gs;
                ret = put_user(base, (unsigned long __user *)addr);
                break;
@@ -898,15 +658,3 @@ long sys_arch_prctl(int code, unsigned long addr)
        return do_arch_prctl(current, code, addr);
 }
 
-unsigned long arch_align_stack(unsigned long sp)
-{
-       if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
-               sp -= get_random_int() % 8192;
-       return sp & ~0xf;
-}
-
-unsigned long arch_randomize_brk(struct mm_struct *mm)
-{
-       unsigned long range_end = mm->brk + 0x02000000;
-       return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
-}