Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (C) 1995 Linus Torvalds |
| 3 | * |
| 4 | * Pentium III FXSR, SSE support |
| 5 | * Gareth Hughes <gareth@valinux.com>, May 2000 |
| 6 | */ |
| 7 | |
| 8 | /* |
| 9 | * This file handles the architecture-dependent parts of process handling.. |
| 10 | */ |
| 11 | |
| 12 | #include <stdarg.h> |
| 13 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 14 | #include <linux/cpu.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/errno.h> |
| 16 | #include <linux/sched.h> |
| 17 | #include <linux/fs.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/mm.h> |
| 20 | #include <linux/elfcore.h> |
| 21 | #include <linux/smp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/stddef.h> |
| 23 | #include <linux/slab.h> |
| 24 | #include <linux/vmalloc.h> |
| 25 | #include <linux/user.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/interrupt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/utsname.h> |
| 28 | #include <linux/delay.h> |
| 29 | #include <linux/reboot.h> |
| 30 | #include <linux/init.h> |
| 31 | #include <linux/mc146818rtc.h> |
| 32 | #include <linux/module.h> |
| 33 | #include <linux/kallsyms.h> |
| 34 | #include <linux/ptrace.h> |
| 35 | #include <linux/random.h> |
Andi Kleen | c16b63e | 2006-09-26 10:52:28 +0200 | [diff] [blame] | 36 | #include <linux/personality.h> |
Ingo Molnar | 7416734 | 2007-02-16 01:28:07 -0800 | [diff] [blame] | 37 | #include <linux/tick.h> |
Jeremy Fitzhardinge | 7c3576d | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 38 | #include <linux/percpu.h> |
Erik Bosman | 529e25f | 2008-04-14 00:24:18 +0200 | [diff] [blame] | 39 | #include <linux/prctl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
| 41 | #include <asm/uaccess.h> |
| 42 | #include <asm/pgtable.h> |
| 43 | #include <asm/system.h> |
| 44 | #include <asm/io.h> |
| 45 | #include <asm/ldt.h> |
| 46 | #include <asm/processor.h> |
| 47 | #include <asm/i387.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | #include <asm/desc.h> |
| 49 | #ifdef CONFIG_MATH_EMULATION |
| 50 | #include <asm/math_emu.h> |
| 51 | #endif |
| 52 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | #include <linux/err.h> |
| 54 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 55 | #include <asm/tlbflush.h> |
| 56 | #include <asm/cpu.h> |
Thomas Gleixner | 718fc13 | 2008-01-30 13:30:17 +0100 | [diff] [blame] | 57 | #include <asm/kdebug.h> |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 58 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); |
| 60 | |
Jeremy Fitzhardinge | 7c3576d | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 61 | DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task; |
| 62 | EXPORT_PER_CPU_SYMBOL(current_task); |
| 63 | |
| 64 | DEFINE_PER_CPU(int, cpu_number); |
| 65 | EXPORT_PER_CPU_SYMBOL(cpu_number); |
| 66 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | /* |
| 68 | * Return saved PC of a blocked thread. |
| 69 | */ |
| 70 | unsigned long thread_saved_pc(struct task_struct *tsk) |
| 71 | { |
H. Peter Anvin | faca622 | 2008-01-30 13:31:02 +0100 | [diff] [blame] | 72 | return ((unsigned long *)tsk->thread.sp)[3]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | } |
| 74 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 75 | #ifdef CONFIG_HOTPLUG_CPU |
| 76 | #include <asm/nmi.h> |
Glauber Costa | 1481a3d | 2008-06-04 15:35:03 -0300 | [diff] [blame] | 77 | |
| 78 | static void cpu_exit_clear(void) |
| 79 | { |
| 80 | int cpu = raw_smp_processor_id(); |
| 81 | |
| 82 | idle_task_exit(); |
| 83 | |
| 84 | cpu_uninit(); |
| 85 | irq_ctx_exit(cpu); |
| 86 | |
| 87 | cpu_clear(cpu, cpu_callout_map); |
| 88 | cpu_clear(cpu, cpu_callin_map); |
| 89 | |
| 90 | numa_remove_cpu(cpu); |
| 91 | } |
| 92 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 93 | /* We don't actually take CPU down, just spin without interrupts. */ |
| 94 | static inline void play_dead(void) |
| 95 | { |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 96 | /* This must be done before dead CPU ack */ |
| 97 | cpu_exit_clear(); |
| 98 | wbinvd(); |
| 99 | mb(); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 100 | /* Ack it */ |
| 101 | __get_cpu_var(cpu_state) = CPU_DEAD; |
| 102 | |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 103 | /* |
| 104 | * With physical CPU hotplug, we should halt the cpu |
| 105 | */ |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 106 | local_irq_disable(); |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 107 | while (1) |
Zachary Amsden | f2ab446 | 2005-09-03 15:56:42 -0700 | [diff] [blame] | 108 | halt(); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 109 | } |
| 110 | #else |
| 111 | static inline void play_dead(void) |
| 112 | { |
| 113 | BUG(); |
| 114 | } |
| 115 | #endif /* CONFIG_HOTPLUG_CPU */ |
| 116 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | /* |
| 118 | * The idle thread. There's no useful work to be |
| 119 | * done, so just try to conserve power and have a |
| 120 | * low exit latency (ie sit in a loop waiting for |
| 121 | * somebody to say that they'd like to reschedule) |
| 122 | */ |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 123 | void cpu_idle(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | { |
Nick Piggin | 5bfb5d6 | 2005-11-08 21:39:01 -0800 | [diff] [blame] | 125 | int cpu = smp_processor_id(); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 126 | |
Andi Kleen | 495ab9c | 2006-06-26 13:59:11 +0200 | [diff] [blame] | 127 | current_thread_info()->status |= TS_POLLING; |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | /* endless idle loop with no priority at all */ |
| 130 | while (1) { |
Ingo Molnar | 7416734 | 2007-02-16 01:28:07 -0800 | [diff] [blame] | 131 | tick_nohz_stop_sched_tick(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | while (!need_resched()) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | |
Christoph Lameter | f1d1a84 | 2007-05-12 11:15:24 -0700 | [diff] [blame] | 134 | check_pgt_cache(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | rmb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | |
Benjamin LaHaise | 0723a69 | 2008-01-30 13:33:13 +0100 | [diff] [blame] | 137 | if (rcu_pending(cpu)) |
| 138 | rcu_check_callbacks(cpu, 0); |
| 139 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 140 | if (cpu_is_offline(cpu)) |
| 141 | play_dead(); |
| 142 | |
Peter Zijlstra | 7f424a8 | 2008-04-25 17:39:01 +0200 | [diff] [blame] | 143 | local_irq_disable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | __get_cpu_var(irq_stat).idle_timestamp = jiffies; |
Steven Rostedt | 6cd8a4b | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 145 | /* Don't trace irqs off for idle */ |
| 146 | stop_critical_timings(); |
Thomas Gleixner | 6ddd2a2 | 2008-06-09 16:59:53 +0200 | [diff] [blame] | 147 | pm_idle(); |
Steven Rostedt | 6cd8a4b | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 148 | start_critical_timings(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | } |
Ingo Molnar | 7416734 | 2007-02-16 01:28:07 -0800 | [diff] [blame] | 150 | tick_nohz_restart_sched_tick(); |
Nick Piggin | 5bfb5d6 | 2005-11-08 21:39:01 -0800 | [diff] [blame] | 151 | preempt_enable_no_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | schedule(); |
Nick Piggin | 5bfb5d6 | 2005-11-08 21:39:01 -0800 | [diff] [blame] | 153 | preempt_disable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | } |
| 155 | } |
| 156 | |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 157 | void __show_registers(struct pt_regs *regs, int all) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | { |
| 159 | unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; |
Alan Stern | bb1995d | 2007-07-21 17:10:42 +0200 | [diff] [blame] | 160 | unsigned long d0, d1, d2, d3, d6, d7; |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 161 | unsigned long sp; |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 162 | unsigned short ss, gs; |
| 163 | |
| 164 | if (user_mode_vm(regs)) { |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 165 | sp = regs->sp; |
| 166 | ss = regs->ss & 0xffff; |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 167 | savesegment(gs, gs); |
| 168 | } else { |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 169 | sp = (unsigned long) (®s->sp); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 170 | savesegment(ss, ss); |
| 171 | savesegment(gs, gs); |
| 172 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | |
| 174 | printk("\n"); |
Linus Torvalds | 60812a4 | 2007-10-19 15:06:00 -0700 | [diff] [blame] | 175 | printk("Pid: %d, comm: %s %s (%s %.*s)\n", |
| 176 | task_pid_nr(current), current->comm, |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 177 | print_tainted(), init_utsname()->release, |
| 178 | (int)strcspn(init_utsname()->version, " "), |
| 179 | init_utsname()->version); |
| 180 | |
| 181 | printk("EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n", |
Harvey Harrison | 92bc205 | 2008-02-08 12:09:56 -0800 | [diff] [blame] | 182 | (u16)regs->cs, regs->ip, regs->flags, |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 183 | smp_processor_id()); |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 184 | print_symbol("EIP is at %s\n", regs->ip); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 187 | regs->ax, regs->bx, regs->cx, regs->dx); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 188 | printk("ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n", |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 189 | regs->si, regs->di, regs->bp, sp); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 190 | printk(" DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n", |
Harvey Harrison | 92bc205 | 2008-02-08 12:09:56 -0800 | [diff] [blame] | 191 | (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 192 | |
| 193 | if (!all) |
| 194 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | |
Zachary Amsden | 4bb0d3e | 2005-09-03 15:56:36 -0700 | [diff] [blame] | 196 | cr0 = read_cr0(); |
| 197 | cr2 = read_cr2(); |
| 198 | cr3 = read_cr3(); |
Zachary Amsden | ff6e8c0 | 2006-01-06 00:11:50 -0800 | [diff] [blame] | 199 | cr4 = read_cr4_safe(); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 200 | printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", |
| 201 | cr0, cr2, cr3, cr4); |
Alan Stern | bb1995d | 2007-07-21 17:10:42 +0200 | [diff] [blame] | 202 | |
| 203 | get_debugreg(d0, 0); |
| 204 | get_debugreg(d1, 1); |
| 205 | get_debugreg(d2, 2); |
| 206 | get_debugreg(d3, 3); |
| 207 | printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", |
| 208 | d0, d1, d2, d3); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 209 | |
Alan Stern | bb1995d | 2007-07-21 17:10:42 +0200 | [diff] [blame] | 210 | get_debugreg(d6, 6); |
| 211 | get_debugreg(d7, 7); |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 212 | printk("DR6: %08lx DR7: %08lx\n", |
| 213 | d6, d7); |
| 214 | } |
Alan Stern | bb1995d | 2007-07-21 17:10:42 +0200 | [diff] [blame] | 215 | |
Pavel Emelyanov | 9d975eb | 2007-10-19 20:35:03 +0200 | [diff] [blame] | 216 | void show_regs(struct pt_regs *regs) |
| 217 | { |
| 218 | __show_registers(regs, 1); |
Arjan van de Ven | 5bc27dc | 2008-01-30 13:33:07 +0100 | [diff] [blame] | 219 | show_trace(NULL, regs, ®s->sp, regs->bp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | } |
| 221 | |
| 222 | /* |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 223 | * This gets run with %bx containing the |
| 224 | * function to call, and %dx containing |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | * the "args". |
| 226 | */ |
| 227 | extern void kernel_thread_helper(void); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | |
| 229 | /* |
| 230 | * Create a kernel thread |
| 231 | */ |
| 232 | int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) |
| 233 | { |
| 234 | struct pt_regs regs; |
| 235 | |
| 236 | memset(®s, 0, sizeof(regs)); |
| 237 | |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 238 | regs.bx = (unsigned long) fn; |
| 239 | regs.dx = (unsigned long) arg; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 241 | regs.ds = __USER_DS; |
| 242 | regs.es = __USER_DS; |
| 243 | regs.fs = __KERNEL_PERCPU; |
| 244 | regs.orig_ax = -1; |
| 245 | regs.ip = (unsigned long) kernel_thread_helper; |
| 246 | regs.cs = __KERNEL_CS | get_kernel_rpl(); |
| 247 | regs.flags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | |
| 249 | /* Ok, create the new process.. */ |
Andi Kleen | 8cf2c51 | 2006-10-21 18:37:02 +0200 | [diff] [blame] | 250 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | } |
Alexey Dobriyan | 129f694 | 2005-06-23 00:08:33 -0700 | [diff] [blame] | 252 | EXPORT_SYMBOL(kernel_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | |
| 254 | /* |
| 255 | * Free current thread data structures etc.. |
| 256 | */ |
| 257 | void exit_thread(void) |
| 258 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 259 | /* The process may have allocated an io port bitmap... nuke it. */ |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 260 | if (unlikely(test_thread_flag(TIF_IO_BITMAP))) { |
| 261 | struct task_struct *tsk = current; |
| 262 | struct thread_struct *t = &tsk->thread; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | int cpu = get_cpu(); |
| 264 | struct tss_struct *tss = &per_cpu(init_tss, cpu); |
| 265 | |
| 266 | kfree(t->io_bitmap_ptr); |
| 267 | t->io_bitmap_ptr = NULL; |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 268 | clear_thread_flag(TIF_IO_BITMAP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | /* |
| 270 | * Careful, clear this in the TSS too: |
| 271 | */ |
| 272 | memset(tss->io_bitmap, 0xff, tss->io_bitmap_max); |
| 273 | t->io_bitmap_max = 0; |
| 274 | tss->io_bitmap_owner = NULL; |
| 275 | tss->io_bitmap_max = 0; |
Rusty Russell | a75c54f | 2007-05-02 19:27:13 +0200 | [diff] [blame] | 276 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | put_cpu(); |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | void flush_thread(void) |
| 282 | { |
| 283 | struct task_struct *tsk = current; |
| 284 | |
Roland McGrath | 0f53409 | 2008-01-30 13:30:59 +0100 | [diff] [blame] | 285 | tsk->thread.debugreg0 = 0; |
| 286 | tsk->thread.debugreg1 = 0; |
| 287 | tsk->thread.debugreg2 = 0; |
| 288 | tsk->thread.debugreg3 = 0; |
| 289 | tsk->thread.debugreg6 = 0; |
| 290 | tsk->thread.debugreg7 = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 292 | clear_tsk_thread_flag(tsk, TIF_DEBUG); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | /* |
| 294 | * Forget coprocessor state.. |
| 295 | */ |
Suresh Siddha | 75118a8 | 2008-06-13 15:47:12 -0700 | [diff] [blame] | 296 | tsk->fpu_counter = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | clear_fpu(tsk); |
| 298 | clear_used_math(); |
| 299 | } |
| 300 | |
| 301 | void release_thread(struct task_struct *dead_task) |
| 302 | { |
Zachary Amsden | 2684927 | 2006-01-06 00:11:59 -0800 | [diff] [blame] | 303 | BUG_ON(dead_task->mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | release_vm86_irqs(dead_task); |
| 305 | } |
| 306 | |
| 307 | /* |
| 308 | * This gets called before we allocate a new thread and copy |
| 309 | * the current task into it. |
| 310 | */ |
| 311 | void prepare_to_copy(struct task_struct *tsk) |
| 312 | { |
| 313 | unlazy_fpu(tsk); |
| 314 | } |
| 315 | |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 316 | int copy_thread(int nr, unsigned long clone_flags, unsigned long sp, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | unsigned long unused, |
| 318 | struct task_struct * p, struct pt_regs * regs) |
| 319 | { |
| 320 | struct pt_regs * childregs; |
| 321 | struct task_struct *tsk; |
| 322 | int err; |
| 323 | |
akpm@osdl.org | 07b047f | 2006-01-12 01:05:41 -0800 | [diff] [blame] | 324 | childregs = task_pt_regs(p); |
Alexander Nyberg | f48d966 | 2005-05-05 16:15:03 -0700 | [diff] [blame] | 325 | *childregs = *regs; |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 326 | childregs->ax = 0; |
| 327 | childregs->sp = sp; |
Alexander Nyberg | f48d966 | 2005-05-05 16:15:03 -0700 | [diff] [blame] | 328 | |
H. Peter Anvin | faca622 | 2008-01-30 13:31:02 +0100 | [diff] [blame] | 329 | p->thread.sp = (unsigned long) childregs; |
| 330 | p->thread.sp0 = (unsigned long) (childregs+1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | |
H. Peter Anvin | faca622 | 2008-01-30 13:31:02 +0100 | [diff] [blame] | 332 | p->thread.ip = (unsigned long) ret_from_fork; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | |
Hiroshi Shimamoto | 6612538 | 2008-01-30 13:31:03 +0100 | [diff] [blame] | 334 | savesegment(gs, p->thread.gs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | |
| 336 | tsk = current; |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 337 | if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { |
Alexey Dobriyan | 52978be | 2006-09-30 23:27:21 -0700 | [diff] [blame] | 338 | p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, |
| 339 | IO_BITMAP_BYTES, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | if (!p->thread.io_bitmap_ptr) { |
| 341 | p->thread.io_bitmap_max = 0; |
| 342 | return -ENOMEM; |
| 343 | } |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 344 | set_tsk_thread_flag(p, TIF_IO_BITMAP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | } |
| 346 | |
Roland McGrath | efd1ca5 | 2008-01-30 13:30:46 +0100 | [diff] [blame] | 347 | err = 0; |
| 348 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | /* |
| 350 | * Set a new TLS for the child thread? |
| 351 | */ |
Roland McGrath | efd1ca5 | 2008-01-30 13:30:46 +0100 | [diff] [blame] | 352 | if (clone_flags & CLONE_SETTLS) |
| 353 | err = do_set_thread_area(p, -1, |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 354 | (struct user_desc __user *)childregs->si, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | if (err && p->thread.io_bitmap_ptr) { |
| 357 | kfree(p->thread.io_bitmap_ptr); |
| 358 | p->thread.io_bitmap_max = 0; |
| 359 | } |
| 360 | return err; |
| 361 | } |
| 362 | |
Ingo Molnar | 513ad84 | 2008-02-21 05:18:40 +0100 | [diff] [blame] | 363 | void |
| 364 | start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) |
| 365 | { |
| 366 | __asm__("movl %0, %%gs" :: "r"(0)); |
| 367 | regs->fs = 0; |
| 368 | set_fs(USER_DS); |
| 369 | regs->ds = __USER_DS; |
| 370 | regs->es = __USER_DS; |
| 371 | regs->ss = __USER_DS; |
| 372 | regs->cs = __USER_CS; |
| 373 | regs->ip = new_ip; |
| 374 | regs->sp = new_sp; |
Suresh Siddha | aa283f4 | 2008-03-10 15:28:05 -0700 | [diff] [blame] | 375 | /* |
| 376 | * Free the old FP and other extended state |
| 377 | */ |
| 378 | free_thread_xstate(current); |
Ingo Molnar | 513ad84 | 2008-02-21 05:18:40 +0100 | [diff] [blame] | 379 | } |
| 380 | EXPORT_SYMBOL_GPL(start_thread); |
| 381 | |
Jan Beulich | bdb4f15 | 2008-01-30 13:31:21 +0100 | [diff] [blame] | 382 | static void hard_disable_TSC(void) |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 383 | { |
| 384 | write_cr4(read_cr4() | X86_CR4_TSD); |
| 385 | } |
Erik Bosman | 529e25f | 2008-04-14 00:24:18 +0200 | [diff] [blame] | 386 | |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 387 | void disable_TSC(void) |
| 388 | { |
| 389 | preempt_disable(); |
| 390 | if (!test_and_set_thread_flag(TIF_NOTSC)) |
| 391 | /* |
| 392 | * Must flip the CPU state synchronously with |
| 393 | * TIF_NOTSC in the current running context. |
| 394 | */ |
| 395 | hard_disable_TSC(); |
| 396 | preempt_enable(); |
| 397 | } |
Erik Bosman | 529e25f | 2008-04-14 00:24:18 +0200 | [diff] [blame] | 398 | |
Jan Beulich | bdb4f15 | 2008-01-30 13:31:21 +0100 | [diff] [blame] | 399 | static void hard_enable_TSC(void) |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 400 | { |
| 401 | write_cr4(read_cr4() & ~X86_CR4_TSD); |
| 402 | } |
Erik Bosman | 529e25f | 2008-04-14 00:24:18 +0200 | [diff] [blame] | 403 | |
Ingo Molnar | a4928cf | 2008-04-23 13:20:56 +0200 | [diff] [blame] | 404 | static void enable_TSC(void) |
Erik Bosman | 529e25f | 2008-04-14 00:24:18 +0200 | [diff] [blame] | 405 | { |
| 406 | preempt_disable(); |
| 407 | if (test_and_clear_thread_flag(TIF_NOTSC)) |
| 408 | /* |
| 409 | * Must flip the CPU state synchronously with |
| 410 | * TIF_NOTSC in the current running context. |
| 411 | */ |
| 412 | hard_enable_TSC(); |
| 413 | preempt_enable(); |
| 414 | } |
| 415 | |
| 416 | int get_tsc_mode(unsigned long adr) |
| 417 | { |
| 418 | unsigned int val; |
| 419 | |
| 420 | if (test_thread_flag(TIF_NOTSC)) |
| 421 | val = PR_TSC_SIGSEGV; |
| 422 | else |
| 423 | val = PR_TSC_ENABLE; |
| 424 | |
| 425 | return put_user(val, (unsigned int __user *)adr); |
| 426 | } |
| 427 | |
| 428 | int set_tsc_mode(unsigned int val) |
| 429 | { |
| 430 | if (val == PR_TSC_SIGSEGV) |
| 431 | disable_TSC(); |
| 432 | else if (val == PR_TSC_ENABLE) |
| 433 | enable_TSC(); |
| 434 | else |
| 435 | return -EINVAL; |
| 436 | |
| 437 | return 0; |
| 438 | } |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 439 | |
| 440 | static noinline void |
| 441 | __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, |
| 442 | struct tss_struct *tss) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | { |
Roland McGrath | 7e99160 | 2008-01-30 13:30:54 +0100 | [diff] [blame] | 444 | struct thread_struct *prev, *next; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 445 | unsigned long debugctl; |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 446 | |
Roland McGrath | 7e99160 | 2008-01-30 13:30:54 +0100 | [diff] [blame] | 447 | prev = &prev_p->thread; |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 448 | next = &next_p->thread; |
| 449 | |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 450 | debugctl = prev->debugctlmsr; |
| 451 | if (next->ds_area_msr != prev->ds_area_msr) { |
| 452 | /* we clear debugctl to make sure DS |
| 453 | * is not in use when we change it */ |
| 454 | debugctl = 0; |
Jan Beulich | 5b0e508 | 2008-03-10 13:11:17 +0000 | [diff] [blame] | 455 | update_debugctlmsr(0); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 456 | wrmsr(MSR_IA32_DS_AREA, next->ds_area_msr, 0); |
| 457 | } |
| 458 | |
| 459 | if (next->debugctlmsr != debugctl) |
Jan Beulich | 5b0e508 | 2008-03-10 13:11:17 +0000 | [diff] [blame] | 460 | update_debugctlmsr(next->debugctlmsr); |
Roland McGrath | 7e99160 | 2008-01-30 13:30:54 +0100 | [diff] [blame] | 461 | |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 462 | if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { |
Roland McGrath | 0f53409 | 2008-01-30 13:30:59 +0100 | [diff] [blame] | 463 | set_debugreg(next->debugreg0, 0); |
| 464 | set_debugreg(next->debugreg1, 1); |
| 465 | set_debugreg(next->debugreg2, 2); |
| 466 | set_debugreg(next->debugreg3, 3); |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 467 | /* no 4 and 5 */ |
Roland McGrath | 0f53409 | 2008-01-30 13:30:59 +0100 | [diff] [blame] | 468 | set_debugreg(next->debugreg6, 6); |
| 469 | set_debugreg(next->debugreg7, 7); |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 470 | } |
| 471 | |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 472 | if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^ |
| 473 | test_tsk_thread_flag(next_p, TIF_NOTSC)) { |
| 474 | /* prev and next are different */ |
| 475 | if (test_tsk_thread_flag(next_p, TIF_NOTSC)) |
| 476 | hard_disable_TSC(); |
| 477 | else |
| 478 | hard_enable_TSC(); |
| 479 | } |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 480 | |
Ingo Molnar | b4ef95d | 2008-02-26 09:40:27 +0100 | [diff] [blame] | 481 | #ifdef X86_BTS |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 482 | if (test_tsk_thread_flag(prev_p, TIF_BTS_TRACE_TS)) |
| 483 | ptrace_bts_take_timestamp(prev_p, BTS_TASK_DEPARTS); |
| 484 | |
| 485 | if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS)) |
| 486 | ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES); |
Ingo Molnar | b4ef95d | 2008-02-26 09:40:27 +0100 | [diff] [blame] | 487 | #endif |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 488 | |
| 489 | |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 490 | if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | /* |
| 492 | * Disable the bitmap via an invalid offset. We still cache |
| 493 | * the previous bitmap owner and the IO bitmap contents: |
| 494 | */ |
Rusty Russell | a75c54f | 2007-05-02 19:27:13 +0200 | [diff] [blame] | 495 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | return; |
| 497 | } |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 498 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 499 | if (likely(next == tss->io_bitmap_owner)) { |
| 500 | /* |
| 501 | * Previous owner of the bitmap (hence the bitmap content) |
| 502 | * matches the next task, we dont have to do anything but |
| 503 | * to set a valid offset in the TSS: |
| 504 | */ |
Rusty Russell | a75c54f | 2007-05-02 19:27:13 +0200 | [diff] [blame] | 505 | tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | return; |
| 507 | } |
| 508 | /* |
| 509 | * Lazy TSS's I/O bitmap copy. We set an invalid offset here |
| 510 | * and we let the task to get a GPF in case an I/O instruction |
| 511 | * is performed. The handler of the GPF will verify that the |
| 512 | * faulting task has a valid I/O bitmap and, it true, does the |
| 513 | * real copy and restart the instruction. This will save us |
| 514 | * redundant copies when the currently switched task does not |
| 515 | * perform any I/O during its timeslice. |
| 516 | */ |
Rusty Russell | a75c54f | 2007-05-02 19:27:13 +0200 | [diff] [blame] | 517 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | |
| 520 | /* |
| 521 | * switch_to(x,yn) should switch tasks from x to y. |
| 522 | * |
| 523 | * We fsave/fwait so that an exception goes off at the right time |
| 524 | * (as a call from the fsave or fwait in effect) rather than to |
| 525 | * the wrong process. Lazy FP saving no longer makes any sense |
| 526 | * with modern CPU's, and this simplifies a lot of things (SMP |
| 527 | * and UP become the same). |
| 528 | * |
| 529 | * NOTE! We used to use the x86 hardware context switching. The |
| 530 | * reason for not using it any more becomes apparent when you |
| 531 | * try to recover gracefully from saved state that is no longer |
| 532 | * valid (stale segment register values in particular). With the |
| 533 | * hardware task-switch, there is no way to fix up bad state in |
| 534 | * a reasonable manner. |
| 535 | * |
| 536 | * The fact that Intel documents the hardware task-switching to |
| 537 | * be slow is a fairly red herring - this code is not noticeably |
| 538 | * faster. However, there _is_ some room for improvement here, |
| 539 | * so the performance issues may eventually be a valid point. |
| 540 | * More important, however, is the fact that this allows us much |
| 541 | * more flexibility. |
| 542 | * |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 543 | * The return value (in %ax) will be the "prev" task after |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | * the task-switch, and shows up in ret_from_fork in entry.S, |
| 545 | * for example. |
| 546 | */ |
Harvey Harrison | 75604d7 | 2008-01-30 13:31:17 +0100 | [diff] [blame] | 547 | struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | { |
| 549 | struct thread_struct *prev = &prev_p->thread, |
| 550 | *next = &next_p->thread; |
| 551 | int cpu = smp_processor_id(); |
| 552 | struct tss_struct *tss = &per_cpu(init_tss, cpu); |
| 553 | |
| 554 | /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ |
| 555 | |
| 556 | __unlazy_fpu(prev_p); |
| 557 | |
Chuck Ebbert | acc2076 | 2006-12-07 02:14:01 +0100 | [diff] [blame] | 558 | |
| 559 | /* we're going to use this soon, after a few expensive things */ |
| 560 | if (next_p->fpu_counter > 5) |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 561 | prefetch(next->xstate); |
Chuck Ebbert | acc2076 | 2006-12-07 02:14:01 +0100 | [diff] [blame] | 562 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | /* |
Zachary Amsden | e7a2ff5 | 2005-09-03 15:56:39 -0700 | [diff] [blame] | 564 | * Reload esp0. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | */ |
H. Peter Anvin | faca622 | 2008-01-30 13:31:02 +0100 | [diff] [blame] | 566 | load_sp0(tss, next); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | |
| 568 | /* |
Jeremy Fitzhardinge | 464d1a7 | 2007-02-13 13:26:20 +0100 | [diff] [blame] | 569 | * Save away %gs. No need to save %fs, as it was saved on the |
Jeremy Fitzhardinge | f95d47c | 2006-12-07 02:14:02 +0100 | [diff] [blame] | 570 | * stack on entry. No need to save %es and %ds, as those are |
| 571 | * always kernel segments while inside the kernel. Doing this |
| 572 | * before setting the new TLS descriptors avoids the situation |
| 573 | * where we temporarily have non-reloadable segments in %fs |
| 574 | * and %gs. This could be an issue if the NMI handler ever |
| 575 | * used %fs or %gs (it does not today), or if the kernel is |
| 576 | * running inside of a hypervisor layer. |
Zachary Amsden | e7a2ff5 | 2005-09-03 15:56:39 -0700 | [diff] [blame] | 577 | */ |
Jeremy Fitzhardinge | 464d1a7 | 2007-02-13 13:26:20 +0100 | [diff] [blame] | 578 | savesegment(gs, prev->gs); |
Zachary Amsden | e7a2ff5 | 2005-09-03 15:56:39 -0700 | [diff] [blame] | 579 | |
| 580 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | * Load the per-thread Thread-Local Storage descriptor. |
| 582 | */ |
| 583 | load_TLS(next, cpu); |
| 584 | |
| 585 | /* |
Zachary Amsden | 8b15114 | 2007-02-13 13:26:21 +0100 | [diff] [blame] | 586 | * Restore IOPL if needed. In normal use, the flags restore |
| 587 | * in the switch assembly will handle this. But if the kernel |
| 588 | * is running virtualized at a non-zero CPL, the popf will |
| 589 | * not restore flags, so it must be done in a separate step. |
| 590 | */ |
| 591 | if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) |
| 592 | set_iopl_mask(next->iopl); |
| 593 | |
| 594 | /* |
Stephane Eranian | b3cf257 | 2006-07-09 21:12:39 -0400 | [diff] [blame] | 595 | * Now maybe handle debug registers and/or IO bitmaps |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | */ |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 597 | if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV || |
| 598 | task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT)) |
| 599 | __switch_to_xtra(prev_p, next_p, tss); |
Andrea Arcangeli | ffaa8bd | 2005-06-27 14:36:36 -0700 | [diff] [blame] | 600 | |
Zachary Amsden | 9226d12 | 2007-02-13 13:26:21 +0100 | [diff] [blame] | 601 | /* |
| 602 | * Leave lazy mode, flushing any hypercalls made here. |
| 603 | * This must be done before restoring TLS segments so |
| 604 | * the GDT and LDT are properly updated, and must be |
| 605 | * done before math_state_restore, so the TS bit is up |
| 606 | * to date. |
| 607 | */ |
| 608 | arch_leave_lazy_cpu_mode(); |
| 609 | |
Chuck Ebbert | acc2076 | 2006-12-07 02:14:01 +0100 | [diff] [blame] | 610 | /* If the task has used fpu the last 5 timeslices, just do a full |
| 611 | * restore of the math state immediately to avoid the trap; the |
| 612 | * chances of needing FPU soon are obviously high now |
Suresh Siddha | 870568b | 2008-06-02 15:57:27 -0700 | [diff] [blame] | 613 | * |
| 614 | * tsk_used_math() checks prevent calling math_state_restore(), |
| 615 | * which can sleep in the case of !tsk_used_math() |
Chuck Ebbert | acc2076 | 2006-12-07 02:14:01 +0100 | [diff] [blame] | 616 | */ |
Suresh Siddha | 870568b | 2008-06-02 15:57:27 -0700 | [diff] [blame] | 617 | if (tsk_used_math(next_p) && next_p->fpu_counter > 5) |
Chuck Ebbert | acc2076 | 2006-12-07 02:14:01 +0100 | [diff] [blame] | 618 | math_state_restore(); |
| 619 | |
Zachary Amsden | 9226d12 | 2007-02-13 13:26:21 +0100 | [diff] [blame] | 620 | /* |
| 621 | * Restore %gs if needed (which is common) |
| 622 | */ |
| 623 | if (prev->gs | next->gs) |
| 624 | loadsegment(gs, next->gs); |
| 625 | |
Jeremy Fitzhardinge | 7c3576d | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 626 | x86_write_percpu(current_task, next_p); |
Zachary Amsden | 9226d12 | 2007-02-13 13:26:21 +0100 | [diff] [blame] | 627 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | return prev_p; |
| 629 | } |
| 630 | |
| 631 | asmlinkage int sys_fork(struct pt_regs regs) |
| 632 | { |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 633 | return do_fork(SIGCHLD, regs.sp, ®s, 0, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 634 | } |
| 635 | |
| 636 | asmlinkage int sys_clone(struct pt_regs regs) |
| 637 | { |
| 638 | unsigned long clone_flags; |
| 639 | unsigned long newsp; |
| 640 | int __user *parent_tidptr, *child_tidptr; |
| 641 | |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 642 | clone_flags = regs.bx; |
| 643 | newsp = regs.cx; |
| 644 | parent_tidptr = (int __user *)regs.dx; |
| 645 | child_tidptr = (int __user *)regs.di; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | if (!newsp) |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 647 | newsp = regs.sp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr); |
| 649 | } |
| 650 | |
| 651 | /* |
| 652 | * This is trivial, and on the face of it looks like it |
| 653 | * could equally well be done in user mode. |
| 654 | * |
| 655 | * Not so, for quite unobvious reasons - register pressure. |
| 656 | * In user mode vfork() cannot have a stack frame, and if |
| 657 | * done by calling the "clone()" system call directly, you |
| 658 | * do not have enough call-clobbered registers to hold all |
| 659 | * the information you need. |
| 660 | */ |
| 661 | asmlinkage int sys_vfork(struct pt_regs regs) |
| 662 | { |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 663 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.sp, ®s, 0, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | } |
| 665 | |
| 666 | /* |
| 667 | * sys_execve() executes a new program. |
| 668 | */ |
| 669 | asmlinkage int sys_execve(struct pt_regs regs) |
| 670 | { |
| 671 | int error; |
| 672 | char * filename; |
| 673 | |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 674 | filename = getname((char __user *) regs.bx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | error = PTR_ERR(filename); |
| 676 | if (IS_ERR(filename)) |
| 677 | goto out; |
| 678 | error = do_execve(filename, |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 679 | (char __user * __user *) regs.cx, |
| 680 | (char __user * __user *) regs.dx, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | ®s); |
| 682 | if (error == 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | /* Make sure we don't return using sysenter.. */ |
| 684 | set_thread_flag(TIF_IRET); |
| 685 | } |
| 686 | putname(filename); |
| 687 | out: |
| 688 | return error; |
| 689 | } |
| 690 | |
| 691 | #define top_esp (THREAD_SIZE - sizeof(unsigned long)) |
| 692 | #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long)) |
| 693 | |
| 694 | unsigned long get_wchan(struct task_struct *p) |
| 695 | { |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 696 | unsigned long bp, sp, ip; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | unsigned long stack_page; |
| 698 | int count = 0; |
| 699 | if (!p || p == current || p->state == TASK_RUNNING) |
| 700 | return 0; |
Al Viro | 65e0fdf | 2006-01-12 01:05:41 -0800 | [diff] [blame] | 701 | stack_page = (unsigned long)task_stack_page(p); |
H. Peter Anvin | faca622 | 2008-01-30 13:31:02 +0100 | [diff] [blame] | 702 | sp = p->thread.sp; |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 703 | if (!stack_page || sp < stack_page || sp > top_esp+stack_page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | return 0; |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 705 | /* include/asm-i386/system.h:switch_to() pushes bp last. */ |
| 706 | bp = *(unsigned long *) sp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 707 | do { |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 708 | if (bp < stack_page || bp > top_ebp+stack_page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | return 0; |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 710 | ip = *(unsigned long *) (bp+4); |
| 711 | if (!in_sched_functions(ip)) |
| 712 | return ip; |
| 713 | bp = *(unsigned long *) bp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 714 | } while (count++ < 16); |
| 715 | return 0; |
| 716 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 718 | unsigned long arch_align_stack(unsigned long sp) |
| 719 | { |
Andi Kleen | c16b63e | 2006-09-26 10:52:28 +0200 | [diff] [blame] | 720 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | sp -= get_random_int() % 8192; |
| 722 | return sp & ~0xf; |
| 723 | } |
Jiri Kosina | c1d171a | 2008-01-30 13:30:40 +0100 | [diff] [blame] | 724 | |
| 725 | unsigned long arch_randomize_brk(struct mm_struct *mm) |
| 726 | { |
| 727 | unsigned long range_end = mm->brk + 0x02000000; |
| 728 | return randomize_range(mm->brk, range_end, 0) ? : mm->brk; |
| 729 | } |