Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/i386/kernel/process.c |
| 3 | * |
| 4 | * Copyright (C) 1995 Linus Torvalds |
| 5 | * |
| 6 | * Pentium III FXSR, SSE support |
| 7 | * Gareth Hughes <gareth@valinux.com>, May 2000 |
| 8 | */ |
| 9 | |
| 10 | /* |
| 11 | * This file handles the architecture-dependent parts of process handling.. |
| 12 | */ |
| 13 | |
| 14 | #include <stdarg.h> |
| 15 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 16 | #include <linux/cpu.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/errno.h> |
| 18 | #include <linux/sched.h> |
| 19 | #include <linux/fs.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/mm.h> |
| 22 | #include <linux/elfcore.h> |
| 23 | #include <linux/smp.h> |
| 24 | #include <linux/smp_lock.h> |
| 25 | #include <linux/stddef.h> |
| 26 | #include <linux/slab.h> |
| 27 | #include <linux/vmalloc.h> |
| 28 | #include <linux/user.h> |
| 29 | #include <linux/a.out.h> |
| 30 | #include <linux/interrupt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/utsname.h> |
| 32 | #include <linux/delay.h> |
| 33 | #include <linux/reboot.h> |
| 34 | #include <linux/init.h> |
| 35 | #include <linux/mc146818rtc.h> |
| 36 | #include <linux/module.h> |
| 37 | #include <linux/kallsyms.h> |
| 38 | #include <linux/ptrace.h> |
| 39 | #include <linux/random.h> |
| 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> |
Matt Mackall | 64ca900 | 2006-01-08 01:05:26 -0800 | [diff] [blame] | 49 | #include <asm/vm86.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | #ifdef CONFIG_MATH_EMULATION |
| 51 | #include <asm/math_emu.h> |
| 52 | #endif |
| 53 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | #include <linux/err.h> |
| 55 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 56 | #include <asm/tlbflush.h> |
| 57 | #include <asm/cpu.h> |
| 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 | |
| 61 | static int hlt_counter; |
| 62 | |
| 63 | unsigned long boot_option_idle_override = 0; |
| 64 | EXPORT_SYMBOL(boot_option_idle_override); |
| 65 | |
| 66 | /* |
| 67 | * Return saved PC of a blocked thread. |
| 68 | */ |
| 69 | unsigned long thread_saved_pc(struct task_struct *tsk) |
| 70 | { |
| 71 | return ((unsigned long *)tsk->thread.esp)[3]; |
| 72 | } |
| 73 | |
| 74 | /* |
| 75 | * Powermanagement idle function, if any.. |
| 76 | */ |
| 77 | void (*pm_idle)(void); |
Alexey Dobriyan | 129f694 | 2005-06-23 00:08:33 -0700 | [diff] [blame] | 78 | EXPORT_SYMBOL(pm_idle); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | static DEFINE_PER_CPU(unsigned int, cpu_idle_state); |
| 80 | |
| 81 | void disable_hlt(void) |
| 82 | { |
| 83 | hlt_counter++; |
| 84 | } |
| 85 | |
| 86 | EXPORT_SYMBOL(disable_hlt); |
| 87 | |
| 88 | void enable_hlt(void) |
| 89 | { |
| 90 | hlt_counter--; |
| 91 | } |
| 92 | |
| 93 | EXPORT_SYMBOL(enable_hlt); |
| 94 | |
| 95 | /* |
| 96 | * We use this if we don't have any better |
| 97 | * idle routine.. |
| 98 | */ |
| 99 | void default_idle(void) |
| 100 | { |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 101 | local_irq_enable(); |
| 102 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | if (!hlt_counter && boot_cpu_data.hlt_works_ok) { |
Andi Kleen | 495ab9c | 2006-06-26 13:59:11 +0200 | [diff] [blame] | 104 | current_thread_info()->status &= ~TS_POLLING; |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 105 | smp_mb__after_clear_bit(); |
| 106 | while (!need_resched()) { |
| 107 | local_irq_disable(); |
| 108 | if (!need_resched()) |
| 109 | safe_halt(); |
| 110 | else |
| 111 | local_irq_enable(); |
| 112 | } |
Andi Kleen | 495ab9c | 2006-06-26 13:59:11 +0200 | [diff] [blame] | 113 | current_thread_info()->status |= TS_POLLING; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | } else { |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 115 | while (!need_resched()) |
| 116 | cpu_relax(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | } |
| 118 | } |
Alexey Dobriyan | 129f694 | 2005-06-23 00:08:33 -0700 | [diff] [blame] | 119 | #ifdef CONFIG_APM_MODULE |
| 120 | EXPORT_SYMBOL(default_idle); |
| 121 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | |
| 123 | /* |
| 124 | * On SMP it's slightly faster (but much more power-consuming!) |
| 125 | * to poll the ->work.need_resched flag instead of waiting for the |
| 126 | * cross-CPU IPI to arrive. Use this option with caution. |
| 127 | */ |
| 128 | static void poll_idle (void) |
| 129 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | local_irq_enable(); |
| 131 | |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 132 | asm volatile( |
| 133 | "2:" |
| 134 | "testl %0, %1;" |
| 135 | "rep; nop;" |
| 136 | "je 2b;" |
| 137 | : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | } |
| 139 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 140 | #ifdef CONFIG_HOTPLUG_CPU |
| 141 | #include <asm/nmi.h> |
| 142 | /* We don't actually take CPU down, just spin without interrupts. */ |
| 143 | static inline void play_dead(void) |
| 144 | { |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 145 | /* This must be done before dead CPU ack */ |
| 146 | cpu_exit_clear(); |
| 147 | wbinvd(); |
| 148 | mb(); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 149 | /* Ack it */ |
| 150 | __get_cpu_var(cpu_state) = CPU_DEAD; |
| 151 | |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 152 | /* |
| 153 | * With physical CPU hotplug, we should halt the cpu |
| 154 | */ |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 155 | local_irq_disable(); |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 156 | while (1) |
Zachary Amsden | f2ab446 | 2005-09-03 15:56:42 -0700 | [diff] [blame] | 157 | halt(); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 158 | } |
| 159 | #else |
| 160 | static inline void play_dead(void) |
| 161 | { |
| 162 | BUG(); |
| 163 | } |
| 164 | #endif /* CONFIG_HOTPLUG_CPU */ |
| 165 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | /* |
| 167 | * The idle thread. There's no useful work to be |
| 168 | * done, so just try to conserve power and have a |
| 169 | * low exit latency (ie sit in a loop waiting for |
| 170 | * somebody to say that they'd like to reschedule) |
| 171 | */ |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 172 | void cpu_idle(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | { |
Nick Piggin | 5bfb5d6 | 2005-11-08 21:39:01 -0800 | [diff] [blame] | 174 | int cpu = smp_processor_id(); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 175 | |
Andi Kleen | 495ab9c | 2006-06-26 13:59:11 +0200 | [diff] [blame] | 176 | current_thread_info()->status |= TS_POLLING; |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 177 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | /* endless idle loop with no priority at all */ |
| 179 | while (1) { |
| 180 | while (!need_resched()) { |
| 181 | void (*idle)(void); |
| 182 | |
| 183 | if (__get_cpu_var(cpu_idle_state)) |
| 184 | __get_cpu_var(cpu_idle_state) = 0; |
| 185 | |
| 186 | rmb(); |
| 187 | idle = pm_idle; |
| 188 | |
| 189 | if (!idle) |
| 190 | idle = default_idle; |
| 191 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 192 | if (cpu_is_offline(cpu)) |
| 193 | play_dead(); |
| 194 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | __get_cpu_var(irq_stat).idle_timestamp = jiffies; |
| 196 | idle(); |
| 197 | } |
Nick Piggin | 5bfb5d6 | 2005-11-08 21:39:01 -0800 | [diff] [blame] | 198 | preempt_enable_no_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | schedule(); |
Nick Piggin | 5bfb5d6 | 2005-11-08 21:39:01 -0800 | [diff] [blame] | 200 | preempt_disable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | } |
| 202 | } |
| 203 | |
| 204 | void cpu_idle_wait(void) |
| 205 | { |
| 206 | unsigned int cpu, this_cpu = get_cpu(); |
| 207 | cpumask_t map; |
| 208 | |
| 209 | set_cpus_allowed(current, cpumask_of_cpu(this_cpu)); |
| 210 | put_cpu(); |
| 211 | |
| 212 | cpus_clear(map); |
| 213 | for_each_online_cpu(cpu) { |
| 214 | per_cpu(cpu_idle_state, cpu) = 1; |
| 215 | cpu_set(cpu, map); |
| 216 | } |
| 217 | |
| 218 | __get_cpu_var(cpu_idle_state) = 0; |
| 219 | |
| 220 | wmb(); |
| 221 | do { |
| 222 | ssleep(1); |
| 223 | for_each_online_cpu(cpu) { |
| 224 | if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu)) |
| 225 | cpu_clear(cpu, map); |
| 226 | } |
| 227 | cpus_and(map, map, cpu_online_map); |
| 228 | } while (!cpus_empty(map)); |
| 229 | } |
| 230 | EXPORT_SYMBOL_GPL(cpu_idle_wait); |
| 231 | |
| 232 | /* |
| 233 | * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, |
| 234 | * which can obviate IPI to trigger checking of need_resched. |
| 235 | * We execute MONITOR against need_resched and enter optimized wait state |
| 236 | * through MWAIT. Whenever someone changes need_resched, we would be woken |
| 237 | * up from MWAIT (without an IPI). |
| 238 | */ |
| 239 | static void mwait_idle(void) |
| 240 | { |
| 241 | local_irq_enable(); |
| 242 | |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 243 | while (!need_resched()) { |
| 244 | __monitor((void *)¤t_thread_info()->flags, 0, 0); |
| 245 | smp_mb(); |
| 246 | if (need_resched()) |
| 247 | break; |
| 248 | __mwait(0, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | } |
| 250 | } |
| 251 | |
Li Shaohua | 0bb3184 | 2005-06-25 14:54:55 -0700 | [diff] [blame] | 252 | void __devinit select_idle_routine(const struct cpuinfo_x86 *c) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | { |
| 254 | if (cpu_has(c, X86_FEATURE_MWAIT)) { |
| 255 | printk("monitor/mwait feature present.\n"); |
| 256 | /* |
| 257 | * Skip, if setup has overridden idle. |
| 258 | * One CPU supports mwait => All CPUs supports mwait |
| 259 | */ |
| 260 | if (!pm_idle) { |
| 261 | printk("using mwait in idle threads.\n"); |
| 262 | pm_idle = mwait_idle; |
| 263 | } |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | static int __init idle_setup (char *str) |
| 268 | { |
| 269 | if (!strncmp(str, "poll", 4)) { |
| 270 | printk("using polling idle threads.\n"); |
| 271 | pm_idle = poll_idle; |
| 272 | #ifdef CONFIG_X86_SMP |
| 273 | if (smp_num_siblings > 1) |
| 274 | printk("WARNING: polling idle and HT enabled, performance may degrade.\n"); |
| 275 | #endif |
| 276 | } else if (!strncmp(str, "halt", 4)) { |
| 277 | printk("using halt in idle threads.\n"); |
| 278 | pm_idle = default_idle; |
| 279 | } |
| 280 | |
| 281 | boot_option_idle_override = 1; |
| 282 | return 1; |
| 283 | } |
| 284 | |
| 285 | __setup("idle=", idle_setup); |
| 286 | |
| 287 | void show_regs(struct pt_regs * regs) |
| 288 | { |
| 289 | unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; |
| 290 | |
| 291 | printk("\n"); |
| 292 | printk("Pid: %d, comm: %20s\n", current->pid, current->comm); |
| 293 | printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id()); |
| 294 | print_symbol("EIP is at %s\n", regs->eip); |
| 295 | |
Jan Beulich | db753bd | 2006-03-23 02:59:46 -0800 | [diff] [blame] | 296 | if (user_mode_vm(regs)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp); |
Chuck Ebbert | b53e8f6 | 2006-02-04 23:28:04 -0800 | [diff] [blame] | 298 | printk(" EFLAGS: %08lx %s (%s %.*s)\n", |
| 299 | regs->eflags, print_tainted(), system_utsname.release, |
| 300 | (int)strcspn(system_utsname.version, " "), |
| 301 | system_utsname.version); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", |
| 303 | regs->eax,regs->ebx,regs->ecx,regs->edx); |
| 304 | printk("ESI: %08lx EDI: %08lx EBP: %08lx", |
| 305 | regs->esi, regs->edi, regs->ebp); |
| 306 | printk(" DS: %04x ES: %04x\n", |
| 307 | 0xffff & regs->xds,0xffff & regs->xes); |
| 308 | |
Zachary Amsden | 4bb0d3e | 2005-09-03 15:56:36 -0700 | [diff] [blame] | 309 | cr0 = read_cr0(); |
| 310 | cr2 = read_cr2(); |
| 311 | cr3 = read_cr3(); |
Zachary Amsden | ff6e8c0 | 2006-01-06 00:11:50 -0800 | [diff] [blame] | 312 | cr4 = read_cr4_safe(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4); |
Jan Beulich | 176a271 | 2006-06-26 13:57:41 +0200 | [diff] [blame] | 314 | show_trace(NULL, regs, ®s->esp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | } |
| 316 | |
| 317 | /* |
| 318 | * This gets run with %ebx containing the |
| 319 | * function to call, and %edx containing |
| 320 | * the "args". |
| 321 | */ |
| 322 | extern void kernel_thread_helper(void); |
| 323 | __asm__(".section .text\n" |
| 324 | ".align 4\n" |
| 325 | "kernel_thread_helper:\n\t" |
| 326 | "movl %edx,%eax\n\t" |
| 327 | "pushl %edx\n\t" |
| 328 | "call *%ebx\n\t" |
| 329 | "pushl %eax\n\t" |
| 330 | "call do_exit\n" |
| 331 | ".previous"); |
| 332 | |
| 333 | /* |
| 334 | * Create a kernel thread |
| 335 | */ |
| 336 | int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) |
| 337 | { |
| 338 | struct pt_regs regs; |
| 339 | |
| 340 | memset(®s, 0, sizeof(regs)); |
| 341 | |
| 342 | regs.ebx = (unsigned long) fn; |
| 343 | regs.edx = (unsigned long) arg; |
| 344 | |
| 345 | regs.xds = __USER_DS; |
| 346 | regs.xes = __USER_DS; |
| 347 | regs.orig_eax = -1; |
| 348 | regs.eip = (unsigned long) kernel_thread_helper; |
| 349 | regs.xcs = __KERNEL_CS; |
| 350 | regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2; |
| 351 | |
| 352 | /* Ok, create the new process.. */ |
| 353 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); |
| 354 | } |
Alexey Dobriyan | 129f694 | 2005-06-23 00:08:33 -0700 | [diff] [blame] | 355 | EXPORT_SYMBOL(kernel_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | |
| 357 | /* |
| 358 | * Free current thread data structures etc.. |
| 359 | */ |
| 360 | void exit_thread(void) |
| 361 | { |
| 362 | struct task_struct *tsk = current; |
| 363 | struct thread_struct *t = &tsk->thread; |
| 364 | |
| 365 | /* The process may have allocated an io port bitmap... nuke it. */ |
| 366 | if (unlikely(NULL != t->io_bitmap_ptr)) { |
| 367 | int cpu = get_cpu(); |
| 368 | struct tss_struct *tss = &per_cpu(init_tss, cpu); |
| 369 | |
| 370 | kfree(t->io_bitmap_ptr); |
| 371 | t->io_bitmap_ptr = NULL; |
| 372 | /* |
| 373 | * Careful, clear this in the TSS too: |
| 374 | */ |
| 375 | memset(tss->io_bitmap, 0xff, tss->io_bitmap_max); |
| 376 | t->io_bitmap_max = 0; |
| 377 | tss->io_bitmap_owner = NULL; |
| 378 | tss->io_bitmap_max = 0; |
| 379 | tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET; |
| 380 | put_cpu(); |
| 381 | } |
| 382 | } |
| 383 | |
| 384 | void flush_thread(void) |
| 385 | { |
| 386 | struct task_struct *tsk = current; |
| 387 | |
| 388 | memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8); |
| 389 | memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); |
| 390 | /* |
| 391 | * Forget coprocessor state.. |
| 392 | */ |
| 393 | clear_fpu(tsk); |
| 394 | clear_used_math(); |
| 395 | } |
| 396 | |
| 397 | void release_thread(struct task_struct *dead_task) |
| 398 | { |
Zachary Amsden | 2684927 | 2006-01-06 00:11:59 -0800 | [diff] [blame] | 399 | BUG_ON(dead_task->mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | release_vm86_irqs(dead_task); |
| 401 | } |
| 402 | |
| 403 | /* |
| 404 | * This gets called before we allocate a new thread and copy |
| 405 | * the current task into it. |
| 406 | */ |
| 407 | void prepare_to_copy(struct task_struct *tsk) |
| 408 | { |
| 409 | unlazy_fpu(tsk); |
| 410 | } |
| 411 | |
| 412 | int copy_thread(int nr, unsigned long clone_flags, unsigned long esp, |
| 413 | unsigned long unused, |
| 414 | struct task_struct * p, struct pt_regs * regs) |
| 415 | { |
| 416 | struct pt_regs * childregs; |
| 417 | struct task_struct *tsk; |
| 418 | int err; |
| 419 | |
akpm@osdl.org | 07b047f | 2006-01-12 01:05:41 -0800 | [diff] [blame] | 420 | childregs = task_pt_regs(p); |
Alexander Nyberg | f48d966 | 2005-05-05 16:15:03 -0700 | [diff] [blame] | 421 | *childregs = *regs; |
| 422 | childregs->eax = 0; |
| 423 | childregs->esp = esp; |
| 424 | |
| 425 | p->thread.esp = (unsigned long) childregs; |
| 426 | p->thread.esp0 = (unsigned long) (childregs+1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | |
| 428 | p->thread.eip = (unsigned long) ret_from_fork; |
| 429 | |
| 430 | savesegment(fs,p->thread.fs); |
| 431 | savesegment(gs,p->thread.gs); |
| 432 | |
| 433 | tsk = current; |
| 434 | if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) { |
| 435 | p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); |
| 436 | if (!p->thread.io_bitmap_ptr) { |
| 437 | p->thread.io_bitmap_max = 0; |
| 438 | return -ENOMEM; |
| 439 | } |
| 440 | memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr, |
| 441 | IO_BITMAP_BYTES); |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * Set a new TLS for the child thread? |
| 446 | */ |
| 447 | if (clone_flags & CLONE_SETTLS) { |
| 448 | struct desc_struct *desc; |
| 449 | struct user_desc info; |
| 450 | int idx; |
| 451 | |
| 452 | err = -EFAULT; |
| 453 | if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info))) |
| 454 | goto out; |
| 455 | err = -EINVAL; |
| 456 | if (LDT_empty(&info)) |
| 457 | goto out; |
| 458 | |
| 459 | idx = info.entry_number; |
| 460 | if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) |
| 461 | goto out; |
| 462 | |
| 463 | desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN; |
| 464 | desc->a = LDT_entry_a(&info); |
| 465 | desc->b = LDT_entry_b(&info); |
| 466 | } |
| 467 | |
| 468 | err = 0; |
| 469 | out: |
| 470 | if (err && p->thread.io_bitmap_ptr) { |
| 471 | kfree(p->thread.io_bitmap_ptr); |
| 472 | p->thread.io_bitmap_max = 0; |
| 473 | } |
| 474 | return err; |
| 475 | } |
| 476 | |
| 477 | /* |
| 478 | * fill in the user structure for a core dump.. |
| 479 | */ |
| 480 | void dump_thread(struct pt_regs * regs, struct user * dump) |
| 481 | { |
| 482 | int i; |
| 483 | |
| 484 | /* changed the size calculations - should hopefully work better. lbt */ |
| 485 | dump->magic = CMAGIC; |
| 486 | dump->start_code = 0; |
| 487 | dump->start_stack = regs->esp & ~(PAGE_SIZE - 1); |
| 488 | dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT; |
| 489 | dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT; |
| 490 | dump->u_dsize -= dump->u_tsize; |
| 491 | dump->u_ssize = 0; |
| 492 | for (i = 0; i < 8; i++) |
| 493 | dump->u_debugreg[i] = current->thread.debugreg[i]; |
| 494 | |
| 495 | if (dump->start_stack < TASK_SIZE) |
| 496 | dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT; |
| 497 | |
| 498 | dump->regs.ebx = regs->ebx; |
| 499 | dump->regs.ecx = regs->ecx; |
| 500 | dump->regs.edx = regs->edx; |
| 501 | dump->regs.esi = regs->esi; |
| 502 | dump->regs.edi = regs->edi; |
| 503 | dump->regs.ebp = regs->ebp; |
| 504 | dump->regs.eax = regs->eax; |
| 505 | dump->regs.ds = regs->xds; |
| 506 | dump->regs.es = regs->xes; |
| 507 | savesegment(fs,dump->regs.fs); |
| 508 | savesegment(gs,dump->regs.gs); |
| 509 | dump->regs.orig_eax = regs->orig_eax; |
| 510 | dump->regs.eip = regs->eip; |
| 511 | dump->regs.cs = regs->xcs; |
| 512 | dump->regs.eflags = regs->eflags; |
| 513 | dump->regs.esp = regs->esp; |
| 514 | dump->regs.ss = regs->xss; |
| 515 | |
| 516 | dump->u_fpvalid = dump_fpu (regs, &dump->i387); |
| 517 | } |
Alexey Dobriyan | 129f694 | 2005-06-23 00:08:33 -0700 | [diff] [blame] | 518 | EXPORT_SYMBOL(dump_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | |
| 520 | /* |
| 521 | * Capture the user space registers if the task is not running (in user space) |
| 522 | */ |
| 523 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
| 524 | { |
akpm@osdl.org | 07b047f | 2006-01-12 01:05:41 -0800 | [diff] [blame] | 525 | struct pt_regs ptregs = *task_pt_regs(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | ptregs.xcs &= 0xffff; |
| 527 | ptregs.xds &= 0xffff; |
| 528 | ptregs.xes &= 0xffff; |
| 529 | ptregs.xss &= 0xffff; |
| 530 | |
| 531 | elf_core_copy_regs(regs, &ptregs); |
| 532 | |
| 533 | return 1; |
| 534 | } |
| 535 | |
| 536 | static inline void |
| 537 | handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss) |
| 538 | { |
| 539 | if (!next->io_bitmap_ptr) { |
| 540 | /* |
| 541 | * Disable the bitmap via an invalid offset. We still cache |
| 542 | * the previous bitmap owner and the IO bitmap contents: |
| 543 | */ |
| 544 | tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET; |
| 545 | return; |
| 546 | } |
| 547 | if (likely(next == tss->io_bitmap_owner)) { |
| 548 | /* |
| 549 | * Previous owner of the bitmap (hence the bitmap content) |
| 550 | * matches the next task, we dont have to do anything but |
| 551 | * to set a valid offset in the TSS: |
| 552 | */ |
| 553 | tss->io_bitmap_base = IO_BITMAP_OFFSET; |
| 554 | return; |
| 555 | } |
| 556 | /* |
| 557 | * Lazy TSS's I/O bitmap copy. We set an invalid offset here |
| 558 | * and we let the task to get a GPF in case an I/O instruction |
| 559 | * is performed. The handler of the GPF will verify that the |
| 560 | * faulting task has a valid I/O bitmap and, it true, does the |
| 561 | * real copy and restart the instruction. This will save us |
| 562 | * redundant copies when the currently switched task does not |
| 563 | * perform any I/O during its timeslice. |
| 564 | */ |
| 565 | tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY; |
| 566 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | |
| 568 | /* |
Andrea Arcangeli | ffaa8bd | 2005-06-27 14:36:36 -0700 | [diff] [blame] | 569 | * This function selects if the context switch from prev to next |
| 570 | * has to tweak the TSC disable bit in the cr4. |
| 571 | */ |
| 572 | static inline void disable_tsc(struct task_struct *prev_p, |
| 573 | struct task_struct *next_p) |
| 574 | { |
| 575 | struct thread_info *prev, *next; |
| 576 | |
| 577 | /* |
| 578 | * gcc should eliminate the ->thread_info dereference if |
| 579 | * has_secure_computing returns 0 at compile time (SECCOMP=n). |
| 580 | */ |
Al Viro | 06b425d | 2006-01-12 01:05:40 -0800 | [diff] [blame] | 581 | prev = task_thread_info(prev_p); |
| 582 | next = task_thread_info(next_p); |
Andrea Arcangeli | ffaa8bd | 2005-06-27 14:36:36 -0700 | [diff] [blame] | 583 | |
| 584 | if (has_secure_computing(prev) || has_secure_computing(next)) { |
| 585 | /* slow path here */ |
| 586 | if (has_secure_computing(prev) && |
| 587 | !has_secure_computing(next)) { |
| 588 | write_cr4(read_cr4() & ~X86_CR4_TSD); |
| 589 | } else if (!has_secure_computing(prev) && |
| 590 | has_secure_computing(next)) |
| 591 | write_cr4(read_cr4() | X86_CR4_TSD); |
| 592 | } |
| 593 | } |
| 594 | |
| 595 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | * switch_to(x,yn) should switch tasks from x to y. |
| 597 | * |
| 598 | * We fsave/fwait so that an exception goes off at the right time |
| 599 | * (as a call from the fsave or fwait in effect) rather than to |
| 600 | * the wrong process. Lazy FP saving no longer makes any sense |
| 601 | * with modern CPU's, and this simplifies a lot of things (SMP |
| 602 | * and UP become the same). |
| 603 | * |
| 604 | * NOTE! We used to use the x86 hardware context switching. The |
| 605 | * reason for not using it any more becomes apparent when you |
| 606 | * try to recover gracefully from saved state that is no longer |
| 607 | * valid (stale segment register values in particular). With the |
| 608 | * hardware task-switch, there is no way to fix up bad state in |
| 609 | * a reasonable manner. |
| 610 | * |
| 611 | * The fact that Intel documents the hardware task-switching to |
| 612 | * be slow is a fairly red herring - this code is not noticeably |
| 613 | * faster. However, there _is_ some room for improvement here, |
| 614 | * so the performance issues may eventually be a valid point. |
| 615 | * More important, however, is the fact that this allows us much |
| 616 | * more flexibility. |
| 617 | * |
| 618 | * The return value (in %eax) will be the "prev" task after |
| 619 | * the task-switch, and shows up in ret_from_fork in entry.S, |
| 620 | * for example. |
| 621 | */ |
| 622 | struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) |
| 623 | { |
| 624 | struct thread_struct *prev = &prev_p->thread, |
| 625 | *next = &next_p->thread; |
| 626 | int cpu = smp_processor_id(); |
| 627 | struct tss_struct *tss = &per_cpu(init_tss, cpu); |
| 628 | |
| 629 | /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ |
| 630 | |
| 631 | __unlazy_fpu(prev_p); |
| 632 | |
| 633 | /* |
Zachary Amsden | e7a2ff5 | 2005-09-03 15:56:39 -0700 | [diff] [blame] | 634 | * Reload esp0. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | */ |
| 636 | load_esp0(tss, next); |
| 637 | |
| 638 | /* |
Zachary Amsden | e7a2ff5 | 2005-09-03 15:56:39 -0700 | [diff] [blame] | 639 | * Save away %fs and %gs. No need to save %es and %ds, as |
| 640 | * those are always kernel segments while inside the kernel. |
| 641 | * Doing this before setting the new TLS descriptors avoids |
| 642 | * the situation where we temporarily have non-reloadable |
| 643 | * segments in %fs and %gs. This could be an issue if the |
| 644 | * NMI handler ever used %fs or %gs (it does not today), or |
| 645 | * if the kernel is running inside of a hypervisor layer. |
| 646 | */ |
| 647 | savesegment(fs, prev->fs); |
| 648 | savesegment(gs, prev->gs); |
| 649 | |
| 650 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | * Load the per-thread Thread-Local Storage descriptor. |
| 652 | */ |
| 653 | load_TLS(next, cpu); |
| 654 | |
| 655 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | * Restore %fs and %gs if needed. |
Linus Torvalds | b339a18 | 2005-07-22 15:23:47 -0400 | [diff] [blame] | 657 | * |
| 658 | * Glibc normally makes %fs be zero, and %gs is one of |
| 659 | * the TLS segments. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | */ |
Linus Torvalds | b339a18 | 2005-07-22 15:23:47 -0400 | [diff] [blame] | 661 | if (unlikely(prev->fs | next->fs)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | loadsegment(fs, next->fs); |
Linus Torvalds | b339a18 | 2005-07-22 15:23:47 -0400 | [diff] [blame] | 663 | |
| 664 | if (prev->gs | next->gs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | loadsegment(gs, next->gs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | |
| 667 | /* |
Zachary Amsden | a520112 | 2005-09-03 15:56:44 -0700 | [diff] [blame] | 668 | * Restore IOPL if needed. |
| 669 | */ |
| 670 | if (unlikely(prev->iopl != next->iopl)) |
| 671 | set_iopl_mask(next->iopl); |
| 672 | |
| 673 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 674 | * Now maybe reload the debug registers |
| 675 | */ |
| 676 | if (unlikely(next->debugreg[7])) { |
Linus Torvalds | b339a18 | 2005-07-22 15:23:47 -0400 | [diff] [blame] | 677 | set_debugreg(next->debugreg[0], 0); |
| 678 | set_debugreg(next->debugreg[1], 1); |
| 679 | set_debugreg(next->debugreg[2], 2); |
| 680 | set_debugreg(next->debugreg[3], 3); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | /* no 4 and 5 */ |
Linus Torvalds | b339a18 | 2005-07-22 15:23:47 -0400 | [diff] [blame] | 682 | set_debugreg(next->debugreg[6], 6); |
| 683 | set_debugreg(next->debugreg[7], 7); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | } |
| 685 | |
| 686 | if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr)) |
| 687 | handle_io_bitmap(next, tss); |
| 688 | |
Andrea Arcangeli | ffaa8bd | 2005-06-27 14:36:36 -0700 | [diff] [blame] | 689 | disable_tsc(prev_p, next_p); |
| 690 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | return prev_p; |
| 692 | } |
| 693 | |
| 694 | asmlinkage int sys_fork(struct pt_regs regs) |
| 695 | { |
| 696 | return do_fork(SIGCHLD, regs.esp, ®s, 0, NULL, NULL); |
| 697 | } |
| 698 | |
| 699 | asmlinkage int sys_clone(struct pt_regs regs) |
| 700 | { |
| 701 | unsigned long clone_flags; |
| 702 | unsigned long newsp; |
| 703 | int __user *parent_tidptr, *child_tidptr; |
| 704 | |
| 705 | clone_flags = regs.ebx; |
| 706 | newsp = regs.ecx; |
| 707 | parent_tidptr = (int __user *)regs.edx; |
| 708 | child_tidptr = (int __user *)regs.edi; |
| 709 | if (!newsp) |
| 710 | newsp = regs.esp; |
| 711 | return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr); |
| 712 | } |
| 713 | |
| 714 | /* |
| 715 | * This is trivial, and on the face of it looks like it |
| 716 | * could equally well be done in user mode. |
| 717 | * |
| 718 | * Not so, for quite unobvious reasons - register pressure. |
| 719 | * In user mode vfork() cannot have a stack frame, and if |
| 720 | * done by calling the "clone()" system call directly, you |
| 721 | * do not have enough call-clobbered registers to hold all |
| 722 | * the information you need. |
| 723 | */ |
| 724 | asmlinkage int sys_vfork(struct pt_regs regs) |
| 725 | { |
| 726 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, ®s, 0, NULL, NULL); |
| 727 | } |
| 728 | |
| 729 | /* |
| 730 | * sys_execve() executes a new program. |
| 731 | */ |
| 732 | asmlinkage int sys_execve(struct pt_regs regs) |
| 733 | { |
| 734 | int error; |
| 735 | char * filename; |
| 736 | |
| 737 | filename = getname((char __user *) regs.ebx); |
| 738 | error = PTR_ERR(filename); |
| 739 | if (IS_ERR(filename)) |
| 740 | goto out; |
| 741 | error = do_execve(filename, |
| 742 | (char __user * __user *) regs.ecx, |
| 743 | (char __user * __user *) regs.edx, |
| 744 | ®s); |
| 745 | if (error == 0) { |
| 746 | task_lock(current); |
| 747 | current->ptrace &= ~PT_DTRACE; |
| 748 | task_unlock(current); |
| 749 | /* Make sure we don't return using sysenter.. */ |
| 750 | set_thread_flag(TIF_IRET); |
| 751 | } |
| 752 | putname(filename); |
| 753 | out: |
| 754 | return error; |
| 755 | } |
| 756 | |
| 757 | #define top_esp (THREAD_SIZE - sizeof(unsigned long)) |
| 758 | #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long)) |
| 759 | |
| 760 | unsigned long get_wchan(struct task_struct *p) |
| 761 | { |
| 762 | unsigned long ebp, esp, eip; |
| 763 | unsigned long stack_page; |
| 764 | int count = 0; |
| 765 | if (!p || p == current || p->state == TASK_RUNNING) |
| 766 | return 0; |
Al Viro | 65e0fdf | 2006-01-12 01:05:41 -0800 | [diff] [blame] | 767 | stack_page = (unsigned long)task_stack_page(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | esp = p->thread.esp; |
| 769 | if (!stack_page || esp < stack_page || esp > top_esp+stack_page) |
| 770 | return 0; |
| 771 | /* include/asm-i386/system.h:switch_to() pushes ebp last. */ |
| 772 | ebp = *(unsigned long *) esp; |
| 773 | do { |
| 774 | if (ebp < stack_page || ebp > top_ebp+stack_page) |
| 775 | return 0; |
| 776 | eip = *(unsigned long *) (ebp+4); |
| 777 | if (!in_sched_functions(eip)) |
| 778 | return eip; |
| 779 | ebp = *(unsigned long *) ebp; |
| 780 | } while (count++ < 16); |
| 781 | return 0; |
| 782 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 783 | |
| 784 | /* |
| 785 | * sys_alloc_thread_area: get a yet unused TLS descriptor index. |
| 786 | */ |
| 787 | static int get_free_idx(void) |
| 788 | { |
| 789 | struct thread_struct *t = ¤t->thread; |
| 790 | int idx; |
| 791 | |
| 792 | for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++) |
| 793 | if (desc_empty(t->tls_array + idx)) |
| 794 | return idx + GDT_ENTRY_TLS_MIN; |
| 795 | return -ESRCH; |
| 796 | } |
| 797 | |
| 798 | /* |
| 799 | * Set a given TLS descriptor: |
| 800 | */ |
| 801 | asmlinkage int sys_set_thread_area(struct user_desc __user *u_info) |
| 802 | { |
| 803 | struct thread_struct *t = ¤t->thread; |
| 804 | struct user_desc info; |
| 805 | struct desc_struct *desc; |
| 806 | int cpu, idx; |
| 807 | |
| 808 | if (copy_from_user(&info, u_info, sizeof(info))) |
| 809 | return -EFAULT; |
| 810 | idx = info.entry_number; |
| 811 | |
| 812 | /* |
| 813 | * index -1 means the kernel should try to find and |
| 814 | * allocate an empty descriptor: |
| 815 | */ |
| 816 | if (idx == -1) { |
| 817 | idx = get_free_idx(); |
| 818 | if (idx < 0) |
| 819 | return idx; |
| 820 | if (put_user(idx, &u_info->entry_number)) |
| 821 | return -EFAULT; |
| 822 | } |
| 823 | |
| 824 | if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) |
| 825 | return -EINVAL; |
| 826 | |
| 827 | desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN; |
| 828 | |
| 829 | /* |
| 830 | * We must not get preempted while modifying the TLS. |
| 831 | */ |
| 832 | cpu = get_cpu(); |
| 833 | |
| 834 | if (LDT_empty(&info)) { |
| 835 | desc->a = 0; |
| 836 | desc->b = 0; |
| 837 | } else { |
| 838 | desc->a = LDT_entry_a(&info); |
| 839 | desc->b = LDT_entry_b(&info); |
| 840 | } |
| 841 | load_TLS(t, cpu); |
| 842 | |
| 843 | put_cpu(); |
| 844 | |
| 845 | return 0; |
| 846 | } |
| 847 | |
| 848 | /* |
| 849 | * Get the current Thread-Local Storage area: |
| 850 | */ |
| 851 | |
| 852 | #define GET_BASE(desc) ( \ |
| 853 | (((desc)->a >> 16) & 0x0000ffff) | \ |
| 854 | (((desc)->b << 16) & 0x00ff0000) | \ |
| 855 | ( (desc)->b & 0xff000000) ) |
| 856 | |
| 857 | #define GET_LIMIT(desc) ( \ |
| 858 | ((desc)->a & 0x0ffff) | \ |
| 859 | ((desc)->b & 0xf0000) ) |
| 860 | |
| 861 | #define GET_32BIT(desc) (((desc)->b >> 22) & 1) |
| 862 | #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3) |
| 863 | #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1) |
| 864 | #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1) |
| 865 | #define GET_PRESENT(desc) (((desc)->b >> 15) & 1) |
| 866 | #define GET_USEABLE(desc) (((desc)->b >> 20) & 1) |
| 867 | |
| 868 | asmlinkage int sys_get_thread_area(struct user_desc __user *u_info) |
| 869 | { |
| 870 | struct user_desc info; |
| 871 | struct desc_struct *desc; |
| 872 | int idx; |
| 873 | |
| 874 | if (get_user(idx, &u_info->entry_number)) |
| 875 | return -EFAULT; |
| 876 | if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) |
| 877 | return -EINVAL; |
| 878 | |
Blaisorblade | 71ae18e | 2005-07-27 11:45:18 -0700 | [diff] [blame] | 879 | memset(&info, 0, sizeof(info)); |
| 880 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 881 | desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN; |
| 882 | |
| 883 | info.entry_number = idx; |
| 884 | info.base_addr = GET_BASE(desc); |
| 885 | info.limit = GET_LIMIT(desc); |
| 886 | info.seg_32bit = GET_32BIT(desc); |
| 887 | info.contents = GET_CONTENTS(desc); |
| 888 | info.read_exec_only = !GET_WRITABLE(desc); |
| 889 | info.limit_in_pages = GET_LIMIT_PAGES(desc); |
| 890 | info.seg_not_present = !GET_PRESENT(desc); |
| 891 | info.useable = GET_USEABLE(desc); |
| 892 | |
| 893 | if (copy_to_user(u_info, &info, sizeof(info))) |
| 894 | return -EFAULT; |
| 895 | return 0; |
| 896 | } |
| 897 | |
| 898 | unsigned long arch_align_stack(unsigned long sp) |
| 899 | { |
| 900 | if (randomize_va_space) |
| 901 | sp -= get_random_int() % 8192; |
| 902 | return sp & ~0xf; |
| 903 | } |