diff options
Diffstat (limited to 'arch/i386/kernel/process.c')
| -rw-r--r-- | arch/i386/kernel/process.c | 848 |
1 files changed, 848 insertions, 0 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c new file mode 100644 index 00000000000..c36fedf40e9 --- /dev/null +++ b/arch/i386/kernel/process.c @@ -0,0 +1,848 @@ +/* + * linux/arch/i386/kernel/process.c + * + * Copyright (C) 1995 Linus Torvalds + * + * Pentium III FXSR, SSE support + * Gareth Hughes <gareth@valinux.com>, May 2000 + */ + +/* + * This file handles the architecture-dependent parts of process handling.. + */ + +#include <stdarg.h> + +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/elfcore.h> +#include <linux/smp.h> +#include <linux/smp_lock.h> +#include <linux/stddef.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/user.h> +#include <linux/a.out.h> +#include <linux/interrupt.h> +#include <linux/config.h> +#include <linux/utsname.h> +#include <linux/delay.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <linux/mc146818rtc.h> +#include <linux/module.h> +#include <linux/kallsyms.h> +#include <linux/ptrace.h> +#include <linux/random.h> + +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/system.h> +#include <asm/io.h> +#include <asm/ldt.h> +#include <asm/processor.h> +#include <asm/i387.h> +#include <asm/irq.h> +#include <asm/desc.h> +#ifdef CONFIG_MATH_EMULATION +#include <asm/math_emu.h> +#endif + +#include <linux/irq.h> +#include <linux/err.h> + +asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); + +static int hlt_counter; + +unsigned long boot_option_idle_override = 0; +EXPORT_SYMBOL(boot_option_idle_override); + +/* + * Return saved PC of a blocked thread. + */ +unsigned long thread_saved_pc(struct task_struct *tsk) +{ + return ((unsigned long *)tsk->thread.esp)[3]; +} + +/* + * Powermanagement idle function, if any.. + */ +void (*pm_idle)(void); +static DEFINE_PER_CPU(unsigned int, cpu_idle_state); + +void disable_hlt(void) +{ + hlt_counter++; +} + +EXPORT_SYMBOL(disable_hlt); + +void enable_hlt(void) +{ + hlt_counter--; +} + +EXPORT_SYMBOL(enable_hlt); + +/* + * We use this if we don't have any better + * idle routine.. + */ +void default_idle(void) +{ + if (!hlt_counter && boot_cpu_data.hlt_works_ok) { + local_irq_disable(); + if (!need_resched()) + safe_halt(); + else + local_irq_enable(); + } else { + cpu_relax(); + } +} + +/* + * On SMP it's slightly faster (but much more power-consuming!) + * to poll the ->work.need_resched flag instead of waiting for the + * cross-CPU IPI to arrive. Use this option with caution. + */ +static void poll_idle (void) +{ + int oldval; + + local_irq_enable(); + + /* + * Deal with another CPU just having chosen a thread to + * run here: + */ + oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED); + + if (!oldval) { + set_thread_flag(TIF_POLLING_NRFLAG); + asm volatile( + "2:" + "testl %0, %1;" + "rep; nop;" + "je 2b;" + : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags)); + + clear_thread_flag(TIF_POLLING_NRFLAG); + } else { + set_need_resched(); + } +} + +/* + * The idle thread. There's no useful work to be + * done, so just try to conserve power and have a + * low exit latency (ie sit in a loop waiting for + * somebody to say that they'd like to reschedule) + */ +void cpu_idle (void) +{ + /* endless idle loop with no priority at all */ + while (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; + + __get_cpu_var(irq_stat).idle_timestamp = jiffies; + idle(); + } + schedule(); + } +} + +void cpu_idle_wait(void) +{ + unsigned int cpu, this_cpu = get_cpu(); + cpumask_t map; + + 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); + } while (!cpus_empty(map)); +} +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). + */ +static void mwait_idle(void) +{ + local_irq_enable(); + + if (!need_resched()) { + set_thread_flag(TIF_POLLING_NRFLAG); + do { + __monitor((void *)¤t_thread_info()->flags, 0, 0); + if (need_resched()) + break; + __mwait(0, 0); + } while (!need_resched()); + clear_thread_flag(TIF_POLLING_NRFLAG); + } +} + +void __init select_idle_routine(const struct cpuinfo_x86 *c) +{ + if (cpu_has(c, X86_FEATURE_MWAIT)) { + printk("monitor/mwait feature present.\n"); + /* + * Skip, if setup has overridden idle. + * One CPU supports mwait => All CPUs supports mwait + */ + if (!pm_idle) { + printk("using mwait in idle threads.\n"); + pm_idle = mwait_idle; + } + } +} + +static int __init idle_setup (char *str) +{ + if (!strncmp(str, "poll", 4)) { + printk("using polling idle threads.\n"); + pm_idle = poll_idle; +#ifdef CONFIG_X86_SMP + if (smp_num_siblings > 1) + printk("WARNING: polling idle and HT enabled, performance may degrade.\n"); +#endif + } else if (!strncmp(str, "halt", 4)) { + printk("using halt in idle threads.\n"); + pm_idle = default_idle; + } + + boot_option_idle_override = 1; + return 1; +} + +__setup("idle=", idle_setup); + +void show_regs(struct pt_regs * regs) +{ + unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; + + printk("\n"); + printk("Pid: %d, comm: %20s\n", current->pid, current->comm); + printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id()); + print_symbol("EIP is at %s\n", regs->eip); + + if (regs->xcs & 3) + printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp); + printk(" EFLAGS: %08lx %s (%s)\n", + regs->eflags, print_tainted(), system_utsname.release); + printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", + regs->eax,regs->ebx,regs->ecx,regs->edx); + printk("ESI: %08lx EDI: %08lx EBP: %08lx", + regs->esi, regs->edi, regs->ebp); + printk(" DS: %04x ES: %04x\n", + 0xffff & regs->xds,0xffff & regs->xes); + + __asm__("movl %%cr0, %0": "=r" (cr0)); + __asm__("movl %%cr2, %0": "=r" (cr2)); + __asm__("movl %%cr3, %0": "=r" (cr3)); + /* This could fault if %cr4 does not exist */ + __asm__("1: movl %%cr4, %0 \n" + "2: \n" + ".section __ex_table,\"a\" \n" + ".long 1b,2b \n" + ".previous \n" + : "=r" (cr4): "0" (0)); + printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4); + show_trace(NULL, ®s->esp); +} + +/* + * This gets run with %ebx containing the + * function to call, and %edx containing + * the "args". + */ +extern void kernel_thread_helper(void); +__asm__(".section .text\n" + ".align 4\n" + "kernel_thread_helper:\n\t" + "movl %edx,%eax\n\t" + "pushl %edx\n\t" + "call *%ebx\n\t" + "pushl %eax\n\t" + "call do_exit\n" + ".previous"); + +/* + * Create a kernel thread + */ +int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) +{ + struct pt_regs regs; + + memset(®s, 0, sizeof(regs)); + + regs.ebx = (unsigned long) fn; + regs.edx = (unsigned long) arg; + + regs.xds = __USER_DS; + regs.xes = __USER_DS; + regs.orig_eax = -1; + regs.eip = (unsigned long) kernel_thread_helper; + regs.xcs = __KERNEL_CS; + regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2; + + /* Ok, create the new process.. */ + return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); +} + +/* + * Free current thread data structures etc.. + */ +void exit_thread(void) +{ + struct task_struct *tsk = current; + struct thread_struct *t = &tsk->thread; + + /* The process may have allocated an io port bitmap... nuke it. */ + if (unlikely(NULL != t->io_bitmap_ptr)) { + int cpu = get_cpu(); + struct tss_struct *tss = &per_cpu(init_tss, cpu); + + kfree(t->io_bitmap_ptr); + t->io_bitmap_ptr = NULL; + /* + * Careful, clear this in the TSS too: + */ + memset(tss->io_bitmap, 0xff, tss->io_bitmap_max); + t->io_bitmap_max = 0; + tss->io_bitmap_owner = NULL; + tss->io_bitmap_max = 0; + tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET; + put_cpu(); + } +} + +void flush_thread(void) +{ + struct task_struct *tsk = current; + + memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8); + 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) { + // temporary debugging check + if (dead_task->mm->context.size) { + printk("WARNING: dead process %8s still has LDT? <%p/%d>\n", + dead_task->comm, + dead_task->mm->context.ldt, + dead_task->mm->context.size); + BUG(); + } + } + + release_vm86_irqs(dead_task); +} + +/* + * This gets called before we allocate a new thread and copy + * the current task into it. + */ +void prepare_to_copy(struct task_struct *tsk) +{ + unlazy_fpu(tsk); +} + +int copy_thread(int nr, unsigned long clone_flags, unsigned long esp, + unsigned long unused, + struct task_struct * p, struct pt_regs * regs) +{ + struct pt_regs * childregs; + struct task_struct *tsk; + int err; + + childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1; + *childregs = *regs; + childregs->eax = 0; + childregs->esp = esp; + + p->thread.esp = (unsigned long) childregs; + p->thread.esp0 = (unsigned long) (childregs+1); + + p->thread.eip = (unsigned long) ret_from_fork; + + savesegment(fs,p->thread.fs); + savesegment(gs,p->thread.gs); + + tsk = current; + if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) { + p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); + if (!p->thread.io_bitmap_ptr) { + p->thread.io_bitmap_max = 0; + return -ENOMEM; + } + memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr, + IO_BITMAP_BYTES); + } + + /* + * Set a new TLS for the child thread? + */ + if (clone_flags & CLONE_SETTLS) { + struct desc_struct *desc; + struct user_desc info; + int idx; + + err = -EFAULT; + if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info))) + goto out; + err = -EINVAL; + if (LDT_empty(&info)) + goto out; + + idx = info.entry_number; + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) + goto out; + + desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN; + desc->a = LDT_entry_a(&info); + desc->b = LDT_entry_b(&info); + } + + err = 0; + out: + if (err && p->thread.io_bitmap_ptr) { + kfree(p->thread.io_bitmap_ptr); + p->thread.io_bitmap_max = 0; + } + return err; +} + +/* + * fill in the user structure for a core dump.. + */ +void dump_thread(struct pt_regs * regs, struct user * dump) +{ + int i; + +/* changed the size calculations - should hopefully work better. lbt */ + dump->magic = CMAGIC; + dump->start_code = 0; + dump->start_stack = regs->esp & ~(PAGE_SIZE - 1); + dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT; + dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT; + dump->u_dsize -= dump->u_tsize; + dump->u_ssize = 0; + for (i = 0; i < 8; i++) + dump->u_debugreg[i] = current->thread.debugreg[i]; + + if (dump->start_stack < TASK_SIZE) + dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT; + + dump->regs.ebx = regs->ebx; + dump->regs.ecx = regs->ecx; + dump->regs.edx = regs->edx; + dump->regs.esi = regs->esi; + dump->regs.edi = regs->edi; + dump->regs.ebp = regs->ebp; + dump->regs.eax = regs->eax; + dump->regs.ds = regs->xds; + dump->regs.es = regs->xes; + savesegment(fs,dump->regs.fs); + savesegment(gs,dump->regs.gs); + dump->regs.orig_eax = regs->orig_eax; + dump->regs.eip = regs->eip; + dump->regs.cs = regs->xcs; + dump->regs.eflags = regs->eflags; + dump->regs.esp = regs->esp; + dump->regs.ss = regs->xss; + + dump->u_fpvalid = dump_fpu (regs, &dump->i387); +} + +/* + * Capture the user space registers if the task is not running (in user space) + */ +int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) +{ + struct pt_regs ptregs; + + ptregs = *(struct pt_regs *) + ((unsigned long)tsk->thread_info+THREAD_SIZE - sizeof(ptregs)); + ptregs.xcs &= 0xffff; + ptregs.xds &= 0xffff; + ptregs.xes &= 0xffff; + ptregs.xss &= 0xffff; + + elf_core_copy_regs(regs, &ptregs); + + return 1; +} + +static inline void +handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss) +{ + if (!next->io_bitmap_ptr) { + /* + * Disable the bitmap via an invalid offset. We still cache + * the previous bitmap owner and the IO bitmap contents: + */ + tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET; + return; + } + if (likely(next == tss->io_bitmap_owner)) { + /* + * Previous owner of the bitmap (hence the bitmap content) + * matches the next task, we dont have to do anything but + * to set a valid offset in the TSS: + */ + tss->io_bitmap_base = IO_BITMAP_OFFSET; + return; + } + /* + * Lazy TSS's I/O bitmap copy. We set an invalid offset here + * and we let the task to get a GPF in case an I/O instruction + * is performed. The handler of the GPF will verify that the + * faulting task has a valid I/O bitmap and, it true, does the + * real copy and restart the instruction. This will save us + * redundant copies when the currently switched task does not + * perform any I/O during its timeslice. + */ + tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY; +} +/* + * This special macro can be used to load a debugging register + */ +#define loaddebug(thread,register) \ + __asm__("movl %0,%%db" #register \ + : /* no output */ \ + :"r" (thread->debugreg[register])) + +/* + * switch_to(x,yn) should switch tasks from x to y. + * + * We fsave/fwait so that an exception goes off at the right time + * (as a call from the fsave or fwait in effect) rather than to + * the wrong process. Lazy FP saving no longer makes any sense + * with modern CPU's, and this simplifies a lot of things (SMP + * and UP become the same). + * + * NOTE! We used to use the x86 hardware context switching. The + * reason for not using it any more becomes apparent when you + * try to recover gracefully from saved state that is no longer + * valid (stale segment register values in particular). With the + * hardware task-switch, there is no way to fix up bad state in + * a reasonable manner. + * + * The fact that Intel documents the hardware task-switching to + * be slow is a fairly red herring - this code is not noticeably + * faster. However, there _is_ some room for improvement here, + * so the performance issues may eventually be a valid point. + * More important, however, is the fact that this allows us much + * more flexibility. + * + * The return value (in %eax) will be the "prev" task after + * the task-switch, and shows up in ret_from_fork in entry.S, + * for example. + */ +struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) +{ + struct thread_struct *prev = &prev_p->thread, + *next = &next_p->thread; + int cpu = smp_processor_id(); + struct tss_struct *tss = &per_cpu(init_tss, cpu); + + /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ + + __unlazy_fpu(prev_p); + + /* + * Reload esp0, LDT and the page table pointer: + */ + load_esp0(tss, next); + + /* + * Load the per-thread Thread-Local Storage descriptor. + */ + load_TLS(next, cpu); + + /* + * Save away %fs and %gs. No need to save %es and %ds, as + * those are always kernel segments while inside the kernel. + */ + asm volatile("movl %%fs,%0":"=m" (*(int *)&prev->fs)); + asm volatile("movl %%gs,%0":"=m" (*(int *)&prev->gs)); + + /* + * Restore %fs and %gs if needed. + */ + if (unlikely(prev->fs | prev->gs | next->fs | next->gs)) { + loadsegment(fs, next->fs); + loadsegment(gs, next->gs); + } + + /* + * Now maybe reload the debug registers + */ + if (unlikely(next->debugreg[7])) { + loaddebug(next, 0); + loaddebug(next, 1); + loaddebug(next, 2); + loaddebug(next, 3); + /* no 4 and 5 */ + loaddebug(next, 6); + loaddebug(next, 7); + } + + if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr)) + handle_io_bitmap(next, tss); + + return prev_p; +} + +asmlinkage int sys_fork(struct pt_regs regs) +{ + return do_fork(SIGCHLD, regs.esp, ®s, 0, NULL, NULL); +} + +asmlinkage int sys_clone(struct pt_regs regs) +{ + unsigned long clone_flags; + unsigned long newsp; + int __user *parent_tidptr, *child_tidptr; + + clone_flags = regs.ebx; + newsp = regs.ecx; + parent_tidptr = (int __user *)regs.edx; + child_tidptr = (int __user *)regs.edi; + if (!newsp) + newsp = regs.esp; + return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr); +} + +/* + * 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 int sys_vfork(struct pt_regs regs) +{ + return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, ®s, 0, NULL, NULL); +} + +/* + * sys_execve() executes a new program. + */ +asmlinkage int sys_execve(struct pt_regs regs) +{ + int error; + char * filename; + + filename = getname((char __user *) regs.ebx); + error = PTR_ERR(filename); + if (IS_ERR(filename)) + goto out; + error = do_execve(filename, + (char __user * __user *) regs.ecx, + (char __user * __user *) regs.edx, + ®s); + if (error == 0) { + task_lock(current); + current->ptrace &= ~PT_DTRACE; + task_unlock(current); + /* Make sure we don't return using sysenter.. */ + set_thread_flag(TIF_IRET); + } + putname(filename); +out: + return error; +} + +#define top_esp (THREAD_SIZE - sizeof(unsigned long)) +#define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long)) + +unsigned long get_wchan(struct task_struct *p) +{ + unsigned long ebp, esp, eip; + unsigned long stack_page; + int count = 0; + if (!p || p == current || p->state == TASK_RUNNING) + return 0; + stack_page = (unsigned long)p->thread_info; + esp = p->thread.esp; + if (!stack_page || esp < stack_page || esp > top_esp+stack_page) + return 0; + /* include/asm-i386/system.h:switch_to() pushes ebp last. */ + ebp = *(unsigned long *) esp; + do { + if (ebp < stack_page || ebp > top_ebp+stack_page) + return 0; + eip = *(unsigned long *) (ebp+4); + if (!in_sched_functions(eip)) + return eip; + ebp = *(unsigned long *) ebp; + } while (count++ < 16); + return 0; +} + +/* + * sys_alloc_thread_area: get a yet unused TLS descriptor index. + */ +static int get_free_idx(void) +{ + struct thread_struct *t = ¤t->thread; + int idx; + + for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++) + if (desc_empty(t->tls_array + idx)) + return idx + GDT_ENTRY_TLS_MIN; + return -ESRCH; +} + +/* + * Set a given TLS descriptor: + */ +asmlinkage int sys_set_thread_area(struct user_desc __user *u_info) +{ + struct thread_struct *t = ¤t->thread; + struct user_desc info; + struct desc_struct *desc; + int cpu, idx; + + if (copy_from_user(&info, u_info, sizeof(info))) + return -EFAULT; + idx = info.entry_number; + + /* + * index -1 means the kernel should try to find and + * allocate an empty descriptor: + */ + if (idx == -1) { + idx = get_free_idx(); + if (idx < 0) + return idx; + if (put_user(idx, &u_info->entry_number)) + return -EFAULT; + } + + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) + return -EINVAL; + + desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN; + + /* + * We must not get preempted while modifying the TLS. + */ + cpu = get_cpu(); + + if (LDT_empty(&info)) { + desc->a = 0; + desc->b = 0; + } else { + desc->a = LDT_entry_a(&info); + desc->b = LDT_entry_b(&info); + } + load_TLS(t, cpu); + + put_cpu(); + + return 0; +} + +/* + * Get the current Thread-Local Storage area: + */ + +#define GET_BASE(desc) ( \ + (((desc)->a >> 16) & 0x0000ffff) | \ + (((desc)->b << 16) & 0x00ff0000) | \ + ( (desc)->b & 0xff000000) ) + +#define GET_LIMIT(desc) ( \ + ((desc)->a & 0x0ffff) | \ + ((desc)->b & 0xf0000) ) + +#define GET_32BIT(desc) (((desc)->b >> 22) & 1) +#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3) +#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1) +#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1) +#define GET_PRESENT(desc) (((desc)->b >> 15) & 1) +#define GET_USEABLE(desc) (((desc)->b >> 20) & 1) + +asmlinkage int sys_get_thread_area(struct user_desc __user *u_info) +{ + struct user_desc info; + struct desc_struct *desc; + int idx; + + if (get_user(idx, &u_info->entry_number)) + return -EFAULT; + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) + return -EINVAL; + + desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN; + + info.entry_number = idx; + info.base_addr = GET_BASE(desc); + info.limit = GET_LIMIT(desc); + info.seg_32bit = GET_32BIT(desc); + info.contents = GET_CONTENTS(desc); + info.read_exec_only = !GET_WRITABLE(desc); + info.limit_in_pages = GET_LIMIT_PAGES(desc); + info.seg_not_present = !GET_PRESENT(desc); + info.useable = GET_USEABLE(desc); + + if (copy_to_user(u_info, &info, sizeof(info))) + return -EFAULT; + return 0; +} + +unsigned long arch_align_stack(unsigned long sp) +{ + if (randomize_va_space) + sp -= get_random_int() % 8192; + return sp & ~0xf; +} |