![Pekka Enberg](/assets/img/avatar_default.png)
Currently the low-level function to dump user-passed registers on i386 is called __show_registers() whereas on x86-64 it's called __show_regs(). Unify the API to simplify porting of kmemcheck to x86-64. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
734 lines
18 KiB
C
734 lines
18 KiB
C
/*
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* Copyright (C) 1995 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*/
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/*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <stdarg.h>
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/smp.h>
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#include <linux/stddef.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/user.h>
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#include <linux/interrupt.h>
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#include <linux/utsname.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/mc146818rtc.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/ptrace.h>
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#include <linux/random.h>
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#include <linux/personality.h>
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#include <linux/tick.h>
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#include <linux/percpu.h>
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#include <linux/prctl.h>
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#include <linux/dmi.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/ldt.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#include <asm/desc.h>
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#ifdef CONFIG_MATH_EMULATION
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#include <asm/math_emu.h>
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#endif
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#include <linux/err.h>
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#include <asm/tlbflush.h>
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#include <asm/cpu.h>
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#include <asm/kdebug.h>
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#include <asm/idle.h>
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#include <asm/syscalls.h>
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#include <asm/smp.h>
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asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
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DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
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EXPORT_PER_CPU_SYMBOL(current_task);
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DEFINE_PER_CPU(int, cpu_number);
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EXPORT_PER_CPU_SYMBOL(cpu_number);
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/*
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* Return saved PC of a blocked thread.
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*/
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unsigned long thread_saved_pc(struct task_struct *tsk)
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{
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return ((unsigned long *)tsk->thread.sp)[3];
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}
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#ifndef CONFIG_SMP
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static inline void play_dead(void)
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{
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BUG();
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}
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#endif
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/*
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* The idle thread. There's no useful work to be
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* done, so just try to conserve power and have a
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* low exit latency (ie sit in a loop waiting for
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* somebody to say that they'd like to reschedule)
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*/
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void cpu_idle(void)
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{
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int cpu = smp_processor_id();
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current_thread_info()->status |= TS_POLLING;
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/* endless idle loop with no priority at all */
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while (1) {
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tick_nohz_stop_sched_tick(1);
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while (!need_resched()) {
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check_pgt_cache();
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rmb();
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if (rcu_pending(cpu))
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rcu_check_callbacks(cpu, 0);
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if (cpu_is_offline(cpu))
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play_dead();
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local_irq_disable();
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__get_cpu_var(irq_stat).idle_timestamp = jiffies;
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/* Don't trace irqs off for idle */
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stop_critical_timings();
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pm_idle();
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start_critical_timings();
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}
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tick_nohz_restart_sched_tick();
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preempt_enable_no_resched();
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schedule();
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preempt_disable();
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}
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}
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void __show_regs(struct pt_regs *regs, int all)
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{
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unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
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unsigned long d0, d1, d2, d3, d6, d7;
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unsigned long sp;
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unsigned short ss, gs;
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const char *board;
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if (user_mode_vm(regs)) {
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sp = regs->sp;
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ss = regs->ss & 0xffff;
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savesegment(gs, gs);
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} else {
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sp = (unsigned long) (®s->sp);
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savesegment(ss, ss);
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savesegment(gs, gs);
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}
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printk("\n");
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board = dmi_get_system_info(DMI_PRODUCT_NAME);
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if (!board)
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board = "";
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printk("Pid: %d, comm: %s %s (%s %.*s) %s\n",
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task_pid_nr(current), current->comm,
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print_tainted(), init_utsname()->release,
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(int)strcspn(init_utsname()->version, " "),
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init_utsname()->version, board);
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printk("EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n",
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(u16)regs->cs, regs->ip, regs->flags,
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smp_processor_id());
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print_symbol("EIP is at %s\n", regs->ip);
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printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
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regs->ax, regs->bx, regs->cx, regs->dx);
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printk("ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
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regs->si, regs->di, regs->bp, sp);
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printk(" DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n",
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(u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss);
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if (!all)
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return;
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cr0 = read_cr0();
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cr2 = read_cr2();
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cr3 = read_cr3();
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cr4 = read_cr4_safe();
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printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n",
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cr0, cr2, cr3, cr4);
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get_debugreg(d0, 0);
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get_debugreg(d1, 1);
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get_debugreg(d2, 2);
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get_debugreg(d3, 3);
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printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
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d0, d1, d2, d3);
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get_debugreg(d6, 6);
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get_debugreg(d7, 7);
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printk("DR6: %08lx DR7: %08lx\n",
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d6, d7);
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}
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void show_regs(struct pt_regs *regs)
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{
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__show_regs(regs, 1);
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show_trace(NULL, regs, ®s->sp, regs->bp);
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}
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/*
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* This gets run with %bx containing the
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* function to call, and %dx containing
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* the "args".
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*/
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extern void kernel_thread_helper(void);
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/*
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* Create a kernel thread
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*/
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int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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regs.bx = (unsigned long) fn;
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regs.dx = (unsigned long) arg;
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regs.ds = __USER_DS;
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regs.es = __USER_DS;
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regs.fs = __KERNEL_PERCPU;
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regs.orig_ax = -1;
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regs.ip = (unsigned long) kernel_thread_helper;
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regs.cs = __KERNEL_CS | get_kernel_rpl();
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regs.flags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
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/* Ok, create the new process.. */
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
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}
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EXPORT_SYMBOL(kernel_thread);
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/*
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* Free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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/* The process may have allocated an io port bitmap... nuke it. */
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if (unlikely(test_thread_flag(TIF_IO_BITMAP))) {
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struct task_struct *tsk = current;
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struct thread_struct *t = &tsk->thread;
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int cpu = get_cpu();
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struct tss_struct *tss = &per_cpu(init_tss, cpu);
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kfree(t->io_bitmap_ptr);
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t->io_bitmap_ptr = NULL;
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clear_thread_flag(TIF_IO_BITMAP);
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/*
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* Careful, clear this in the TSS too:
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*/
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memset(tss->io_bitmap, 0xff, tss->io_bitmap_max);
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t->io_bitmap_max = 0;
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tss->io_bitmap_owner = NULL;
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tss->io_bitmap_max = 0;
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tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
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put_cpu();
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}
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#ifdef CONFIG_X86_DS
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/* Free any DS contexts that have not been properly released. */
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if (unlikely(current->thread.ds_ctx)) {
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/* we clear debugctl to make sure DS is not used. */
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update_debugctlmsr(0);
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ds_free(current->thread.ds_ctx);
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}
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#endif /* CONFIG_X86_DS */
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}
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void flush_thread(void)
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{
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struct task_struct *tsk = current;
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tsk->thread.debugreg0 = 0;
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tsk->thread.debugreg1 = 0;
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tsk->thread.debugreg2 = 0;
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tsk->thread.debugreg3 = 0;
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tsk->thread.debugreg6 = 0;
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tsk->thread.debugreg7 = 0;
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memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
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clear_tsk_thread_flag(tsk, TIF_DEBUG);
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/*
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* Forget coprocessor state..
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*/
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tsk->fpu_counter = 0;
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clear_fpu(tsk);
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clear_used_math();
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}
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void release_thread(struct task_struct *dead_task)
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{
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BUG_ON(dead_task->mm);
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release_vm86_irqs(dead_task);
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}
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/*
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* This gets called before we allocate a new thread and copy
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* the current task into it.
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*/
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void prepare_to_copy(struct task_struct *tsk)
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{
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unlazy_fpu(tsk);
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}
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int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
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unsigned long unused,
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struct task_struct * p, struct pt_regs * regs)
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{
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struct pt_regs * childregs;
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struct task_struct *tsk;
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int err;
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childregs = task_pt_regs(p);
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*childregs = *regs;
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childregs->ax = 0;
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childregs->sp = sp;
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p->thread.sp = (unsigned long) childregs;
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p->thread.sp0 = (unsigned long) (childregs+1);
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p->thread.ip = (unsigned long) ret_from_fork;
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savesegment(gs, p->thread.gs);
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tsk = current;
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if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
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p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,
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IO_BITMAP_BYTES, GFP_KERNEL);
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if (!p->thread.io_bitmap_ptr) {
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p->thread.io_bitmap_max = 0;
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return -ENOMEM;
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}
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set_tsk_thread_flag(p, TIF_IO_BITMAP);
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}
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err = 0;
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/*
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* Set a new TLS for the child thread?
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*/
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if (clone_flags & CLONE_SETTLS)
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err = do_set_thread_area(p, -1,
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(struct user_desc __user *)childregs->si, 0);
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if (err && p->thread.io_bitmap_ptr) {
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kfree(p->thread.io_bitmap_ptr);
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p->thread.io_bitmap_max = 0;
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}
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return err;
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}
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void
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start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
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{
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__asm__("movl %0, %%gs" :: "r"(0));
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regs->fs = 0;
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set_fs(USER_DS);
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regs->ds = __USER_DS;
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regs->es = __USER_DS;
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regs->ss = __USER_DS;
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regs->cs = __USER_CS;
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regs->ip = new_ip;
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regs->sp = new_sp;
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/*
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* Free the old FP and other extended state
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*/
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free_thread_xstate(current);
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}
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EXPORT_SYMBOL_GPL(start_thread);
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static void hard_disable_TSC(void)
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{
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write_cr4(read_cr4() | X86_CR4_TSD);
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}
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void disable_TSC(void)
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{
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preempt_disable();
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if (!test_and_set_thread_flag(TIF_NOTSC))
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/*
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* Must flip the CPU state synchronously with
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* TIF_NOTSC in the current running context.
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*/
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hard_disable_TSC();
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preempt_enable();
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}
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static void hard_enable_TSC(void)
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{
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write_cr4(read_cr4() & ~X86_CR4_TSD);
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}
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static void enable_TSC(void)
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{
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preempt_disable();
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if (test_and_clear_thread_flag(TIF_NOTSC))
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/*
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* Must flip the CPU state synchronously with
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* TIF_NOTSC in the current running context.
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*/
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hard_enable_TSC();
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preempt_enable();
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}
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int get_tsc_mode(unsigned long adr)
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{
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unsigned int val;
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if (test_thread_flag(TIF_NOTSC))
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val = PR_TSC_SIGSEGV;
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else
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val = PR_TSC_ENABLE;
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return put_user(val, (unsigned int __user *)adr);
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}
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int set_tsc_mode(unsigned int val)
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{
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if (val == PR_TSC_SIGSEGV)
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disable_TSC();
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else if (val == PR_TSC_ENABLE)
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enable_TSC();
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else
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return -EINVAL;
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return 0;
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}
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#ifdef CONFIG_X86_DS
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static int update_debugctl(struct thread_struct *prev,
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struct thread_struct *next, unsigned long debugctl)
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{
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unsigned long ds_prev = 0;
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unsigned long ds_next = 0;
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if (prev->ds_ctx)
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ds_prev = (unsigned long)prev->ds_ctx->ds;
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if (next->ds_ctx)
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ds_next = (unsigned long)next->ds_ctx->ds;
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if (ds_next != ds_prev) {
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/* we clear debugctl to make sure DS
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* is not in use when we change it */
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debugctl = 0;
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update_debugctlmsr(0);
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wrmsr(MSR_IA32_DS_AREA, ds_next, 0);
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}
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return debugctl;
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}
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#else
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static int update_debugctl(struct thread_struct *prev,
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struct thread_struct *next, unsigned long debugctl)
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{
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return debugctl;
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}
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#endif /* CONFIG_X86_DS */
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static noinline void
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__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
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struct tss_struct *tss)
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{
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struct thread_struct *prev, *next;
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unsigned long debugctl;
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prev = &prev_p->thread;
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next = &next_p->thread;
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debugctl = update_debugctl(prev, next, prev->debugctlmsr);
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if (next->debugctlmsr != debugctl)
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update_debugctlmsr(next->debugctlmsr);
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if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
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set_debugreg(next->debugreg0, 0);
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set_debugreg(next->debugreg1, 1);
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set_debugreg(next->debugreg2, 2);
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set_debugreg(next->debugreg3, 3);
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/* no 4 and 5 */
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set_debugreg(next->debugreg6, 6);
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set_debugreg(next->debugreg7, 7);
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}
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if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
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test_tsk_thread_flag(next_p, TIF_NOTSC)) {
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/* prev and next are different */
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if (test_tsk_thread_flag(next_p, TIF_NOTSC))
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hard_disable_TSC();
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else
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hard_enable_TSC();
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}
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#ifdef CONFIG_X86_PTRACE_BTS
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if (test_tsk_thread_flag(prev_p, TIF_BTS_TRACE_TS))
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ptrace_bts_take_timestamp(prev_p, BTS_TASK_DEPARTS);
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if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS))
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ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES);
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#endif /* CONFIG_X86_PTRACE_BTS */
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if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
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/*
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* Disable the bitmap via an invalid offset. We still cache
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* the previous bitmap owner and the IO bitmap contents:
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*/
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tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
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return;
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}
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if (likely(next == tss->io_bitmap_owner)) {
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/*
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* Previous owner of the bitmap (hence the bitmap content)
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* matches the next task, we dont have to do anything but
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* to set a valid offset in the TSS:
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*/
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tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
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|
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->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY;
|
|
}
|
|
|
|
/*
|
|
* 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 %ax) will be the "prev" task after
|
|
* the task-switch, and shows up in ret_from_fork in entry.S,
|
|
* for example.
|
|
*/
|
|
struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
|
|
{
|
|
struct thread_struct *prev = &prev_p->thread,
|
|
*next = &next_p->thread;
|
|
int cpu = smp_processor_id();
|
|
struct tss_struct *tss = &per_cpu(init_tss, cpu);
|
|
|
|
/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
|
|
|
|
__unlazy_fpu(prev_p);
|
|
|
|
|
|
/* we're going to use this soon, after a few expensive things */
|
|
if (next_p->fpu_counter > 5)
|
|
prefetch(next->xstate);
|
|
|
|
/*
|
|
* Reload esp0.
|
|
*/
|
|
load_sp0(tss, next);
|
|
|
|
/*
|
|
* Save away %gs. No need to save %fs, as it was saved on the
|
|
* stack on entry. No need to save %es and %ds, as those are
|
|
* always kernel segments while inside the kernel. Doing this
|
|
* before setting the new TLS descriptors avoids the situation
|
|
* where we temporarily have non-reloadable segments in %fs
|
|
* and %gs. This could be an issue if the NMI handler ever
|
|
* used %fs or %gs (it does not today), or if the kernel is
|
|
* running inside of a hypervisor layer.
|
|
*/
|
|
savesegment(gs, prev->gs);
|
|
|
|
/*
|
|
* Load the per-thread Thread-Local Storage descriptor.
|
|
*/
|
|
load_TLS(next, cpu);
|
|
|
|
/*
|
|
* Restore IOPL if needed. In normal use, the flags restore
|
|
* in the switch assembly will handle this. But if the kernel
|
|
* is running virtualized at a non-zero CPL, the popf will
|
|
* not restore flags, so it must be done in a separate step.
|
|
*/
|
|
if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl))
|
|
set_iopl_mask(next->iopl);
|
|
|
|
/*
|
|
* Now maybe handle debug registers and/or IO bitmaps
|
|
*/
|
|
if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV ||
|
|
task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT))
|
|
__switch_to_xtra(prev_p, next_p, tss);
|
|
|
|
/*
|
|
* Leave lazy mode, flushing any hypercalls made here.
|
|
* This must be done before restoring TLS segments so
|
|
* the GDT and LDT are properly updated, and must be
|
|
* done before math_state_restore, so the TS bit is up
|
|
* to date.
|
|
*/
|
|
arch_leave_lazy_cpu_mode();
|
|
|
|
/* If the task has used fpu the last 5 timeslices, just do a full
|
|
* restore of the math state immediately to avoid the trap; the
|
|
* chances of needing FPU soon are obviously high now
|
|
*
|
|
* tsk_used_math() checks prevent calling math_state_restore(),
|
|
* which can sleep in the case of !tsk_used_math()
|
|
*/
|
|
if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
|
|
math_state_restore();
|
|
|
|
/*
|
|
* Restore %gs if needed (which is common)
|
|
*/
|
|
if (prev->gs | next->gs)
|
|
loadsegment(gs, next->gs);
|
|
|
|
x86_write_percpu(current_task, next_p);
|
|
|
|
return prev_p;
|
|
}
|
|
|
|
asmlinkage int sys_fork(struct pt_regs regs)
|
|
{
|
|
return do_fork(SIGCHLD, regs.sp, ®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.bx;
|
|
newsp = regs.cx;
|
|
parent_tidptr = (int __user *)regs.dx;
|
|
child_tidptr = (int __user *)regs.di;
|
|
if (!newsp)
|
|
newsp = regs.sp;
|
|
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.sp, ®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.bx);
|
|
error = PTR_ERR(filename);
|
|
if (IS_ERR(filename))
|
|
goto out;
|
|
error = do_execve(filename,
|
|
(char __user * __user *) regs.cx,
|
|
(char __user * __user *) regs.dx,
|
|
®s);
|
|
if (error == 0) {
|
|
/* 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 bp, sp, ip;
|
|
unsigned long stack_page;
|
|
int count = 0;
|
|
if (!p || p == current || p->state == TASK_RUNNING)
|
|
return 0;
|
|
stack_page = (unsigned long)task_stack_page(p);
|
|
sp = p->thread.sp;
|
|
if (!stack_page || sp < stack_page || sp > top_esp+stack_page)
|
|
return 0;
|
|
/* include/asm-i386/system.h:switch_to() pushes bp last. */
|
|
bp = *(unsigned long *) sp;
|
|
do {
|
|
if (bp < stack_page || bp > top_ebp+stack_page)
|
|
return 0;
|
|
ip = *(unsigned long *) (bp+4);
|
|
if (!in_sched_functions(ip))
|
|
return ip;
|
|
bp = *(unsigned long *) bp;
|
|
} while (count++ < 16);
|
|
return 0;
|
|
}
|
|
|
|
unsigned long arch_align_stack(unsigned long sp)
|
|
{
|
|
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
|
|
sp -= get_random_int() % 8192;
|
|
return sp & ~0xf;
|
|
}
|
|
|
|
unsigned long arch_randomize_brk(struct mm_struct *mm)
|
|
{
|
|
unsigned long range_end = mm->brk + 0x02000000;
|
|
return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
|
|
}
|