Initial import

1 files changed, 355 insertions, 0 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
new file mode 100644
index 000000000..8ed2106b0
--- /dev/null
+++ b/arch/x86/kernel/process_32.c
@@ -0,0 +1,355 @@
+/*
+ *  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 <linux/cpu.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/stddef.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/user.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/mc146818rtc.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/ptrace.h>
+#include <linux/personality.h>
+#include <linux/percpu.h>
+#include <linux/prctl.h>
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/kdebug.h>
+
+#include <asm/pgtable.h>
+#include <asm/ldt.h>
+#include <asm/processor.h>
+#include <asm/i387.h>
+#include <asm/fpu-internal.h>
+#include <asm/desc.h>
+#ifdef CONFIG_MATH_EMULATION
+#include <asm/math_emu.h>
+#endif
+
+#include <linux/err.h>
+
+#include <asm/tlbflush.h>
+#include <asm/cpu.h>
+#include <asm/idle.h>
+#include <asm/syscalls.h>
+#include <asm/debugreg.h>
+#include <asm/switch_to.h>
+
+asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
+
+/*
+ * Return saved PC of a blocked thread.
+ */
+unsigned long thread_saved_pc(struct task_struct *tsk)
+{
+	return ((unsigned long *)tsk->thread.sp)[3];
+}
+
+void __show_regs(struct pt_regs *regs, int all)
+{
+	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
+	unsigned long d0, d1, d2, d3, d6, d7;
+	unsigned long sp;
+	unsigned short ss, gs;
+
+	if (user_mode(regs)) {
+		sp = regs->sp;
+		ss = regs->ss & 0xffff;
+		gs = get_user_gs(regs);
+	} else {
+		sp = kernel_stack_pointer(regs);
+		savesegment(ss, ss);
+		savesegment(gs, gs);
+	}
+
+	printk(KERN_DEFAULT "EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n",
+			(u16)regs->cs, regs->ip, regs->flags,
+			smp_processor_id());
+	print_symbol("EIP is at %s\n", regs->ip);
+
+	printk(KERN_DEFAULT "EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
+		regs->ax, regs->bx, regs->cx, regs->dx);
+	printk(KERN_DEFAULT "ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
+		regs->si, regs->di, regs->bp, sp);
+	printk(KERN_DEFAULT " DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n",
+	       (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss);
+
+	if (!all)
+		return;
+
+	cr0 = read_cr0();
+	cr2 = read_cr2();
+	cr3 = read_cr3();
+	cr4 = __read_cr4_safe();
+	printk(KERN_DEFAULT "CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n",
+			cr0, cr2, cr3, cr4);
+
+	get_debugreg(d0, 0);
+	get_debugreg(d1, 1);
+	get_debugreg(d2, 2);
+	get_debugreg(d3, 3);
+	get_debugreg(d6, 6);
+	get_debugreg(d7, 7);
+
+	/* Only print out debug registers if they are in their non-default state. */
+	if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
+	    (d6 == DR6_RESERVED) && (d7 == 0x400))
+		return;
+
+	printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
+			d0, d1, d2, d3);
+	printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n",
+			d6, d7);
+}
+
+void release_thread(struct task_struct *dead_task)
+{
+	BUG_ON(dead_task->mm);
+	release_vm86_irqs(dead_task);
+}
+
+int copy_thread(unsigned long clone_flags, unsigned long sp,
+	unsigned long arg, struct task_struct *p)
+{
+	struct pt_regs *childregs = task_pt_regs(p);
+	struct task_struct *tsk;
+	int err;
+
+	p->thread.sp = (unsigned long) childregs;
+	p->thread.sp0 = (unsigned long) (childregs+1);
+	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		/* kernel thread */
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread.ip = (unsigned long) ret_from_kernel_thread;
+		task_user_gs(p) = __KERNEL_STACK_CANARY;
+		childregs->ds = __USER_DS;
+		childregs->es = __USER_DS;
+		childregs->fs = __KERNEL_PERCPU;
+		childregs->bx = sp;	/* function */
+		childregs->bp = arg;
+		childregs->orig_ax = -1;
+		childregs->cs = __KERNEL_CS | get_kernel_rpl();
+		childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
+		p->thread.io_bitmap_ptr = NULL;
+		return 0;
+	}
+	*childregs = *current_pt_regs();
+	childregs->ax = 0;
+	if (sp)
+		childregs->sp = sp;
+
+	p->thread.ip = (unsigned long) ret_from_fork;
+	task_user_gs(p) = get_user_gs(current_pt_regs());
+
+	p->thread.io_bitmap_ptr = NULL;
+	tsk = current;
+	err = -ENOMEM;
+
+	if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
+		p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,
+						IO_BITMAP_BYTES, GFP_KERNEL);
+		if (!p->thread.io_bitmap_ptr) {
+			p->thread.io_bitmap_max = 0;
+			return -ENOMEM;
+		}
+		set_tsk_thread_flag(p, TIF_IO_BITMAP);
+	}
+
+	err = 0;
+
+	/*
+	 * Set a new TLS for the child thread?
+	 */
+	if (clone_flags & CLONE_SETTLS)
+		err = do_set_thread_area(p, -1,
+			(struct user_desc __user *)childregs->si, 0);
+
+	if (err && p->thread.io_bitmap_ptr) {
+		kfree(p->thread.io_bitmap_ptr);
+		p->thread.io_bitmap_max = 0;
+	}
+	return err;
+}
+
+void
+start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
+{
+	set_user_gs(regs, 0);
+	regs->fs		= 0;
+	regs->ds		= __USER_DS;
+	regs->es		= __USER_DS;
+	regs->ss		= __USER_DS;
+	regs->cs		= __USER_CS;
+	regs->ip		= new_ip;
+	regs->sp		= new_sp;
+	regs->flags		= X86_EFLAGS_IF;
+	force_iret();
+}
+EXPORT_SYMBOL_GPL(start_thread);
+
+
+/*
+ *	switch_to(x,y) 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.
+ */
+__visible __notrace_funcgraph struct task_struct *
+__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
+{
+	struct thread_struct *prev = &prev_p->thread,
+				 *next = &next_p->thread;
+	int cpu = smp_processor_id();
+	struct tss_struct *tss = &per_cpu(cpu_tss, cpu);
+	fpu_switch_t fpu;
+
+	/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
+
+	fpu = switch_fpu_prepare(prev_p, next_p, cpu);
+
+	/*
+	 * 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.
+	 */
+	lazy_save_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);
+
+	/*
+	 * If it were not for PREEMPT_ACTIVE we could guarantee that the
+	 * preempt_count of all tasks was equal here and this would not be
+	 * needed.
+	 */
+	task_thread_info(prev_p)->saved_preempt_count = this_cpu_read(__preempt_count);
+	this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count);
+
+	/*
+	 * 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_end_context_switch(next_p);
+
+	/*
+	 * Reload esp0, kernel_stack, and current_top_of_stack.  This changes
+	 * current_thread_info().
+	 */
+	load_sp0(tss, next);
+	this_cpu_write(kernel_stack,
+		       (unsigned long)task_stack_page(next_p) +
+		       THREAD_SIZE);
+	this_cpu_write(cpu_current_top_of_stack,
+		       (unsigned long)task_stack_page(next_p) +
+		       THREAD_SIZE);
+
+	/*
+	 * Restore %gs if needed (which is common)
+	 */
+	if (prev->gs | next->gs)
+		lazy_load_gs(next->gs);
+
+	switch_fpu_finish(next_p, fpu);
+
+	this_cpu_write(current_task, next_p);
+
+	return prev_p;
+}
+
+#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;
+}
+