Release 4.11 arch/x86/kernel/process_32.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 <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.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/export.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/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/syscalls.h>
#include <asm/debugreg.h>
#include <asm/switch_to.h>
#include <asm/vm86.h>
#include <asm/intel_rdt.h>



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: %pS\n", (void *)regs->ip);
	printk(KERN_DEFAULT "EFLAGS: %08lx CPU: %d\n", regs->flags,
		smp_processor_id());

	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();
	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);
}

Contributors
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Linus Torvalds (pre-git)
84
23.66%
3
15.00%
Pavel Emelyanov
69
19.44%
1
5.00%
Alan Stern
65
18.31%
1
5.00%
Dave Jones
54
15.21%
1
5.00%
H. Peter Anvin
19
5.35%
2
10.00%
Zachary Amsden
19
5.35%
1
5.00%
Harvey Harrison
11
3.10%
1
5.00%
Josh Poimboeuf
9
2.54%
1
5.00%
Pekka J Enberg
7
1.97%
2
10.00%
Ingo Molnar
4
1.13%
1
5.00%
Linus Torvalds
4
1.13%
1
5.00%
Tejun Heo
4
1.13%
1
5.00%
Jeremy Fitzhardinge
2
0.56%
1
5.00%
Andrew Lutomirski
2
0.56%
2
10.00%
Vincent Hanquez
2
0.56%
1
5.00%
Total
355
100.00%
20
100.00%



void release_thread(struct task_struct *dead_task)
{
	BUG_ON(dead_task->mm);
	release_vm86_irqs(dead_task);
}

Contributors
Person
Tokens
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Commits
CommitProp
Linus Torvalds (pre-git)
13
59.09%
4
50.00%
William Lee Irwin III
4
18.18%
1
12.50%
Dave Jones
3
13.64%
1
12.50%
Zachary Amsden
1
4.55%
1
12.50%
Ingo Molnar
1
4.55%
1
12.50%
Total
22
100.00%
8
100.00%



int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
	unsigned long arg, struct task_struct *p, unsigned long tls)
{
	struct pt_regs *childregs = task_pt_regs(p);
	struct fork_frame *fork_frame = container_of(childregs, struct fork_frame, regs);
	struct inactive_task_frame *frame = &fork_frame->frame;
	struct task_struct *tsk;
	int err;

	frame->bp = 0;
	frame->ret_addr = (unsigned long) ret_from_fork;
	p->thread.sp = (unsigned long) fork_frame;
	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));
		frame->bx = sp;		/* function */
		frame->di = arg;
		p->thread.io_bitmap_ptr = NULL;
		return 0;
	}
	frame->bx = 0;
	*childregs = *current_pt_regs();
	childregs->ax = 0;
	if (sp)
		childregs->sp = sp;

	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 *)tls, 0);

	if (err && p->thread.io_bitmap_ptr) {
		kfree(p->thread.io_bitmap_ptr);
		p->thread.io_bitmap_max = 0;
	}
	return err;
}

Contributors
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Al Viro
97
26.43%
2
8.00%
Ingo Molnar
65
17.71%
3
12.00%
Brian Gerst
51
13.90%
2
8.00%
Linus Torvalds (pre-git)
36
9.81%
5
20.00%
Andrew Morton
25
6.81%
1
4.00%
Oleg Nesterov
20
5.45%
1
4.00%
Roland McGrath
12
3.27%
1
4.00%
Stéphane Eranian
12
3.27%
1
4.00%
K.Prasad
11
3.00%
1
4.00%
Benjamin LaHaise
9
2.45%
1
4.00%
Alexey Dobriyan
7
1.91%
1
4.00%
Josh Triplett
6
1.63%
1
4.00%
Tejun Heo
5
1.36%
1
4.00%
Albert D. Cahalan
4
1.09%
1
4.00%
Vineet Gupta
4
1.09%
1
4.00%
H. Peter Anvin
2
0.54%
1
4.00%
Linus Torvalds
1
0.27%
1
4.00%
Total
367
100.00%
25
100.00%


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();
}
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CommitProp
Ingo Molnar
60
78.95%
1
20.00%
Tejun Heo
7
9.21%
1
20.00%
Al Viro
7
9.21%
2
40.00%
Brian Gerst
2
2.63%
1
20.00%
Total
76
100.00%
5
100.00%


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;
        struct fpu *prev_fpu = &prev->fpu;
        struct fpu *next_fpu = &next->fpu;
	int cpu = smp_processor_id();
        struct tss_struct *tss = &per_cpu(cpu_tss, cpu);

	/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */

	switch_fpu_prepare(prev_fpu, 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);

	/*
         * 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 fpu__restore(), so the TS bit is up
         * to date.
         */
	arch_end_context_switch(next_p);

	/*
         * Reload esp0 and cpu_current_top_of_stack.  This changes
         * current_thread_info().
         */
	load_sp0(tss, next);
	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_fpu, cpu);

	this_cpu_write(current_task, next_p);

	/* Load the Intel cache allocation PQR MSR. */
	intel_rdt_sched_in();

	return prev_p;
}
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Linus Torvalds (pre-git)
206
17.53%
25
20.49%
Ingo Molnar
170
14.47%
13
10.66%
Al Viro
104
8.85%
4
3.28%
Zachary Amsden
71
6.04%
5
4.10%
Pavel Emelyanov
69
5.87%
1
0.82%
Alan Stern
65
5.53%
1
0.82%
Dave Jones
62
5.28%
4
3.28%
Brian Gerst
56
4.77%
4
3.28%
Jeremy Fitzhardinge
35
2.98%
6
4.92%
Andi Kleen
27
2.30%
2
1.64%
Andrew Lutomirski
26
2.21%
5
4.10%
Andrew Morton
25
2.13%
1
0.82%
Oleg Nesterov
25
2.13%
2
1.64%
Linus Torvalds
22
1.87%
8
6.56%
H. Peter Anvin
21
1.79%
2
1.64%
Tejun Heo
18
1.53%
2
1.64%
Stéphane Eranian
18
1.53%
1
0.82%
Andrea Arcangeli
17
1.45%
2
1.64%
Roland McGrath
12
1.02%
1
0.82%
K.Prasad
12
1.02%
1
0.82%
Harvey Harrison
11
0.94%
1
0.82%
Benjamin LaHaise
9
0.77%
1
0.82%
Jaswinder Singh Rajput
9
0.77%
3
2.46%
Josh Poimboeuf
9
0.77%
1
0.82%
Zwane Mwaikambo
9
0.77%
1
0.82%
Fenghua Yu
7
0.60%
1
0.82%
Pekka J Enberg
7
0.60%
2
1.64%
Alexey Dobriyan
7
0.60%
1
0.82%
Josh Triplett
6
0.51%
1
0.82%
William Lee Irwin III
4
0.34%
1
0.82%
Vineet Gupta
4
0.34%
1
0.82%
Albert D. Cahalan
4
0.34%
1
0.82%
Rusty Russell
3
0.26%
1
0.82%
Vincent Hanquez
3
0.26%
2
1.64%
Daniel Jacobowitz
3
0.26%
1
0.82%
Frédéric Weisbecker
3
0.26%
1
0.82%
Erik Bosman
3
0.26%
1
0.82%
David Howells
2
0.17%
2
1.64%
Thomas Gleixner
2
0.17%
1
0.82%
Don Zickus
2
0.17%
1
0.82%
Alex Shi
1
0.09%
1
0.82%
Shai Fultheim
1
0.09%
1
0.82%
Rik Van Riel
1
0.09%
1
0.82%
Kamalesh Babulal
1
0.09%
1
0.82%
Chuck Ebbert
1
0.09%
1
0.82%
Denys Vlasenko
1
0.09%
1
0.82%
Paul Gortmaker
1
0.09%
1
0.82%
Total
1175
100.00%
122
100.00%
Directory: arch/x86/kernel

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