328 lines
8.5 KiB
C
328 lines
8.5 KiB
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/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/init.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");
|
|
|
|
/*
|
|
* 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_vm(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);
|
|
}
|
|
|
|
show_regs_common();
|
|
|
|
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);
|
|
printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
|
|
d0, d1, d2, d3);
|
|
|
|
get_debugreg(d6, 6);
|
|
get_debugreg(d7, 7);
|
|
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 unused,
|
|
struct task_struct *p, struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *childregs;
|
|
struct task_struct *tsk;
|
|
int err;
|
|
|
|
childregs = task_pt_regs(p);
|
|
*childregs = *regs;
|
|
childregs->ax = 0;
|
|
childregs->sp = sp;
|
|
|
|
p->thread.sp = (unsigned long) childregs;
|
|
p->thread.sp0 = (unsigned long) (childregs+1);
|
|
|
|
p->thread.ip = (unsigned long) ret_from_fork;
|
|
|
|
task_user_gs(p) = get_user_gs(regs);
|
|
|
|
p->fpu_counter = 0;
|
|
p->thread.io_bitmap_ptr = NULL;
|
|
tsk = current;
|
|
err = -ENOMEM;
|
|
|
|
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
|
|
|
|
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;
|
|
/*
|
|
* Free the old FP and other extended state
|
|
*/
|
|
free_thread_xstate(current);
|
|
}
|
|
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.
|
|
*/
|
|
__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(init_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);
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
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 math_state_restore, so the TS bit is up
|
|
* to date.
|
|
*/
|
|
arch_end_context_switch(next_p);
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|