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Diff for /src/sys/arch/i386/i386/locore.S between version 1.47 and 1.48

version 1.47, 2007/02/19 11:46:10 version 1.48, 2007/05/17 14:51:21
Line 1 
Line 1 
 /*      $NetBSD$        */  /*      $NetBSD$        */
   
 /*-  /*-
  * Copyright (c) 1998, 2000, 2004 The NetBSD Foundation, Inc.   * Copyright (c) 1998, 2000, 2004, 2006, 2007 The NetBSD Foundation, Inc.
  * All rights reserved.   * All rights reserved.
  *   *
  * This code is derived from software contributed to The NetBSD Foundation   * This code is derived from software contributed to The NetBSD Foundation
Line 70 
Line 70 
  *      @(#)locore.s    7.3 (Berkeley) 5/13/91   *      @(#)locore.s    7.3 (Berkeley) 5/13/91
  */   */
   
 #include "opt_compat_netbsd.h"  
 #include "opt_compat_oldboot.h"  #include "opt_compat_oldboot.h"
 #include "opt_cputype.h"  #include "opt_cputype.h"
 #include "opt_ddb.h"  #include "opt_ddb.h"
 #include "opt_ipkdb.h"  
 #include "opt_lockdebug.h"  
 #include "opt_multiprocessor.h"  
 #include "opt_realmem.h"  #include "opt_realmem.h"
 #include "opt_user_ldt.h"  
 #include "opt_vm86.h"  #include "opt_vm86.h"
   
 #include "npx.h"  #include "npx.h"
Line 94 
Line 89 
 #include <machine/segments.h>  #include <machine/segments.h>
 #include <machine/specialreg.h>  #include <machine/specialreg.h>
 #include <machine/trap.h>  #include <machine/trap.h>
   
 #if NLAPIC > 0  
 #include <machine/i82489reg.h>  #include <machine/i82489reg.h>
 #endif  
   
 #include <machine/multiboot.h>  #include <machine/multiboot.h>
   
 /* LINTSTUB: include <sys/types.h> */  
 /* LINTSTUB: include <machine/cpu.h> */  
 /* LINTSTUB: include <sys/systm.h> */  
   
 #include <machine/asm.h>  #include <machine/asm.h>
   #include <machine/frameasm.h>
 #if defined(MULTIPROCESSOR)  #include <machine/i82489reg.h>
   
 #define SET_CURLWP(lwp,cpu)                             \  
         movl    CPUVAR(SELF),cpu                ;       \  
         movl    lwp,CPUVAR(CURLWP)      ;       \  
         movl    cpu,L_CPU(lwp)  
   
 #else  
   
 #define SET_CURLWP(lwp,tcpu)            movl    lwp,CPUVAR(CURLWP)  
 #define GET_CURLWP(reg)                 movl    CPUVAR(CURLWP),reg  
   
 #endif  
   
 #define SET_CURPCB(reg)                 movl    reg,CPUVAR(CURPCB)  
   
 #define CLEAR_RESCHED(reg)              movl    reg,CPUVAR(RESCHED)  
   
 /* XXX temporary kluge; these should not be here */  /* XXX temporary kluge; these should not be here */
 /* Get definitions for IOM_BEGIN, IOM_END, and IOM_SIZE */  /* Get definitions for IOM_BEGIN, IOM_END, and IOM_SIZE */
 #include <dev/isa/isareg.h>  #include <dev/isa/isareg.h>
   
   
 /* Disallow old names for REALBASEMEM */  
 #ifdef BIOSBASEMEM  
 #error BIOSBASEMEM option deprecated; use REALBASEMEM only if memory size reported by latest boot block is incorrect  
 #endif  
   
 /* Disallow old names for REALEXTMEM */  
 #ifdef EXTMEM_SIZE  
 #error EXTMEM_SIZE option deprecated; use REALEXTMEM only if memory size reported by latest boot block is incorrect  
 #endif  
 #ifdef BIOSEXTMEM  
 #error BIOSEXTMEM option deprecated; use REALEXTMEM only if memory size reported by latest boot block is incorrect  
 #endif  
   
 #include <machine/frameasm.h>  
   
   
 #ifdef MULTIPROCESSOR  
 #include <machine/i82489reg.h>  
 #endif  
   
 /*  /*
  * Initialization   * Initialization
  */   */
Line 160 
Line 109 
         .globl  _C_LABEL(atdevbase)          .globl  _C_LABEL(atdevbase)
         .globl  _C_LABEL(proc0uarea),_C_LABEL(PDPpaddr)          .globl  _C_LABEL(proc0uarea),_C_LABEL(PDPpaddr)
         .globl  _C_LABEL(gdt)          .globl  _C_LABEL(gdt)
 #ifdef I586_CPU  
         .globl  _C_LABEL(idt)          .globl  _C_LABEL(idt)
 #endif  
         .globl  _C_LABEL(lapic_tpr)          .globl  _C_LABEL(lapic_tpr)
   
 #if NLAPIC > 0  #if NLAPIC > 0
Line 188  _C_LABEL(lapic_tpr):
Line 135  _C_LABEL(lapic_tpr):
         .long 0          .long 0
 #endif  #endif
   
   _C_LABEL(cpu):          .long   0       # are we 80486, Pentium, or..
 _C_LABEL(cpu):          .long   0       # are we 386, 386sx, or 486,  
                                         #   or Pentium, or..  
 _C_LABEL(atdevbase):    .long   0       # location of start of iomem in virtual  _C_LABEL(atdevbase):    .long   0       # location of start of iomem in virtual
 _C_LABEL(proc0uarea):   .long   0  _C_LABEL(proc0uarea):   .long   0
 _C_LABEL(PDPpaddr):     .long   0       # paddr of PDP, for libkvm  _C_LABEL(PDPpaddr):     .long   0       # paddr of PDP, for libkvm
Line 642  begin:
Line 587  begin:
         call    _C_LABEL(main)          call    _C_LABEL(main)
   
 /*  /*
  * void proc_trampoline(void);   * void lwp_trampoline(void);
    *
  * This is a trampoline function pushed onto the stack of a newly created   * This is a trampoline function pushed onto the stack of a newly created
  * process in order to do some additional setup.  The trampoline is entered by   * process in order to do some additional setup.  The trampoline is entered by
  * cpu_switch()ing to the process, so we abuse the callee-saved registers used   * cpu_switch()ing to the process, so we abuse the callee-saved registers used
  * by cpu_switch() to store the information about the stub to call.   * by cpu_switch() to store the information about the stub to call.
  * NOTE: This function does not have a normal calling sequence!   * NOTE: This function does not have a normal calling sequence!
  */   */
 /* LINTSTUB: Func: void proc_trampoline(void) */  NENTRY(lwp_trampoline)
 NENTRY(proc_trampoline)          pushl   %ebp
 #ifdef MULTIPROCESSOR          xorl    %ebp,%ebp
         call    _C_LABEL(proc_trampoline_mp)          pushl   %eax
 #endif          call    _C_LABEL(lwp_startup)
         movl    $IPL_NONE,CPUVAR(ILEVEL)          addl    $8,%esp
         pushl   %ebx          pushl   %ebx
         call    *%esi          call    *%esi
         addl    $4,%esp          addl    $4,%esp
Line 662  NENTRY(proc_trampoline)
Line 608  NENTRY(proc_trampoline)
         INTRFASTEXIT          INTRFASTEXIT
         /* NOTREACHED */          /* NOTREACHED */
   
 /*****************************************************************************/  
 #ifdef COMPAT_16  
 /*  /*
  * Signal trampoline; copied to top of user stack.   * sigcode()
    *
    * Signal trampoline; copied to top of user stack.  Used only for
    * compatibility with old releases of NetBSD.
  */   */
 /* LINTSTUB: Var: char sigcode[1], esigcode[1]; */  
 NENTRY(sigcode)  NENTRY(sigcode)
         /*          /*
          * Handler has returned here as if we called it.  The sigcontext           * Handler has returned here as if we called it.  The sigcontext
Line 682  NENTRY(sigcode)
Line 628  NENTRY(sigcode)
         int     $0x80                   # exit if sigreturn fails          int     $0x80                   # exit if sigreturn fails
         .globl  _C_LABEL(esigcode)          .globl  _C_LABEL(esigcode)
 _C_LABEL(esigcode):  _C_LABEL(esigcode):
 #endif  
   
 /*****************************************************************************/  
   
 /*  
  * The following is i386-specific nonsense.  
  */  
   
 /*  /*
  * void lgdt(struct region_descriptor *rdp);   * void lgdt(struct region_descriptor *rdp);
    *
  * Load a new GDT pointer (and do any necessary cleanup).   * Load a new GDT pointer (and do any necessary cleanup).
  * XXX It's somewhat questionable whether reloading all the segment registers   * XXX It's somewhat questionable whether reloading all the segment registers
  * is necessary, since the actual descriptor data is not changed except by   * is necessary, since the actual descriptor data is not changed except by
  * process creation and exit, both of which clean up via task switches.  OTOH,   * process creation and exit, both of which clean up via task switches.  OTOH,
  * this only happens at run time when the GDT is resized.   * this only happens at run time when the GDT is resized.
  */   */
 /* LINTSTUB: Func: void lgdt(struct region_descriptor *rdp) */  
 NENTRY(lgdt)  NENTRY(lgdt)
         /* Reload the descriptor table. */          /* Reload the descriptor table. */
         movl    4(%esp),%eax          movl    4(%esp),%eax
Line 720  NENTRY(lgdt)
Line 659  NENTRY(lgdt)
         pushl   %eax          pushl   %eax
         lret          lret
   
   /*
    * void x86_flush()
    *
    * Flush instruction pipelines by doing an intersegment (far) return.
    */
 NENTRY(x86_flush)  NENTRY(x86_flush)
         /* Reload code selector by doing intersegment return. */  
         popl    %eax          popl    %eax
         pushl   $GSEL(GCODE_SEL, SEL_KPL)          pushl   $GSEL(GCODE_SEL, SEL_KPL)
         pushl   %eax          pushl   %eax
         lret          lret
   
 /*****************************************************************************/  
   
 /*  /*
  * These functions are primarily used by DDB.   * int setjmp(label_t *)
    *
    * Used primarily by DDB.
  */   */
   
 /* LINTSTUB: Func: int setjmp (label_t *l) */  
 ENTRY(setjmp)  ENTRY(setjmp)
         movl    4(%esp),%eax          movl    4(%esp),%eax
         movl    %ebx,(%eax)             # save ebx          movl    %ebx,(%eax)             # save ebx
Line 743  ENTRY(setjmp)
Line 684  ENTRY(setjmp)
         movl    %edi,16(%eax)           # save edi          movl    %edi,16(%eax)           # save edi
         movl    (%esp),%edx             # get rta          movl    (%esp),%edx             # get rta
         movl    %edx,20(%eax)           # save eip          movl    %edx,20(%eax)           # save eip
         xorl    %eax,%eax               # return (0);          xorl    %eax,%eax               # return 0
         ret          ret
   
 /* LINTSTUB: Func: void longjmp (label_t *l) */  /*
    * int longjmp(label_t *)
    *
    * Used primarily by DDB.
    */
 ENTRY(longjmp)  ENTRY(longjmp)
         movl    4(%esp),%eax          movl    4(%esp),%eax
         movl    (%eax),%ebx             # restore ebx          movl    (%eax),%ebx             # restore ebx
Line 756  ENTRY(longjmp)
Line 701  ENTRY(longjmp)
         movl    16(%eax),%edi           # restore edi          movl    16(%eax),%edi           # restore edi
         movl    20(%eax),%edx           # get rta          movl    20(%eax),%edx           # get rta
         movl    %edx,(%esp)             # put in return frame          movl    %edx,(%esp)             # put in return frame
         xorl    %eax,%eax               # return (1);          movl    $1,%eax                 # return 1
         incl    %eax  
         ret          ret
   
 /*****************************************************************************/  
   
         .globl  _C_LABEL(sched_whichqs),_C_LABEL(sched_qs)  
         .globl  _C_LABEL(uvmexp),_C_LABEL(panic)  
   
 #ifdef DIAGNOSTIC  
 NENTRY(switch_error)  
         pushl   $1f  
         call    _C_LABEL(panic)  
         /* NOTREACHED */  
 1:      .asciz  "cpu_switch"  
 #endif /* DIAGNOSTIC */  
   
 /*  /*
  * void cpu_switch(struct lwp *)   * struct lwp *cpu_switchto(struct lwp *oldlwp, struct newlwp)
  * Find a runnable lwp and switch to it.  Wait if necessary.  If the new  
  * lwp is the same as the old one, we short-circuit the context save and  
  * restore.  
  *   *
  * Note that the stack frame layout is known to "struct switchframe"   *      1. if (oldlwp != NULL), save its context.
  * in <machine/frame.h> and to the code in cpu_fork() which initializes   *      2. then, restore context of newlwp.
    *
    * Note that the stack frame layout is known to "struct switchframe" in
    * <machine/frame.h> and to the code in cpu_lwp_fork() which initializes
  * it for a new lwp.   * it for a new lwp.
  */   */
 ENTRY(cpu_switch)  ENTRY(cpu_switchto)
         pushl   %ebx          pushl   %ebx
         pushl   %esi          pushl   %esi
         pushl   %edi          pushl   %edi
   
 #ifdef DEBUG          movl    16(%esp),%esi           # oldlwp
         cmpl    $IPL_SCHED,CPUVAR(ILEVEL)          movl    20(%esp),%edi           # newlwp
         jae     1f  
         pushl   $2f  
         call    _C_LABEL(panic)  
         /* NOTREACHED */  
 2:      .asciz  "not splsched() in cpu_switch!"  
 1:  
 #endif /* DEBUG */  
   
         movl    16(%esp),%esi           # current  
   
         /*  
          * Clear curlwp so that we don't accumulate system time while idle.  
          * This also insures that schedcpu() will move the old lwp to  
          * the correct queue if it happens to get called from the spllower()  
          * below and changes the priority.  (See corresponding comment in  
          * userret()).  
          */  
         movl    $0,CPUVAR(CURLWP)  
         /*  
          * First phase: find new lwp.  
          *  
          * Registers:  
          *   %eax - queue head, scratch, then zero  
          *   %ebx - queue number  
          *   %ecx - cached value of whichqs  
          *   %edx - next lwp in queue  
          *   %esi - old lwp  
          *   %edi - new lwp  
          */  
   
         /* Look for new lwp. */  
         cli                             # splhigh doesn't do a cli  
         movl    _C_LABEL(sched_whichqs),%ecx  
         bsfl    %ecx,%ebx               # find a full q  
         jnz     switch_dequeue  
   
         /*  
          * idling:      save old context.  
          *  
          * Registers:  
          *   %eax, %ecx - scratch  
          *   %esi - old lwp, then old pcb  
          *   %edi - idle pcb  
          */  
   
         pushl   %esi  
         call    _C_LABEL(pmap_deactivate2)      # pmap_deactivate(oldproc)  
         addl    $4,%esp  
   
         movl    L_ADDR(%esi),%esi  
   
         /* Save stack pointers. */  
         movl    %esp,PCB_ESP(%esi)  
         movl    %ebp,PCB_EBP(%esi)  
   
         /* Find idle PCB for this CPU */  
 #ifndef MULTIPROCESSOR  
         movl    $_C_LABEL(lwp0),%ebx  
         movl    L_ADDR(%ebx),%edi  
         movl    L_MD_TSS_SEL(%ebx),%edx  
 #else  
         movl    CPUVAR(IDLE_PCB),%edi  
         movl    CPUVAR(IDLE_TSS_SEL),%edx  
 #endif  
         movl    $0,CPUVAR(CURLWP)               /* In case we fault... */  
   
         /* Restore the idle context (avoid interrupts) */  
         cli  
   
         /* Restore stack pointers. */  
         movl    PCB_ESP(%edi),%esp  
         movl    PCB_EBP(%edi),%ebp  
   
         /* Switch TSS. Reset "task busy" flag before loading. */  
         movl    %cr3,%eax  
         movl    %eax,PCB_CR3(%edi)  
 #ifdef MULTIPROCESSOR  
         movl    CPUVAR(GDT),%eax  
 #else  
         movl    _C_LABEL(gdt),%eax  
 #endif  
         andl    $~0x0200,4-SEL_KPL(%eax,%edx,1)  
         ltr     %dx  
   
         /* We're always in the kernel, so we don't need the LDT. */  
   
         /* Restore cr0 (including FPU state). */  
         movl    PCB_CR0(%edi),%ecx  
         movl    %ecx,%cr0  
   
         /* Record new pcb. */  
         SET_CURPCB(%edi)  
   
         xorl    %esi,%esi  
         sti  
 idle_unlock:  
         call    _C_LABEL(sched_unlock_idle)  
         /* Interrupts are okay again. */  
         pushl   $IPL_NONE               # spl0()  
         call    _C_LABEL(spllower)      # process pending interrupts  
         addl    $4,%esp  
         jmp     idle_start  
 idle_zero:  
         sti  
         call    _C_LABEL(uvm_pageidlezero)  
         cli  
         cmpl    $0,_C_LABEL(sched_whichqs)  
         jnz     idle_exit  
 idle_loop:  
         /* Try to zero some pages. */  
         movl    _C_LABEL(uvm)+UVM_PAGE_IDLE_ZERO,%ecx  
         testl   %ecx,%ecx  
         jnz     idle_zero  
         sti  
         hlt  
 NENTRY(mpidle)  
 idle_start:  
         cli  
         cmpl    $0,_C_LABEL(sched_whichqs)  
         jz      idle_loop  
 idle_exit:  
         movl    $IPL_HIGH,CPUVAR(ILEVEL)                # splhigh  
         sti  
         call    _C_LABEL(sched_lock_idle)  
         movl    _C_LABEL(sched_whichqs),%ecx  
         bsfl    %ecx,%ebx  
         jz      idle_unlock  
   
 switch_dequeue:  
         /*  
          * we're running at splhigh(), but it's otherwise okay to take  
          * interrupts here.  
          */  
         sti  
         leal    _C_LABEL(sched_qs)(,%ebx,8),%eax # select q  
   
         movl    L_FORW(%eax),%edi       # unlink from front of process q  
 #ifdef  DIAGNOSTIC  
         cmpl    %edi,%eax               # linked to self (i.e. nothing queued)?  
         je      _C_LABEL(switch_error)  # not possible  
 #endif /* DIAGNOSTIC */  
         movl    L_FORW(%edi),%edx  
         movl    %edx,L_FORW(%eax)  
         movl    %eax,L_BACK(%edx)  
   
         cmpl    %edx,%eax               # q empty?  
         jne     3f  
   
         btrl    %ebx,%ecx               # yes, clear to indicate empty  
         movl    %ecx,_C_LABEL(sched_whichqs) # update q status  
   
 3:      /* We just did it. */  
         xorl    %eax,%eax  
         CLEAR_RESCHED(%eax)  
   
 switch_resume:  
 #ifdef  DIAGNOSTIC  
         cmpl    %eax,L_WCHAN(%edi)      # Waiting for something?  
         jne     _C_LABEL(switch_error)  # Yes; shouldn't be queued.  
         cmpb    $LSRUN,L_STAT(%edi)     # In run state?  
         jne     _C_LABEL(switch_error)  # No; shouldn't be queued.  
 #endif /* DIAGNOSTIC */  
   
         /* Isolate lwp.  XXX Is this necessary? */  
         movl    %eax,L_BACK(%edi)  
   
         /* Record new lwp. */  
         movb    $LSONPROC,L_STAT(%edi)  # l->l_stat = LSONPROC  
         SET_CURLWP(%edi,%ecx)  
   
         /* Skip context switch if same lwp. */  
         xorl    %ebx,%ebx  
         cmpl    %edi,%esi  
         je      switch_return  
   
         /* If old lwp exited, don't bother. */  
         testl   %esi,%esi          testl   %esi,%esi
         jz      switch_exited          jz      1f
   
         /*  
          * Second phase: save old context.  
          *  
          * Registers:  
          *   %eax, %ecx - scratch  
          *   %esi - old lwp, then old pcb  
          *   %edi - new lwp  
          */  
   
         pushl   %esi  
         call    _C_LABEL(pmap_deactivate2)      # pmap_deactivate(oldproc)  
         addl    $4,%esp  
   
         movl    L_ADDR(%esi),%esi  
   
         /* Save stack pointers. */  
         movl    %esp,PCB_ESP(%esi)  
         movl    %ebp,PCB_EBP(%esi)  
   
 switch_exited:  
         /*  
          * Third phase: restore saved context.  
          *  
          * Registers:  
          *   %eax, %ebx, %ecx, %edx - scratch  
          *   %esi - new pcb  
          *   %edi - new lwp  
          */  
   
         /* No interrupts while loading new state. */  
         cli  
         movl    L_ADDR(%edi),%esi  
   
         /* Restore stack pointers. */  
         movl    PCB_ESP(%esi),%esp  
         movl    PCB_EBP(%esi),%ebp  
   
 #if 0          /* Save old context. */
         /* Don't bother with the rest if switching to a system process. */          movl    L_ADDR(%esi),%eax
         testl   $PK_SYSTEM,L_FLAG(%edi);        XXX NJWLWP lwp's don't have PK_SYSTEM!          movl    %esp,PCB_ESP(%eax)
         jnz     switch_restored          movl    %ebp,PCB_EBP(%eax)
 #endif  
           /* Switch to newlwp's stack. */
   1:      movl    L_ADDR(%edi),%ebx
           movl    PCB_EBP(%ebx),%ebp
           movl    PCB_ESP(%ebx),%esp
   
         /* Switch TSS. Reset "task busy" flag before loading. */          /* Switch TSS.  Reset "task busy" flag before loading. */
         movl    %cr3,%eax          movl    %cr3,%eax
         movl    %eax,PCB_CR3(%esi) /* XXX should be done by pmap_activate? */          movl    %eax,PCB_CR3(%ebx)      # for TSS gates
 #ifdef MULTIPROCESSOR  
         movl    CPUVAR(GDT),%eax          movl    CPUVAR(GDT),%eax
 #else  
         /* Load TSS info. */  
         movl    _C_LABEL(gdt),%eax  
 #endif  
         movl    L_MD_TSS_SEL(%edi),%edx          movl    L_MD_TSS_SEL(%edi),%edx
   
         andl    $~0x0200,4(%eax,%edx, 1)          andl    $~0x0200,4(%eax,%edx, 1)
         ltr     %dx          ltr     %dx
   
         pushl   %edi          /* Set curlwp. */
         call    _C_LABEL(pmap_activate)         # pmap_activate(p)          movl    %edi,CPUVAR(CURLWP)
         addl    $4,%esp  
           /* Don't bother with the rest if switching to a system process. */
           testl   $LW_SYSTEM,L_FLAG(%edi)
           jnz     4f
   
           /* Is this process using RAS (restartable atomic sequences)? */
           movl    L_PROC(%edi),%eax
           cmpl    $0,P_RASLIST(%eax)
           jne     5f
   
           /*
            * Restore cr0 (including FPU state).  Raise the IPL to IPL_IPI.
            * FPU IPIs can alter the LWP's saved cr0.  Dropping the priority
            * is deferred until mi_switch(), when cpu_switchto() returns.
            */
   2:      movl    $IPL_IPI,CPUVAR(ILEVEL)
           movl    PCB_CR0(%ebx),%ecx
           movl    %cr0,%edx
   
 #if 0  
 switch_restored:  
 #endif  
         /* Restore cr0 (including FPU state). */  
         movl    PCB_CR0(%esi),%ecx  
 #ifdef MULTIPROCESSOR  
         /*          /*
          * If our floating point registers are on a different CPU,           * If our floating point registers are on a different CPU,
          * clear CR0_TS so we'll trap rather than reuse bogus state.           * set CR0_TS so we'll trap rather than reuse bogus state.
          */           */
         movl    PCB_FPCPU(%esi),%ebx          movl    PCB_FPCPU(%ebx),%eax
         cmpl    CPUVAR(SELF),%ebx          cmpl    CPUVAR(SELF),%eax
         jz      1f          je      3f
         orl     $CR0_TS,%ecx          orl     $CR0_TS,%ecx
 1:  
 #endif  
         movl    %ecx,%cr0  
   
         /* Record new pcb. */  
         SET_CURPCB(%esi)  
   
         /* Interrupts are okay again. */          /* Reloading CR0 is very expensive - avoid if possible. */
         sti  3:      cmpl    %edx,%ecx
           je      4f
 /*          movl    %ecx,%cr0
  *  Check for restartable atomic sequences (RAS)  
  */  
         movl    CPUVAR(CURLWP),%edi  
         movl    L_PROC(%edi),%esi  
         cmpl    $0,P_RASLIST(%esi)  
         jne     2f  
 1:  
         movl    $1,%ebx  
   
 switch_return:  
         call    _C_LABEL(sched_unlock_idle)  
         cmpl    $0,CPUVAR(IPENDING)  
         jz      3f  
         pushl   $IPL_NONE               # spl0()  
         call    _C_LABEL(spllower)      # process pending interrupts  
         addl    $4,%esp  
 3:  
         movl    $IPL_HIGH,CPUVAR(ILEVEL)        # splhigh()  
   
         movl    %ebx,%eax  
   
           /* Return to the new LWP, returning 'oldlwp' in %eax. */
   4:      movl    %esi,%eax
         popl    %edi          popl    %edi
         popl    %esi          popl    %esi
         popl    %ebx          popl    %ebx
         ret          ret
   
 2:                                      # check RAS list          /* Check for restartable atomic sequences (RAS). */
         movl    L_MD_REGS(%edi),%ebx  5:      movl    L_MD_REGS(%edi),%ecx
         movl    TF_EIP(%ebx),%eax          pushl   TF_EIP(%ecx)
         pushl   %eax          pushl   %eax
         pushl   %esi  
         call    _C_LABEL(ras_lookup)          call    _C_LABEL(ras_lookup)
         addl    $8,%esp          addl    $8,%esp
         cmpl    $-1,%eax          cmpl    $-1,%eax
         je      1b          je      2b
         movl    %eax,TF_EIP(%ebx)          movl    %eax,TF_EIP(%ebx)
         jmp     1b          jmp     2b
   
 /*  
  * void cpu_switchto(struct lwp *current, struct lwp *next)  
  * Switch to the specified next LWP.  
  */  
 ENTRY(cpu_switchto)  
         pushl   %ebx  
         pushl   %esi  
         pushl   %edi  
   
 #ifdef DEBUG  
         cmpl    $IPL_SCHED,CPUVAR(ILEVEL)  
         jae     1f  
         pushl   $2f  
         call    _C_LABEL(panic)  
         /* NOTREACHED */  
 2:      .asciz  "not splsched() in cpu_switchto!"  
 1:  
 #endif /* DEBUG */  
   
         movl    16(%esp),%esi           # current  
         movl    20(%esp),%edi           # next  
   
         /*  
          * Clear curlwp so that we don't accumulate system time while idle.  
          * This also insures that schedcpu() will move the old process to  
          * the correct queue if it happens to get called from the spllower()  
          * below and changes the priority.  (See corresponding comment in  
          * usrret()).  
          *  
          * XXX Is this necessary?  We know we won't go idle.  
          */  
         movl    $0,CPUVAR(CURLWP)  
   
         /*  
          * We're running at splhigh(), but it's otherwise okay to take  
          * interrupts here.  
          */  
         sti  
   
         /* Jump into the middle of cpu_switch */  
         xorl    %eax,%eax  
         jmp     switch_resume  
   
 /*  
  * void cpu_exit(struct lwp *l)  
  * Switch to the appropriate idle context (lwp0's if uniprocessor; the CPU's  
  * if multiprocessor) and deallocate the address space and kernel stack for p.  
  * Then jump into cpu_switch(), as if we were in the idle proc all along.  
  */  
 #ifndef MULTIPROCESSOR  
         .globl  _C_LABEL(lwp0)  
 #endif  
 /* LINTSTUB: Func: void cpu_exit(struct lwp *l) */  
 ENTRY(cpu_exit)  
         movl    4(%esp),%edi            # old process  
 #ifndef MULTIPROCESSOR  
         movl    $_C_LABEL(lwp0),%ebx  
         movl    L_ADDR(%ebx),%esi  
         movl    L_MD_TSS_SEL(%ebx),%edx  
 #else  
         movl    CPUVAR(IDLE_PCB),%esi  
         movl    CPUVAR(IDLE_TSS_SEL),%edx  
 #endif  
   
         /* Restore the idle context. */  
         cli  
   
         /* Restore stack pointers. */  
         movl    PCB_ESP(%esi),%esp  
         movl    PCB_EBP(%esi),%ebp  
   
         /* Switch TSS. Reset "task busy" flag before loading. */  
         movl    %cr3,%eax  
         movl    %eax,PCB_CR3(%esi)  
 #ifdef MULTIPROCESSOR  
         movl    CPUVAR(GDT),%eax  
 #else  
         /* Load TSS info. */  
         movl    _C_LABEL(gdt),%eax  
 #endif  
   
         andl    $~0x0200,4-SEL_KPL(%eax,%edx,1)  
         ltr     %dx  
   
         /* We're always in the kernel, so we don't need the LDT. */  
   
         /* Restore cr0 (including FPU state). */  
         movl    PCB_CR0(%esi),%ecx  
         movl    %ecx,%cr0  
   
         /* Record new pcb. */  
         SET_CURPCB(%esi)  
   
         /* Now off the CPU. */  
         movl    $0,CPUVAR(CURLWP)  
   
         /* Interrupts are okay again. */  
         sti  
   
         /* Jump into cpu_switch() with the right state. */  
         xorl    %esi,%esi  
         jmp     idle_start  
   
 /*  /*
  * void savectx(struct pcb *pcb);   * void savectx(struct pcb *pcb);
    *
  * Update pcb, saving current processor state.   * Update pcb, saving current processor state.
  */   */
 /* LINTSTUB: Func: void savectx(struct pcb *pcb) */  
 ENTRY(savectx)  ENTRY(savectx)
         movl    4(%esp),%edx            # edx = pcb          movl    4(%esp),%edx            # edx = pcb
   
         /* Save stack pointers. */  
         movl    %esp,PCB_ESP(%edx)          movl    %esp,PCB_ESP(%edx)
         movl    %ebp,PCB_EBP(%edx)          movl    %ebp,PCB_EBP(%edx)
   
         ret          ret
   
 /*  /*
    * osyscall()
    *
  * Old call gate entry for syscall   * Old call gate entry for syscall
  */   */
 /* LINTSTUB: Var: char Xosyscall[1]; */  
 IDTVEC(osyscall)  IDTVEC(osyscall)
         /* Set eflags in trap frame. */          pushfl                  # set eflags in trap frame
         pushfl  
         popl    8(%esp)          popl    8(%esp)
         pushl   $7              # size of instruction for restart          pushl   $7              # size of instruction for restart
         jmp     syscall1          jmp     syscall1
   
 /*  /*
    * syscall()
    *
  * Trap gate entry for syscall   * Trap gate entry for syscall
  */   */
 /* LINTSTUB: Var: char Xsyscall[1]; */  
 IDTVEC(syscall)  IDTVEC(syscall)
         pushl   $2              # size of instruction for restart          pushl   $2              # size of instruction for restart
 syscall1:  syscall1:
Line 1300  syscall1:
Line 897  syscall1:
  * latch stuff in probintr() can be moved to npxprobe().   * latch stuff in probintr() can be moved to npxprobe().
  */   */
   
 /* LINTSTUB: Func: void probeintr(void) */  /*
    * void probeintr(void)
    */
 NENTRY(probeintr)  NENTRY(probeintr)
         ss          ss
         incl    _C_LABEL(npx_intrs_while_probing)          incl    _C_LABEL(npx_intrs_while_probing)
Line 1313  NENTRY(probeintr)
Line 912  NENTRY(probeintr)
         popl    %eax          popl    %eax
         iret          iret
   
 /* LINTSTUB: Func: void probetrap(void) */  /*
    * void probetrap(void)
    */
 NENTRY(probetrap)  NENTRY(probetrap)
         ss          ss
         incl    _C_LABEL(npx_traps_while_probing)          incl    _C_LABEL(npx_traps_while_probing)
         fnclex          fnclex
         iret          iret
   
 /* LINTSTUB: Func: int npx586bug1(int a, int b) */  /*
    * int npx586bug1(int a, int b)
    */
 NENTRY(npx586bug1)  NENTRY(npx586bug1)
         fildl   4(%esp)         # x          fildl   4(%esp)         # x
         fildl   8(%esp)         # y          fildl   8(%esp)         # y

Legend:
Removed from v.1.47  
changed lines
  Added in v.1.48

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