exception.s

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    1 /*-
    2  * Copyright (c) 1989, 1990 William F. Jolitz.
    3  * Copyright (c) 1990 The Regents of the University of California.
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  * 3. All advertising materials mentioning features or use of this software
   15  *    must display the following acknowledgement:
   16  *      This product includes software developed by the University of
   17  *      California, Berkeley and its contributors.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  * $FreeBSD: releng/5.0/sys/i386/i386/exception.s 106542 2002-11-07 01:34:23Z davidxu $
   35  */
   36 
   37 #include "opt_npx.h"
   38 
   39 #include <machine/asmacros.h>
   40 #include <sys/mutex.h>
   41 #include <machine/psl.h>
   42 #include <machine/trap.h>
   43 #ifdef SMP
   44 #include <machine/smptests.h>           /** various SMP options */
   45 #endif
   46 
   47 #include "assym.s"
   48 
   49 #define SEL_RPL_MASK    0x0003
   50 
   51         .text
   52 
   53 /*****************************************************************************/
   54 /* Trap handling                                                             */
   55 /*****************************************************************************/
   56 /*
   57  * Trap and fault vector routines.
   58  *
   59  * Most traps are 'trap gates', SDT_SYS386TGT.  A trap gate pushes state on
   60  * the stack that mostly looks like an interrupt, but does not disable 
   61  * interrupts.  A few of the traps we are use are interrupt gates, 
   62  * SDT_SYS386IGT, which are nearly the same thing except interrupts are
   63  * disabled on entry.
   64  *
   65  * The cpu will push a certain amount of state onto the kernel stack for
   66  * the current process.  The amount of state depends on the type of trap 
   67  * and whether the trap crossed rings or not.  See i386/include/frame.h.  
   68  * At the very least the current EFLAGS (status register, which includes 
   69  * the interrupt disable state prior to the trap), the code segment register,
   70  * and the return instruction pointer are pushed by the cpu.  The cpu 
   71  * will also push an 'error' code for certain traps.  We push a dummy 
   72  * error code for those traps where the cpu doesn't in order to maintain 
   73  * a consistent frame.  We also push a contrived 'trap number'.
   74  *
   75  * The cpu does not push the general registers, we must do that, and we 
   76  * must restore them prior to calling 'iret'.  The cpu adjusts the %cs and
   77  * %ss segment registers, but does not mess with %ds, %es, or %fs.  Thus we
   78  * must load them with appropriate values for supervisor mode operation.
   79  */
   80 #define IDTVEC(name)    ALIGN_TEXT; .globl __CONCAT(X,name); \
   81                         .type __CONCAT(X,name),@function; __CONCAT(X,name):
   82 #define TRAP(a)         pushl $(a) ; jmp alltraps
   83 
   84 #ifdef BDE_DEBUGGER
   85 #define BDBTRAP(name) \
   86         ss ; \
   87         cmpb    $0,_bdb_exists ; \
   88         je      1f ; \
   89         testb   $SEL_RPL_MASK,4(%esp) ; \
   90         jne     1f ; \
   91         ss ; \
   92         .globl  __CONCAT(__CONCAT(bdb_,name),_ljmp); \
   93 __CONCAT(__CONCAT(bdb_,name),_ljmp): \
   94         ljmp    $0,$0 ; \
   95 1:
   96 #else
   97 #define BDBTRAP(name)
   98 #endif
   99 
  100 MCOUNT_LABEL(user)
  101 MCOUNT_LABEL(btrap)
  102 
  103 IDTVEC(div)
  104         pushl $0; TRAP(T_DIVIDE)
  105 IDTVEC(dbg)
  106         BDBTRAP(dbg)
  107         pushl $0; TRAP(T_TRCTRAP)
  108 IDTVEC(nmi)
  109         pushl $0; TRAP(T_NMI)
  110 IDTVEC(bpt)
  111         BDBTRAP(bpt)
  112         pushl $0; TRAP(T_BPTFLT)
  113 IDTVEC(ofl)
  114         pushl $0; TRAP(T_OFLOW)
  115 IDTVEC(bnd)
  116         pushl $0; TRAP(T_BOUND)
  117 IDTVEC(ill)
  118         pushl $0; TRAP(T_PRIVINFLT)
  119 IDTVEC(dna)
  120         pushl $0; TRAP(T_DNA)
  121 IDTVEC(fpusegm)
  122         pushl $0; TRAP(T_FPOPFLT)
  123 IDTVEC(tss)
  124         TRAP(T_TSSFLT)
  125 IDTVEC(missing)
  126         TRAP(T_SEGNPFLT)
  127 IDTVEC(stk)
  128         TRAP(T_STKFLT)
  129 IDTVEC(prot)
  130         TRAP(T_PROTFLT)
  131 IDTVEC(page)
  132         TRAP(T_PAGEFLT)
  133 IDTVEC(mchk)
  134         pushl $0; TRAP(T_MCHK)
  135 IDTVEC(rsvd)
  136         pushl $0; TRAP(T_RESERVED)
  137 IDTVEC(fpu)
  138         pushl $0; TRAP(T_ARITHTRAP)
  139 IDTVEC(align)
  140         TRAP(T_ALIGNFLT)
  141 
  142 IDTVEC(xmm)
  143         pushl $0; TRAP(T_XMMFLT)
  144         
  145         /*
  146          * alltraps entry point.  Interrupts are enabled if this was a trap
  147          * gate (TGT), else disabled if this was an interrupt gate (IGT).
  148          * Note that int0x80_syscall is a trap gate.  Only page faults
  149          * use an interrupt gate.
  150          */
  151 
  152         SUPERALIGN_TEXT
  153         .globl  alltraps
  154         .type   alltraps,@function
  155 alltraps:
  156         pushal
  157         pushl   %ds
  158         pushl   %es
  159         pushl   %fs
  160 alltraps_with_regs_pushed:
  161         mov     $KDSEL,%ax
  162         mov     %ax,%ds
  163         mov     %ax,%es
  164         mov     $KPSEL,%ax
  165         mov     %ax,%fs
  166         FAKE_MCOUNT(13*4(%esp))
  167 calltrap:
  168         FAKE_MCOUNT(btrap)              /* init "from" btrap -> calltrap */
  169         call    trap
  170 
  171         /*
  172          * Return via doreti to handle ASTs.
  173          */
  174         MEXITCOUNT
  175         jmp     doreti
  176 
  177 /*
  178  * SYSCALL CALL GATE (old entry point for a.out binaries)
  179  *
  180  * The intersegment call has been set up to specify one dummy parameter.
  181  *
  182  * This leaves a place to put eflags so that the call frame can be
  183  * converted to a trap frame. Note that the eflags is (semi-)bogusly
  184  * pushed into (what will be) tf_err and then copied later into the
  185  * final spot. It has to be done this way because esp can't be just
  186  * temporarily altered for the pushfl - an interrupt might come in
  187  * and clobber the saved cs/eip.
  188  */
  189         SUPERALIGN_TEXT
  190 IDTVEC(lcall_syscall)
  191         pushfl                          /* save eflags */
  192         popl    8(%esp)                 /* shuffle into tf_eflags */
  193         pushl   $7                      /* sizeof "lcall 7,0" */
  194         subl    $4,%esp                 /* skip over tf_trapno */
  195         pushal
  196         pushl   %ds
  197         pushl   %es
  198         pushl   %fs
  199         mov     $KDSEL,%ax              /* switch to kernel segments */
  200         mov     %ax,%ds
  201         mov     %ax,%es
  202         mov     $KPSEL,%ax
  203         mov     %ax,%fs
  204         FAKE_MCOUNT(13*4(%esp))
  205         call    syscall
  206         MEXITCOUNT
  207         jmp     doreti
  208 
  209 /*
  210  * Call gate entry for FreeBSD ELF and Linux/NetBSD syscall (int 0x80)
  211  *
  212  * Even though the name says 'int0x80', this is actually a TGT (trap gate)
  213  * rather then an IGT (interrupt gate).  Thus interrupts are enabled on
  214  * entry just as they are for a normal syscall.
  215  */
  216         SUPERALIGN_TEXT
  217 IDTVEC(int0x80_syscall)
  218         pushl   $2                      /* sizeof "int 0x80" */
  219         subl    $4,%esp                 /* skip over tf_trapno */
  220         pushal
  221         pushl   %ds
  222         pushl   %es
  223         pushl   %fs
  224         mov     $KDSEL,%ax              /* switch to kernel segments */
  225         mov     %ax,%ds
  226         mov     %ax,%es
  227         mov     $KPSEL,%ax
  228         mov     %ax,%fs
  229         FAKE_MCOUNT(13*4(%esp))
  230         call    syscall
  231         MEXITCOUNT
  232         jmp     doreti
  233 
  234 ENTRY(fork_trampoline)
  235         pushl   %esp                    /* trapframe pointer */
  236         pushl   %ebx                    /* arg1 */
  237         pushl   %esi                    /* function */
  238         movl    PCPU(CURTHREAD),%ebx    /* setup critnest */
  239         movl    $1,TD_CRITNEST(%ebx)
  240         sti                             /* enable interrupts */
  241         call    fork_exit
  242         addl    $12,%esp
  243         /* cut from syscall */
  244 
  245         /*
  246          * Return via doreti to handle ASTs.
  247          */
  248         MEXITCOUNT
  249         jmp     doreti
  250 
  251 
  252 /*
  253  * Include vm86 call routines, which want to call doreti.
  254  */
  255 #include "i386/i386/vm86bios.s"
  256 
  257 /*
  258  * Include what was once config+isa-dependent code.
  259  * XXX it should be in a stand-alone file.  It's still icu-dependent and
  260  * belongs in i386/isa.
  261  */
  262 #include "i386/isa/vector.s"
  263 
  264         .data
  265         ALIGN_DATA
  266 
  267 /*
  268  * void doreti(struct trapframe)
  269  *
  270  * Handle return from interrupts, traps and syscalls.
  271  */
  272         .text
  273         SUPERALIGN_TEXT
  274         .type   doreti,@function
  275 doreti:
  276         FAKE_MCOUNT(bintr)              /* init "from" bintr -> doreti */
  277 doreti_next:
  278         /*
  279          * Check if ASTs can be handled now.  PSL_VM must be checked first
  280          * since segment registers only have an RPL in non-VM86 mode.
  281          */
  282         testl   $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */
  283         jz      doreti_notvm86
  284         movl    PCPU(CURPCB),%ecx
  285         testl   $PCB_VM86CALL,PCB_FLAGS(%ecx)   /* are we in a vm86 call? */
  286         jz      doreti_ast              /* can handle ASTS now if not */
  287         jmp     doreti_exit
  288 
  289 doreti_notvm86:
  290         testb   $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */
  291         jz      doreti_exit             /* can't handle ASTs now if not */
  292 
  293 doreti_ast:
  294         /*
  295          * Check for ASTs atomically with returning.  Disabling CPU
  296          * interrupts provides sufficient locking evein the SMP case,
  297          * since we will be informed of any new ASTs by an IPI.
  298          */
  299         cli
  300         movl    PCPU(CURTHREAD),%eax
  301         movl    TD_KSE(%eax), %eax
  302         testl   $KEF_ASTPENDING | KEF_NEEDRESCHED,KE_FLAGS(%eax)
  303         je      doreti_exit
  304         sti
  305         pushl   %esp                    /* pass a pointer to the trapframe */
  306         call    ast
  307         add     $4,%esp
  308         jmp     doreti_ast
  309 
  310         /*
  311          * doreti_exit: pop registers, iret.
  312          *
  313          *      The segment register pop is a special case, since it may
  314          *      fault if (for example) a sigreturn specifies bad segment
  315          *      registers.  The fault is handled in trap.c.
  316          */
  317 doreti_exit:
  318         MEXITCOUNT
  319 
  320         .globl  doreti_popl_fs
  321 doreti_popl_fs:
  322         popl    %fs
  323         .globl  doreti_popl_es
  324 doreti_popl_es:
  325         popl    %es
  326         .globl  doreti_popl_ds
  327 doreti_popl_ds:
  328         popl    %ds
  329         popal
  330         addl    $8,%esp
  331         .globl  doreti_iret
  332 doreti_iret:
  333         iret
  334 
  335         /*
  336          * doreti_iret_fault and friends.  Alternative return code for
  337          * the case where we get a fault in the doreti_exit code
  338          * above.  trap() (i386/i386/trap.c) catches this specific
  339          * case, sends the process a signal and continues in the
  340          * corresponding place in the code below.
  341          */
  342         ALIGN_TEXT
  343         .globl  doreti_iret_fault
  344 doreti_iret_fault:
  345         subl    $8,%esp
  346         pushal
  347         pushl   %ds
  348         .globl  doreti_popl_ds_fault
  349 doreti_popl_ds_fault:
  350         pushl   %es
  351         .globl  doreti_popl_es_fault
  352 doreti_popl_es_fault:
  353         pushl   %fs
  354         .globl  doreti_popl_fs_fault
  355 doreti_popl_fs_fault:
  356         movl    $0,TF_ERR(%esp) /* XXX should be the error code */
  357         movl    $T_PROTFLT,TF_TRAPNO(%esp)
  358         jmp     alltraps_with_regs_pushed
  359 
  360 #ifdef APIC_IO
  361 #include "i386/isa/apic_ipl.s"
  362 #else
  363 #include "i386/isa/icu_ipl.s"
  364 #endif /* APIC_IO */
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FreeBSD/Linux Kernel Cross Reference sys/i386/i386/exception.s

FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/exception.s
