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Annotation of coherent/b/kernel/i386/msig.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * i386/msig.c
        !             3:  *
        !             4:  * signal handler start and return
        !             5:  *
        !             6:  * Revised: Tue May 11 14:24:00 1993 CDT
        !             7:  */
        !             8: 
        !             9: /*
        !            10:  * ----------------------------------------------------------------------
        !            11:  * Includes.
        !            12:  */
        !            13: #include <sys/coherent.h>
        !            14: 
        !            15: /*
        !            16:  * ----------------------------------------------------------------------
        !            17:  * Definitions.
        !            18:  *     Constants.
        !            19:  *     Macros with argument lists.
        !            20:  *     Typedefs.
        !            21:  *     Enums.
        !            22:  */
        !            23: 
        !            24: /*
        !            25:  * ----------------------------------------------------------------------
        !            26:  * Functions.
        !            27:  *     Import Functions.
        !            28:  *     Export Functions.
        !            29:  *     Local Functions.
        !            30:  */
        !            31: void   msigend();
        !            32: void   msigstart();
        !            33: 
        !            34: /*
        !            35:  * ----------------------------------------------------------------------
        !            36:  * Global Data.
        !            37:  *     Import Variables.
        !            38:  *     Export Variables.
        !            39:  *     Local Variables.
        !            40:  */
        !            41: extern void    (*ndpKfsave)();
        !            42: extern void    (*ndpKfrstor)();
        !            43: 
        !            44: /*
        !            45:  * ----------------------------------------------------------------------
        !            46:  * Code.
        !            47:  */
        !            48: 
        !            49: /*
        !            50:  * msigstart(signum, func)
        !            51:  *
        !            52:  * signum is 1-based signal number
        !            53:  * func points to signal handler in user text,
        !            54:  *   or func is magic value (SIG_DFL, etc.)
        !            55:  *
        !            56:  * This routine will set up the stack as shown before entering the user
        !            57:  * signal handler:
        !            58:  *
        !            59:  *     ndp/emulator context (struct _fpstate or struct _fpemstate or absent)
        !            60:  *     ndp/emulator flags
        !            61:  *     fpstackframe:
        !            62:  *             wsp (Weitek context pointer - always null, but part of BCS)
        !            63:  *             fpsp (floating point context pointer, possibly null)
        !            64:  *             CPU register set (SS+1 long registers)
        !            65:  *             1-based signal number
        !            66:  *     u.u_sigreturn (in place of user return address)
        !            67:  */
        !            68: 
        !            69: /*
        !            70:  * A special define for signal stack arithmetic:
        !            71:  * Will copy at least u_sigreturn, _fpstackframe, and ndpFlags.
        !            72:  */
        !            73: #define SIG_AREA_BASE  (sizeof(struct _fpstackframe) + 2 * sizeof(long))
        !            74: 
        !            75: void
        !            76: msigstart(signum, func)
        !            77: {
        !            78:        register int uesp;
        !            79:        int sphi, splo;
        !            80:        SEG * segp;
        !            81:        cseg_t * pp;
        !            82:        int sigArea;    /* number of bytes written to user's stack */
        !            83:        struct _fpstate * fpsp;
        !            84: 
        !            85:        /*
        !            86:         * If signal handler was attached with sigset(), temporarily
        !            87:         * hold further instances of the same signal.
        !            88:         * Otherwise, signal handler was attached with signal(), so
        !            89:         * unless at a breakpoint, we detach it and restore SIG_DFL handling.
        !            90:         */
        !            91:        if (sigSet(signum))
        !            92:                sigHold(signum);
        !            93:        else if (signum != SIGTRAP)
        !            94:                sigDefault(signum);
        !            95: 
        !            96:        /*
        !            97:         * Will copy at least u_sigreturn, _fpstackframe, and ndpFlags.
        !            98:         * If using ndp, need room for an _fpstate.
        !            99:         * If emulating, need room for an _fpemstate.
        !           100:         */
        !           101:        sigArea = SIG_AREA_BASE;
        !           102:        if (rdNdpUser() || rdEmTrapped())
        !           103:                sigArea += sizeof(struct _fpstate);
        !           104:        uesp = u.u_regl[UESP] - sigArea;
        !           105: 
        !           106:        /* Add to user stack if necessary. */
        !           107:        segp = u.u_segl[SISTACK].sr_segp;
        !           108:        sphi = (XMODE_286) ? ISP_286 : ISP_386;
        !           109:        splo = sphi - segp->s_size;
        !           110: 
        !           111:        if (splo > uesp) {
        !           112:                pp = c_extend(segp->s_vmem, btoc(segp->s_size));
        !           113:                if (pp==0) {
        !           114:                        printf("Signal failed.  cmd=%s  c_extend(%x,%x)=0 ",
        !           115:                          u.u_comm, segp->s_vmem, btoc(segp->s_size));
        !           116:                        return;
        !           117:                }
        !           118: 
        !           119:                segp->s_vmem = pp;
        !           120:                segp->s_size += NBPC;
        !           121:                if (sproto(0)==0) {
        !           122:                        printf("Signal failed.  cmd=%s  sproto(0)=0 ",
        !           123:                          u.u_comm);
        !           124:                        return;
        !           125:                }
        !           126: 
        !           127:                segload();
        !           128:        }
        !           129: 
        !           130:        /*
        !           131:         * Set the ndp/emulator context pointer fpsp.
        !           132:         * Fp context is immediately above SIG_AREA_BASE.
        !           133:         */
        !           134:        if (rdNdpUser() || rdEmTrapped())
        !           135:                fpsp = (struct _fpstate *)(uesp + SIG_AREA_BASE);
        !           136:        else
        !           137:                fpsp = 0;
        !           138: 
        !           139:        /*
        !           140:         * Write fpsp and wsp (Weitek state pointer always null).
        !           141:         */
        !           142:        putuwd(uesp + (SS+3) * sizeof(long), fpsp);
        !           143:        putuwd(uesp + (SS+4) * sizeof(long), 0);
        !           144: 
        !           145:        kucopy(u.u_regl, uesp + 2*sizeof(long), (SS+1) * sizeof(long));
        !           146:        putuwd(uesp+sizeof(long), signum);
        !           147:        putuwd(uesp, u.u_sigreturn);
        !           148:        u.u_regl[EFL] &= ~MFTTB;
        !           149:        u.u_regl[EIP] = func;
        !           150:        u.u_regl[UESP] = uesp;
        !           151: 
        !           152:        /*
        !           153:         * We are about to enter a signal handling function for the process.
        !           154:         * If current process is using ndp
        !           155:         *   copy ndp state and related flags into signal handler stack
        !           156:         *   mark the process as not using ndp
        !           157:         *   arm EM traps in case signal handler uses ndp
        !           158:         * Else if process is using emulator
        !           159:         *   copy emulator state and flags into signal handler stack
        !           160:         *   mark the process as not using emulator
        !           161:         * Else
        !           162:         *   put ndp/emulator flags on stack
        !           163:         */
        !           164:        if (rdNdpUser()) {
        !           165:                /* if ndp state not saved yet for this process, save it now */
        !           166:                if (!rdNdpSaved()) {
        !           167:                        ndpSave(&u.u_ndpCon);
        !           168:                        wrNdpSaved(1);
        !           169:                }
        !           170: 
        !           171:                putuwd(uesp + (SS+5) * sizeof(long), u.u_ndpFlags);
        !           172: 
        !           173:                kucopy(&u.u_ndpCon, fpsp, sizeof(struct _fpstate));
        !           174:                ndpDetach();
        !           175: 
        !           176:                wrNdpUser(0);
        !           177:                wrNdpSaved(0);
        !           178:                ndpEmTraps(1);
        !           179:        } else if (rdEmTrapped()) {
        !           180:                putuwd(uesp + (SS+5) * sizeof(long), u.u_ndpFlags);
        !           181:                if (ndpKfsave) {
        !           182:                        unsigned long sw_old;
        !           183:                        (*ndpKfsave)(&u.u_ndpCon, fpsp);
        !           184:                        sw_old = getuwd(&fpsp->sw);
        !           185:                        putuwd(&fpsp->status, sw_old);
        !           186:                        putuwd(&fpsp->sw, sw_old & 0x7f00);
        !           187:                }
        !           188:                wrEmTrapped(0);
        !           189:        } else {
        !           190:                putuwd(uesp + (SS+5) * sizeof(long), u.u_ndpFlags);
        !           191:        }
        !           192: }
        !           193: 
        !           194: void
        !           195: msigend(gs, fs, es, ds, edi, esi, ebp, esp, ebx, edx, ecx, eax, trapno, err,
        !           196:   eip, cs, efl, uesp, ss)
        !           197: {
        !           198:        register int signo;
        !           199:        register PROC *pp = SELF;
        !           200:        int savedNdpFlags;
        !           201:        int sigNdpUser;
        !           202: 
        !           203:        u.u_regl = &gs;
        !           204: 
        !           205:        /*
        !           206:         * BOGUS - assumes nothing clobbers user stack.
        !           207:         * There is a small probability that the u_sigreturn code,
        !           208:         * which is
        !           209:         *      add     $4,%esp
        !           210:         *      lcall   $0xf,$0
        !           211:         * might get a signal hit between the first and second instructions.
        !           212:         * This will clobber the value being fetched to signo.
        !           213:         */
        !           214:        signo = getuwd(uesp-sizeof(long)); 
        !           215: 
        !           216:        savedNdpFlags = getuwd(uesp + (SS+3) * sizeof(long));
        !           217: 
        !           218:        sigNdpUser = rdNdpUser();
        !           219:        u.u_ndpFlags = savedNdpFlags;
        !           220: 
        !           221:        /*
        !           222:         * We are about to leave a signal handling function for this process.
        !           223:         * If signal function for this process was using ndp
        !           224:         * And main process was *not* using ndp
        !           225:         *   Detach signal function from ndp
        !           226:         *   Restore current EM to its pre-signal value.
        !           227:         * If main process *was* using ndp
        !           228:         *   restore its ndp state and make it ndp owner again.
        !           229:         * If main process was using emulator
        !           230:         *   restore emulator state.
        !           231:         */
        !           232:        if (sigNdpUser && !rdNdpUser()) {
        !           233:                ndpDetach();
        !           234:                ndpEmTraps(1);
        !           235:        }
        !           236: 
        !           237:        if (rdNdpUser()) {
        !           238:                ndpEmTraps(0);
        !           239:                ukcopy(uesp + (SS+4)*sizeof(long), &u.u_ndpCon,
        !           240:                  sizeof(struct _fpstate));
        !           241:                ndpRestore(&u.u_ndpCon);
        !           242:                wrNdpSaved(0);
        !           243:                ndpMine();
        !           244:        } else if (rdEmTrapped()) {
        !           245:                if (ndpKfrstor)
        !           246:                        (*ndpKfrstor)(uesp + (SS+4)*sizeof(long), &u.u_ndpCon);
        !           247:        }
        !           248: 
        !           249:        /* Restore process state to pre-signal values. */
        !           250:        ukcopy(uesp, u.u_regl, (SS+1) * sizeof(long));
        !           251: 
        !           252:        /*
        !           253:         * If the signal has been sigset simulate a sigrelse(signal).
        !           254:         *
        !           255:         * As per S5, if the user's signal handler tries to do a sighold,
        !           256:         * it will be ignored.
        !           257:         */
        !           258:        sigRelease(signo);
        !           259: }

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