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

1.1     ! root        1: /*
        !             2:  * fakeff.c
        !             3:  * Simulate all the calls for far memory access from COH 286.
        !             4:  * Far pointers are simulated with virtual addresses.
        !             5:  */
        !             6: #include <sys/coherent.h>
        !             7: #include <sys/seg.h>
        !             8: #include <sys/fakeff.h>
        !             9: 
        !            10: extern SR allocp;
        !            11: 
        !            12: /*
        !            13:  * Initialize a virtual address to access physical memory at location
        !            14:  * 'paddr', of size 'len' bytes.  It provides read and write (but not
        !            15:  * execute) access.  When no longer required, a virtual address should be
        !            16:  * released by vrelse.
        !            17:  */
        !            18: faddr_t
        !            19: map_pv(paddr, len)
        !            20: __paddr_t paddr;
        !            21: fsize_t len;
        !            22: {
        !            23:        int s;                  /* Return value of sphi().  */
        !            24:        int npage;              /* Number of pages we must allocate.  */
        !            25:        faddr_t chunk_start;    /* Start of allocated segment in vmem.  */
        !            26:        faddr_t retval;         /* Address of desired physical memory in vmem.  */
        !            27:        int base1;              /* Offset into ptable1_v[].  */
        !            28:        cseg_t  pte;            /* Build page table entries here.  */
        !            29: 
        !            30:        /* Figure out how many clicks we need to map.
        !            31:         *         [                ]           What we want.
        !            32:         *      [       |       |       ]       What we get.
        !            33:         * Total number of clicks is:
        !            34:         *      (click up from (paddr+len)) - (click down from paddr)
        !            35:         */
        !            36:                
        !            37:        npage = btoc(paddr+len) - btocrd(paddr);
        !            38: 
        !            39:        /* Note that sysmem.vaddre is ALWAYS click aligned.  */
        !            40:        
        !            41:        /*
        !            42:         * Allocate the required chunk of virtual memory space.
        !            43:         * This could be a lot more sophisticated.  For expedience,
        !            44:         * there is no way to free this after it has been allocated,
        !            45:         * and there are no checks to see if we ran out of virtual space.
        !            46:         */
        !            47:        s = sphi();
        !            48:        chunk_start = sysmem.vaddre;
        !            49:        sysmem.vaddre += ctob(npage);
        !            50:        spl(s);
        !            51: 
        !            52:        /*
        !            53:         * Figure out where the desired physical address ends up in vmem.
        !            54:         */
        !            55:        retval = chunk_start + (paddr - ctob(btoc(paddr)));
        !            56:        
        !            57:        /*
        !            58:         * Load the page table.
        !            59:         */
        !            60:        base1 = btocrd(chunk_start);
        !            61:        pte = ctob(btocrd(paddr));
        !            62:        do {
        !            63:                ptable1_v[base1] = pte | SEG_SRW;
        !            64:                base1++;
        !            65:                pte += ctob(1); /* Bump up to next physical click.  */
        !            66:        } while (--npage > 0);
        !            67:        mmuupd();       /* Tell the mmu about the new map.  */
        !            68: 
        !            69:        return(retval);
        !            70: } /* map_pv() */
        !            71: 
        !            72: /*
        !            73:  * Release a virtual address that we previously obtained with function
        !            74:  * map_pv().
        !            75:  */
        !            76: void
        !            77: unmap_pv(faddr)
        !            78: faddr_t faddr;
        !            79: {
        !            80:        /* For the moment, this function does nothing.  */
        !            81: }              
        !            82: 
        !            83: /*
        !            84:  * Translate virtual address to physical address.
        !            85:  * Returns the current physical address associated with virtual address 'vaddr'.
        !            86:  * Returns 0 if that portion of virtual address space is not associated with
        !            87:  * any physical memory.
        !            88:  */
        !            89: paddr_t
        !            90: vtop(vaddr)
        !            91: caddr_t vaddr;
        !            92: {
        !            93:        paddr_t retval;
        !            94:        unsigned int ptable_idx;        /* Index into ptable1_v[].  */
        !            95: 
        !            96:        ptable_idx = btocrd(vaddr);
        !            97: 
        !            98:        /*
        !            99:         * There is a 4Mbyte virtual page table ptable1_v[] which is
        !           100:         * all the bottom level page tables appended into a big array.
        !           101:         * Note that there are huge holes in this data structure, for
        !           102:         * unmapped virtual address space.
        !           103:         *
        !           104:         * We are going to look up 'vaddr' in the virtual page table
        !           105:         * ptable1_v[].
        !           106:         *
        !           107:         * But first, we have to see if the portion of page table we are
        !           108:         * going to look at exists.  We do this by looking at the one click
        !           109:         * long page table that maps the virtual page table, PPTABLE1_V[].
        !           110:         */
        !           111:        retval = 0;     /* Assume entry not found.  */
        !           112: 
        !           113:        if (ptable0_v[btosrd(vaddr)] & SEG_SRO) {
        !           114:                /*
        !           115:                 * ASSERTION:  The portion of ptable1_v[] we want is valid.
        !           116:                 */
        !           117:                if (ptable1_v[ptable_idx] & SEG_SRO) {
        !           118: 
        !           119:                        /*
        !           120:                         * ASSERTION:  'vaddr' corresponds to some
        !           121:                         * physical memory.
        !           122:                         *
        !           123:                         * Note that the address of a physical click is
        !           124:                         * all above bit 11 in the PTE.
        !           125:                         */
        !           126:                        retval = (ptable1_v[ptable_idx] & ~(NBPC - 1));
        !           127:                        retval += ((long) vaddr & (NBPC - 1));
        !           128:                }
        !           129:        }
        !           130: 
        !           131:        T_PIGGY( 0x10, printf("vtop(%x)=%x, ", vaddr, retval); );
        !           132: 
        !           133:        return(retval);
        !           134: } /* vtop() */ 
        !           135: 
        !           136: /*
        !           137:  * Translate system global address 'vpaddr' to physical address.
        !           138:  *
        !           139:  * May cause a panic if 'vpaddr' does not correspond to a real physical
        !           140:  * address.
        !           141:  */
        !           142: paddr_t
        !           143: vptop(vpaddr)
        !           144: paddr_t vpaddr;
        !           145: {
        !           146:        paddr_t retval;
        !           147:        cseg_t pte;     /* Page table entry from sysmem.u.pbase[].  */
        !           148: 
        !           149:        T_PIGGY( 0x10, printf("vptop(%x)=", vpaddr); );
        !           150: 
        !           151:        pte = sysmem.u.pbase[btocrd(vpaddr)];
        !           152:        pte &= ~(NBPC - 1);     /* Strip off the non-address information.  */
        !           153: 
        !           154:        retval = pte | (vpaddr & (NBPC - 1));
        !           155: 
        !           156:        T_PIGGY( 0x10, printf("%x,", retval); );
        !           157: 
        !           158:        return(retval);
        !           159: } /* vptop() */
        !           160: 
        !           161: /*
        !           162:  * Convert from virtual address to system global address.  Similar to MAPIO(),
        !           163:  * but does not require separate segment and offset.
        !           164:  *
        !           165:  * Only works for Kernel Space virtual addresses.
        !           166:  */
        !           167: paddr_t
        !           168: vtovp(vaddr)
        !           169: caddr_t vaddr;
        !           170: {
        !           171:        paddr_t retval;
        !           172: 
        !           173:        T_PIGGY( 0x10, printf("vtopvp(%x)=", vaddr); );
        !           174: 
        !           175:        retval = MAPIO((allocp.sr_segp->s_vmem), (vaddr - allocp.sr_base));
        !           176: 
        !           177:        T_PIGGY( 0x10, printf("%x, ", retval); );
        !           178: 
        !           179:        return( retval );
        !           180: }

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