Add original unix v6
This commit is contained in:
memnoth
+636
@@ -0,0 +1,636 @@
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#
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/*
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*/
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#include "../param.h"
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#include "../user.h"
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#include "../buf.h"
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#include "../conf.h"
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#include "../systm.h"
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#include "../proc.h"
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#include "../seg.h"
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/*
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* This is the set of buffers proper, whose heads
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* were declared in buf.h. There can exist buffer
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* headers not pointing here that are used purely
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* as arguments to the I/O routines to describe
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* I/O to be done-- e.g. swbuf, just below, for
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* swapping.
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*/
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char buffers[NBUF][514];
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struct buf swbuf;
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/*
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* Declarations of the tables for the magtape devices;
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* see bdwrite.
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*/
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int tmtab;
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int httab;
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/*
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* The following several routines allocate and free
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* buffers with various side effects. In general the
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* arguments to an allocate routine are a device and
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* a block number, and the value is a pointer to
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* to the buffer header; the buffer is marked "busy"
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* so that no on else can touch it. If the block was
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* already in core, no I/O need be done; if it is
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* already busy, the process waits until it becomes free.
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* The following routines allocate a buffer:
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* getblk
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* bread
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* breada
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* Eventually the buffer must be released, possibly with the
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* side effect of writing it out, by using one of
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* bwrite
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* bdwrite
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* bawrite
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* brelse
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*/
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/*
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* Read in (if necessary) the block and return a buffer pointer.
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*/
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bread(dev, blkno)
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{
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register struct buf *rbp;
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rbp = getblk(dev, blkno);
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if (rbp->b_flags&B_DONE)
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return(rbp);
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rbp->b_flags =| B_READ;
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rbp->b_wcount = -256;
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(*bdevsw[dev.d_major].d_strategy)(rbp);
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iowait(rbp);
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return(rbp);
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}
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/*
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* Read in the block, like bread, but also start I/O on the
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* read-ahead block (which is not allocated to the caller)
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*/
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breada(adev, blkno, rablkno)
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{
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register struct buf *rbp, *rabp;
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register int dev;
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dev = adev;
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rbp = 0;
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if (!incore(dev, blkno)) {
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rbp = getblk(dev, blkno);
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if ((rbp->b_flags&B_DONE) == 0) {
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rbp->b_flags =| B_READ;
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rbp->b_wcount = -256;
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(*bdevsw[adev.d_major].d_strategy)(rbp);
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}
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}
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if (rablkno && !incore(dev, rablkno)) {
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rabp = getblk(dev, rablkno);
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if (rabp->b_flags & B_DONE)
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brelse(rabp);
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else {
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rabp->b_flags =| B_READ|B_ASYNC;
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rabp->b_wcount = -256;
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(*bdevsw[adev.d_major].d_strategy)(rabp);
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}
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}
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if (rbp==0)
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return(bread(dev, blkno));
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iowait(rbp);
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return(rbp);
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}
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/*
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* Write the buffer, waiting for completion.
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* Then release the buffer.
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*/
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bwrite(bp)
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struct buf *bp;
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{
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register struct buf *rbp;
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register flag;
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rbp = bp;
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flag = rbp->b_flags;
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rbp->b_flags =& ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
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rbp->b_wcount = -256;
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(*bdevsw[rbp->b_dev.d_major].d_strategy)(rbp);
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if ((flag&B_ASYNC) == 0) {
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iowait(rbp);
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brelse(rbp);
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} else if ((flag&B_DELWRI)==0)
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geterror(rbp);
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}
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/*
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* Release the buffer, marking it so that if it is grabbed
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* for another purpose it will be written out before being
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* given up (e.g. when writing a partial block where it is
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* assumed that another write for the same block will soon follow).
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* This can't be done for magtape, since writes must be done
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* in the same order as requested.
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*/
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bdwrite(bp)
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struct buf *bp;
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{
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register struct buf *rbp;
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register struct devtab *dp;
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rbp = bp;
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dp = bdevsw[rbp->b_dev.d_major].d_tab;
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if (dp == &tmtab || dp == &httab)
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bawrite(rbp);
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else {
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rbp->b_flags =| B_DELWRI | B_DONE;
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brelse(rbp);
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}
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}
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/*
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* Release the buffer, start I/O on it, but don't wait for completion.
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*/
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bawrite(bp)
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struct buf *bp;
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{
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register struct buf *rbp;
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rbp = bp;
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rbp->b_flags =| B_ASYNC;
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bwrite(rbp);
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}
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/*
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* release the buffer, with no I/O implied.
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*/
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brelse(bp)
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struct buf *bp;
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{
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register struct buf *rbp, **backp;
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register int sps;
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rbp = bp;
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if (rbp->b_flags&B_WANTED)
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wakeup(rbp);
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if (bfreelist.b_flags&B_WANTED) {
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bfreelist.b_flags =& ~B_WANTED;
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wakeup(&bfreelist);
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}
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if (rbp->b_flags&B_ERROR)
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rbp->b_dev.d_minor = -1; /* no assoc. on error */
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backp = &bfreelist.av_back;
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sps = PS->integ;
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spl6();
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rbp->b_flags =& ~(B_WANTED|B_BUSY|B_ASYNC);
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(*backp)->av_forw = rbp;
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rbp->av_back = *backp;
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*backp = rbp;
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rbp->av_forw = &bfreelist;
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PS->integ = sps;
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}
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/*
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* See if the block is associated with some buffer
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* (mainly to avoid getting hung up on a wait in breada)
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*/
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incore(adev, blkno)
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{
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register int dev;
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register struct buf *bp;
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register struct devtab *dp;
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dev = adev;
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dp = bdevsw[adev.d_major].d_tab;
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for (bp=dp->b_forw; bp != dp; bp = bp->b_forw)
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if (bp->b_blkno==blkno && bp->b_dev==dev)
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return(bp);
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return(0);
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}
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/*
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* Assign a buffer for the given block. If the appropriate
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* block is already associated, return it; otherwise search
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* for the oldest non-busy buffer and reassign it.
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* When a 512-byte area is wanted for some random reason
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* (e.g. during exec, for the user arglist) getblk can be called
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* with device NODEV to avoid unwanted associativity.
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*/
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getblk(dev, blkno)
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{
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register struct buf *bp;
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register struct devtab *dp;
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extern lbolt;
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if(dev.d_major >= nblkdev)
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panic("blkdev");
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loop:
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if (dev < 0)
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dp = &bfreelist;
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else {
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dp = bdevsw[dev.d_major].d_tab;
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if(dp == NULL)
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panic("devtab");
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for (bp=dp->b_forw; bp != dp; bp = bp->b_forw) {
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if (bp->b_blkno!=blkno || bp->b_dev!=dev)
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continue;
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spl6();
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if (bp->b_flags&B_BUSY) {
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bp->b_flags =| B_WANTED;
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sleep(bp, PRIBIO);
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spl0();
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goto loop;
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}
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spl0();
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notavail(bp);
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return(bp);
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}
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}
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spl6();
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if (bfreelist.av_forw == &bfreelist) {
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bfreelist.b_flags =| B_WANTED;
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sleep(&bfreelist, PRIBIO);
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spl0();
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goto loop;
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}
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spl0();
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notavail(bp = bfreelist.av_forw);
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if (bp->b_flags & B_DELWRI) {
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bp->b_flags =| B_ASYNC;
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bwrite(bp);
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goto loop;
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}
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bp->b_flags = B_BUSY | B_RELOC;
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bp->b_back->b_forw = bp->b_forw;
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bp->b_forw->b_back = bp->b_back;
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bp->b_forw = dp->b_forw;
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bp->b_back = dp;
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dp->b_forw->b_back = bp;
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dp->b_forw = bp;
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bp->b_dev = dev;
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bp->b_blkno = blkno;
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return(bp);
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}
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/*
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* Wait for I/O completion on the buffer; return errors
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* to the user.
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*/
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iowait(bp)
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struct buf *bp;
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{
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register struct buf *rbp;
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rbp = bp;
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spl6();
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while ((rbp->b_flags&B_DONE)==0)
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sleep(rbp, PRIBIO);
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spl0();
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geterror(rbp);
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}
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/*
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* Unlink a buffer from the available list and mark it busy.
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* (internal interface)
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*/
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notavail(bp)
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struct buf *bp;
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{
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register struct buf *rbp;
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register int sps;
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rbp = bp;
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sps = PS->integ;
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spl6();
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rbp->av_back->av_forw = rbp->av_forw;
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rbp->av_forw->av_back = rbp->av_back;
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rbp->b_flags =| B_BUSY;
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PS->integ = sps;
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}
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/*
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* Mark I/O complete on a buffer, release it if I/O is asynchronous,
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* and wake up anyone waiting for it.
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*/
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iodone(bp)
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struct buf *bp;
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{
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register struct buf *rbp;
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rbp = bp;
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if(rbp->b_flags&B_MAP)
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mapfree(rbp);
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rbp->b_flags =| B_DONE;
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if (rbp->b_flags&B_ASYNC)
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brelse(rbp);
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else {
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rbp->b_flags =& ~B_WANTED;
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wakeup(rbp);
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}
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}
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/*
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* Zero the core associated with a buffer.
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*/
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clrbuf(bp)
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int *bp;
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{
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register *p;
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register c;
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p = bp->b_addr;
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c = 256;
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do
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*p++ = 0;
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while (--c);
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}
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/*
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* Initialize the buffer I/O system by freeing
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* all buffers and setting all device buffer lists to empty.
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*/
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binit()
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{
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register struct buf *bp;
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register struct devtab *dp;
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register int i;
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struct bdevsw *bdp;
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bfreelist.b_forw = bfreelist.b_back =
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bfreelist.av_forw = bfreelist.av_back = &bfreelist;
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for (i=0; i<NBUF; i++) {
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bp = &buf[i];
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bp->b_dev = -1;
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bp->b_addr = buffers[i];
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bp->b_back = &bfreelist;
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bp->b_forw = bfreelist.b_forw;
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bfreelist.b_forw->b_back = bp;
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||||
bfreelist.b_forw = bp;
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bp->b_flags = B_BUSY;
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brelse(bp);
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}
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i = 0;
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for (bdp = bdevsw; bdp->d_open; bdp++) {
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dp = bdp->d_tab;
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if(dp) {
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dp->b_forw = dp;
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dp->b_back = dp;
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}
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i++;
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||||
}
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nblkdev = i;
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||||
}
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|
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/*
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||||
* Device start routine for disks
|
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* and other devices that have the register
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||||
* layout of the older DEC controllers (RF, RK, RP, TM)
|
||||
*/
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||||
#define IENABLE 0100
|
||||
#define WCOM 02
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||||
#define RCOM 04
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||||
#define GO 01
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devstart(bp, devloc, devblk, hbcom)
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struct buf *bp;
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||||
int *devloc;
|
||||
{
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||||
register int *dp;
|
||||
register struct buf *rbp;
|
||||
register int com;
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||||
|
||||
dp = devloc;
|
||||
rbp = bp;
|
||||
*dp = devblk; /* block address */
|
||||
*--dp = rbp->b_addr; /* buffer address */
|
||||
*--dp = rbp->b_wcount; /* word count */
|
||||
com = (hbcom<<8) | IENABLE | GO |
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||||
((rbp->b_xmem & 03) << 4);
|
||||
if (rbp->b_flags&B_READ) /* command + x-mem */
|
||||
com =| RCOM;
|
||||
else
|
||||
com =| WCOM;
|
||||
*--dp = com;
|
||||
}
|
||||
|
||||
/*
|
||||
* startup routine for RH controllers.
|
||||
*/
|
||||
#define RHWCOM 060
|
||||
#define RHRCOM 070
|
||||
|
||||
rhstart(bp, devloc, devblk, abae)
|
||||
struct buf *bp;
|
||||
int *devloc, *abae;
|
||||
{
|
||||
register int *dp;
|
||||
register struct buf *rbp;
|
||||
register int com;
|
||||
|
||||
dp = devloc;
|
||||
rbp = bp;
|
||||
if(cputype == 70)
|
||||
*abae = rbp->b_xmem;
|
||||
*dp = devblk; /* block address */
|
||||
*--dp = rbp->b_addr; /* buffer address */
|
||||
*--dp = rbp->b_wcount; /* word count */
|
||||
com = IENABLE | GO |
|
||||
((rbp->b_xmem & 03) << 8);
|
||||
if (rbp->b_flags&B_READ) /* command + x-mem */
|
||||
com =| RHRCOM; else
|
||||
com =| RHWCOM;
|
||||
*--dp = com;
|
||||
}
|
||||
|
||||
/*
|
||||
* 11/70 routine to allocate the
|
||||
* UNIBUS map and initialize for
|
||||
* a unibus device.
|
||||
* The code here and in
|
||||
* rhstart assumes that an rh on an 11/70
|
||||
* is an rh70 and contains 22 bit addressing.
|
||||
*/
|
||||
int maplock;
|
||||
mapalloc(abp)
|
||||
struct buf *abp;
|
||||
{
|
||||
register i, a;
|
||||
register struct buf *bp;
|
||||
|
||||
if(cputype != 70)
|
||||
return;
|
||||
spl6();
|
||||
while(maplock&B_BUSY) {
|
||||
maplock =| B_WANTED;
|
||||
sleep(&maplock, PSWP);
|
||||
}
|
||||
maplock =| B_BUSY;
|
||||
spl0();
|
||||
bp = abp;
|
||||
bp->b_flags =| B_MAP;
|
||||
a = bp->b_xmem;
|
||||
for(i=16; i<32; i=+2)
|
||||
UBMAP->r[i+1] = a;
|
||||
for(a++; i<48; i=+2)
|
||||
UBMAP->r[i+1] = a;
|
||||
bp->b_xmem = 1;
|
||||
}
|
||||
|
||||
mapfree(bp)
|
||||
struct buf *bp;
|
||||
{
|
||||
|
||||
bp->b_flags =& ~B_MAP;
|
||||
if(maplock&B_WANTED)
|
||||
wakeup(&maplock);
|
||||
maplock = 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* swap I/O
|
||||
*/
|
||||
swap(blkno, coreaddr, count, rdflg)
|
||||
{
|
||||
register int *fp;
|
||||
|
||||
fp = &swbuf.b_flags;
|
||||
spl6();
|
||||
while (*fp&B_BUSY) {
|
||||
*fp =| B_WANTED;
|
||||
sleep(fp, PSWP);
|
||||
}
|
||||
*fp = B_BUSY | B_PHYS | rdflg;
|
||||
swbuf.b_dev = swapdev;
|
||||
swbuf.b_wcount = - (count<<5); /* 32 w/block */
|
||||
swbuf.b_blkno = blkno;
|
||||
swbuf.b_addr = coreaddr<<6; /* 64 b/block */
|
||||
swbuf.b_xmem = (coreaddr>>10) & 077;
|
||||
(*bdevsw[swapdev>>8].d_strategy)(&swbuf);
|
||||
spl6();
|
||||
while((*fp&B_DONE)==0)
|
||||
sleep(fp, PSWP);
|
||||
if (*fp&B_WANTED)
|
||||
wakeup(fp);
|
||||
spl0();
|
||||
*fp =& ~(B_BUSY|B_WANTED);
|
||||
return(*fp&B_ERROR);
|
||||
}
|
||||
|
||||
/*
|
||||
* make sure all write-behind blocks
|
||||
* on dev (or NODEV for all)
|
||||
* are flushed out.
|
||||
* (from umount and update)
|
||||
*/
|
||||
bflush(dev)
|
||||
{
|
||||
register struct buf *bp;
|
||||
|
||||
loop:
|
||||
spl6();
|
||||
for (bp = bfreelist.av_forw; bp != &bfreelist; bp = bp->av_forw) {
|
||||
if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) {
|
||||
bp->b_flags =| B_ASYNC;
|
||||
notavail(bp);
|
||||
bwrite(bp);
|
||||
goto loop;
|
||||
}
|
||||
}
|
||||
spl0();
|
||||
}
|
||||
|
||||
/*
|
||||
* Raw I/O. The arguments are
|
||||
* The strategy routine for the device
|
||||
* A buffer, which will always be a special buffer
|
||||
* header owned exclusively by the device for this purpose
|
||||
* The device number
|
||||
* Read/write flag
|
||||
* Essentially all the work is computing physical addresses and
|
||||
* validating them.
|
||||
*/
|
||||
physio(strat, abp, dev, rw)
|
||||
struct buf *abp;
|
||||
int (*strat)();
|
||||
{
|
||||
register struct buf *bp;
|
||||
register char *base;
|
||||
register int nb;
|
||||
int ts;
|
||||
|
||||
bp = abp;
|
||||
base = u.u_base;
|
||||
/*
|
||||
* Check odd base, odd count, and address wraparound
|
||||
*/
|
||||
if (base&01 || u.u_count&01 || base>=base+u.u_count)
|
||||
goto bad;
|
||||
ts = (u.u_tsize+127) & ~0177;
|
||||
if (u.u_sep)
|
||||
ts = 0;
|
||||
nb = (base>>6) & 01777;
|
||||
/*
|
||||
* Check overlap with text. (ts and nb now
|
||||
* in 64-byte clicks)
|
||||
*/
|
||||
if (nb < ts)
|
||||
goto bad;
|
||||
/*
|
||||
* Check that transfer is either entirely in the
|
||||
* data or in the stack: that is, either
|
||||
* the end is in the data or the start is in the stack
|
||||
* (remember wraparound was already checked).
|
||||
*/
|
||||
if ((((base+u.u_count)>>6)&01777) >= ts+u.u_dsize
|
||||
&& nb < 1024-u.u_ssize)
|
||||
goto bad;
|
||||
spl6();
|
||||
while (bp->b_flags&B_BUSY) {
|
||||
bp->b_flags =| B_WANTED;
|
||||
sleep(bp, PRIBIO);
|
||||
}
|
||||
bp->b_flags = B_BUSY | B_PHYS | rw;
|
||||
bp->b_dev = dev;
|
||||
/*
|
||||
* Compute physical address by simulating
|
||||
* the segmentation hardware.
|
||||
*/
|
||||
bp->b_addr = base&077;
|
||||
base = (u.u_sep? UDSA: UISA)->r[nb>>7] + (nb&0177);
|
||||
bp->b_addr =+ base<<6;
|
||||
bp->b_xmem = (base>>10) & 077;
|
||||
bp->b_blkno = lshift(u.u_offset, -9);
|
||||
bp->b_wcount = -((u.u_count>>1) & 077777);
|
||||
bp->b_error = 0;
|
||||
u.u_procp->p_flag =| SLOCK;
|
||||
(*strat)(bp);
|
||||
spl6();
|
||||
while ((bp->b_flags&B_DONE) == 0)
|
||||
sleep(bp, PRIBIO);
|
||||
u.u_procp->p_flag =& ~SLOCK;
|
||||
if (bp->b_flags&B_WANTED)
|
||||
wakeup(bp);
|
||||
spl0();
|
||||
bp->b_flags =& ~(B_BUSY|B_WANTED);
|
||||
u.u_count = (-bp->b_resid)<<1;
|
||||
geterror(bp);
|
||||
return;
|
||||
bad:
|
||||
u.u_error = EFAULT;
|
||||
}
|
||||
|
||||
/*
|
||||
* Pick up the device's error number and pass it to the user;
|
||||
* if there is an error but the number is 0 set a generalized
|
||||
* code. Actually the latter is always true because devices
|
||||
* don't yet return specific errors.
|
||||
*/
|
||||
geterror(abp)
|
||||
struct buf *abp;
|
||||
{
|
||||
register struct buf *bp;
|
||||
|
||||
bp = abp;
|
||||
if (bp->b_flags&B_ERROR)
|
||||
if ((u.u_error = bp->b_error)==0)
|
||||
u.u_error = EIO;
|
||||
}
|
||||
Reference in New Issue
Block a user