[src/uebayasi-xip]: src/sys/miscfs/genfs genfs_getpages() for XIP.

[uebayasi <uebayasi%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c32902efed46
branches:  uebayasi-xip
changeset: 751569:c32902efed46
user:      uebayasi <uebayasi%NetBSD.org@localhost>
date:      Thu Feb 11 06:23:04 2010 +0000

description:
genfs_getpages() for XIP.

Pages are directly mappable, and always there.  What we need to do here is
to address filesystem blocks and tell those addresses back to the fault
handler by encoding the physical addresses in struct vm_page * pointers.

(I hate code duplication.  What can I do?)

diffstat:

 sys/miscfs/genfs/genfs_io.c |  127 +++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 125 insertions(+), 2 deletions(-)

diffs (162 lines):

diff -r 4d34b2535c88 -r c32902efed46 sys/miscfs/genfs/genfs_io.c
--- a/sys/miscfs/genfs/genfs_io.c       Thu Feb 11 05:38:20 2010 +0000
+++ b/sys/miscfs/genfs/genfs_io.c       Thu Feb 11 06:23:04 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: genfs_io.c,v 1.36 2010/01/30 12:06:20 uebayasi Exp $   */
+/*     $NetBSD: genfs_io.c,v 1.36.2.1 2010/02/11 06:23:04 uebayasi Exp $       */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -31,7 +31,9 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.36 2010/01/30 12:06:20 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.36.2.1 2010/02/11 06:23:04 uebayasi Exp $");
+
+#include "opt_xip.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -56,6 +58,8 @@
 #include <uvm/uvm.h>
 #include <uvm/uvm_pager.h>
 
+static int genfs_do_getpages(void *);
+static int genfs_do_getpages_xip(void *);
 static int genfs_do_directio(struct vmspace *, vaddr_t, size_t, struct vnode *,
     off_t, enum uio_rw);
 static void genfs_dio_iodone(struct buf *);
@@ -104,6 +108,29 @@
                int a_advice;
                int a_flags;
        } */ * const ap = v;
+       struct vnode * const vp = ap->a_vp;
+
+#ifdef XIP
+       if ((vp->v_vflag & VV_XIP) != 0)
+               return genfs_do_getpages_xip(v);
+       else
+#endif
+               return genfs_do_getpages(v);
+}
+
+static int
+genfs_do_getpages(void *v)
+{
+       struct vop_getpages_args /* {
+               struct vnode *a_vp;
+               voff_t a_offset;
+               struct vm_page **a_m;
+               int *a_count;
+               int a_centeridx;
+               vm_prot_t a_access_type;
+               int a_advice;
+               int a_flags;
+       } */ * const ap = v;
 
        off_t diskeof, memeof;
        int i, error, npages;
@@ -711,6 +738,102 @@
        return (error);
 }
 
+#ifdef XIP
+static int
+genfs_do_getpages_xip(void *v)
+{
+       struct vop_getpages_args /* {
+               struct vnode *a_vp;
+               voff_t a_offset;
+               struct vm_page **a_m;
+               int *a_count;
+               int a_centeridx;
+               vm_prot_t a_access_type;
+               int a_advice;
+               int a_flags;
+       } */ * const ap = v;
+
+       struct vnode * const vp = ap->a_vp;
+       int *npagesp = ap->a_count;
+       const off_t offset = ap->a_offset;
+       struct vm_page **pps = ap->a_m;
+       struct uvm_object * const uobj = &vp->v_uobj;
+       const int flags = ap->a_flags;
+
+       int error;
+       off_t eof, sbkoff, ebkoff, off;
+       int npages;
+       int fs_bshift, fs_bsize, dev_bshift, dev_bsize;
+       int i;
+       paddr_t phys_addr;
+
+       KASSERT((vp->v_vflag & VV_XIP) != 0);
+
+       UVMHIST_LOG(ubchist, "xip!", 0, 0, 0, 0);
+
+       /* XXXUEBS should we care about PGO_LOCKED? */
+
+       GOP_SIZE(vp, vp->v_size, &eof, GOP_SIZE_MEM);
+       npages = MIN(*npagesp, round_page(eof - offset) >> PAGE_SHIFT);
+
+       fs_bshift = vp->v_mount->mnt_fs_bshift;
+       fs_bsize = 1 << fs_bshift;
+       dev_bshift = vp->v_mount->mnt_dev_bshift;
+       dev_bsize = 1 << dev_bshift;
+
+       sbkoff = offset & ~(fs_bsize - 1);
+       ebkoff = ((offset + PAGE_SIZE * npages) + (fs_bsize - 1)) & ~(fs_bsize - 1);
+
+       UVMHIST_LOG(ubchist, "xip npages=%d sbkoff=%lx ebkoff=%lx", npages, (long)sbkoff, (long)ebkoff, 0);
+
+       /* XXX optimize */
+       off = offset;
+       i = 0;
+       while (i < npages) {
+               daddr_t lbn, blkno;
+               int run;
+               struct vnode *devvp;
+
+               lbn = (off & ~(fs_bsize - 1)) >> fs_bshift;
+
+               error = VOP_BMAP(vp, lbn, &devvp, &blkno, &run);
+               KASSERT(error == 0);
+               UVMHIST_LOG(ubchist, "xip VOP_BMAP: lbn=%ld blkno=%ld run=%d", (long)lbn, (long)blkno, run, 0);
+
+               if (blkno < 0) {
+                       /* unallocated page is redirected to read-only zero-filled page */
+                       phys_addr = uvm_pageofzero_xip_phys_addr();
+               } else {
+                       phys_addr = vp->v_mount->mnt_phys_addr +
+                           (blkno << dev_bshift) +
+                           (off - (lbn << fs_bshift));
+               }
+
+               pps[i] = PHYS_TO_VM_PAGE(phys_addr);
+
+               UVMHIST_LOG(ubchist, "xip pgs %d => phys_addr=0x%lx (%p)",
+                       i,
+                       (long)phys_addr,
+                       pps[i],
+                       0);
+               printf("xip pgs %d => phys_addr=0x%lx (%p)\n",
+                       i,
+                       (long)phys_addr,
+                       pps[i]);
+
+               off += PAGE_SIZE;
+               i++;
+       }
+
+       *npagesp = i;
+
+       if ((flags & PGO_LOCKED) == 0)
+               mutex_exit(&uobj->vmobjlock);
+
+       return 0;
+}
+#endif
+
 /*
  * generic VM putpages routine.
  * Write the given range of pages to backing store.