kernel: vm: Add vnode pager

Signed-off-by: Ian Moffett <ian@osmora.org>

7 files changed, 324 insertions, 0 deletions

diff --git a/sys/include/sys/vnode.h b/sys/include/sys/vnode.h
index ea537f6..6dc2cbc 100644
--- a/sys/include/sys/vnode.h
+++ b/sys/include/sys/vnode.h
@@ -33,6 +33,7 @@
 #include <sys/types.h>
 #include <sys/queue.h>
 #include <sys/mount.h>
+#include <vm/obj.h>
 #include <sys/sio.h>
 
 struct vnode;
@@ -53,6 +54,7 @@ struct vattr {
 struct vnode {
     int type;
     int flags;
+    struct vm_object *vmobj;
     struct mount *mp;   /* Ptr to vfs vnode is in */
     struct vops *vops;
     struct vnode *parent;
diff --git a/sys/include/vm/obj.h b/sys/include/vm/obj.h
new file mode 100644
index 0000000..d44454e
--- /dev/null
+++ b/sys/include/vm/obj.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _VM_OBJ_H_
+#define _VM_OBJ_H_
+
+#include <sys/spinlock.h>
+#include <sys/types.h>
+#include <sys/vnode.h>
+#include <vm/map.h>
+#include <vm/pager.h>
+
+struct vm_object {
+    struct spinlock lock;           /* Protects this object */
+    struct vm_mapspace mapspace;    /* Mapspace this object points to */
+    struct vm_pagerops *pgops;      /* Pager operations */
+
+    uint8_t is_anon : 1;
+    struct vnode *vnode;
+};
+
+int vm_obj_init(struct vm_object **res, struct vnode *vnode);
+int vm_obj_destroy(struct vm_object *obj);
+
+#endif  /* !_VM_OBJ_H_ */
diff --git a/sys/include/vm/page.h b/sys/include/vm/page.h
index d1e89ea..80fa74f 100644
--- a/sys/include/vm/page.h
+++ b/sys/include/vm/page.h
@@ -32,6 +32,10 @@
 
 #include <sys/types.h>
 
+struct vm_page {
+    paddr_t physaddr;
+};
+
 void vm_zero_page(void *page, size_t page_count);
 
 #endif  /* !_VM_PAGE_H_ */
diff --git a/sys/include/vm/pager.h b/sys/include/vm/pager.h
new file mode 100644
index 0000000..5f36bfc
--- /dev/null
+++ b/sys/include/vm/pager.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _VM_PAGER_H_
+#define _VM_PAGER_H_
+
+#include <sys/types.h>
+#include <vm/page.h>
+
+struct vm_object;
+
+struct vm_pagerops {
+    int(*get)(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg);
+    int(*store)(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg);
+};
+
+extern struct vm_pagerops g_vnode_pagerops;
+
+int vm_pager_get(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg);
+
+#endif  /* !_VM_PAGER_H_ */
diff --git a/sys/vm/vm_obj.c b/sys/vm/vm_obj.c
new file mode 100644
index 0000000..c5fc921
--- /dev/null
+++ b/sys/vm/vm_obj.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <vm/obj.h>
+#include <vm/dynalloc.h>
+#include <sys/errno.h>
+#include <string.h>
+
+int
+vm_obj_init(struct vm_object **res, struct vnode *vnode)
+{
+    struct vm_object *obj = dynalloc(sizeof(struct vm_object));
+
+    if (obj == NULL) {
+        return -ENOMEM;
+    }
+
+    memset(obj, 0, sizeof(struct vm_object));
+    obj->vnode = vnode;
+    obj->pgops = &g_vnode_pagerops;
+    *res = obj;
+    return 0;
+}
+
+int
+vm_obj_destroy(struct vm_object *obj)
+{
+    struct vnode *vp = obj->vnode;
+
+    if (vp->vmobj != NULL)
+        vp->vmobj = NULL;
+
+    dynfree(obj);
+    return 0;
+}
diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c
new file mode 100644
index 0000000..b82a9e1
--- /dev/null
+++ b/sys/vm/vm_pager.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <vm/pager.h>
+#include <vm/obj.h>
+#include <sys/types.h>
+
+/*
+ * Get pages from backing store.
+ */
+int
+vm_pager_get(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg)
+{
+    struct vm_pagerops *pgops = obj->pgops;
+
+    if (obj->is_anon) {
+        return -1;
+    }
+
+    return pgops->get(obj, off, len, pg);
+}
diff --git a/sys/vm/vm_vnode.c b/sys/vm/vm_vnode.c
new file mode 100644
index 0000000..707f7b4
--- /dev/null
+++ b/sys/vm/vm_vnode.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/errno.h>
+#include <sys/sio.h>
+#include <sys/vfs.h>
+#include <sys/cdefs.h>
+#include <vm/obj.h>
+#include <vm/vm.h>
+#include <vm/pager.h>
+
+static int vn_pager_get(struct vm_object *obj, off_t off, size_t len,
+                        struct vm_page *pg);
+
+static int vn_pager_store(struct vm_object *obj, off_t off, size_t len,
+                          struct vm_page *pg);
+
+/* Pager operations */
+struct vm_pagerops g_vnode_pagerops = {
+    .get = vn_pager_get,
+    .store = vn_pager_store
+};
+
+static inline void
+vn_prep_sio(struct sio_txn *sio, char *pg, off_t off, size_t len)
+{
+    sio->len = __ALIGN_DOWN(len, vm_get_page_size());
+    sio->buf = pg;
+    sio->offset = off;
+    sio->len = len;
+}
+
+static int
+vn_pager_io(struct vm_object *obj, off_t off, size_t len,
+            struct vm_page *pg, bool out)
+{
+    struct sio_txn sio;
+    struct vnode *vp;
+    ssize_t paged_bytes;
+    char *dest;
+    int res = 0;
+
+    if (obj == NULL || pg == NULL) {
+        return -EIO;
+    }
+
+    spinlock_acquire(&obj->lock);
+    dest = PHYS_TO_VIRT(pg->physaddr);
+
+    /* Attempt to fetch the vnode */
+    if ((vp = obj->vnode) == NULL) {
+        res = -EIO;
+        goto done;
+    }
+
+    /* Prepare the SIO transaction */
+    vn_prep_sio(&sio, dest, off, len);
+    if (sio.len == 0) {
+        res = -EIO;
+        goto done;
+    }
+
+    /* Perform I/O on the backing store */
+    paged_bytes = out ? vfs_write(vp, &sio) : vfs_read(vp, &sio);
+    if (paged_bytes < 0) {
+        /* Failure */
+        res = paged_bytes;
+        goto done;
+    }
+done:
+    spinlock_release(&obj->lock);
+    return res;
+}
+
+static int
+vn_pager_store(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg)
+{
+    return vn_pager_io(obj, off, len, pg, true);
+}
+
+static int
+vn_pager_get(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg)
+{
+    return vn_pager_io(obj, off, len, pg, false);
+}