From 0e24592cb32f61bb59caad30ea9acc524974c6dd Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Thu, 18 Apr 2024 15:06:22 -0400 Subject: kernel: vm: Add device pager Signed-off-by: Ian Moffett --- sys/vm/vm_device.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++ sys/vm/vm_obj.c | 19 ++++++++- sys/vm/vm_pager.c | 21 ++++++++++ 3 files changed, 158 insertions(+), 1 deletion(-) create mode 100644 sys/vm/vm_device.c (limited to 'sys/vm') diff --git a/sys/vm/vm_device.c b/sys/vm/vm_device.c new file mode 100644 index 0000000..976dec7 --- /dev/null +++ b/sys/vm/vm_device.c @@ -0,0 +1,119 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include + +static int dv_pager_get(struct vm_object *obj, off_t off, size_t len, + struct vm_page *pg); + +static int dv_pager_store(struct vm_object *obj, off_t off, size_t len, + struct vm_page *pg); + +static int dv_pager_paddr(struct vm_object *obj, paddr_t *paddr, + vm_prot_t prot); + +/* Pager operations */ +struct vm_pagerops g_dev_pagerops = { + .get = dv_pager_get, + .store = dv_pager_store, + .get_paddr = dv_pager_paddr +}; + +/* + * Fetch a device descriptor from a memory + * object. + * + * Returns 0 on success. + */ +static int +dv_get_dev(struct vm_object *obj, struct device **res) +{ + struct device *dev; + struct vnode *vp; + int status; + + if ((vp = obj->vnode) == NULL) + return -EIO; + + /* Now try to fetch the device */ + if ((status = devfs_get_dev(vp, &dev)) != 0) + return status; + + *res = dev; + return 0; +} + +static int +dv_pager_paddr(struct vm_object *obj, paddr_t *paddr, vm_prot_t prot) +{ + struct device *dev; + int status; + + if (paddr == NULL) { + return -EINVAL; + } + + /* Try to fetch the device */ + if ((status = dv_get_dev(obj, &dev)) != 0) { + return status; + } + + if (dev->mmap == NULL) { + /* + * mmap() is not supported, this is not an object + * we can handle so try switching its operations + * to the vnode pager ops... + */ + obj->pgops = &g_vnode_pagerops; + return -ENOTSUP; + } + + *paddr = dev->mmap(dev, 0, prot); + return 0; +} + +static int +dv_pager_store(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg) +{ + return -1; +} + +static int +dv_pager_get(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg) +{ + return -1; +} diff --git a/sys/vm/vm_obj.c b/sys/vm/vm_obj.c index c5fc921..589ca47 100644 --- a/sys/vm/vm_obj.c +++ b/sys/vm/vm_obj.c @@ -32,6 +32,22 @@ #include #include +static void +vm_set_pgops(struct vm_object *obj, struct vnode *vnode) +{ + if (vnode == NULL) { + obj->vnode = NULL; + return; + } + + /* Is this a device? */ + if (vnode->type == VCHR || vnode->type == VBLK) { + obj->pgops = &g_dev_pagerops; + } else { + obj->pgops = &g_vnode_pagerops; + } +} + int vm_obj_init(struct vm_object **res, struct vnode *vnode) { @@ -43,7 +59,8 @@ vm_obj_init(struct vm_object **res, struct vnode *vnode) memset(obj, 0, sizeof(struct vm_object)); obj->vnode = vnode; - obj->pgops = &g_vnode_pagerops; + + vm_set_pgops(obj, vnode); *res = obj; return 0; } diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c index b82a9e1..0046e9c 100644 --- a/sys/vm/vm_pager.c +++ b/sys/vm/vm_pager.c @@ -45,3 +45,24 @@ vm_pager_get(struct vm_object *obj, off_t off, size_t len, struct vm_page *pg) return pgops->get(obj, off, len, pg); } + +/* + * Get physical address. + * + * TODO: Remove this and add demanding paging. + */ +int +vm_pager_paddr(struct vm_object *obj, paddr_t *paddr, vm_prot_t prot) +{ + struct vm_pagerops *pgops = obj->pgops; + + if (obj->is_anon) { + return -1; + } + + if (pgops->get_paddr == NULL) { + return 0; + } + + return pgops->get_paddr(obj, paddr, prot); +} -- cgit v1.2.3