diff options
| -rw-r--r-- | sys/include/vm/vm_pager.h | 1 | ||||
| -rw-r--r-- | sys/vm/vm_anon.c | 116 |
2 files changed, 117 insertions, 0 deletions
diff --git a/sys/include/vm/vm_pager.h b/sys/include/vm/vm_pager.h index 34815a3..e0503e0 100644 --- a/sys/include/vm/vm_pager.h +++ b/sys/include/vm/vm_pager.h @@ -38,6 +38,7 @@ struct vm_object; struct vm_pagerops; extern const struct vm_pagerops vm_vnops; +extern const struct vm_pagerops vm_anonops; /* diff --git a/sys/vm/vm_anon.c b/sys/vm/vm_anon.c new file mode 100644 index 0000000..9ca8842 --- /dev/null +++ b/sys/vm/vm_anon.c @@ -0,0 +1,116 @@ +/* + * Copyright (c) 2023-2025 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/param.h> +#include <sys/spinlock.h> +#include <sys/syslog.h> +#include <sys/errno.h> +#include <sys/param.h> +#include <vm/physmem.h> +#include <vm/vm_pager.h> +#include <vm/vm_page.h> +#include <vm/vm.h> + +#define pr_trace(fmt, ...) kprintf("vm_anon: " fmt, ##__VA_ARGS__) +#define pr_error(...) pr_trace(__VA_ARGS__) + +#define ANON_TIMEOUT_USEC 200000 + +/* + * Get pages from physical memory. + * + * @obp: Object representing the backing store (in memory). + * @pgs: Page descriptors to be filled. + * @off: Offset to read from in backing store. + * @len: Length to read in bytes. + */ +static int +anon_get(struct vm_object *obp, struct vm_page **pgs, off_t off, size_t len) +{ + struct vm_page *pgtmp, *pgres; + int retval = 0; + size_t j, npgs; + + len = ALIGN_DOWN(len, DEFAULT_PAGESIZE); + if (obp == NULL || pgs == NULL) { + return -EINVAL; + } + + /* Zero bytes is invalid */ + if (len == 0) { + len = 4096; + } + + spinlock_acquire(&obp->lock); + npgs = len >> 12; + + for (int i = 0; i < npgs; ++i) { + j = i / DEFAULT_PAGESIZE; + pgtmp = vm_pagelookup(obp, i); + pgres = pgs[j]; + + /* Do we need to create our own entry? */ + if (pgtmp == NULL) { + pgtmp = vm_pagealloc(obp, PALLOC_ZERO); + } + + if (pgtmp == NULL) { + pr_trace("anon_get: failed to add page %d, marking invalid\n", j); + pgres->flags &= ~PG_VALID; + continue; + } + + /* + * We are *just* populating `pgs' and therefore nobody + * should even attempt to acquire this lock... Shit + * happens though, so just make sure we can grab it + * without assuming success. + */ + if (spinlock_usleep(&pgres->lock, ANON_TIMEOUT_USEC) < 0) { + vm_pagefree(obp, pgtmp, 0); + pr_error("anon_get: pgres spin timeout\n"); + return -ETIMEDOUT; + } + + /* Hold pgres before configuring it */ + spinlock_acquire(&pgres->lock); + *pgres = *pgtmp; + pgres->flags |= (PG_VALID | PG_CLEAN); + spinlock_release(&pgres->lock); + + } + + spinlock_release(&obp->lock); + return retval; +} + +const struct vm_pagerops vm_anonops = { + .get = anon_get +}; |