diff options
Diffstat (limited to 'drivers/xen/xencomm.c')
| -rw-r--r-- | drivers/xen/xencomm.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/xen/xencomm.c b/drivers/xen/xencomm.c new file mode 100644 index 00000000000..797cb4e31f0 --- /dev/null +++ b/drivers/xen/xencomm.c @@ -0,0 +1,232 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Copyright (C) IBM Corp. 2006 + * + * Authors: Hollis Blanchard <hollisb@us.ibm.com> + */ + +#include <linux/gfp.h> +#include <linux/mm.h> +#include <asm/page.h> +#include <xen/xencomm.h> +#include <xen/interface/xen.h> +#ifdef __ia64__ +#include <asm/xen/xencomm.h> /* for is_kern_addr() */ +#endif + +#ifdef HAVE_XEN_PLATFORM_COMPAT_H +#include <xen/platform-compat.h> +#endif + +static int xencomm_init(struct xencomm_desc *desc, + void *buffer, unsigned long bytes) +{ + unsigned long recorded = 0; + int i = 0; + + while ((recorded < bytes) && (i < desc->nr_addrs)) { + unsigned long vaddr = (unsigned long)buffer + recorded; + unsigned long paddr; + int offset; + int chunksz; + + offset = vaddr % PAGE_SIZE; /* handle partial pages */ + chunksz = min(PAGE_SIZE - offset, bytes - recorded); + + paddr = xencomm_vtop(vaddr); + if (paddr == ~0UL) { + printk(KERN_DEBUG "%s: couldn't translate vaddr %lx\n", + __func__, vaddr); + return -EINVAL; + } + + desc->address[i++] = paddr; + recorded += chunksz; + } + + if (recorded < bytes) { + printk(KERN_DEBUG + "%s: could only translate %ld of %ld bytes\n", + __func__, recorded, bytes); + return -ENOSPC; + } + + /* mark remaining addresses invalid (just for safety) */ + while (i < desc->nr_addrs) + desc->address[i++] = XENCOMM_INVALID; + + desc->magic = XENCOMM_MAGIC; + + return 0; +} + +static struct xencomm_desc *xencomm_alloc(gfp_t gfp_mask, + void *buffer, unsigned long bytes) +{ + struct xencomm_desc *desc; + unsigned long buffer_ulong = (unsigned long)buffer; + unsigned long start = buffer_ulong & PAGE_MASK; + unsigned long end = (buffer_ulong + bytes) | ~PAGE_MASK; + unsigned long nr_addrs = (end - start + 1) >> PAGE_SHIFT; + unsigned long size = sizeof(*desc) + + sizeof(desc->address[0]) * nr_addrs; + + /* + * slab allocator returns at least sizeof(void*) aligned pointer. + * When sizeof(*desc) > sizeof(void*), struct xencomm_desc might + * cross page boundary. + */ + if (sizeof(*desc) > sizeof(void *)) { + unsigned long order = get_order(size); + desc = (struct xencomm_desc *)__get_free_pages(gfp_mask, + order); + if (desc == NULL) + return NULL; + + desc->nr_addrs = + ((PAGE_SIZE << order) - sizeof(struct xencomm_desc)) / + sizeof(*desc->address); + } else { + desc = kmalloc(size, gfp_mask); + if (desc == NULL) + return NULL; + + desc->nr_addrs = nr_addrs; + } + return desc; +} + +void xencomm_free(struct xencomm_handle *desc) +{ + if (desc && !((ulong)desc & XENCOMM_INLINE_FLAG)) { + struct xencomm_desc *desc__ = (struct xencomm_desc *)desc; + if (sizeof(*desc__) > sizeof(void *)) { + unsigned long size = sizeof(*desc__) + + sizeof(desc__->address[0]) * desc__->nr_addrs; + unsigned long order = get_order(size); + free_pages((unsigned long)__va(desc), order); + } else + kfree(__va(desc)); + } +} + +static int xencomm_create(void *buffer, unsigned long bytes, + struct xencomm_desc **ret, gfp_t gfp_mask) +{ + struct xencomm_desc *desc; + int rc; + + pr_debug("%s: %p[%ld]\n", __func__, buffer, bytes); + + if (bytes == 0) { + /* don't create a descriptor; Xen recognizes NULL. */ + BUG_ON(buffer != NULL); + *ret = NULL; + return 0; + } + + BUG_ON(buffer == NULL); /* 'bytes' is non-zero */ + + desc = xencomm_alloc(gfp_mask, buffer, bytes); + if (!desc) { + printk(KERN_DEBUG "%s failure\n", "xencomm_alloc"); + return -ENOMEM; + } + + rc = xencomm_init(desc, buffer, bytes); + if (rc) { + printk(KERN_DEBUG "%s failure: %d\n", "xencomm_init", rc); + xencomm_free((struct xencomm_handle *)__pa(desc)); + return rc; + } + + *ret = desc; + return 0; +} + +/* check if memory address is within VMALLOC region */ +static int is_phys_contiguous(unsigned long addr) +{ + if (!is_kernel_addr(addr)) + return 0; + + return (addr < VMALLOC_START) || (addr >= VMALLOC_END); +} + +static struct xencomm_handle *xencomm_create_inline(void *ptr) +{ + unsigned long paddr; + + BUG_ON(!is_phys_contiguous((unsigned long)ptr)); + + paddr = (unsigned long)xencomm_pa(ptr); + BUG_ON(paddr & XENCOMM_INLINE_FLAG); + return (struct xencomm_handle *)(paddr | XENCOMM_INLINE_FLAG); +} + +/* "mini" routine, for stack-based communications: */ +static int xencomm_create_mini(void *buffer, + unsigned long bytes, struct xencomm_mini *xc_desc, + struct xencomm_desc **ret) +{ + int rc = 0; + struct xencomm_desc *desc; + BUG_ON(((unsigned long)xc_desc) % sizeof(*xc_desc) != 0); + + desc = (void *)xc_desc; + + desc->nr_addrs = XENCOMM_MINI_ADDRS; + + rc = xencomm_init(desc, buffer, bytes); + if (!rc) + *ret = desc; + + return rc; +} + +struct xencomm_handle *xencomm_map(void *ptr, unsigned long bytes) +{ + int rc; + struct xencomm_desc *desc; + + if (is_phys_contiguous((unsigned long)ptr)) + return xencomm_create_inline(ptr); + + rc = xencomm_create(ptr, bytes, &desc, GFP_KERNEL); + + if (rc || desc == NULL) + return NULL; + + return xencomm_pa(desc); +} + +struct xencomm_handle *__xencomm_map_no_alloc(void *ptr, unsigned long bytes, + struct xencomm_mini *xc_desc) +{ + int rc; + struct xencomm_desc *desc = NULL; + + if (is_phys_contiguous((unsigned long)ptr)) + return xencomm_create_inline(ptr); + + rc = xencomm_create_mini(ptr, bytes, xc_desc, + &desc); + + if (rc) + return NULL; + + return xencomm_pa(desc); +} |