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/*
* 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/mm.h>
#include <linux/slab.h>
#include <asm/page.h>
#include <xen/xencomm.h>
#include <xen/interface/xen.h>
#include <asm/xen/xencomm.h> /* for xencomm_is_phys_contiguous() */
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;
}
static struct xencomm_handle *xencomm_create_inline(void *ptr)
{
unsigned long paddr;
BUG_ON(!xencomm_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 (xencomm_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 (xencomm_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);
}
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