/*
* Copyright (c) 2006 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/** @addtogroup libc
* @{
*/
/** @file
*/
#include <as.h>
#include <libc.h>
#include <unistd.h>
#include <align.h>
#include <sys/types.h>
#include <bitops.h>
/**
* Either 4*256M on 32-bit architecures or 16*256M on 64-bit architectures.
*/
#define MAX_HEAP_SIZE (sizeof(uintptr_t)<<28)
/** Create address space area.
*
* @param address Virtual address where to place new address space area.
* @param size Size of the area.
* @param flags Flags describing type of the area.
*
* @return address on success, (void *) -1 otherwise.
*/
void *as_area_create(void *address, size_t size, int flags)
{
return (void *) __SYSCALL3(SYS_AS_AREA_CREATE, (sysarg_t ) address,
(sysarg_t) size, (sysarg_t) flags);
}
/** Resize address space area.
*
* @param address Virtual address pointing into already existing address space
* area.
* @param size New requested size of the area.
* @param flags Currently unused.
*
* @return Zero on success or a code from @ref errno.h on failure.
*/
int as_area_resize(void *address, size_t size, int flags)
{
return __SYSCALL3(SYS_AS_AREA_RESIZE, (sysarg_t ) address,
(sysarg_t) size, (sysarg_t) flags);
}
/** Destroy address space area.
*
* @param address Virtual address pointing into the address space area being
* destroyed.
*
* @return Zero on success or a code from @ref errno.h on failure.
*/
int as_area_destroy(void *address)
{
return __SYSCALL1(SYS_AS_AREA_DESTROY, (sysarg_t ) address);
}
/** Change address-space area flags.
*
* @param address Virtual address pointing into the address space area being
* modified.
* @param flags New flags describing type of the area.
*
* @return Zero on success or a code from @ref errno.h on failure.
*/
int as_area_change_flags(void *address, int flags)
{
return __SYSCALL2(SYS_AS_AREA_DESTROY, (sysarg_t) address,
(sysarg_t) flags);
}
static size_t heapsize = 0;
static size_t maxheapsize = (size_t) (-1);
static void * last_allocated = 0;
/* Start of heap linker symbol */
extern char _heap;
/** Sbrk emulation
*
* @param incr New area that should be allocated or negative,
if it should be shrinked
* @return Pointer to newly allocated area
*/
void *sbrk(ssize_t incr)
{
int rc;
void *res;
/* Check for invalid values */
if (incr < 0 && -incr > heapsize)
return NULL;
/* Check for too large value */
if (incr > 0 && incr+heapsize < heapsize)
return NULL;
/* Check for too small values */
if (incr < 0 && incr+heapsize > heapsize)
return NULL;
/* Check for user limit */
if ((maxheapsize != (size_t) (-1)) && (heapsize + incr) > maxheapsize)
return NULL;
rc = as_area_resize(&_heap, heapsize + incr, 0);
if (rc != 0)
return NULL;
/* Compute start of new area */
res = (void *) &_heap + heapsize;
heapsize += incr;
return res;
}
/** Set maximum heap size and return pointer just after the heap */
void *set_maxheapsize(size_t mhs)
{
maxheapsize = mhs;
/* Return pointer to area not managed by sbrk */
return ((void *) &_heap + maxheapsize);
}
/** Return pointer to some unmapped area, where fits new as_area
*
* @param sz Requested size of the allocation.
*
* @return Pointer to the beginning
*
* TODO: make some first_fit/... algorithm, we are now just incrementing
* the pointer to last area
*/
void *as_get_mappable_page(size_t sz)
{
void *res;
uint64_t asz;
int i;
if (!sz)
return NULL;
asz = 1 << (fnzb64(sz - 1) + 1);
/* Set heapsize to some meaningful value */
if (maxheapsize == -1)
set_maxheapsize(MAX_HEAP_SIZE);
/*
* Make sure we allocate from naturally aligned address.
*/
i = 0;
if (!last_allocated) {
last_allocated = (void *) ALIGN_UP((void *) &_heap +
maxheapsize, asz);
} else {
last_allocated = (void *) ALIGN_UP(((uintptr_t)
last_allocated) + (int) (i > 0), asz);
}
res = last_allocated;
last_allocated += ALIGN_UP(sz, PAGE_SIZE);
return res;
}
/** @}
*/