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sel4: clear dataspace page wise 

Creating mappings inside core may exhaust the internal allocators
if very large dataspaces must be cleared.

Issue #2044
This commit is contained in:
Alexander Boettcher 2016-07-13 11:50:26 +02:00 committed by Christian Helmuth
parent 253f2aef0f
commit 738ca74166
1 changed files with 35 additions and 29 deletions
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64
repos/base-sel4/src/core/ram_session_support.cc
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@ -11,9 +11,6 @@
* under the terms of the GNU General Public License version 2.
*/
/* Genode includes */
#include <base/log.h>
/* core includes */
#include <ram_session_component.h>
#include <platform.h>
@ -25,45 +22,54 @@ using namespace Genode;
void Ram_session_component::_export_ram_ds(Dataspace_component *ds)
{
size_t const num_pages = ds->size() >> get_page_size_log2();
size_t const page_rounded_size = (ds->size() + get_page_size() - 1) & get_page_mask();
size_t const num_pages = page_rounded_size >> get_page_size_log2();
Untyped_memory::convert_to_page_frames(ds->phys_addr(), num_pages);
}
void Ram_session_component::_revoke_ram_ds(Dataspace_component *ds)
{
Untyped_memory::convert_to_untyped_frames(ds->phys_addr(), ds->size());
size_t const page_rounded_size = (ds->size() + get_page_size() - 1) & get_page_mask();
Untyped_memory::convert_to_untyped_frames(ds->phys_addr(), page_rounded_size);
}
void Ram_session_component::_clear_ds (Dataspace_component *ds)
{
size_t page_rounded_size = (ds->size() + get_page_size() - 1) & get_page_mask();
size_t const page_rounded_size = (ds->size() + get_page_size() - 1) & get_page_mask();
/* allocate range in core's virtual address space */
void *virt_addr;
if (!platform()->region_alloc()->alloc(page_rounded_size, &virt_addr)) {
error("could not allocate virtual address range in core of size ",
page_rounded_size);
return;
enum { ONE_PAGE = 1 };
/* allocate one page in core's virtual address space */
void *virt_addr_ptr = nullptr;
if (!platform()->region_alloc()->alloc(get_page_size(), &virt_addr_ptr) ||
!virt_addr_ptr)
ASSERT(!"could not map 4k inside core");
addr_t const virt_addr = reinterpret_cast<addr_t const>(virt_addr_ptr);
/* map each page of dataspace one at a time and clear it */
for (addr_t offset = 0; offset < page_rounded_size; offset += get_page_size())
{
addr_t const phys_addr = ds->phys_addr() + offset;
/* map one physical page to the core-local address */
if (!map_local(phys_addr, virt_addr, ONE_PAGE)) {
ASSERT(!"could not map 4k inside core");
}
/* clear one page */
size_t num_longwords = get_page_size()/sizeof(long);
for (long *dst = reinterpret_cast<long *>(virt_addr); num_longwords--;)
*dst++ = 0;
/* unmap cleared page from core */
unmap_local(virt_addr, ONE_PAGE);
}
/* map the dataspace's physical pages to core-local virtual addresses */
size_t num_pages = page_rounded_size >> get_page_size_log2();
if (!map_local(ds->phys_addr(), (addr_t)virt_addr, num_pages)) {
error("could not map virtual address range in core of size ",
page_rounded_size);
return;
}
/* clear dataspace */
size_t num_longwords = page_rounded_size/sizeof(long);
for (long *dst = (long *)virt_addr; num_longwords--;)
*dst++ = 0;
/* unmap dataspace from core */
unmap_local((addr_t)virt_addr, num_pages);
/* free core's virtual address space */
platform()->region_alloc()->free(virt_addr, page_rounded_size);
platform()->region_alloc()->free(virt_addr_ptr, get_page_size());
}