genode/repos/base-nova/src/core/ram_dataspace_support.cc

100 lines
2.9 KiB
C++

/*
* \brief Export RAM dataspace as shared memory object
* \author Norman Feske
* \date 2009-10-02
*/
/*
* Copyright (C) 2009-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
/* Genode includes */
#include <base/thread.h>
/* core includes */
#include <ram_dataspace_factory.h>
#include <platform.h>
#include <util.h>
#include <nova_util.h>
/* NOVA includes */
#include <nova/syscalls.h>
using namespace Genode;
void Ram_dataspace_factory::_revoke_ram_ds(Dataspace_component &) { }
static inline void * alloc_region(Dataspace_component &ds, const size_t size)
{
/*
* Allocate range in core's virtual address space
*
* Start with trying to use natural alignment. If this does not work,
* successively weaken the alignment constraint until we hit the page size.
*/
void *virt_addr = 0;
size_t align_log2 = log2(ds.size());
for (; align_log2 >= get_page_size_log2(); align_log2--) {
if (platform().region_alloc().alloc_aligned(size,
&virt_addr, align_log2).ok())
break;
}
return virt_addr;
}
void Ram_dataspace_factory::_clear_ds(Dataspace_component &ds)
{
size_t const page_rounded_size = align_addr(ds.size(), get_page_size_log2());
size_t memset_count = page_rounded_size / 4;
addr_t memset_ptr = ds.core_local_addr();
if ((memset_count * 4 == page_rounded_size) && !(memset_ptr & 0x3))
asm volatile ("rep stosl" : "+D" (memset_ptr), "+c" (memset_count)
: "a" (0) : "memory");
else
memset(reinterpret_cast<void *>(memset_ptr), 0, page_rounded_size);
/* we don't keep any core-local mapping */
unmap_local(*reinterpret_cast<Nova::Utcb *>(Thread::myself()->utcb()),
ds.core_local_addr(),
page_rounded_size >> get_page_size_log2());
platform().region_alloc().free((void*)ds.core_local_addr(),
page_rounded_size);
ds.assign_core_local_addr(nullptr);
}
void Ram_dataspace_factory::_export_ram_ds(Dataspace_component &ds) {
size_t page_rounded_size = align_addr(ds.size(), get_page_size_log2());
/* allocate the virtual region contiguous for the dataspace */
void * const virt_ptr = alloc_region(ds, page_rounded_size);
if (!virt_ptr)
throw Core_virtual_memory_exhausted();
/* map it writeable for _clear_ds */
Nova::Utcb &utcb = *reinterpret_cast<Nova::Utcb *>(Thread::myself()->utcb());
const Nova::Rights rights_rw(true, true, false);
if (map_local(platform_specific().core_pd_sel(), utcb, ds.phys_addr(),
reinterpret_cast<addr_t>(virt_ptr),
page_rounded_size >> get_page_size_log2(), rights_rw, true)) {
platform().region_alloc().free(virt_ptr, page_rounded_size);
throw Core_virtual_memory_exhausted();
}
/* assign virtual address to the dataspace to be used by clear_ds */
ds.assign_core_local_addr(virt_ptr);
}