ExternalVendorCode/genode
1
0
Fork 0
mirror of https://github.com/genodelabs/genode.git synced 2025-01-29 23:54:14 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

hw: clear RAM dataspaces in chunks

Browse Source 
Clearing very large RAM dataspaces could fill up core's page table,
because the dataspaces are locally mapped to clear them.
This would manifest in a loop where exhausting the local page table
leads to its flushing (which does not work for core) and a retry that
again fills up the page table and so on.

To prevent this, flush RAM dataspaces in chunks of at most 128MiB.

Fixes #5086
This commit is contained in:
Benjamin Lamowski 2024-01-05 11:40:17 +01:00 committed by Christian Helmuth
parent 41731a2439
commit 25c7204b2a
1 changed files with 30 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
repos/base-hw/src/core/ram_dataspace_support.cc
View File

@ -16,6 +16,7 @@
#include <ram_dataspace_factory.h>
#include <platform.h>
#include <map_local.h>
#include <util/misc_math.h>
using namespace Core;
@ -51,19 +52,35 @@ void Ram_dataspace_factory::_clear_ds (Dataspace_component &ds)
if (!guard.virt_ptr)
return;
/* map the dataspace's physical pages to corresponding virtual addresses */
size_t num_pages = page_rounded_size >> get_page_size_log2();
if (!map_local(ds.phys_addr(), (addr_t)guard.virt_ptr, num_pages)) {
error("core-local memory mapping failed");
return;
/*
* Map and clear dataspaces in chucks of 128MiB max to prevent large
* mappings from filling up core's page table.
*/
static size_t constexpr max_chunk_size = 128 * 1024 * 1024;
size_t size_remaining = page_rounded_size;
addr_t chunk_phys_addr = ds.phys_addr();
while (size_remaining) {
size_t chunk_size = min(size_remaining, max_chunk_size);
size_t num_pages = chunk_size >> get_page_size_log2();
/* map the dataspace's physical pages to corresponding virtual addresses */
if (!map_local(chunk_phys_addr, (addr_t)guard.virt_ptr, num_pages)) {
error("core-local memory mapping failed");
return;
}
/* dependent on the architecture, cache maintainance might be necessary */
Cpu::clear_memory_region((addr_t)guard.virt_ptr, chunk_size,
ds.cacheability() != CACHED);
/* unmap dataspace from core */
if (!unmap_local((addr_t)guard.virt_ptr, num_pages))
error("could not unmap core-local address range at ", guard.virt_ptr);
size_remaining -= chunk_size;
chunk_phys_addr += chunk_size;
}
/* dependent on the architecture, cache maintainance might be necessary */
Cpu::clear_memory_region((addr_t)guard.virt_ptr, page_rounded_size,
ds.cacheability() != CACHED);
/* unmap dataspace from core */
if (!unmap_local((addr_t)guard.virt_ptr, num_pages))
error("could not unmap core-local address range at ", guard.virt_ptr);
}