sel4: flush page table allocator if full

Issue #2044

repos/base-sel4/src/core/include/map_local.h

@@ -35,7 +35,13 @@ namespace Genode {
 	 */
 	inline bool map_local(addr_t from_phys, addr_t to_virt, size_t num_pages)
 	{
-		platform_specific()->core_vm_space().map(from_phys, to_virt, num_pages);
+		enum { DONT_FLUSH = false };
+		try {
+			platform_specific()->core_vm_space().map(from_phys, to_virt,
+			                                         num_pages, DONT_FLUSH);
+		} catch (Page_table_registry::Mapping_cache_full) {
+			return false;
+		}
 		return true;
 	}
 

repos/base-sel4/src/core/include/page_table_registry.h

@@ -17,6 +17,7 @@
 /* Genode includes */
 #include <util/list.h>
 #include <base/exception.h>
+#include <base/log.h>
 
 /* core includes */
 #include <util.h>
@@ -30,6 +31,7 @@ class Genode::Page_table_registry
 	public:
 
 		class Lookup_failed : Exception { };
+		class Mapping_cache_full : Exception { };
 
 	private:
 
@@ -93,7 +95,11 @@ class Genode::Page_table_registry
 						return;
 					}
 
-					_entries.insert(new (entry_alloc) Entry(addr, sel));
+					try {
+						_entries.insert(new (entry_alloc) Entry(addr, sel));
+					} catch (Genode::Allocator::Out_of_memory) {
+						throw Mapping_cache_full();
+					}
 				}
 
 				void remove_entry(Allocator &entry_alloc, addr_t addr)
@@ -107,6 +113,14 @@ class Genode::Page_table_registry
 							PWRN("trying to remove non-existing page frame for 0x%lx", addr);
 					}
 				}
+
+				void flush_all(Allocator &entry_alloc)
+				{
+					for (; Entry *entry = _entries.first();) {
+						_entries.remove(entry);
+						destroy(entry_alloc, entry);
+					}
+				}
 		};
 
 		/**
@@ -257,6 +271,13 @@ class Genode::Page_table_registry
 			}
 		}
 
+
+		void flush_cache()
+		{
+			for (Page_table *pt = _page_tables.first(); pt; pt = pt->next())
+				pt->flush_all(_page_table_entry_alloc);
+		}
+
 		/**
 		 * Apply functor 'fn' to selector of specified virtual address
 		 *

repos/base-sel4/src/core/include/vm_space.h

@@ -148,7 +148,7 @@ class Genode::Vm_space
 		 */
 		unsigned _idx_to_sel(unsigned idx) const { return (_id << 20) | idx; }
 
-		void _map_page(addr_t from_phys, addr_t to_virt)
+		void _map_page(addr_t from_phys, addr_t to_virt, bool flush_support)
 		{
 			/* allocate page-table entry selector */
 			unsigned pte_idx = _sel_alloc.alloc();
@@ -164,7 +164,19 @@ class Genode::Vm_space
 			                          Cnode_index(_leaf_cnode_entry(pte_idx)));
 
 			/* remember relationship between pte_sel and the virtual address */
-			_page_table_registry.insert_page_table_entry(to_virt, pte_idx);
+			try {
+				_page_table_registry.insert_page_table_entry(to_virt, pte_idx);
+			} catch (Page_table_registry::Mapping_cache_full) {
+				if (!flush_support)
+					throw;
+
+				warning("flush page table entries - mapping cache full");
+
+				_page_table_registry.flush_cache();
+
+				/* re-try once */
+				_page_table_registry.insert_page_table_entry(to_virt, pte_idx);
+			}
 
 			/*
 			 * Insert copy of page-frame selector into page table
@@ -300,7 +312,8 @@ class Genode::Vm_space
 				_vm_cnodes[i].destruct(_cap_sel_alloc);
 		}
 
-		void map(addr_t from_phys, addr_t to_virt, size_t num_pages)
+		void map(addr_t from_phys, addr_t to_virt, size_t num_pages,
+		         bool flush_support = true)
 		{
 			Lock::Guard guard(_lock);
 
@@ -310,7 +323,7 @@ class Genode::Vm_space
 
 			for (size_t i = 0; i < num_pages; i++) {
 				off_t const offset = i << get_page_size_log2();
-				_map_page(from_phys + offset, to_virt + offset);
+				_map_page(from_phys + offset, to_virt + offset, flush_support);
 			}
 		}
 

repos/base-sel4/src/core/ram_session_support.cc

@@ -12,7 +12,7 @@
  */
 
 /* Genode includes */
-#include <base/printf.h>
+#include <base/log.h>
 
 /* core includes */
 #include <ram_session_component.h>
@@ -43,14 +43,18 @@ void Ram_session_component::_clear_ds (Dataspace_component *ds)
 	/* allocate range in core's virtual address space */
 	void *virt_addr;
 	if (!platform()->region_alloc()->alloc(page_rounded_size, &virt_addr)) {
-		PERR("could not allocate virtual address range in core of size %zd\n",
-		     page_rounded_size);
+		error("could not allocate virtual address range in core of size ",
+		      page_rounded_size);
 		return;
 	}
 
 	/* map the dataspace's physical pages to core-local virtual addresses */
 	size_t num_pages = page_rounded_size >> get_page_size_log2();
-	map_local(ds->phys_addr(), (addr_t)virt_addr, num_pages);
+	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);