Implement basic non-paged pool allocator

xtoskrnl/includes/mm/alloc.hh

@@ -17,6 +17,9 @@ namespace MM
 {
     class Allocator
     {
+        private:
+            STATIC LIST_ENTRY NonPagedPoolFreeList[MM_MAX_FREE_PAGE_LIST_HEADS];
+
         public:
             STATIC XTAPI XTSTATUS AllocatePages(IN MMPOOL_TYPE PoolType,
                                                 IN SIZE_T Bytes,

xtoskrnl/mm/alloc.cc

@@ -27,10 +27,155 @@ XTSTATUS
 MM::Allocator::AllocateNonPagedPoolPages(IN PFN_COUNT Pages,
                                          OUT PVOID *Memory)
 {
-    UNIMPLEMENTED;
+    PLIST_ENTRY Entry, LastHead, ListHead;
+    PMMPTE PointerPte, ValidPte;
+    PMMFREE_POOL_ENTRY FreePage;
+    PFN_NUMBER PageFrameNumber;
+    PVOID BaseAddress;
+    ULONG Index;
+    PMMPFN Pfn;
 
-    /* Return not implemented status code */
-    return STATUS_NOT_IMPLEMENTED;
+    /* Calculate the free list index based on the requested page count, capped at the maximum list head index */
+    Index = MIN(Pages, MM_MAX_FREE_PAGE_LIST_HEADS) - 1;
+
+    /* Set the starting list head and the boundary for the search loop */
+    ListHead = &NonPagedPoolFreeList[Index];
+    LastHead = &NonPagedPoolFreeList[MM_MAX_FREE_PAGE_LIST_HEADS];
+
+    /* Start a guarded code block */
+    {
+        /* Acquire the Non-Paged pool lock and raise runlevel to DISPATCH_LEVEL */
+        KE::RaiseRunLevel RunLevel(DISPATCH_LEVEL);
+        KE::QueuedSpinLockGuard NonPagedPoolSpinLock(NonPagedPoolLock);
+
+        /* Iterate through the free lists */
+        do
+        {
+            /* Iterate through the free entries in the current list */
+            Entry = ListHead->Flink;
+            while(Entry != ListHead)
+            {
+                /* Get the free pool entry structure from the list entry */
+                FreePage = CONTAIN_RECORD(Entry, MMFREE_POOL_ENTRY, List);
+
+                /* Check if this block is large enough to satisfy the request */
+                if(FreePage->Size >= Pages)
+                {
+                    /* Adjust the size of the free block to account for the allocated pages */
+                    FreePage->Size -= Pages;
+
+                    /* Calculate the base address of the allocated block */
+                    BaseAddress = (PVOID)((ULONG_PTR)FreePage + (FreePage->Size  << MM_PAGE_SHIFT));
+
+                    /* Remove the entry from the free list */
+                    RTL::LinkedList::RemoveEntryList(&FreePage->List);
+
+                    /* Check if there is remaining space in the entry */
+                    if(FreePage->Size != 0)
+                    {
+                        /* Calculate the new list index for the remaining fragment */
+                        Index = MIN(FreePage->Size, MM_MAX_FREE_PAGE_LIST_HEADS) - 1;
+
+                        /* Insert the entry into the free list */
+                        RTL::LinkedList::InsertTailList(&NonPagedPoolFreeList[Index], &FreePage->List);
+                    }
+
+                    /* Get the Page Table Entry (PTE) for the allocated address */
+                    PointerPte = MM::Paging::GetPteAddress(BaseAddress);
+
+                    /* Get the Page Frame Number (PFN) database entry for the corresponding physical page */
+                    Pfn = MM::Pfn::GetPfnEntry(MM::Paging::GetPageFrameNumber(PointerPte));
+
+                    /* Denote allocation boundaries */
+                    Pfn->u3.e1.ReadInProgress = 1;
+
+                    /* Check if multiple pages were requested */
+                    if(Pages != 1)
+                    {
+                        /* Advance to the PTE of the last page in the allocation */
+                        PointerPte = MM::Paging::AdvancePte(PointerPte, Pages - 1);
+
+                        /* Get the PFN entry for the last page */
+                        Pfn = MM::Pfn::GetPfnEntry(MM::Paging::GetPageFrameNumber(PointerPte));
+                    }
+
+                    /* Denote allocation boundaries */
+                    Pfn->u3.e1.WriteInProgress = 1;
+
+                    /* Set the allocated memory address and return success */
+                    *Memory = BaseAddress;
+                    return STATUS_SUCCESS;
+                }
+
+                /* Move to the next entry in the free list */
+                Entry = FreePage->List.Flink;
+            }
+        }
+        while(++ListHead < LastHead);
+    }
+
+    /* No suitable free block found; try to expand the pool by reserving system PTEs */
+    PointerPte = MM::Pte::ReserveSystemPtes(Pages, NonPagedPoolExpansion);
+    if(PointerPte == NULLPTR)
+    {
+        /* PTE reservation failed, return insufficient resources */
+        return STATUS_INSUFFICIENT_RESOURCES;
+    }
+
+    /* Acquire the Non-Paged pool lock and raise runlevel to DISPATCH_LEVEL */
+    KE::RaiseRunLevel RunLevel(DISPATCH_LEVEL);
+    KE::QueuedSpinLockGuard NonPagedPoolSpinLock(NonPagedPoolLock);
+
+    /* Acquire the PFN database lock */
+    KE::QueuedSpinLockGuard PfnSpinLock(PfnLock);
+
+    /* Check if there are enough available physical pages to back the allocation */
+    if(Pages >= MM::Pfn::GetAvailablePages())
+    {
+        /* Not enough physical pages, release the reserved system PTEs */
+        MM::Pte::ReleaseSystemPtes(PointerPte, Pages, NonPagedPoolExpansion);
+
+        /* Return failure due to insufficient resources */
+        return STATUS_INSUFFICIENT_RESOURCES;
+    }
+
+    /* Get a template valid PTE and loop through the allocation to map physical pages */
+    ValidPte = MM::Pte::GetValidPte();
+    do
+    {
+        /* Allocate a physical page */
+        PageFrameNumber = MM::Pfn::AllocatePhysicalPage(MM::Colors::GetNextColor());
+
+        /* Initialize the PFN entry for the allocated physical page */
+        Pfn = MM::Pfn::GetPfnEntry(PageFrameNumber);
+        Pfn->PteAddress = PointerPte;
+        Pfn->u2.ShareCount = 1;
+        Pfn->u3.e1.PageLocation = ActiveAndValid;
+        Pfn->u3.e2.ReferenceCount = 1;
+        Pfn->u4.VerifierAllocation = 0;
+
+        /* Build a valid PTE pointing to the allocated page frame */
+        MM::Paging::SetPte(ValidPte, PageFrameNumber, 0);
+
+        /* Write the valid PTE into the system PTE range */
+        *(MM::Paging::GetNextPte(PointerPte)) = *ValidPte;
+    }
+    while(--Pages > 0);
+
+    /* Dnote allocation boundaries */
+    Pfn->u3.e1.WriteInProgress = 1;
+
+    /* Get the PFN entry for the first page of the allocation */
+    Pfn = MM::Pfn::GetPfnEntry(MM::Paging::GetPageFrameNumber(PointerPte));
+
+    /* Denote allocation boundaries */
+    Pfn->u3.e1.ReadInProgress = 1;
+
+    /* Convert the PTE address to the virtual address and store in the buffer */
+    *Memory = MM::Paging::GetPteVirtualAddress(PointerPte);
+
+    /* Return success */
+    return STATUS_SUCCESS;
 }
 
 /**
@@ -120,10 +265,37 @@ XTAPI
 VOID
 MM::Allocator::InitializeNonPagedPool(VOID)
 {
-	UNIMPLEMENTED;
+    PMMMEMORY_LAYOUT MemoryLayout;
+    PMMFREE_POOL_ENTRY FreeEntry;
+    ULONG Index;
+
+    /* Retrieve memory layout */
+    MemoryLayout = MM::Manager::GetMemoryLayout();
 
     /* Map PTEs for the non-paged pool */
     MapNonPagedPool();
+
+    /* Iterate over the free page list heads */
+    for(Index = 0; Index < MM_MAX_FREE_PAGE_LIST_HEADS; Index++)
+    {
+        /* Initialize a free page list head */
+        RTL::LinkedList::InitializeListHead(&NonPagedPoolFreeList[Index]);
+    }
+
+    /* Take the first free page from the pool */
+    FreeEntry = (PMMFREE_POOL_ENTRY)MemoryLayout->NonPagedPoolStart;
+
+    /* Take number of pages in the pool */
+    Index = (ULONG)(MemoryLayout->NonPagedPoolSize - 1);
+    if(Index >= MM_MAX_FREE_PAGE_LIST_HEADS)
+    {
+        /* Number of pages exceeds the number of free page list heads */
+        Index = MM_MAX_FREE_PAGE_LIST_HEADS - 1;
+    }
+
+    /* Insert the first free page into the free page list and set its size */
+    RTL::LinkedList::InsertHeadList(&NonPagedPoolFreeList[Index], &FreeEntry->List);
+    FreeEntry->Size = MemoryLayout->NonPagedPoolSize;
 }
 
 /**

xtoskrnl/mm/data.cc

@@ -9,6 +9,9 @@
 #include <xtos.hh>
 
 
+/* Array of non-paged pool free list heads */
+LIST_ENTRY MM::Allocator::NonPagedPoolFreeList[MM_MAX_FREE_PAGE_LIST_HEADS];
+
 /* Array of free page lists segregated by cache color */
 PMMCOLOR_TABLES MM::Colors::FreePages[FreePageList + 1];