From: Matthias Kruk <m@m10k.eu>
Date: Tue, 17 Sep 2019 07:48:40 +0000 (+0900)
Subject: Make _pg_dir_map_legacy() map large pages, where possible
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=ec65b4d6a5294861b15dac1af017c9295941489e;p=corax

Make _pg_dir_map_legacy() map large pages, where possible
---

diff --git a/kernel/arch/paging.c b/kernel/arch/paging.c
index 5277d10..7991817 100644
--- a/kernel/arch/paging.c
+++ b/kernel/arch/paging.c
@@ -355,17 +355,32 @@ static int _pg_dir_map_legacy(page_table_t *pd, u32_t paddr, u32_t vaddr, u32_t
 
 		/* allocate a new page table if not present */
 		if(!(pd->pt_entries[pde] & PAGE_ATTR_PRESENT)) {
-			pd->pt_entries[pde] = (u32_t)pg_frame_alloc_end();
+			/*
+			 * Allocate a large page if we're at a large page boundary
+			 * and we're supposed to allocate at least the size of a large page
+			 */
+			if(size >= PAGE_SIZE_LARGE && ALIGNED(vaddr, PAGE_SIZE_LARGE)) {
+				pd->pt_entries[pde] = vaddr | PAGE_ATTR_SIZE | PAGE_ATTR_PRESENT | flags;
 
-			if(!pd->pt_entries[pde]) {
-				ret_val = -ENOMEM;
-				break;
+				paddr += PAGE_SIZE_LARGE;
+				vaddr += PAGE_SIZE_LARGE;
+				size -= PAGE_SIZE_LARGE;
+
+				/* skip the rest of the loop, which would attempt to populate the page table */
+				continue;
 			} else {
-				/* wipe the page table before using it */
-				memset((void*)pd->pt_entries[pde], 0, PAGE_SIZE);
-			}
+				pd->pt_entries[pde] = (u32_t)pg_frame_alloc_end();
+
+				if(!pd->pt_entries[pde]) {
+					ret_val = -ENOMEM;
+					break;
+				} else {
+					/* wipe the page table before using it */
+					memset((void*)pd->pt_entries[pde], 0, PAGE_SIZE);
+				}
 
-			pd->pt_entries[pde] |= PAGE_ATTR_PRESENT | flags;
+				pd->pt_entries[pde] |= PAGE_ATTR_PRESENT | flags;
+			}
 		}
 
 		pt = (page_table_t*)(pd->pt_entries[pde] & 0xfffff000);