vpm readability

src/kernel/arch/x86/consts.h

@@ -17,4 +17,10 @@
 #define PAGE_BIT_WRITABLE 2
 #define PAGE_BIT_USER 4
 
-#endif
+#define PAGE_PRESENT(p) ((p) & (PAGE_BIT_PRESENT))
+
+#define PAGE_SIZE 4096
+
+#define ROUND_UP_POT(i, n) (((i) + ((n) - 1)) & ~((n) - 1))
+
+#endif

src/kernel/arch/x86/scheduler.c

@@ -21,7 +21,7 @@ uint32_t scheduler_Tick;
 void klogs(const char *str);
 void klogc(int c);
 
-static void klogp(void *p) {
+void klogp(void *p) {
 	static char hex[16]="0123456789ABCDEF";
 	
 	uintptr_t i = (uintptr_t) p;

src/kernel/arch/x86/vpm.c

@@ -2,49 +2,57 @@
 
 #include"ppm.h"
 #include"mem.h"
+#include"consts.h"
 
-extern void *_kernel_end;
+static void invlpg(uint32_t virtaddr) {
+	asm volatile("invlpg %0" : : "m"(*(char*)virtaddr) : "memory");
+}
 
-void set_temporary_mapping(uint32_t addr) {
+static void set_temporary_mapping(uint32_t addr) {
 	if((addr & 0xFFF) != 0) asm volatile("xchgw %bx, %bx");
 	
 	*(volatile uint32_t*) 0xFFFFFFF8 = addr | 3;
 	asm volatile("invlpg 0xFFFFE000" : : : "memory");
 }
 
-static uint32_t nextAllocs[2] = {[VPM_KERNEL] = 0, [VPM_USER] = 1 * 1024 * 1024 * 1024};
+static uint32_t spaceBoundaries[2] = {[VPM_KERNEL] = 4096, [VPM_USER] = 1 * 1024 * 1024 * 1024};
 
 void vpm_init(uint32_t kernelEnd) {
-	nextAllocs[VPM_KERNEL] = (kernelEnd + 4095) & ~4095;
+	//spaceBoundaries[VPM_KERNEL] = (kernelEnd + 4095) & ~4095;
 }
 
-/* TODO: Make better. */
-uint32_t vpm_find_free(uint32_t addrspace, AllocationOwner owner, size_t lenBytes) {
-	size_t len = (lenBytes + 4095) / 4096;
+/* This is a linear search. Improve? */
+uint32_t vpm_find_free(uint32_t addrspace, AllocationOwner owner, size_t len) {
+	len = ROUND_UP_POT(len, PAGE_SIZE);
 	
-	uint32_t ret = nextAllocs[owner];
-	for(size_t i = 0; i < len;) {
-		uint32_t pdeid = (ret + i * 4096) >> 22;
-		uint32_t pteid = ((ret + i * 4096) >> 12) & 1023;
-		
-		set_temporary_mapping(addrspace);
-		
-		volatile uint32_t *pde = &((volatile uint32_t*) 0xFFFFE000)[pdeid];
-		if((*pde & 1) == 0) {
-			i += 4096;
-		} else {
-			set_temporary_mapping(*pde & ~0xFFF);
+	for(uint32_t attempt = spaceBoundaries[owner]; attempt != 0;) {
+		for(size_t i = 0; i < len;) {
+			uint32_t pdeid = (attempt + i) >> 22;
+			uint32_t pteid = ((attempt + i) >> 12) & 1023;
 			
-			if((((volatile uint32_t*) 0xFFFFE000)[pteid] & 1) == 0) {
-				i++;
+			set_temporary_mapping(addrspace);
+			
+			volatile uint32_t *pde = &((volatile uint32_t*) 0xFFFFE000)[pdeid];
+			if(!PAGE_PRESENT(*pde)) {
+				i += PAGE_SIZE * 1024 * 1024; // 4MB
 			} else {
-				ret += (i + 1) * 4096;
-				i = 0;
+				set_temporary_mapping((*pde) & ~0xFFF);
+				
+				volatile uint32_t *pte = &((volatile uint32_t*) 0xFFFFE000)[pteid];
+				
+				if(!PAGE_PRESENT(*pte)) {
+					i += PAGE_SIZE;
+				} else {
+					attempt += i + PAGE_SIZE;
+					goto try_next;
+				}
 			}
 		}
-	}
+		return attempt;
+try_next:
+	} 
 	
-	return ret;
+	return 0;
 }
 
 /* If phys is -1, map to uncontiguous physical pages anywhere, else map contiguous span of physical memory. */
@@ -99,8 +107,8 @@ void *vpm_map(uint32_t addrspace, AllocationOwner owner, uint32_t virt, uint32_t
 		*pte |= 3 | (owner == VPM_USER ? 4 : 0);
 		
 		if(thisspace == addrspace) {
-			//~ asm volatile("xchg %bx, %bx");
-			asm volatile("invlpg %0" : : "m"(*(char*) (virt + i * 4096)) : "memory");
+			invlpg(virt + i * 4096);
+			//asm volatile("invlpg %0" : : "m"(*(char*) (virt + i * 4096)) : "memory");
 		}
 	}
 	
@@ -164,7 +172,8 @@ int vpm_double_map(uint32_t cr3a, uint32_t cr3b, uint32_t *va, uint32_t *vb, uin
 			*pte = backend | 3 | 4;
 			
 			if(thisspace == cr3a) {
-				asm volatile("invlpg %0" : : "m"(*(char*) (*va + i * 4096)) : "memory");
+				invlpg(*va + i * 4096);
+				//asm volatile("invlpg %0" : : "m"(*(char*) (*va + i * 4096)) : "memory");
 			}
 		}
 		
@@ -193,7 +202,8 @@ int vpm_double_map(uint32_t cr3a, uint32_t cr3b, uint32_t *va, uint32_t *vb, uin
 			*pte = backend | 3 | 4;
 			
 			if(thisspace == cr3b) {
-				asm volatile("invlpg %0" : : "m"(*(char*) (*vb + i * 4096)) : "memory");
+				invlpg(*vb + i * 4096);
+				//asm volatile("invlpg %0" : : "m"(*(char*) (*vb + i * 4096)) : "memory");
 			}
 		}
 	}
@@ -262,7 +272,8 @@ void vpm_unmap(uint32_t cr3, uint32_t virt, size_t len) {
 		((volatile uint32_t*) 0xFFFFE000)[pteid] = 0;
 		
 		if(thisspace == cr3) {
-			asm volatile("invlpg %0" : : "m"(*(char*) (virt + i * 4096)) : "memory");
+			invlpg(virt + i * 4096);
+			//asm volatile("invlpg %0" : : "m"(*(char*) (virt + i * 4096)) : "memory");
 		}
 	}
 }

src/kernel/arch/x86/vpm.h

@@ -12,8 +12,6 @@ typedef enum {
 	VPM_KERNEL, VPM_USER
 } AllocationOwner;
 
-void set_temporary_mapping(uint32_t addr);
-
 uint32_t vpm_find_free(uint32_t addrspace, AllocationOwner owner, size_t len);
 void *vpm_map(uint32_t cr3, AllocationOwner owner, uint32_t virt, uint32_t phys, size_t len);
 uint32_t vpm_create_space();
@@ -21,4 +19,4 @@ void vpm_set_space(uint32_t cr3);
 uint32_t vpm_get_phys(uint32_t cr3, uint32_t);
 void vpm_unmap(uint32_t cr3, uint32_t virt, size_t len);
 
-#endif
+#endif