From 272e1889ce14aaea9e3431a93c406d347f5b3c54 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 23 Dec 2021 17:30:40 +0200
Subject: Added stat/mod_vmem

+ In general improved riscv vmem.c
---
 arch/riscv/kernel/vmem.c | 109 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 87 insertions(+), 22 deletions(-)

(limited to 'arch/riscv/kernel/vmem.c')

diff --git a/arch/riscv/kernel/vmem.c b/arch/riscv/kernel/vmem.c
index 744f633..d1d77a1 100644
--- a/arch/riscv/kernel/vmem.c
+++ b/arch/riscv/kernel/vmem.c
@@ -10,11 +10,84 @@
 #define pte_flags(pte) (((pm_t)(pte)) & 0xff)
 #define to_pte(p, f) ((pm_to_pnum((pm_t)__pa(p)) << 10) | (f))
 #define pte_addr(pte) __va(pnum_to_paddr(pte_ppn(pte)))
+#define pte_paddr(pte) (pnum_to_paddr(pte_ppn(pte)))
 #define vm_to_index(a, o) (pm_to_index(a, o))
+#define is_active(pte) (pte_flags(pte) & VM_V)
+#define is_leaf(pte) (is_active(pte) && (pte_flags(pte) & ~VM_V))
+#define is_branch(pte) (is_active(pte) && !(pte_flags(pte) & ~VM_V))
 
-void mod_vmem(struct vm_branch_t *branch, vm_t vaddr, uint8_t flags, enum mm_order_t order)
+static pm_t *__find_vmem(struct vm_branch_t *b, vm_t v, enum mm_order_t *o)
 {
-	/* todo */
+	enum mm_order_t top = __mm_max_order;
+	*o = MM_O0;
+	do {
+		size_t idx = vm_to_index(v, top);
+		pm_t pte = (pm_t)b->leaf[idx];
+
+		if(!pte)
+			return 0;
+
+		if(is_leaf(pte)){
+			if(o)
+				*o = top;
+
+			return (pm_t *)&b->leaf[idx];
+		}
+
+		b = (struct vm_branch_t *)pte_addr(pte);
+	} while (top--);
+
+	return 0;
+}
+
+int mod_vmem(struct vm_branch_t *branch, vm_t vaddr, pm_t paddr, uint8_t flags)
+{
+	pm_t *pte = __find_vmem(branch, vaddr, 0);
+	if(pte){
+		*pte = to_pte(paddr, flags);
+		return 0;
+	}
+
+	return -1;
+}
+
+/* huh, should probably add status flags etc. to all my API functions. Damn, I'm
+ * lazy. */
+int stat_vmem(struct vm_branch_t *branch, vm_t vaddr, pm_t *paddr,
+		enum mm_order_t *order, uint8_t *flags)
+{
+	pm_t *pte = __find_vmem(branch, vaddr, order);
+	if(pte){
+		if(paddr)
+			*paddr = pte_paddr(*pte);
+
+		if(flags)
+			*flags = pte_flags(*pte);
+
+		return 0;
+	}
+
+	return -1;
+}
+
+static struct vm_branch_t *__create_leaf()
+{
+	pm_t new_leaf = alloc_page(MM_KPAGE, 0);
+	memset((void *)new_leaf, 0, sizeof(struct vm_branch_t));
+	return (struct vm_branch_t *)to_pte(new_leaf, VM_V);
+}
+
+static void __destroy_branch(struct vm_branch_t *b)
+{
+	if(!b)
+		return;
+
+	for(size_t i = 0; i < BASE_PAGE_SIZE / sizeof(pm_t); ++i){
+		if(is_branch(b->leaf[i]));
+			__destroy_branch((struct vm_branch_t *)pte_addr(b->leaf[i]));
+
+		free_page(MM_KPAGE, (pm_t)pte_addr(b->leaf[i]));
+	}
 }
 
 void map_vmem(struct vm_branch_t *branch,
@@ -24,18 +97,16 @@ void map_vmem(struct vm_branch_t *branch,
 	while (top != order) {
 		size_t idx = vm_to_index(vaddr, top);
 
-		if (!branch->leaf[idx]) {
-			pm_t new_leaf = alloc_page(MM_KPAGE, 0);
-			branch->leaf[idx] =
-				(struct vm_branch_t *)to_pte(new_leaf, VM_V);
-
-			void *leaf_ptr = (void *)new_leaf;
-			memset(leaf_ptr, 0, sizeof(struct vm_branch_t));
+		if (is_branch(branch->leaf[idx])){
+			__destroy_branch(branch->leaf[idx]);
+			branch->leaf[idx] = 0;
 		}
 
-		pm_t pte = (pm_t)branch->leaf[idx];
-		pm_t branch_pptr = (pm_t)pte_addr(pte);
-		branch = (struct vm_branch_t *)branch_pptr;
+		if (!branch->leaf[idx])
+			branch->leaf[idx] = __create_leaf();
+
+
+		branch = (struct vm_branch_t *)pte_addr(branch->leaf[idx]);
 		top--;
 	}
 
@@ -43,16 +114,10 @@ void map_vmem(struct vm_branch_t *branch,
 	branch->leaf[idx] = (struct vm_branch_t *)to_pte(paddr, flags);
 }
 
-void unmap_vmem(struct vm_branch_t *branch, vm_t vaddr, enum mm_order_t order)
+void unmap_vmem(struct vm_branch_t *branch, vm_t vaddr)
 {
-	while (order) {
-		size_t idx = pm_to_index(vaddr, order);
-		branch = (struct vm_branch_t *)pte_addr(branch->leaf[idx]);
-	}
-
-	size_t idx = pm_to_index(vaddr, order);
-	if (branch->leaf[idx])
-		free_page(order, (pm_t)pte_addr(branch->leaf[idx]));
 
-	branch->leaf[idx] = 0;
+	pm_t *pte = __find_vmem(branch, vaddr, 0);
+	if(pte)
+		*pte = 0;
 }
-- 
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