From 0b2b263060907e8bf732c1d27c66b7358af01e9f Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 5 Sep 2021 18:55:32 +0200
Subject: make virt_iter support iterating over physical memory too

---
 src/kernel/mem/virt.c | 22 +++++++++++++---------
 src/kernel/mem/virt.h |  1 +
 2 files changed, 14 insertions(+), 9 deletions(-)

(limited to 'src/kernel/mem')

diff --git a/src/kernel/mem/virt.c b/src/kernel/mem/virt.c
index 2990668..beeb54f 100644
--- a/src/kernel/mem/virt.c
+++ b/src/kernel/mem/virt.c
@@ -23,21 +23,25 @@ bool virt_iter_next(struct virt_iter *iter) {
 	 * virtual and physical memory, which might not always be the case.
 	 * TODO test this */
 
-	user_ptr virt = iter->_virt;
 	size_t partial = iter->_remaining;
 	iter->prior   += iter->frag_len;
 	if (partial <= 0) return false;
 
-	// don't read past the page
-	if ((virt & PAGE_MASK) + partial > PAGE_SIZE)
-		partial = PAGE_SIZE - (virt & PAGE_MASK);
+	if (iter->_pages) { // if iterating over virtual memory
+		// don't read past the page
+		if ((iter->_virt & PAGE_MASK) + partial > PAGE_SIZE)
+			partial = PAGE_SIZE - (iter->_virt & PAGE_MASK);
 
-	iter->frag = pagedir_virt2phys(iter->_pages,
-			iter->_virt, iter->_user, iter->_writeable);
+		iter->frag = pagedir_virt2phys(iter->_pages,
+				iter->_virt, iter->_user, iter->_writeable);
 
-	if (iter->frag == 0) {
-		iter->error = true;
-		return false;
+		if (iter->frag == 0) {
+			iter->error = true;
+			return false;
+		}
+	} else {
+		// "iterate" over physical memory
+		iter->frag = iter->_virt;
 	}
 
 	iter->frag_len    = partial;
diff --git a/src/kernel/mem/virt.h b/src/kernel/mem/virt.h
index 98a7a16..e87a9fe 100644
--- a/src/kernel/mem/virt.h
+++ b/src/kernel/mem/virt.h
@@ -17,6 +17,7 @@ struct virt_iter {
 	bool _writeable;
 };
 
+/* if pages == NULL, create an iterator over physical memory. */
 void virt_iter_new(
 		struct virt_iter *iter, user_ptr virt, size_t length,
 		struct pagedir *pages, bool user, bool writeable);
-- 
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