mm: common: reset mappings during simple mapping failures

For mapping operations in sys_mm_drv_simple_map_region() and
sys_mm_drv_simple_map_array(), when there was an error with
mapping any pages, it would simple return an error, leaving
already mapped pages still mapped. This modifies the behavior
where any failure during the whole mapping operation will
unmap the already mapped pages.

This also modifies the remapping and moving functions to
reset mappings when error is encountered.

Fixes #73121

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

drivers/mm/mm_drv_common.c

@@ -78,6 +78,41 @@ bool sys_mm_drv_is_virt_region_unmapped(void *virt, size_t size)
 	return ret;
 }
 
+/**
+ * Unmap a memory region with synchronization already locked.
+ *
+ * @param virt Page-aligned base virtual address to un-map
+ * @param size Page-aligned region size
+ * @param is_reset True if resetting the mappings
+ *
+ * @retval 0 if successful
+ * @retval -EINVAL if invalid arguments are provided
+ * @retval -EFAULT if virtual address is not mapped
+ */
+static int unmap_locked(void *virt, size_t size, bool is_reset)
+{
+	int ret = 0;
+	size_t offset;
+
+	for (offset = 0; offset < size; offset += CONFIG_MM_DRV_PAGE_SIZE) {
+		uint8_t *va = (uint8_t *)virt + offset;
+
+		int ret2 = sys_mm_drv_unmap_page(va);
+
+		if (ret2 != 0) {
+			if (is_reset) {
+				__ASSERT(false, "cannot reset mapping %p\n", va);
+			} else {
+				__ASSERT(false, "cannot unmap %p\n", va);
+			}
+
+			ret = ret2;
+		}
+	}
+
+	return ret;
+}
+
 int sys_mm_drv_simple_map_region(void *virt, uintptr_t phys,
 				 size_t size, uint32_t flags)
 {
@@ -98,12 +133,19 @@ int sys_mm_drv_simple_map_region(void *virt, uintptr_t phys,
 		uint8_t *va = (uint8_t *)virt + offset;
 		uintptr_t pa = phys + offset;
 
-		int ret2 = sys_mm_drv_map_page(va, pa, flags);
+		ret = sys_mm_drv_map_page(va, pa, flags);
 
-		if (ret2 != 0) {
+		if (ret != 0) {
 			__ASSERT(false, "cannot map 0x%lx to %p\n", pa, va);
 
-			ret = ret2;
+			/*
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
+			 */
+			(void)unmap_locked(virt, offset, true);
+
+			break;
 		}
 	}
 
@@ -136,12 +178,19 @@ int sys_mm_drv_simple_map_array(void *virt, uintptr_t *phys,
 	while (idx < cnt) {
 		uint8_t *va = (uint8_t *)virt + offset;
 
-		int ret2 = sys_mm_drv_map_page(va, phys[idx], flags);
+		ret = sys_mm_drv_map_page(va, phys[idx], flags);
 
-		if (ret2 != 0) {
+		if (ret != 0) {
 			__ASSERT(false, "cannot map 0x%lx to %p\n", phys[idx], va);
 
-			ret = ret2;
+			/*
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
+			 */
+			(void)unmap_locked(virt, offset, true);
+
+			break;
 		}
 
 		offset += CONFIG_MM_DRV_PAGE_SIZE;
@@ -160,7 +209,6 @@ int sys_mm_drv_simple_unmap_region(void *virt, size_t size)
 {
 	k_spinlock_key_t key;
 	int ret = 0;
-	size_t offset;
 
 	CHECKIF(!sys_mm_drv_is_virt_addr_aligned(virt) ||
 		!sys_mm_drv_is_size_aligned(size)) {
@@ -170,17 +218,7 @@ int sys_mm_drv_simple_unmap_region(void *virt, size_t size)
 
 	key = k_spin_lock(&sys_mm_drv_common_lock);
 
-	for (offset = 0; offset < size; offset += CONFIG_MM_DRV_PAGE_SIZE) {
-		uint8_t *va = (uint8_t *)virt + offset;
-
-		int ret2 = sys_mm_drv_unmap_page(va);
-
-		if (ret2 != 0) {
-			__ASSERT(false, "cannot unmap %p\n", va);
-
-			ret = ret2;
-		}
-	}
+	ret = unmap_locked(virt, size, false);
 
 	k_spin_unlock(&sys_mm_drv_common_lock, key);
 
@@ -224,48 +262,60 @@ int sys_mm_drv_simple_remap_region(void *virt_old, size_t size,
 		uint8_t *va_new = (uint8_t *)virt_new + offset;
 		uintptr_t pa;
 		uint32_t flags;
-		int ret2;
-		bool to_map;
 
 		/*
-		 * va_old is mapped as checked above, so no need
-		 * to check for return value here.
+		 * Grab the physical address of the old mapped page
+		 * so the new page can map to the same physical address.
 		 */
-		(void)sys_mm_drv_page_phys_get(va_old, &pa);
+		ret = sys_mm_drv_page_phys_get(va_old, &pa);
+		if (ret != 0) {
+			__ASSERT(false, "cannot query %p\n", va_old);
 
-		to_map = true;
-		ret2 = sys_mm_drv_page_flag_get(va_old, &flags);
-		if (ret2 != 0) {
-			__ASSERT(false, "cannot query page %p\n", va_old);
+			/*
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
+			 */
+			(void)unmap_locked(virt_new, offset, true);
 
-			ret = ret2;
-			to_map = false;
+			goto unlock_out;
 		}
 
-		ret2 = sys_mm_drv_unmap_page(va_old);
-		if (ret2 != 0) {
-			__ASSERT(false, "cannot unmap %p\n", va_old);
-
-			ret = ret2;
-		}
+		/*
+		 * Grab the flags of the old mapped page
+		 * so the new page can map to the same flags.
+		 */
+		ret = sys_mm_drv_page_flag_get(va_old, &flags);
+		if (ret != 0) {
+			__ASSERT(false, "cannot query page %p\n", va_old);
 
-		if (!to_map) {
 			/*
-			 * Cannot retrieve flags of mapped virtual memory.
-			 * Skip mapping this page as we don't want to map
-			 * with unknown random flags.
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
 			 */
-			continue;
+			(void)unmap_locked(virt_new, offset, true);
+
+			goto unlock_out;
 		}
 
-		ret2 = sys_mm_drv_map_page(va_new, pa, flags);
-		if (ret2 != 0) {
+		ret = sys_mm_drv_map_page(va_new, pa, flags);
+		if (ret != 0) {
 			__ASSERT(false, "cannot map 0x%lx to %p\n", pa, va_new);
 
-			ret = ret2;
+			/*
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
+			 */
+			(void)unmap_locked(virt_new, offset, true);
+
+			goto unlock_out;
 		}
 	}
 
+	(void)unmap_locked(virt_old, size, false);
+
 unlock_out:
 	k_spin_unlock(&sys_mm_drv_common_lock, key);
 
@@ -310,38 +360,46 @@ int sys_mm_drv_simple_move_region(void *virt_old, size_t size,
 		uint8_t *va_new = (uint8_t *)virt_new + offset;
 		uintptr_t pa = phys_new + offset;
 		uint32_t flags;
-		int ret2;
 
-		ret2 = sys_mm_drv_page_flag_get(va_old, &flags);
-		if (ret2 != 0) {
+		ret = sys_mm_drv_page_flag_get(va_old, &flags);
+		if (ret != 0) {
 			__ASSERT(false, "cannot query page %p\n", va_old);
 
-			ret = ret2;
-		} else {
 			/*
-			 * Only map the new page when we can retrieve
-			 * flags of the old mapped page as We don't
-			 * want to map with unknown random flags.
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
 			 */
-			ret2 = sys_mm_drv_map_page(va_new, pa, flags);
-			if (ret2 != 0) {
-				__ASSERT(false, "cannot map 0x%lx to %p\n", pa, va_new);
+			(void)unmap_locked(virt_new, offset, true);
 
-				ret = ret2;
-			} else {
-				(void)memcpy(va_new, va_old,
-					     CONFIG_MM_DRV_PAGE_SIZE);
-			}
+			goto unlock_out;
 		}
 
-		ret2 = sys_mm_drv_unmap_page(va_old);
-		if (ret2 != 0) {
-			__ASSERT(false, "cannot unmap %p\n", va_old);
+		/*
+		 * Map the new page with flags of the old mapped page
+		 * so they both have the same properties.
+		 */
+		ret = sys_mm_drv_map_page(va_new, pa, flags);
+		if (ret != 0) {
+			__ASSERT(false, "cannot map 0x%lx to %p\n", pa, va_new);
 
-			ret = ret2;
+			/*
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
+			 */
+			(void)unmap_locked(virt_new, offset, true);
+
+			goto unlock_out;
 		}
 	}
 
+	/* Once new mappings are in place, copy the content over. */
+	(void)memcpy(virt_new, virt_old, size);
+
+	/* Unmap old virtual memory region once the move is done. */
+	(void)unmap_locked(virt_old, size, false);
+
 unlock_out:
 	k_spin_unlock(&sys_mm_drv_common_lock, key);
 
@@ -388,43 +446,51 @@ int sys_mm_drv_simple_move_array(void *virt_old, size_t size,
 		uint8_t *va_old = (uint8_t *)virt_old + offset;
 		uint8_t *va_new = (uint8_t *)virt_new + offset;
 		uint32_t flags;
-		int ret2;
 
-		ret2 = sys_mm_drv_page_flag_get(va_old, &flags);
-		if (ret2 != 0) {
+		ret = sys_mm_drv_page_flag_get(va_old, &flags);
+		if (ret != 0) {
 			__ASSERT(false, "cannot query page %p\n", va_old);
 
-			ret = ret2;
-		} else {
 			/*
-			 * Only map the new page when we can retrieve
-			 * flags of the old mapped page as We don't
-			 * want to map with unknown random flags.
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
 			 */
-			ret2 = sys_mm_drv_map_page(va_new, phys_new[idx], flags);
-			if (ret2 != 0) {
-				__ASSERT(false, "cannot map 0x%lx to %p\n",
-					 phys_new[idx], va_new);
+			(void)unmap_locked(virt_new, offset, true);
 
-				ret = ret2;
-			} else {
-				(void)memcpy(va_new, va_old,
-					     CONFIG_MM_DRV_PAGE_SIZE);
-			}
+			goto unlock_out;
 		}
 
-		ret2 = sys_mm_drv_unmap_page(va_old);
+		/*
+		 * Only map the new page when we can retrieve
+		 * flags of the old mapped page as We don't
+		 * want to map with unknown random flags.
+		 */
+		ret = sys_mm_drv_map_page(va_new, phys_new[idx], flags);
+		if (ret != 0) {
+			__ASSERT(false, "cannot map 0x%lx to %p\n",
+				 phys_new[idx], va_new);
 
-		if (ret2 != 0) {
-			__ASSERT(false, "cannot unmap %p\n", va_old);
+			/*
+			 * Reset the already mapped virtual addresses.
+			 * Note the offset is at the current failed address
+			 * which will not be included during unmapping.
+			 */
+			(void)unmap_locked(virt_new, offset, true);
 
-			ret = ret2;
+			goto unlock_out;
 		}
 
 		offset += CONFIG_MM_DRV_PAGE_SIZE;
 		idx++;
 	}
 
+	/* Once new mappings are in place, copy the content over. */
+	(void)memcpy(virt_new, virt_old, size);
+
+	/* Unmap old virtual memory region once the move is done. */
+	(void)unmap_locked(virt_old, size, false);
+
 unlock_out:
 	k_spin_unlock(&sys_mm_drv_common_lock, key);