more

core/mem/pmap.c

@@ -2,9 +2,9 @@
 #include <zinnia/errno.h>
 #include <zinnia/pmap.h>
 #include <zinnia/spin.h>
+#include <zinnia/string.h>
 #include <zinnia/vma.h>
 #include <config.h>
-#include <zinnia/string.h>
 
 // TODO: For now, we assume that we can do generic PTE lookups on every arch that has a MMU.
 static_assert(CONFIG_HAVE_MMU_GENERIC);

core/mem/pmm.c

@@ -3,9 +3,9 @@
 #include <zinnia/panic.h>
 #include <zinnia/print.h>
 #include <zinnia/spin.h>
+#include <zinnia/string.h>
 #include <zinnia/virt.h>
 #include <stdint.h>
-#include <zinnia/string.h>
 
 uintptr_t mem_hhdm_base = 0;
 

core/mem/vma.c

@@ -60,7 +60,7 @@ static struct vma_mapping* find_mapping(struct vma* v, size_t page) {
     return nullptr;
 }
 
-static bool access_allowed(enum prot_flags prot, const struct vma_fault_info* info) {
+static bool can_access(enum prot_flags prot, const struct vma_fault_info* info) {
     if (info->caused_by_write)
         return prot & PROT_WRITE;
     if (info->caused_by_fetch)
@@ -87,7 +87,7 @@ bool vma_page_fault(struct vma* v, const struct vma_fault_info* info) {
 
     spin_lock(&v->lock);
     struct vma_mapping* mapping = find_mapping(v, faulty_page);
-    if (!mapping || !access_allowed(mapping->prot, info)) {
+    if (!mapping || !can_access(mapping->prot, info)) {
         spin_unlock(&v->lock);
         return false;
     }
@@ -107,8 +107,7 @@ bool vma_page_fault(struct vma* v, const struct vma_fault_info* info) {
     spin_lock(&v->lock);
     mapping = find_mapping(v, faulty_page);
     const bool still_valid = mapping && mapping->object == object &&
-        (faulty_page - mapping->start_page) + mapping->offset_page == object_page &&
-        access_allowed(mapping->prot, info);
+        (faulty_page - mapping->start_page) + mapping->offset_page == object_page && can_access(mapping->prot, info);
 
     if (still_valid) {
         errno_t status =

core/mem/vmo.c

@@ -1,9 +1,9 @@
 #include <zinnia/alloc.h>
 #include <zinnia/errno.h>
 #include <zinnia/list.h>
+#include <zinnia/string.h>
 #include <zinnia/utils.h>
 #include <zinnia/vmo.h>
-#include <zinnia/string.h>
 
 void vmo_ref(struct vmo* obj) {
     refcount_inc(&obj->rc);
@@ -211,6 +211,25 @@ errno_t vmo_new_phys(struct paged_vmo** out) {
     return vmo_new_paged(phys_pager, out);
 }
 
+void vmo_truncate_paged(struct paged_vmo* paged, size_t length) {
+    const size_t page_size = arch_mem_page_size();
+    const size_t keep_pages = ROUND_UP(length, page_size) / page_size;
+
+    spin_lock(&paged->lock);
+    struct page_list** pp = &list_first(&paged->cache);
+    while (*pp) {
+        struct page_list* entry = *pp;
+        if (entry->offset >= keep_pages) {
+            *pp = list_next(entry, next);
+            paged->source.put_page(&paged->source, entry->offset, entry->value);
+            mem_free(entry);
+        } else {
+            pp = &list_next(entry, next);
+        }
+    }
+    spin_unlock(&paged->lock);
+}
+
 struct phys_range_vmo {
     struct vmo object;
     uintptr_t start;