vm/mmap: add basic MAP_PRIVATE support

JIRA: RTOS-756
phoenix-rtos · Oct 6, 2024 · a57a022 · a57a022
1 parent d99dc74
commit a57a022
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/include/mman.h b/include/mman.h
@@ -28,7 +28,7 @@
 #define MAP_FIXED      (1 << 7)
 /* NOTE: vm uses u8 to store flags, if more flags are needed this type needs to be changed. */
 #define MAP_SHARED     0x0
-#define MAP_PRIVATE    0x0
+#define MAP_PRIVATE    MAP_NEEDSCOPY
 
 
 #define PROT_NONE  0x0

diff --git a/vm/map.c b/vm/map.c
@@ -875,6 +875,10 @@ int vm_mprotect(vm_map_t *map, void *vaddr, size_t len, int prot)
 			e->prot = prot;
 
 			attr = vm_protToAttr(e->prot) | vm_flagsToAttr(e->flags);
+			/* If an entry needs copy, enter it as a readonly to copy it on first access. */
+			if ((e->flags & MAP_NEEDSCOPY) != 0) {
+				attr &= ~(vm_protToAttr(PROT_WRITE));
+			}
 			for (currVaddr = e->vaddr; currVaddr < (e->vaddr + e->size); currVaddr += SIZE_PAGE) {
 				pa = pmap_resolve(&map->pmap, currVaddr);
 				if (pa != 0) {