9os

commit 4387497cba74b53fc5dd3858d985327d0e8a8a94
parent 31f0ece115a4b80a6fa447626e5226bf826fdea1
Author: Roberto E. Vargas Caballero <roberto.vargas@midokura.com>
Date:   Sat, 19 Nov 2022 17:16:03 +0100

os9: Copy page content in newmap()

When we duplicate a map we have to map a new set of pages
but we also have to duplicate the actual content of the
pages.

Diffstat:
M
include/os9/os9.h
 | 
1
+
M
src/os9/hosted/arch.c
 | 
7
+++++++
M
src/os9/map.c
 | 
17
++++++++++++++++-

3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/include/os9/os9.h b/include/os9/os9.h
@@ -319,6 +319,7 @@ extern void ictx(Task *, void *);
 extern int dupctx(Task *);
 extern char *getconf(char *);
 extern void idle(void);
+extern char bufto[], buffrom[];
 
 /* dev functions */
 extern void idev(void);
diff --git a/src/os9/hosted/arch.c b/src/os9/hosted/arch.c
@@ -11,6 +11,13 @@ jmp_buf recover;
 noreturn void abort(void);
 noreturn void longjmp(jmp_buf env, int val);
 
+char bufto[PAGESIZE], buffrom[PAGESIZE];
+
+void
+barrier(int what)
+{
+}
+
 void
 halt(void)
 {
diff --git a/src/os9/map.c b/src/os9/map.c
@@ -2,6 +2,8 @@
 
 #include <libk.h>
 
+#include <string.h>
+
 Map *
 newstack(Task *tp)
 {
@@ -121,13 +123,26 @@ Map *
 newmap(Map *from)
 {
 	Map *mp;
+	Page *pfrom, *pto;
 
 	if ((mp = allocmap()) == NULL)
 		return NULL;
 
 	*mp = *from;
+	mp->pages = NULL;
+	mp->next = NULL;
 	initref(&mp->ref);
-	mapseg(mp); /* FIXME: we have to duplicate the pages */
+	mapseg(mp);
+
+	pto = mp->pages;
+	for (pfrom = from->pages; pfrom; pfrom = pfrom->next) {
+		assert(pfrom->va == pto->va);
+		vmap(pto->pa, (uintptr_t) bufto, MW);
+		vmap(pfrom->pa, (uintptr_t) buffrom, MR);
+		memcpy(bufto, buffrom, PAGESIZE);
+		barrier(DATA);
+		pto = pto->next;
+	}
 
 	return mp;
 }