add local shootdown, and test case for remote shootdown (not working yet)

41fc9e5e · Nickolai Zeldovich · 06047fd7 · 41fc9e5e · 41fc9e5e · 41fc9e5e
--- a/defs.h
+++ b/defs.h
@@ -183,6 +183,7 @@ void            switchkvm(void);
 int             copyout(struct vmap *, uint, void*, uint);
 int             copyin(struct vmap *, uint, void*, uint);
 int             pagefault(pde_t*, struct vmap *, uint, uint);
+void            clearpages(pde_t *pgdir, void *begin, void *end);

 // number of elements in fixed-size array
 #define NELEM(x) (sizeof(x)/sizeof((x)[0]))

--- a/maptest.c
+++ b/maptest.c
@@ -5,31 +5,84 @@
 #include "x86.h"
 #include "uspinlock.h"

+static volatile char *p;
+static struct uspinlock l;
+static volatile uint state;
+
+static void
+spin(void)
+{
+  volatile uint i;
+  for (i = 0; i < 10000; i++)
+    ;
+}
+
+void
+thr(void)
+{
+  for (;;) {
+    acquire(&l);
+    if (state == 1) {
+      p[0] = 'x';
+      p[4096] = 'y';
+      state = 2;
+    }
+
+    if (state == 3) {
+      state = 4;
+      printf(1, "about to access after unmap\n");
+      release(&l);
+
+      p[0] = 'X';
+      p[4096] = 'Y';
+
+      acquire(&l);
+      printf(1, "still alive after unmap write\n");
+      exit();
+    }
+    release(&l);
+    spin();
+  }
+}
+
 int
 main(void)
 {
-  volatile char *p = (char *) 0x80000;
+  p = (char *) 0x80000;
  if (map((void *) p, 8192) < 0) {
    printf(1, "map failed\n");
    exit();
  }

-  p[0] = 'x';
-  p[4096] = 'y';
+  sbrk(4096);
+  forkt(sbrk(0), thr);
+
+  acquire(&l);
+  state = 1;
+  while (state != 2) {
+    release(&l);
+    spin();
+    acquire(&l);
+  }
+
  if (p[0] != 'x' || p[4096] != 'y') {
    printf(1, "mismatch\n");
    exit();
  }

+  printf(1, "shm ok\n");
+
  if (unmap((void *) p, 8192) < 0) {
    printf(1, "unmap failed\n");
    exit();
  }

-  p[0] = 'z';
-  if (p[0] == 'z') {
-    printf(1, "still mapped\n");
-    exit();
+  state = 3;
+  printf(1, "waiting for unmap access\n");
+  while (state != 4) {
+    release(&l);
+    spin();
+    acquire(&l);
  }

  exit();

--- a/sysproc.c
+++ b/sysproc.c
@@ -130,6 +130,11 @@ sys_unmap(void)
    return -1;
  if (vmap_remove(proc->vmap, PGROUNDDOWN(addr), PGROUNDUP(len)) < 0)
    return -1;
+
+  clearpages(proc->pgdir,
+	     (void*) (PGROUNDDOWN(addr)),
+	     (void*) (PGROUNDDOWN(addr)+PGROUNDUP(len)));
+  lcr3(PADDR(proc->pgdir));
  return 0;
 }


--- a/vm.c
+++ b/vm.c
@@ -104,7 +104,7 @@ mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm)
  return 0;
 }

-static int
+static void
 updatepages(pde_t *pgdir, void *begin, void *end, int perm)
 {
  char *a, *last;
@@ -120,10 +120,9 @@ updatepages(pde_t *pgdir, void *begin, void *end, int perm)
      break;
    a += PGSIZE;
  }
-  return 0;
 }

-static int
+void
 clearpages(pde_t *pgdir, void *begin, void *end)
 {
  char *a, *last;
@@ -139,7 +138,6 @@ clearpages(pde_t *pgdir, void *begin, void *end)
      break;
    a += PGSIZE;
  }
-  return 0;
 }

 // The mappings from logical to linear are one to one (i.e.,
@@ -416,7 +414,7 @@ vmap_lookup(struct vmap *m, uint va)
  acquire(&m->lock);
  for(uint i = 0; i < sizeof(m->e) / sizeof(m->e[0]); i++) {
    struct vma *e = &m->e[i];
-    if (va >= e->va_start && va < e->va_end) {
+    if (e->n && va >= e->va_start && va < e->va_end) {
      acquire(&e->lock);
      release(&m->lock);
      return e;
@@ -633,8 +631,10 @@ pagefault(pde_t *pgdir, struct vmap *vmap, uint va, uint err)
    *pte = PADDR(m->n->page[npg]) | PTE_P | PTE_U | PTE_COW;
  } else {
    // cprintf("fill in pte\n");
-    if (m->n->ref > 1)
+    if (m->n->ref > 1) {
+      cprintf("pagefault: va 0x%x\n", va);
      panic("pagefault");
+    }
    *pte = PADDR(m->n->page[npg]) | PTE_P | PTE_U | PTE_W;
  }
  lcr3(PADDR(pgdir));  // Reload hardware page tables