fix validate test

78b3e8c8 · Nickolai Zeldovich · 41f6fab5 · 78b3e8c8 · 78b3e8c8 · 78b3e8c8
--- a/bin/usertests.cc
+++ b/bin/usertests.cc
@@ -1403,10 +1403,10 @@ validatetest(void)
  uptr lo, hi, p;

  fprintf(stdout, "validate test\n");
-  // Do 16 pages below the bottom of userspace and 16 pages above,
+  // Do 16 pages below KBASE and 16 pages above,
  // which should be code pages and read-only
-  lo = (1024*1024) - 16*4096;
-  hi = (1024*1024) + 16*4096;
+  lo = 0xFFFFFF0000000000ull - 16*4096;
+  hi = 0xFFFFFF0000000000ull + 16*4096;

  for(p = lo; p <= hi; p += 4096){
    if((pid = fork(0)) == 0){

--- a/kernel/trap.cc
+++ b/kernel/trap.cc
@@ -120,7 +120,7 @@ trap(struct trapframe *tf)
    if(tf->trapno == T_PGFLT){
      uptr addr = rcr2();
      sti();
-      if(addr < USERTOP && pagefault(myproc()->vmap, addr, tf->err) >= 0){
+      if(pagefault(myproc()->vmap, addr, tf->err) >= 0){
 #if MTRACE
        mtstop(myproc());
        if (myproc()->mtrace_stacks.curr >= 0)

--- a/kernel/vm.cc
+++ b/kernel/vm.cc
@@ -384,6 +384,9 @@ vmap::pagefault_wcow(vma *m)
 int
 vmap::pagefault(uptr va, u32 err)
 {
+  if (va >= USERTOP)
+    return -1;
+
  atomic<pme_t> *pte = walkpgdir(pml4, va, 1);

 retry: