Remove the stack guard page. Processes are now contiguous from 0 to proc->sz, which means our syscall argument validation is correct. Add a pointer validation test and remove the stack test, which tested for the guard page.

1 files changed, 1 insertions, 4 deletions

diff --git a/syscall.c b/syscall.c
index 9296cff..f8aeae7 100644
--- a/syscall.c
+++ b/syscall.c
@@ -22,8 +22,6 @@ fetchint(struct proc *p, uint addr, int *ip)
   return 0;
 }
 
-// XXX should we copy the string?
-
 // Fetch the nul-terminated string at addr from process p.
 // Doesn't actually copy the string - just sets *pp to point at it.
 // Returns length of string, not including nul.
@@ -62,8 +60,7 @@ argptr(int n, char **pp, int size)
     return -1;
   if((uint)i >= proc->sz || (uint)i+size >= proc->sz)
     return -1;
-  // *pp = proc->mem + i;   // XXXXX
-  *pp = (char *) i;   // XXXXX
+  *pp = (char *) i;
   return 0;
 }