xv6

commit 2ef3a64bb4923d3458bac1393dd9e205f0acd93a
parent 64659055bd8ed3717a691d0311666d94195aebee
Author: rsc <rsc>
Date:   Tue, 14 Aug 2007 04:55:45 +0000

Because limit gives the address of the last addressable
byte in the segment, the limit argument to SEG16 and SEG
needs to have 1 subtracted from it.

Diffstat:
M
proc.c
 | 
8
++++----

1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/proc.c b/proc.c
@@ -38,13 +38,13 @@ setupsegs(struct proc *p)
   }
 
   c->gdt[0] = SEG_NULL;
-  c->gdt[SEG_KCODE] = SEG(STA_X|STA_R, 0, 0x100000 + 64*1024, 0);
+  c->gdt[SEG_KCODE] = SEG(STA_X|STA_R, 0, 0x100000 + 64*1024-1, 0);
   c->gdt[SEG_KDATA] = SEG(STA_W, 0, 0xffffffff, 0);
-  c->gdt[SEG_TSS] = SEG16(STS_T32A, (uint) &c->ts, sizeof(c->ts), 0);
+  c->gdt[SEG_TSS] = SEG16(STS_T32A, (uint)&c->ts, sizeof(c->ts)-1, 0);
   c->gdt[SEG_TSS].s = 0;
   if(p){
-    c->gdt[SEG_UCODE] = SEG(STA_X|STA_R, (uint)p->mem, p->sz, DPL_USER);
-    c->gdt[SEG_UDATA] = SEG(STA_W, (uint)p->mem, p->sz, DPL_USER);
+    c->gdt[SEG_UCODE] = SEG(STA_X|STA_R, (uint)p->mem, p->sz-1, DPL_USER);
+    c->gdt[SEG_UDATA] = SEG(STA_W, (uint)p->mem, p->sz-1, DPL_USER);
   } else {
     c->gdt[SEG_UCODE] = SEG_NULL;
     c->gdt[SEG_UDATA] = SEG_NULL;