From: Ben Pfaff <blp@cs.stanford.edu>
Date: Sat, 2 Aug 2008 11:30:43 +0000 (+0000)
Subject: Fix asm constraints to avoid SI, DI for byte and word access.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=pintos-anon;a=commitdiff_plain;h=e587ab7ffa2d548029189e540d5716f880932cb1

Fix asm constraints to avoid SI, DI for byte and word access.
Thanks to Ed Lyle Karrels <karrels@stanford.edu> for reporting the
problem.
---

diff --git a/doc/userprog.texi b/doc/userprog.texi
index 5bd0bb2..612bb81 100644
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -443,7 +443,7 @@ put_user (uint8_t *udst, uint8_t byte)
 {
   int error_code;
   asm ("movl $1f, %0; movb %b2, %1; 1:"
-       : "=&a" (error_code), "=m" (*udst) : "r" (byte));
+       : "=&a" (error_code), "=m" (*udst) : "q" (byte));
   return error_code != -1;
 }
 @end verbatim
diff --git a/src/userprog/gdt.c b/src/userprog/gdt.c
index a7423b7..e866037 100644
--- a/src/userprog/gdt.c
+++ b/src/userprog/gdt.c
@@ -50,7 +50,7 @@ gdt_init (void)
      6.2.4 "Task Register".  */
   gdtr_operand = make_gdtr_operand (sizeof gdt - 1, gdt);
   asm volatile ("lgdt %0" : : "m" (gdtr_operand));
-  asm volatile ("ltr %w0" : : "r" (SEL_TSS));
+  asm volatile ("ltr %w0" : : "q" (SEL_TSS));
 }
 
 /* System segment or code/data segment? */