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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2011-08-31 02:39:45 +0200
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2011-08-31 02:39:45 +0200
commitdc8e2985370f05184d47f956d98fc2404dbb6316 (patch)
tree9dfa359d39444fcef06bf0a598fd5e01bf0cf622
parentfa57c51ac74a8301db7ab8b2fc9cbd63d69d26b3 (diff)
Fix copyout retry on lazy allocation on >= i486
* i386/i386/locore.S (copyout): Add a >=i486 variant of copyout which uses no loop, but simply retries rep mov.
-rw-r--r--i386/i386/locore.S35
1 files changed, 28 insertions, 7 deletions
diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index 58d5efd..221201c 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -1288,14 +1288,36 @@ Entry(copyoutmsg)
movl $USER_DS,%eax /* use user data segment for accesses */
mov %ax,%es
+#if !defined(MACH_HYP) && !PAE
+ cmpl $3,machine_slot+SUB_TYPE_CPU_TYPE
+ jbe copyout_retry /* Use slow version on i386 */
+#endif /* !defined(MACH_HYP) && !PAE */
+
+ movl %edx,%eax /* use count */
+ /*cld*/ /* count up: always this way in GCC code */
+ movl %eax,%ecx /* move by longwords first */
+ shrl $2,%ecx
+ RECOVER(copyout_fail)
+ RETRY(copyout_retry_longs)
+copyout_retry_longs:
+ rep
+ movsl
+ movl %eax,%ecx /* now move remaining bytes */
+ andl $3,%ecx
+ RECOVER(copyout_fail)
+ RETRY(copyout_retry_bytes)
+copyout_retry_bytes:
+ rep
+ movsb /* move */
+ xorl %eax,%eax /* return 0 for success */
+ jmp copyout_ret
+
+#if !defined(MACH_HYP) && !PAE
/*
* Check whether user address space is writable
* before writing to it - i386 hardware is broken.
*/
copyout_retry:
-#if !defined(MACH_HYP) && !PAE
- cmpl $3,machine_slot+SUB_TYPE_CPU_TYPE
- ja 1f /* Skip on i486 and above */
movl %cr3,%ecx /* point to page directory */
movl %edi,%eax /* get page directory bits */
shrl $(PDESHIFT),%eax /* from user address */
@@ -1330,11 +1352,9 @@ copyout_retry:
andl $(-NBPG),%eax /* start of next page */
subl %edi,%eax /* get number of bytes to that point */
cmpl %edx,%eax /* bigger than count? */
- jle 2f /* if so, */
-1:
-#endif /* !defined(MACH_HYP) && !PAE */
+ jle 1f /* if so, */
movl %edx,%eax /* use count */
-2:
+1:
/*cld*/ /* count up: always this way in GCC code */
movl %eax,%ecx /* move by longwords first */
@@ -1352,6 +1372,7 @@ copyout_retry:
subl %eax,%edx /* decrement count */
jg copyout_retry /* restart on next page if not done */
xorl %eax,%eax /* return 0 for success */
+#endif /* !defined(MACH_HYP) && !PAE */
copyout_ret:
mov %ss,%di /* restore ES to kernel segment */