Commit 2022c1f1 authored by Russ Anderson's avatar Russ Anderson Committed by Tony Luck

[IA64] Update Altix nofault code

Montecito and Montvale behaves slightly differently than previous
Itanium processors, resulting in the MCA due to a failed PIO read
to sometimes surfacing outside the nofault code.  This code is
based on discussions with Intel CPU architects and verified at
customer sites.
Signed-off-by: default avatarRuss Anderson <rja@sgi.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 4ca8ad7e
......@@ -3,7 +3,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (c) 2004-2005 Silicon Graphics, Inc. All Rights Reserved.
* Copyright (c) 2004-2007 Silicon Graphics, Inc. All Rights Reserved.
*/
......@@ -14,6 +14,11 @@
* PIO read fails, the MCA handler will force the error to look
* corrected and vector to the xp_error_PIOR which will return an error.
*
* The definition of "consumption" and the time it takes for an MCA
* to surface is processor implementation specific. This code
* is sufficient on Itanium through the Montvale processor family.
* It may need to be adjusted for future processor implementations.
*
* extern int xp_nofault_PIOR(void *remote_register);
*/
......@@ -22,11 +27,10 @@ xp_nofault_PIOR:
mov r8=r0 // Stage a success return value
ld8.acq r9=[r32];; // PIO Read the specified register
adds r9=1,r9;; // Add to force consumption
or r9=r9,r9;; // Or to force consumption
srlz.i;; // Allow time for MCA to surface
br.ret.sptk.many b0;; // Return success
.global xp_error_PIOR
xp_error_PIOR:
mov r8=1 // Return value of 1
br.ret.sptk.many b0;; // Return failure
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