1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
7 */
8
9/*
10 * The xp_nofault_PIOR function takes a pointer to a remote PIO register
11 * and attempts to load and consume a value from it.  This function
12 * will be registered as a nofault code block.  In the event that the
13 * PIO read fails, the MCA handler will force the error to look
14 * corrected and vector to the xp_error_PIOR which will return an error.
15 *
16 * The definition of "consumption" and the time it takes for an MCA
17 * to surface is processor implementation specific.  This code
18 * is sufficient on Itanium through the Montvale processor family.
19 * It may need to be adjusted for future processor implementations.
20 *
21 *	extern int xp_nofault_PIOR(void *remote_register);
22 */
23
24	.global xp_nofault_PIOR
25xp_nofault_PIOR:
26	mov	r8=r0			// Stage a success return value
27	ld8.acq	r9=[r32];;		// PIO Read the specified register
28	adds	r9=1,r9;;		// Add to force consumption
29	srlz.i;;			// Allow time for MCA to surface
30	br.ret.sptk.many b0;;		// Return success
31
32	.global xp_error_PIOR
33xp_error_PIOR:
34	mov	r8=1			// Return value of 1
35	br.ret.sptk.many b0;;		// Return failure
36