[patch] Update 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: Russ Anderson <rja@xxxxxxx> --- arch/ia64/sn/kernel/xp_nofault.S | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) Index: test/arch/ia64/sn/kernel/xp_nofault.S =================================================================== --- test.orig/arch/ia64/sn/kernel/xp_nofault.S 2008-01-03 10:00:46.106785444 -0600 +++ test/arch/ia64/sn/kernel/xp_nofault.S 2008-01-03 10:03:28.602998658 -0600 @@ -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 - -- Russ Anderson, OS RAS/Partitioning Project Lead SGI - Silicon Graphics Inc rja@xxxxxxx - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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