From: Janice M. Girouard <jgirouar@redhat.com>
Subject: [RHEL 5.1 PATCH] BZ #220144 PPC:num_pmcs=8 instead of 6 for Power6  in cputable.c
Date: Wed, 14 Mar 2007 13:36:22 -0400 (Eastern Daylight Time)
Bugzilla: 220114
Message-Id: <Pine.WNT.4.64.0703141334290.6332@IBM-3MTQI3AXJFW>
Changelog: [ppc] reduce num_pmcs to 6 for Power6



RHBZ#:
------
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=220114

Description:
------------
The attached patch fixes an abort seen when starting the Oprofile daemon:

Stack trace output:
  [c00000000769fcd0] d0000000004db63c .op_powerpc_cpu_start+0x3c/0x50 [oprofile]
[c00000000769fd40] c00000000002894c .smp_call_function_interrupt+0x84/0xc4
[c00000000769fdc0] c000000000048744 .xics_ipi_dispatch+0x80/0x130
[c00000000769fe50] c000000000095c60 .handle_IRQ_event+0x7c/0xf8
[c00000000769ff00] c000000000097880 .handle_percpu_irq+0x90/0x10c
[c00000000769ff90] c000000000025da8 .call_handle_irq+0x1c/0x2c
[c00000000060b9c0] c00000000000c7d8 .do_IRQ+0xf4/0x1a4
[c00000000060ba50] c0000000000041ec hardware_interrupt_entry+0xc/0x10
--- Exception: 501 (Hardware Interrupt) at c000000000043b48
.plpar_hcall_norets+0x10/0x1c
[link register   ] c000000000044fe0 .pseries_dedicated_idle_sleep+0x1a4/0x1e8
[c00000000060bd40] c00000000060bde0 init_thread_union+0x3de0/0x4000
(unreliable)[c00000000060bdf0] c000000000011aa8 .cpu_idle+0x10c/0x1e0
[c00000000060be70] c000000000009274 .rest_init+0x44/0x5c
[c00000000060bef0] c0000000004097ec .start_kernel+0x324/0x340
[c00000000060bf90] c00000000000855c .start_here_common+0x50/0xf4
This bug fix is required to support RH 196505 already accepted into the RHEL 5.0 kernel.

The values of num_pmcs assigned in cputable.c is erroneously set to 8.  The value should be 6.


RHEL Version Found:
-------------------
RHEL 5.0

Upstream Status:
----------------
This is accepted into 2.6.20.1 as shown by:
http://lxr.linux.no/source/arch/powerpc/kernel/cputable.c


Test Status:
------------
Tested by David Nomura of IBM. It compiles and builds cleanly against the 5.0 base (kernel-2.6.18-9.el5.src.rpm). 

Proposed Patch:
----------------
Please review and ACK for RHEL 5.
-
--- a/arch/powerpc/kernel/cputable.c.orig	2006-11-22 19:51:39.000000000 +0000
+++ b/arch/powerpc/kernel/cputable.c	2006-11-22 19:52:17.000000000 +0000
@@ -259,7 +259,7 @@
 		.cpu_user_features	= COMMON_USER_POWER6,
 		.icache_bsize		= 128,
 		.dcache_bsize		= 128,
-		.num_pmcs		= 8,
+		.num_pmcs		= 6,
 		.oprofile_cpu_type	= "ppc64/power6",
 		.oprofile_type		= PPC_OPROFILE_POWER4,
  		.oprofile_mmcra_sihv	= POWER6_MMCRA_SIHV,