From: John Villalovos <jvillalo@redhat.com>
Date: Tue, 22 Dec 2009 20:30:27 -0500
Subject: Oprofile: Add support for Nehalem-EP processors
Message-id: <20091222203027.GA3530@linuxjohn.usersys.redhat.com>
Patchwork-id: 22266
O-Subject: [RHEL 5.5 BZ498624] Oprofile: Add support for Nehalem-EP processors
Bugzilla: 498624

Add kernel support for using Nehalem-EP processors with oprofile:
https://bugzilla.redhat.com/show_bug.cgi?id=498624

This patch adds support to the kernel so that oprofile can work with Nehalem-EP
processors and Atom processors.
Nehalem-EP processors are:  CPU Family: 6, CPU Model: 26
Atom processors are:	    CPU Family: 6, CPU Model: 28

The oprofile userspace BZ that depends on this patch:
https://bugzilla.redhat.com/show_bug.cgi?id=498619

A listing of Nehalem-EP processors can be found here:
http://ark.intel.com/ProductCollection.aspx?codeName=33163

Atom Processors here:
http://processorfinder.intel.com/List.aspx?ParentRadio=All&ProcFam=3008&SearchKey=

Also this patch adds the ability to specify the following kernel command line
parameter:
    oprofile.cpu_type=arch_perfmon

This will enable a user to force the use of the 'arch_perfmon' type for CPUs
which support arch_perfmon.  For example if you did have a Nehalem-EP
processor, you could force it to use arch_perfmon rather than the Nehalem-EP
performance counters.

All code changes for this patch are isolated to the oprofile kernel module, and
will have no affect on any system unless they load the oprofile module.  This
usually only happens if they run the oprofile userspace tool.

Testing:
I have tested this on a Nehalem-EP system, the oprofile kernel module now
reports "i386/core_i7" as the cpu_type.

I have also tested the usage of the kernel command line parameter to force
usage of arch_perfmon, and that works as expected.

Will Cohen has also done testing with this kernel and has reported success.

Brew build:
https://brewweb.devel.redhat.com/taskinfo?taskID=2165196

Backport of commit 8d7ff4f2a0b22b7d6d7bc3982257d1dadea22824
Upstream Author: Robert Richter <robert.richter@amd.com>
Upstream Date:   Tue Jun 23 11:48:14 2009 +0200

    x86/oprofile: rename kernel parameter for architectural perfmon to arch_perfmon

    The short name of the achitecture is 'arch_perfmon'. This patch
    changes the kernel parameter to use this name.

Backport of commit 7e4e0bd50e80df2fe5501f48f872448376cdd997
Upstream Author: Robert Richter <robert.richter@amd.com>
Upstream Date:   Wed May 6 12:10:23 2009 +0200

    oprofile: introduce module_param oprofile.cpu_type

    This patch removes module_param oprofile.force_arch_perfmon and
    introduces oprofile.cpu_type=archperfmon instead. This new parameter
    can be reused for other models and architectures.

    Currently only archperfmon is supported.

Backport of commit 1dcdb5a9e7c235e6e80f1f4d5b8247b3e5347e48
Upstream Author: Andi Kleen <andi@firstfloor.org>
Upstream Date:   Mon Apr 27 17:44:11 2009 +0200

    oprofile: re-add force_arch_perfmon option

    This re-adds the force_arch_perfmon option that was in the original
    arch perfmon patchkit. Originally this was rejected in favour
    of a generalized perfmon=name option, but it turned out implementing
    the later in a reliable way is hard (and it would have been easy
    to crash the kernel if a user gets it wrong)

    But now Atom and Core i7 support being readded a user would
    need to update their oprofile userland to beyond 0.9.4 to use oprofile again
    on Atom or Core i7.

    To avoid this problem readd the force_arch_perfmon option.

Backport of commit 6adf406f0a0eaf37251018d15f51e93f5b538ee6
Upstream Author: Andi Kleen <andi@firstfloor.org>
Upstream Date:   Mon Apr 27 17:44:13 2009 +0200

    oprofile: add support for Core i7 and Atom

    The registers are about the same as other Family 6 CPUs
    so we only need to add detection.

    I'm not completely happy with calling Nehalem Core i7 because
    there will be undoubtedly other Nehalem based CPUs
    in the future with different marketing names, but it's
    the best we got for now.

    Requires updated oprofile userland for the new event files.

    If you don't want to update right now you can also use
    oprofile.force_arch_perfmon=1 (added in the next patch) with 0.9.4

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1be8288..f9e5c88 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1250,6 +1250,14 @@ running once the system is up.
 	oprofile.timer=	[HW]
 			Use timer interrupt instead of performance counters
 
+	oprofile.cpu_type=	Force an oprofile cpu type
+			This might be useful if you have an older oprofile
+			userland or if you want common events.
+			Format: { arch_perfmon }
+			arch_perfmon: [X86] Force use of architectural
+				perfmon on Intel CPUs instead of the
+				CPU specific event set.
+
 	optcd=		[HW,CD]
 			Format: <io>
 
diff --git a/arch/i386/oprofile/nmi_int.c b/arch/i386/oprofile/nmi_int.c
index 588800e..6e49343 100644
--- a/arch/i386/oprofile/nmi_int.c
+++ b/arch/i386/oprofile/nmi_int.c
@@ -405,11 +405,25 @@ static int __init p4_init(char ** cpu_type)
 	return 0;
 }
 
+static int force_arch_perfmon;
+static int force_cpu_type(const char *str, struct kernel_param *kp)
+{
+	if (!strcmp(str, "arch_perfmon")) {
+		force_arch_perfmon = 1;
+		printk(KERN_INFO "oprofile: forcing architectural perfmon\n");
+	}
+
+	return 0;
+}
+module_param_call(cpu_type, force_cpu_type, NULL, NULL, 0);
 
 static int __init ppro_init(char **cpu_type)
 {
 	__u8 cpu_model = boot_cpu_data.x86_model;
 
+	if (force_arch_perfmon && cpu_has_arch_perfmon)
+		return 0;
+
 	switch (cpu_model) {
 	case 0 ... 2:
 		*cpu_type = "i386/ppro";
@@ -433,7 +447,11 @@ static int __init ppro_init(char **cpu_type)
 		*cpu_type = "i386/core_2";
 		break;
 	case 26:
-		*cpu_type = "i386/core_2";
+		arch_perfmon_setup_counters();
+		*cpu_type = "i386/core_i7";
+		break;
+	case 28:
+		*cpu_type = "i386/atom";
 		break;
 	default:
 		/* Unknown */