linux-kernel - Re: [PATCH 4.8 022/138] thermal/powerclamp: correct cpu support check

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Date:   Wed, 9 Nov 2016 07:05:15 -0800
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Eric Ernst <eric.ernst@...ux.intel.com>,
        Zhang Rui <rui.zhang@...el.com>, jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH 4.8 022/138] thermal/powerclamp: correct cpu support
 check

On Wed,  9 Nov 2016 11:45:05 +0100
Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote:

> 4.8-stable review patch.  If anyone has any objections, please let me
> know.
> 
I just realized that this patch would prevent module auto loading since
we don't have device id table.

I will send out this patch in a minute. So we need to apply both this
patch and the one below.

drivers/thermal/intel_powerclamp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/intel_powerclamp.c
b/drivers/thermal/intel_powerclamp.c
index f0bad48..c82b41f 100644
--- a/drivers/thermal/intel_powerclamp.c
+++ b/drivers/thermal/intel_powerclamp.c
@@ -694,9 +694,16 @@ static int powerclamp_set_cur_state(struct
thermal_cooling_device *cdev,
        .set_cur_state = powerclamp_set_cur_state,
 };

+static const struct x86_cpu_id __initconst intel_powerclamp_ids[] = {
+       { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY,
X86_FEATURE_MWAIT },
+       {}
+};
+MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
+
 static int __init powerclamp_probe(void)
 {
-       if (!boot_cpu_has(X86_FEATURE_MWAIT)) {
+
+       if (!x86_match_cpu(intel_powerclamp_ids)) {
                pr_err("CPU does not support MWAIT");
                return -ENODEV;
        }



> ------------------
> 
> From: Eric Ernst <eric.ernst@...ux.intel.com>
> 
> commit 3105f234e0aba43e44e277c20f9b32ee8add43d4 upstream.
> 
> Initial logic for checking CPU match resulted in OR of CPU features
> rather than the intended AND.
> 
> Updated to use boot_cpu_has macro rather than x86_match_cpu.
> 
> In addition, MWAIT is the only required CPU feature for idle
> injection to work.  Drop other feature requirements since they are
> only needed for optimal efficiency.
> 
> Signed-off-by: Eric Ernst <eric.ernst@...ux.intel.com>
> Acked-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> Signed-off-by: Zhang Rui <rui.zhang@...el.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> 
> ---
>  drivers/thermal/intel_powerclamp.c |   14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)
> 
> --- a/drivers/thermal/intel_powerclamp.c
> +++ b/drivers/thermal/intel_powerclamp.c
> @@ -669,20 +669,10 @@ static struct thermal_cooling_device_ops
>  	.set_cur_state = powerclamp_set_cur_state,
>  };
>  
> -static const struct x86_cpu_id intel_powerclamp_ids[] __initconst = {
> -	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY,
> X86_FEATURE_MWAIT },
> -	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY,
> X86_FEATURE_ARAT },
> -	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY,
> X86_FEATURE_NONSTOP_TSC },
> -	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY,
> X86_FEATURE_CONSTANT_TSC},
> -	{}
> -};
> -MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
> -
>  static int __init powerclamp_probe(void)
>  {
> -	if (!x86_match_cpu(intel_powerclamp_ids)) {
> -		pr_err("Intel powerclamp does not run on family %d
> model %d\n",
> -				boot_cpu_data.x86,
> boot_cpu_data.x86_model);
> +	if (!boot_cpu_has(X86_FEATURE_MWAIT)) {
> +		pr_err("CPU does not support MWAIT");
>  		return -ENODEV;
>  	}
>  
> 
> 

[Jacob Pan]