diff mbox series

[v4,1/7] cpufreq: amd-pstate: initialize new core precision boost state

Message ID 1bd9da56478c07fc2117b7c11f88eb517bd60f0f.1710322310.git.perry.yuan@amd.com (mailing list archive)
State Changes Requested, archived
Headers show
Series AMD Pstate Driver Core Performance Boost | expand

Commit Message

Yuan, Perry March 13, 2024, 10:04 a.m. UTC 
From: Perry Yuan <Perry.Yuan@amd.com>

Add gloal global_params to represent current CPU Performance Boost(cpb)
state for cpu frequency scaling, both active and passive modes all can
support CPU cores frequency boosting control which is based on the BIOS
setting, while BIOS turn on the "Core Performance Boost", it will
allow OS control each core highest perf limitation from OS side.

If core performance boost is disabled while a core is in a boosted P-state,
the core transitions to the highest performance non-boosted P-state,
that is the same as the nominal frequency limit.

Reported-by: Artem S. Tashkinov" <aros@gmx.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 50 ++++++++++++------------------------
 include/linux/amd-pstate.h   | 14 ++++++++++
 2 files changed, 31 insertions(+), 33 deletions(-)

Comments

Gautham R. Shenoy March 14, 2024, 9:04 a.m. UTC | #1 
On Wed, Mar 13, 2024 at 06:04:38PM +0800, Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> Add gloal global_params to represent current CPU Performance Boost(cpb)
> state for cpu frequency scaling, both active and passive modes all can
> support CPU cores frequency boosting control which is based on the BIOS
> setting, while BIOS turn on the "Core Performance Boost", it will
> allow OS control each core highest perf limitation from OS side.
> 
> If core performance boost is disabled while a core is in a boosted P-state,
> the core transitions to the highest performance non-boosted P-state,
> that is the same as the nominal frequency limit.
> 
> Reported-by: Artem S. Tashkinov" <aros@gmx.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 50 ++++++++++++------------------------
>  include/linux/amd-pstate.h   | 14 ++++++++++
>  2 files changed, 31 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 2015c9fcc3c9..ef6381b48e76 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -67,6 +67,8 @@ static struct cpufreq_driver amd_pstate_epp_driver;
>  static int cppc_state = AMD_PSTATE_UNDEFINED;
>  static bool cppc_enabled;
>  static bool amd_pstate_prefcore = true;
> +struct amd_pstate_global_params amd_pstate_global_params;
> +EXPORT_SYMBOL_GPL(amd_pstate_global_params);
>  
>  /*
>   * AMD Energy Preference Performance (EPP)
> @@ -676,43 +678,21 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
>  	return lowest_nonlinear_freq * 1000;
>  }
>  
> -static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
> +static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
>  {
> -	struct amd_cpudata *cpudata = policy->driver_data;
> +	u64 boost_val;
>  	int ret;
>  
> -	if (!cpudata->boost_supported) {
> -		pr_err("Boost mode is not supported by this processor or SBIOS\n");
> -		return -EINVAL;
> -	}
> -
> -	if (state)
> -		policy->cpuinfo.max_freq = cpudata->max_freq;
> -	else
> -		policy->cpuinfo.max_freq = cpudata->nominal_freq;
> -
> -	policy->max = policy->cpuinfo.max_freq;
> -
> -	ret = freq_qos_update_request(&cpudata->req[1],
> -				      policy->cpuinfo.max_freq);
> -	if (ret < 0)
> +	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);
> +	if (ret) {
> +		pr_err_once("failed to read initial CPU boost state!\n");
>  		return ret;
> +	}
>  
> -	return 0;
> -}
> -
> -static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
> -{
> -	u32 highest_perf, nominal_perf;
> -
> -	highest_perf = READ_ONCE(cpudata->highest_perf);
> -	nominal_perf = READ_ONCE(cpudata->nominal_perf);
> -
> -	if (highest_perf <= nominal_perf)
> -		return;
> +	amd_pstate_global_params.cpb_supported = !((boost_val >> 25) & 0x1);

Can we move the definition of MSR_K7_HWCR_CPB_DIS from
drivers/cpufreq/acpi-cpufreq.h to msr-index.h and use it here ?
something like the following:

----------- x8---------------------------------------------------------------------
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index f1bd7b91b3c6..e5380cad903c 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -736,6 +736,8 @@
 #define MSR_K7_HWCR_IRPERF_EN          BIT_ULL(MSR_K7_HWCR_IRPERF_EN_BIT)
 #define MSR_K7_FID_VID_CTL             0xc0010041
 #define MSR_K7_FID_VID_STATUS          0xc0010042
+#define MSR_K7_HWCR_CPB_DIS_BIT                25
+#define MSR_K7_HWCR_CPB_DIS            BIT_ULL(MSR_K7_HWCR_CPB_DIS_BIT)
 
 /* K6 MSRs */
 #define MSR_K6_WHCR                    0xc0000082
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 37f1cdf46d29..7089aca6cc0d 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -31,6 +31,7 @@
 #include <acpi/cppc_acpi.h>
 
 #include <asm/msr.h>
+#include <asm/msr-index.h>
 #include <asm/processor.h>
 #include <asm/cpufeature.h>
 #include <asm/cpu_device_id.h>
@@ -50,8 +51,6 @@ enum {
 #define AMD_MSR_RANGE          (0x7)
 #define HYGON_MSR_RANGE                (0x7)
 
-#define MSR_K7_HWCR_CPB_DIS    (1ULL << 25)
-
 struct acpi_cpufreq_data {
        unsigned int resume;
        unsigned int cpu_feature;



The rest of the patch looks good to me.


--
Thanks and Regards
gautham.


> +	amd_pstate_global_params.cpb_boost = amd_pstate_global_params.cpb_supported;
>  
> -	cpudata->boost_supported = true;
> -	current_pstate_driver->boost_enabled = true;
> +	return ret;
>  }
>  
>  static void amd_perf_ctl_reset(unsigned int cpu)
> @@ -855,6 +835,9 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	if (ret)
>  		goto free_cpudata1;
>  
> +	/* initialize cpu cores boot state */
> +	amd_pstate_boost_init(cpudata);
> +
>  	min_freq = amd_get_min_freq(cpudata);
>  	max_freq = amd_get_max_freq(cpudata);
>  	nominal_freq = amd_get_nominal_freq(cpudata);
> @@ -906,7 +889,6 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  
>  	policy->driver_data = cpudata;
>  
> -	amd_pstate_boost_init(cpudata);
>  	if (!current_pstate_driver->adjust_perf)
>  		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
>  
> @@ -1317,6 +1299,9 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	if (ret)
>  		goto free_cpudata1;
>  
> +	/* initialize cpu cores boot state */
> +	amd_pstate_boost_init(cpudata);
> +
>  	min_freq = amd_get_min_freq(cpudata);
>  	max_freq = amd_get_max_freq(cpudata);
>  	nominal_freq = amd_get_nominal_freq(cpudata);
> @@ -1367,7 +1352,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  			return ret;
>  		WRITE_ONCE(cpudata->cppc_cap1_cached, value);
>  	}
> -	amd_pstate_boost_init(cpudata);
>  
>  	return 0;
>  
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index d21838835abd..c6e2a97913de 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -124,4 +124,18 @@ static const char * const amd_pstate_mode_string[] = {
>  	[AMD_PSTATE_GUIDED]      = "guided",
>  	NULL,
>  };
> +
> +/**
> + * struct amd_pstate_global_params - Global parameters, mostly tunable via sysfs.
> + * @cpb_boost:		Whether or not to use boost CPU P-states.
> + * @cpb_supported:	Whether or not CPU boost P-states are available
> + *			based on the MSR_K7_HWCR bit[25] state
> + */
> +struct amd_pstate_global_params {
> +	bool cpb_boost;
> +	bool cpb_supported;
> +};
> +
> +extern struct amd_pstate_global_params amd_pstate_global_params;
> +
>  #endif /* _LINUX_AMD_PSTATE_H */
> -- 
> 2.34.1
>
Yuan, Perry March 14, 2024, 9:11 a.m. UTC | #2 
[AMD Official Use Only - General]

> -----Original Message-----
> From: Shenoy, Gautham Ranjal <gautham.shenoy@amd.com>
> Sent: Thursday, March 14, 2024 5:05 PM
> To: Yuan, Perry <Perry.Yuan@amd.com>
> Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> <Mario.Limonciello@amd.com>; viresh.kumar@linaro.org; Huang, Ray
> <Ray.Huang@amd.com>; Petkov, Borislav <Borislav.Petkov@amd.com>;
> Deucher, Alexander <Alexander.Deucher@amd.com>; Huang, Shimmer
> <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
> Li (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v4 1/7] cpufreq: amd-pstate: initialize new core precision
> boost state
>
> On Wed, Mar 13, 2024 at 06:04:38PM +0800, Perry Yuan wrote:
> > From: Perry Yuan <Perry.Yuan@amd.com>
> >
> > Add gloal global_params to represent current CPU Performance
> > Boost(cpb) state for cpu frequency scaling, both active and passive
> > modes all can support CPU cores frequency boosting control which is
> > based on the BIOS setting, while BIOS turn on the "Core Performance
> > Boost", it will allow OS control each core highest perf limitation from OS side.
> >
> > If core performance boost is disabled while a core is in a boosted
> > P-state, the core transitions to the highest performance non-boosted
> > P-state, that is the same as the nominal frequency limit.
> >
> > Reported-by: Artem S. Tashkinov" <aros@gmx.com>
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > ---
> >  drivers/cpufreq/amd-pstate.c | 50 ++++++++++++------------------------
> >  include/linux/amd-pstate.h   | 14 ++++++++++
> >  2 files changed, 31 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 2015c9fcc3c9..ef6381b48e76
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -67,6 +67,8 @@ static struct cpufreq_driver amd_pstate_epp_driver;
> > static int cppc_state = AMD_PSTATE_UNDEFINED;  static bool
> > cppc_enabled;  static bool amd_pstate_prefcore = true;
> > +struct amd_pstate_global_params amd_pstate_global_params;
> > +EXPORT_SYMBOL_GPL(amd_pstate_global_params);
> >
> >  /*
> >   * AMD Energy Preference Performance (EPP) @@ -676,43 +678,21 @@
> > static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
> >     return lowest_nonlinear_freq * 1000;  }
> >
> > -static int amd_pstate_set_boost(struct cpufreq_policy *policy, int
> > state)
> > +static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
> >  {
> > -   struct amd_cpudata *cpudata = policy->driver_data;
> > +   u64 boost_val;
> >     int ret;
> >
> > -   if (!cpudata->boost_supported) {
> > -           pr_err("Boost mode is not supported by this processor or
> SBIOS\n");
> > -           return -EINVAL;
> > -   }
> > -
> > -   if (state)
> > -           policy->cpuinfo.max_freq = cpudata->max_freq;
> > -   else
> > -           policy->cpuinfo.max_freq = cpudata->nominal_freq;
> > -
> > -   policy->max = policy->cpuinfo.max_freq;
> > -
> > -   ret = freq_qos_update_request(&cpudata->req[1],
> > -                                 policy->cpuinfo.max_freq);
> > -   if (ret < 0)
> > +   ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);
> > +   if (ret) {
> > +           pr_err_once("failed to read initial CPU boost state!\n");
> >             return ret;
> > +   }
> >
> > -   return 0;
> > -}
> > -
> > -static void amd_pstate_boost_init(struct amd_cpudata *cpudata) -{
> > -   u32 highest_perf, nominal_perf;
> > -
> > -   highest_perf = READ_ONCE(cpudata->highest_perf);
> > -   nominal_perf = READ_ONCE(cpudata->nominal_perf);
> > -
> > -   if (highest_perf <= nominal_perf)
> > -           return;
> > +   amd_pstate_global_params.cpb_supported = !((boost_val >> 25) &
> 0x1);
>
> Can we move the definition of MSR_K7_HWCR_CPB_DIS from
> drivers/cpufreq/acpi-cpufreq.h to msr-index.h and use it here ?
> something like the following:

That's a brilliant idea!
Let me add a new patch to move it in next version.

Perry.


>
> ----------- x8---------------------------------------------------------------------
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-
> index.h
> index f1bd7b91b3c6..e5380cad903c 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -736,6 +736,8 @@
>  #define MSR_K7_HWCR_IRPERF_EN
> BIT_ULL(MSR_K7_HWCR_IRPERF_EN_BIT)
>  #define MSR_K7_FID_VID_CTL             0xc0010041
>  #define MSR_K7_FID_VID_STATUS          0xc0010042
> +#define MSR_K7_HWCR_CPB_DIS_BIT                25
> +#define MSR_K7_HWCR_CPB_DIS
> BIT_ULL(MSR_K7_HWCR_CPB_DIS_BIT)
>
>  /* K6 MSRs */
>  #define MSR_K6_WHCR                    0xc0000082
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 37f1cdf46d29..7089aca6cc0d 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -31,6 +31,7 @@
>  #include <acpi/cppc_acpi.h>
>
>  #include <asm/msr.h>
> +#include <asm/msr-index.h>
>  #include <asm/processor.h>
>  #include <asm/cpufeature.h>
>  #include <asm/cpu_device_id.h>
> @@ -50,8 +51,6 @@ enum {
>  #define AMD_MSR_RANGE          (0x7)
>  #define HYGON_MSR_RANGE                (0x7)
>
> -#define MSR_K7_HWCR_CPB_DIS    (1ULL << 25)
> -
>  struct acpi_cpufreq_data {
>         unsigned int resume;
>         unsigned int cpu_feature;
>
>
>
> The rest of the patch looks good to me.

Thank you for the review!


>
>
> --
> Thanks and Regards
> gautham.
>
>
> > +   amd_pstate_global_params.cpb_boost =
> > +amd_pstate_global_params.cpb_supported;
> >
> > -   cpudata->boost_supported = true;
> > -   current_pstate_driver->boost_enabled = true;
> > +   return ret;
> >  }
> >
> >  static void amd_perf_ctl_reset(unsigned int cpu) @@ -855,6 +835,9 @@
> > static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> >     if (ret)
> >             goto free_cpudata1;
> >
> > +   /* initialize cpu cores boot state */
> > +   amd_pstate_boost_init(cpudata);
> > +
> >     min_freq = amd_get_min_freq(cpudata);
> >     max_freq = amd_get_max_freq(cpudata);
> >     nominal_freq = amd_get_nominal_freq(cpudata); @@ -906,7 +889,6
> @@
> > static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> >
> >     policy->driver_data = cpudata;
> >
> > -   amd_pstate_boost_init(cpudata);
> >     if (!current_pstate_driver->adjust_perf)
> >             current_pstate_driver->adjust_perf =
> amd_pstate_adjust_perf;
> >
> > @@ -1317,6 +1299,9 @@ static int amd_pstate_epp_cpu_init(struct
> cpufreq_policy *policy)
> >     if (ret)
> >             goto free_cpudata1;
> >
> > +   /* initialize cpu cores boot state */
> > +   amd_pstate_boost_init(cpudata);
> > +
> >     min_freq = amd_get_min_freq(cpudata);
> >     max_freq = amd_get_max_freq(cpudata);
> >     nominal_freq = amd_get_nominal_freq(cpudata); @@ -1367,7
> +1352,6 @@
> > static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
> >                     return ret;
> >             WRITE_ONCE(cpudata->cppc_cap1_cached, value);
> >     }
> > -   amd_pstate_boost_init(cpudata);
> >
> >     return 0;
> >
> > diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> > index d21838835abd..c6e2a97913de 100644
> > --- a/include/linux/amd-pstate.h
> > +++ b/include/linux/amd-pstate.h
> > @@ -124,4 +124,18 @@ static const char * const
> amd_pstate_mode_string[] = {
> >     [AMD_PSTATE_GUIDED]      = "guided",
> >     NULL,
> >  };
> > +
> > +/**
> > + * struct amd_pstate_global_params - Global parameters, mostly tunable
> via sysfs.
> > + * @cpb_boost:             Whether or not to use boost CPU P-states.
> > + * @cpb_supported: Whether or not CPU boost P-states are available
> > + *                 based on the MSR_K7_HWCR bit[25] state
> > + */
> > +struct amd_pstate_global_params {
> > +   bool cpb_boost;
> > +   bool cpb_supported;
> > +};
> > +
> > +extern struct amd_pstate_global_params amd_pstate_global_params;
> > +
> >  #endif /* _LINUX_AMD_PSTATE_H */
> > --
> > 2.34.1
> >
diff mbox series

Patch

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 2015c9fcc3c9..ef6381b48e76 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -67,6 +67,8 @@  static struct cpufreq_driver amd_pstate_epp_driver;
 static int cppc_state = AMD_PSTATE_UNDEFINED;
 static bool cppc_enabled;
 static bool amd_pstate_prefcore = true;
+struct amd_pstate_global_params amd_pstate_global_params;
+EXPORT_SYMBOL_GPL(amd_pstate_global_params);
 
 /*
  * AMD Energy Preference Performance (EPP)
@@ -676,43 +678,21 @@  static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
 	return lowest_nonlinear_freq * 1000;
 }
 
-static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
+static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
 {
-	struct amd_cpudata *cpudata = policy->driver_data;
+	u64 boost_val;
 	int ret;
 
-	if (!cpudata->boost_supported) {
-		pr_err("Boost mode is not supported by this processor or SBIOS\n");
-		return -EINVAL;
-	}
-
-	if (state)
-		policy->cpuinfo.max_freq = cpudata->max_freq;
-	else
-		policy->cpuinfo.max_freq = cpudata->nominal_freq;
-
-	policy->max = policy->cpuinfo.max_freq;
-
-	ret = freq_qos_update_request(&cpudata->req[1],
-				      policy->cpuinfo.max_freq);
-	if (ret < 0)
+	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);
+	if (ret) {
+		pr_err_once("failed to read initial CPU boost state!\n");
 		return ret;
+	}
 
-	return 0;
-}
-
-static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
-{
-	u32 highest_perf, nominal_perf;
-
-	highest_perf = READ_ONCE(cpudata->highest_perf);
-	nominal_perf = READ_ONCE(cpudata->nominal_perf);
-
-	if (highest_perf <= nominal_perf)
-		return;
+	amd_pstate_global_params.cpb_supported = !((boost_val >> 25) & 0x1);
+	amd_pstate_global_params.cpb_boost = amd_pstate_global_params.cpb_supported;
 
-	cpudata->boost_supported = true;
-	current_pstate_driver->boost_enabled = true;
+	return ret;
 }
 
 static void amd_perf_ctl_reset(unsigned int cpu)
@@ -855,6 +835,9 @@  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 	if (ret)
 		goto free_cpudata1;
 
+	/* initialize cpu cores boot state */
+	amd_pstate_boost_init(cpudata);
+
 	min_freq = amd_get_min_freq(cpudata);
 	max_freq = amd_get_max_freq(cpudata);
 	nominal_freq = amd_get_nominal_freq(cpudata);
@@ -906,7 +889,6 @@  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 
 	policy->driver_data = cpudata;
 
-	amd_pstate_boost_init(cpudata);
 	if (!current_pstate_driver->adjust_perf)
 		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
 
@@ -1317,6 +1299,9 @@  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 	if (ret)
 		goto free_cpudata1;
 
+	/* initialize cpu cores boot state */
+	amd_pstate_boost_init(cpudata);
+
 	min_freq = amd_get_min_freq(cpudata);
 	max_freq = amd_get_max_freq(cpudata);
 	nominal_freq = amd_get_nominal_freq(cpudata);
@@ -1367,7 +1352,6 @@  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 			return ret;
 		WRITE_ONCE(cpudata->cppc_cap1_cached, value);
 	}
-	amd_pstate_boost_init(cpudata);
 
 	return 0;
 
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index d21838835abd..c6e2a97913de 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -124,4 +124,18 @@  static const char * const amd_pstate_mode_string[] = {
 	[AMD_PSTATE_GUIDED]      = "guided",
 	NULL,
 };
+
+/**
+ * struct amd_pstate_global_params - Global parameters, mostly tunable via sysfs.
+ * @cpb_boost:		Whether or not to use boost CPU P-states.
+ * @cpb_supported:	Whether or not CPU boost P-states are available
+ *			based on the MSR_K7_HWCR bit[25] state
+ */
+struct amd_pstate_global_params {
+	bool cpb_boost;
+	bool cpb_supported;
+};
+
+extern struct amd_pstate_global_params amd_pstate_global_params;
+
 #endif /* _LINUX_AMD_PSTATE_H */