diff mbox series

[1/1] coresight: etm4x: Configure EL2 exception level when kernel is running in HYP

Message ID 20180904142034.19116-1-tnowicki@caviumnetworks.com (mailing list archive)
State New, archived
Headers show
Series [1/1] coresight: etm4x: Configure EL2 exception level when kernel is running in HYP | expand

Commit Message

Tomasz Nowicki Sept. 4, 2018, 2:20 p.m. UTC 
For non-VHE systems host kernel runs at EL1 and jumps to EL2 whenever
hypervisor code should be executed. In this case ETM4x driver must
restrict configuration to EL1 when it setups kernel tracing.
However, there is no separate hypervisor privilege level when VHE
is enabled, the host kernel runs at EL2.

This patch fixes configuration of TRCACATRn register for VHE systems
so that ETM_EXLEVEL_NS_HYP bit is used instead of ETM_EXLEVEL_NS_OS
to on/off kernel tracing. At the same time, it moves common code
to new helper.

Signed-off-by: Tomasz Nowicki <tnowicki@caviumnetworks.com>
---
 drivers/hwtracing/coresight/coresight-etm4x.c | 39 ++++++++++---------
 1 file changed, 20 insertions(+), 19 deletions(-)

Comments

Mathieu Poirier Sept. 5, 2018, 8:34 p.m. UTC | #1 
Hi Tomasz,

On Tue, Sep 04, 2018 at 04:20:34PM +0200, Tomasz Nowicki wrote:
> For non-VHE systems host kernel runs at EL1 and jumps to EL2 whenever
> hypervisor code should be executed. In this case ETM4x driver must
> restrict configuration to EL1 when it setups kernel tracing.
> However, there is no separate hypervisor privilege level when VHE
> is enabled, the host kernel runs at EL2.
> 
> This patch fixes configuration of TRCACATRn register for VHE systems
> so that ETM_EXLEVEL_NS_HYP bit is used instead of ETM_EXLEVEL_NS_OS
> to on/off kernel tracing. At the same time, it moves common code
> to new helper.
> 
> Signed-off-by: Tomasz Nowicki <tnowicki@caviumnetworks.com>
> ---
>  drivers/hwtracing/coresight/coresight-etm4x.c | 39 ++++++++++---------
>  1 file changed, 20 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
> index f79b0ea85d76..5f495c942f99 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -28,6 +28,7 @@
>  #include <linux/pm_runtime.h>
>  #include <asm/sections.h>
>  #include <asm/local.h>
> +#include <asm/virt.h>
>  
>  #include "coresight-etm4x.h"
>  #include "coresight-etm-perf.h"
> @@ -606,7 +607,7 @@ static void etm4_set_default_config(struct etmv4_config *config)
>  	config->vinst_ctrl |= BIT(0);
>  }
>  
> -static u64 etm4_get_access_type(struct etmv4_config *config)
> +static u64 etm4_get_ns_access_type(struct etmv4_config *config)
>  {
>  	u64 access_type = 0;
>  
> @@ -617,17 +618,27 @@ static u64 etm4_get_access_type(struct etmv4_config *config)
>  	 *   Bit[13] Exception level 1 - OS
>  	 *   Bit[14] Exception level 2 - Hypervisor
>  	 *   Bit[15] Never implemented
> -	 *
> -	 * Always stay away from hypervisor mode.
>  	 */
> -	access_type = ETM_EXLEVEL_NS_HYP;
>  

Extra space 

> -	if (config->mode & ETM_MODE_EXCL_KERN)
> -		access_type |= ETM_EXLEVEL_NS_OS;
> +	if (!is_kernel_in_hyp_mode()) {
> +		/* Stay away from hypervisor mode for non-VHE */
> +		access_type =  ETM_EXLEVEL_NS_HYP;
> +		if (config->mode & ETM_MODE_EXCL_KERN)
> +			access_type |= ETM_EXLEVEL_NS_OS;
> +	} else if (config->mode & ETM_MODE_EXCL_KERN) {
> +		access_type = ETM_EXLEVEL_NS_HYP;
> +	}
>  
>  	if (config->mode & ETM_MODE_EXCL_USER)
>  		access_type |= ETM_EXLEVEL_NS_APP;
>  
> +	return access_type;
> +}
> +
> +static u64 etm4_get_access_type(struct etmv4_config *config)
> +{
> +	u64 access_type = etm4_get_ns_access_type(config);
> +
>  	/*
>  	 * EXLEVEL_S, bits[11:8], don't trace anything happening
>  	 * in secure state.
> @@ -881,20 +892,10 @@ void etm4_config_trace_mode(struct etmv4_config *config)
>  
>  	addr_acc = config->addr_acc[ETM_DEFAULT_ADDR_COMP];
>  	/* clear default config */
> -	addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS);
> +	addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS |
> +			ETM_EXLEVEL_NS_HYP);

Indentation problems

>  
> -	/*
> -	 * EXLEVEL_NS, bits[15:12]
> -	 * The Exception levels are:
> -	 *   Bit[12] Exception level 0 - Application
> -	 *   Bit[13] Exception level 1 - OS
> -	 *   Bit[14] Exception level 2 - Hypervisor
> -	 *   Bit[15] Never implemented
> -	 */
> -	if (mode & ETM_MODE_EXCL_KERN)
> -		addr_acc |= ETM_EXLEVEL_NS_OS;
> -	else
> -		addr_acc |= ETM_EXLEVEL_NS_APP;
> +	addr_acc |= etm4_get_ns_access_type(config);
>  
>  	config->addr_acc[ETM_DEFAULT_ADDR_COMP] = addr_acc;
>  	config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] = addr_acc;

I tested your patch on my side and it didn't break kernel space decoding.

Since it would have taken longer to ask you to respin than to make the changes
myself, I applied your patch with the above modifications.

Thanks,
Mathieu

> -- 
> 2.17.1
>
Tomasz Nowicki Sept. 6, 2018, 8:55 a.m. UTC | #2 
Hi Mathieu,

On 05.09.2018 22:34, Mathieu Poirier wrote:
> Hi Tomasz,
> 
> On Tue, Sep 04, 2018 at 04:20:34PM +0200, Tomasz Nowicki wrote:
>> For non-VHE systems host kernel runs at EL1 and jumps to EL2 whenever
>> hypervisor code should be executed. In this case ETM4x driver must
>> restrict configuration to EL1 when it setups kernel tracing.
>> However, there is no separate hypervisor privilege level when VHE
>> is enabled, the host kernel runs at EL2.
>>
>> This patch fixes configuration of TRCACATRn register for VHE systems
>> so that ETM_EXLEVEL_NS_HYP bit is used instead of ETM_EXLEVEL_NS_OS
>> to on/off kernel tracing. At the same time, it moves common code
>> to new helper.
>>
>> Signed-off-by: Tomasz Nowicki <tnowicki@caviumnetworks.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-etm4x.c | 39 ++++++++++---------
>>   1 file changed, 20 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
>> index f79b0ea85d76..5f495c942f99 100644
>> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
>> @@ -28,6 +28,7 @@
>>   #include <linux/pm_runtime.h>
>>   #include <asm/sections.h>
>>   #include <asm/local.h>
>> +#include <asm/virt.h>
>>
>>   #include "coresight-etm4x.h"
>>   #include "coresight-etm-perf.h"
>> @@ -606,7 +607,7 @@ static void etm4_set_default_config(struct etmv4_config *config)
>>        config->vinst_ctrl |= BIT(0);
>>   }
>>
>> -static u64 etm4_get_access_type(struct etmv4_config *config)
>> +static u64 etm4_get_ns_access_type(struct etmv4_config *config)
>>   {
>>        u64 access_type = 0;
>>
>> @@ -617,17 +618,27 @@ static u64 etm4_get_access_type(struct etmv4_config *config)
>>         *   Bit[13] Exception level 1 - OS
>>         *   Bit[14] Exception level 2 - Hypervisor
>>         *   Bit[15] Never implemented
>> -      *
>> -      * Always stay away from hypervisor mode.
>>         */
>> -     access_type = ETM_EXLEVEL_NS_HYP;
>>
> 
> Extra space
> 
>> -     if (config->mode & ETM_MODE_EXCL_KERN)
>> -             access_type |= ETM_EXLEVEL_NS_OS;
>> +     if (!is_kernel_in_hyp_mode()) {
>> +             /* Stay away from hypervisor mode for non-VHE */
>> +             access_type =  ETM_EXLEVEL_NS_HYP;
>> +             if (config->mode & ETM_MODE_EXCL_KERN)
>> +                     access_type |= ETM_EXLEVEL_NS_OS;
>> +     } else if (config->mode & ETM_MODE_EXCL_KERN) {
>> +             access_type = ETM_EXLEVEL_NS_HYP;
>> +     }
>>
>>        if (config->mode & ETM_MODE_EXCL_USER)
>>                access_type |= ETM_EXLEVEL_NS_APP;
>>
>> +     return access_type;
>> +}
>> +
>> +static u64 etm4_get_access_type(struct etmv4_config *config)
>> +{
>> +     u64 access_type = etm4_get_ns_access_type(config);
>> +
>>        /*
>>         * EXLEVEL_S, bits[11:8], don't trace anything happening
>>         * in secure state.
>> @@ -881,20 +892,10 @@ void etm4_config_trace_mode(struct etmv4_config *config)
>>
>>        addr_acc = config->addr_acc[ETM_DEFAULT_ADDR_COMP];
>>        /* clear default config */
>> -     addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS);
>> +     addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS |
>> +                     ETM_EXLEVEL_NS_HYP);
> 
> Indentation problems
> 
>>
>> -     /*
>> -      * EXLEVEL_NS, bits[15:12]
>> -      * The Exception levels are:
>> -      *   Bit[12] Exception level 0 - Application
>> -      *   Bit[13] Exception level 1 - OS
>> -      *   Bit[14] Exception level 2 - Hypervisor
>> -      *   Bit[15] Never implemented
>> -      */
>> -     if (mode & ETM_MODE_EXCL_KERN)
>> -             addr_acc |= ETM_EXLEVEL_NS_OS;
>> -     else
>> -             addr_acc |= ETM_EXLEVEL_NS_APP;
>> +     addr_acc |= etm4_get_ns_access_type(config);
>>
>>        config->addr_acc[ETM_DEFAULT_ADDR_COMP] = addr_acc;
>>        config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] = addr_acc;
> 
> I tested your patch on my side and it didn't break kernel space decoding.
> 
> Since it would have taken longer to ask you to respin than to make the changes
> myself, I applied your patch with the above modifications.
> 

Thank you for comments and corresponding fixes in the patch.

Tomasz
diff mbox series

Patch

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index f79b0ea85d76..5f495c942f99 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -28,6 +28,7 @@ 
 #include <linux/pm_runtime.h>
 #include <asm/sections.h>
 #include <asm/local.h>
+#include <asm/virt.h>
 
 #include "coresight-etm4x.h"
 #include "coresight-etm-perf.h"
@@ -606,7 +607,7 @@  static void etm4_set_default_config(struct etmv4_config *config)
 	config->vinst_ctrl |= BIT(0);
 }
 
-static u64 etm4_get_access_type(struct etmv4_config *config)
+static u64 etm4_get_ns_access_type(struct etmv4_config *config)
 {
 	u64 access_type = 0;
 
@@ -617,17 +618,27 @@  static u64 etm4_get_access_type(struct etmv4_config *config)
 	 *   Bit[13] Exception level 1 - OS
 	 *   Bit[14] Exception level 2 - Hypervisor
 	 *   Bit[15] Never implemented
-	 *
-	 * Always stay away from hypervisor mode.
 	 */
-	access_type = ETM_EXLEVEL_NS_HYP;
 
-	if (config->mode & ETM_MODE_EXCL_KERN)
-		access_type |= ETM_EXLEVEL_NS_OS;
+	if (!is_kernel_in_hyp_mode()) {
+		/* Stay away from hypervisor mode for non-VHE */
+		access_type =  ETM_EXLEVEL_NS_HYP;
+		if (config->mode & ETM_MODE_EXCL_KERN)
+			access_type |= ETM_EXLEVEL_NS_OS;
+	} else if (config->mode & ETM_MODE_EXCL_KERN) {
+		access_type = ETM_EXLEVEL_NS_HYP;
+	}
 
 	if (config->mode & ETM_MODE_EXCL_USER)
 		access_type |= ETM_EXLEVEL_NS_APP;
 
+	return access_type;
+}
+
+static u64 etm4_get_access_type(struct etmv4_config *config)
+{
+	u64 access_type = etm4_get_ns_access_type(config);
+
 	/*
 	 * EXLEVEL_S, bits[11:8], don't trace anything happening
 	 * in secure state.
@@ -881,20 +892,10 @@  void etm4_config_trace_mode(struct etmv4_config *config)
 
 	addr_acc = config->addr_acc[ETM_DEFAULT_ADDR_COMP];
 	/* clear default config */
-	addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS);
+	addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS |
+			ETM_EXLEVEL_NS_HYP);
 
-	/*
-	 * EXLEVEL_NS, bits[15:12]
-	 * The Exception levels are:
-	 *   Bit[12] Exception level 0 - Application
-	 *   Bit[13] Exception level 1 - OS
-	 *   Bit[14] Exception level 2 - Hypervisor
-	 *   Bit[15] Never implemented
-	 */
-	if (mode & ETM_MODE_EXCL_KERN)
-		addr_acc |= ETM_EXLEVEL_NS_OS;
-	else
-		addr_acc |= ETM_EXLEVEL_NS_APP;
+	addr_acc |= etm4_get_ns_access_type(config);
 
 	config->addr_acc[ETM_DEFAULT_ADDR_COMP] = addr_acc;
 	config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] = addr_acc;