[PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[Zhang Yanfei]

For percpu notes, we are exporting only address and not size. So
the userspace tool kexec-tools is putting an upper limit of 1024
and putting the value in p_memsz and p_filesz fields. So the patch
add the new sysfile crash_notes_size to export the exact percpu
note size and let the kexec-tools parse it intead of using 1024.

The idea came from Vivek Goyal. And a later patch will be sent to
kexec-tools to let it parse the size.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
 drivers/base/cpu.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index fb10728..a55b590 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
 	return rc;
 }
 static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
+
+static ssize_t show_crash_notes_size(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	ssize_t rc;
+
+	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
+	return rc;
+}
+static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
 #endif
 
 /*
@@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
 #ifdef CONFIG_KEXEC
 	if (!error)
 		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
+	if (!error)
+		error = device_create_file(&cpu->dev,
+					   &dev_attr_crash_notes_size);
 #endif
 	return error;
 }
-- 
1.7.1

[PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[Zhang Yanfei]

For percpu notes, we are exporting only address and not size. So
the userspace tool kexec-tools is putting an upper limit of 1024
and putting the value in p_memsz and p_filesz fields. So the patch
add the new sysfile crash_notes_size to export the exact percpu
note size and let the kexec-tools parse it intead of using 1024.

The idea came from Vivek Goyal. And a later patch will be sent to
kexec-tools to let it parse the size.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
 drivers/base/cpu.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index fb10728..a55b590 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
 	return rc;
 }
 static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
+
+static ssize_t show_crash_notes_size(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	ssize_t rc;
+
+	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
+	return rc;
+}
+static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
 #endif
 
 /*
@@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
 #ifdef CONFIG_KEXEC
 	if (!error)
 		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
+	if (!error)
+		error = device_create_file(&cpu->dev,
+					   &dev_attr_crash_notes_size);
 #endif
 	return error;
 }
-- 
1.7.1

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[PATCH 2/2] Documentation: Add ABI entry for crash_notes and crash_notes_size

[Zhang Yanfei]

Add an Documentation/ABI entry for /sys/devices/system/cpu/cpu0/crash_notes
and /sys/devices/system/cpu/cpu0/crash_notes_size.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
 Documentation/ABI/testing/sysfs-devices-system-cpu |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 9c978dc..2447698 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -173,3 +173,15 @@ Description:	Processor frequency boosting control
 		Boosting allows the CPU and the firmware to run at a frequency
 		beyound it's nominal limit.
 		More details can be found in Documentation/cpu-freq/boost.txt
+
+
+What:		/sys/devices/system/cpu/cpu#/crash_notes
+		/sys/devices/system/cpu/cpu#/crash_notes_size
+Date:		April 2013
+Contact:	kexec@lists.infradead.org
+Description:	address and size of the percpu note.
+
+		crash_notes: the physical address of the memory that holds the
+		note of cpu#.
+
+		crash_notes_size: size of the note of cpu#.
-- 
1.7.1

[PATCH 2/2] Documentation: Add ABI entry for crash_notes and crash_notes_size

[Zhang Yanfei]

Add an Documentation/ABI entry for /sys/devices/system/cpu/cpu0/crash_notes
and /sys/devices/system/cpu/cpu0/crash_notes_size.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
 Documentation/ABI/testing/sysfs-devices-system-cpu |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 9c978dc..2447698 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -173,3 +173,15 @@ Description:	Processor frequency boosting control
 		Boosting allows the CPU and the firmware to run at a frequency
 		beyound it's nominal limit.
 		More details can be found in Documentation/cpu-freq/boost.txt
+
+
+What:		/sys/devices/system/cpu/cpu#/crash_notes
+		/sys/devices/system/cpu/cpu#/crash_notes_size
+Date:		April 2013
+Contact:	kexec@lists.infradead.org
+Description:	address and size of the percpu note.
+
+		crash_notes: the physical address of the memory that holds the
+		note of cpu#.
+
+		crash_notes_size: size of the note of cpu#.
-- 
1.7.1


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Re: [PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[Zhang Yanfei]

Hi, simon

I forgot to add your email in the CC, could you please help
reviewing this patch since I will send the kexec-tools patch
if this patch is accepted.

Thanks
Zhang

于 2013年03月28日 16:15, Zhang Yanfei 写道:
> For percpu notes, we are exporting only address and not size. So
> the userspace tool kexec-tools is putting an upper limit of 1024
> and putting the value in p_memsz and p_filesz fields. So the patch
> add the new sysfile crash_notes_size to export the exact percpu
> note size and let the kexec-tools parse it intead of using 1024.
> 
> The idea came from Vivek Goyal. And a later patch will be sent to
> kexec-tools to let it parse the size.
> 
> Cc: Greg KH <gregkh@linuxfoundation.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
>  drivers/base/cpu.c |   14 ++++++++++++++
>  1 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index fb10728..a55b590 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
>  	return rc;
>  }
>  static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
> +
> +static ssize_t show_crash_notes_size(struct device *dev,
> +				     struct device_attribute *attr,
> +				     char *buf)
> +{
> +	ssize_t rc;
> +
> +	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
> +	return rc;
> +}
> +static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
>  #endif
>  
>  /*
> @@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
>  #ifdef CONFIG_KEXEC
>  	if (!error)
>  		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
> +	if (!error)
> +		error = device_create_file(&cpu->dev,
> +					   &dev_attr_crash_notes_size);
>  #endif
>  	return error;
>  }

Re: [PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[Zhang Yanfei]

Hi, simon

I forgot to add your email in the CC, could you please help
reviewing this patch since I will send the kexec-tools patch
if this patch is accepted.

Thanks
Zhang

于 2013年03月28日 16:15, Zhang Yanfei 写道:
> For percpu notes, we are exporting only address and not size. So
> the userspace tool kexec-tools is putting an upper limit of 1024
> and putting the value in p_memsz and p_filesz fields. So the patch
> add the new sysfile crash_notes_size to export the exact percpu
> note size and let the kexec-tools parse it intead of using 1024.
> 
> The idea came from Vivek Goyal. And a later patch will be sent to
> kexec-tools to let it parse the size.
> 
> Cc: Greg KH <gregkh@linuxfoundation.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
>  drivers/base/cpu.c |   14 ++++++++++++++
>  1 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index fb10728..a55b590 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
>  	return rc;
>  }
>  static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
> +
> +static ssize_t show_crash_notes_size(struct device *dev,
> +				     struct device_attribute *attr,
> +				     char *buf)
> +{
> +	ssize_t rc;
> +
> +	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
> +	return rc;
> +}
> +static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
>  #endif
>  
>  /*
> @@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
>  #ifdef CONFIG_KEXEC
>  	if (!error)
>  		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
> +	if (!error)
> +		error = device_create_file(&cpu->dev,
> +					   &dev_attr_crash_notes_size);
>  #endif
>  	return error;
>  }


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Re: [PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[Simon Horman]

On Fri, Mar 29, 2013 at 11:50:35AM +0800, Zhang Yanfei wrote:
> Hi, simon
> 
> I forgot to add your email in the CC, could you please help
> reviewing this patch since I will send the kexec-tools patch
> if this patch is accepted.
> 
> Thanks
> Zhang
> 
> 于 2013年03月28日 16:15, Zhang Yanfei 写道:
> > For percpu notes, we are exporting only address and not size. So
> > the userspace tool kexec-tools is putting an upper limit of 1024
> > and putting the value in p_memsz and p_filesz fields. So the patch
> > add the new sysfile crash_notes_size to export the exact percpu
> > note size and let the kexec-tools parse it intead of using 1024.
> > 
> > The idea came from Vivek Goyal. And a later patch will be sent to
> > kexec-tools to let it parse the size.

Acked-by: Simon Horman <horms@verge.net.au>

> > 
> > Cc: Greg KH <gregkh@linuxfoundation.org>
> > Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> > Cc: Vivek Goyal <vgoyal@redhat.com>
> > Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> > ---
> >  drivers/base/cpu.c |   14 ++++++++++++++
> >  1 files changed, 14 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> > index fb10728..a55b590 100644
> > --- a/drivers/base/cpu.c
> > +++ b/drivers/base/cpu.c
> > @@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
> >  	return rc;
> >  }
> >  static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
> > +
> > +static ssize_t show_crash_notes_size(struct device *dev,
> > +				     struct device_attribute *attr,
> > +				     char *buf)
> > +{
> > +	ssize_t rc;
> > +
> > +	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
> > +	return rc;
> > +}
> > +static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
> >  #endif
> >  
> >  /*
> > @@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
> >  #ifdef CONFIG_KEXEC
> >  	if (!error)
> >  		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
> > +	if (!error)
> > +		error = device_create_file(&cpu->dev,
> > +					   &dev_attr_crash_notes_size);
> >  #endif
> >  	return error;
> >  }
> 
> 

Re: [PATCH 1/2] sysfs: Add crash_notes_size to export percpu note size

[Simon Horman]

On Fri, Mar 29, 2013 at 11:50:35AM +0800, Zhang Yanfei wrote:
> Hi, simon
> 
> I forgot to add your email in the CC, could you please help
> reviewing this patch since I will send the kexec-tools patch
> if this patch is accepted.
> 
> Thanks
> Zhang
> 
> 于 2013年03月28日 16:15, Zhang Yanfei 写道:
> > For percpu notes, we are exporting only address and not size. So
> > the userspace tool kexec-tools is putting an upper limit of 1024
> > and putting the value in p_memsz and p_filesz fields. So the patch
> > add the new sysfile crash_notes_size to export the exact percpu
> > note size and let the kexec-tools parse it intead of using 1024.
> > 
> > The idea came from Vivek Goyal. And a later patch will be sent to
> > kexec-tools to let it parse the size.

Acked-by: Simon Horman <horms@verge.net.au>

> > 
> > Cc: Greg KH <gregkh@linuxfoundation.org>
> > Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> > Cc: Vivek Goyal <vgoyal@redhat.com>
> > Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> > ---
> >  drivers/base/cpu.c |   14 ++++++++++++++
> >  1 files changed, 14 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> > index fb10728..a55b590 100644
> > --- a/drivers/base/cpu.c
> > +++ b/drivers/base/cpu.c
> > @@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
> >  	return rc;
> >  }
> >  static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
> > +
> > +static ssize_t show_crash_notes_size(struct device *dev,
> > +				     struct device_attribute *attr,
> > +				     char *buf)
> > +{
> > +	ssize_t rc;
> > +
> > +	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
> > +	return rc;
> > +}
> > +static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
> >  #endif
> >  
> >  /*
> > @@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
> >  #ifdef CONFIG_KEXEC
> >  	if (!error)
> >  		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
> > +	if (!error)
> > +		error = device_create_file(&cpu->dev,
> > +					   &dev_attr_crash_notes_size);
> >  #endif
> >  	return error;
> >  }
> 
> 

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Re: [PATCH 2/2] Documentation: Add ABI entry for crash_notes and crash_notes_size

[Simon Horman]

On Thu, Mar 28, 2013 at 04:16:45PM +0800, Zhang Yanfei wrote:
> Add an Documentation/ABI entry for /sys/devices/system/cpu/cpu0/crash_notes
> and /sys/devices/system/cpu/cpu0/crash_notes_size.
> 
> Cc: Greg KH <gregkh@linuxfoundation.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>

Assuming that patch 1 of this series is accepted:

Acked-by: Simon Horman <horms@verge.net.au>

> ---
>  Documentation/ABI/testing/sysfs-devices-system-cpu |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 9c978dc..2447698 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -173,3 +173,15 @@ Description:	Processor frequency boosting control
>  		Boosting allows the CPU and the firmware to run at a frequency
>  		beyound it's nominal limit.
>  		More details can be found in Documentation/cpu-freq/boost.txt
> +
> +
> +What:		/sys/devices/system/cpu/cpu#/crash_notes
> +		/sys/devices/system/cpu/cpu#/crash_notes_size
> +Date:		April 2013
> +Contact:	kexec@lists.infradead.org
> +Description:	address and size of the percpu note.
> +
> +		crash_notes: the physical address of the memory that holds the
> +		note of cpu#.
> +
> +		crash_notes_size: size of the note of cpu#.
> -- 
> 1.7.1
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
> 

Re: [PATCH 2/2] Documentation: Add ABI entry for crash_notes and crash_notes_size

[Simon Horman]

On Thu, Mar 28, 2013 at 04:16:45PM +0800, Zhang Yanfei wrote:
> Add an Documentation/ABI entry for /sys/devices/system/cpu/cpu0/crash_notes
> and /sys/devices/system/cpu/cpu0/crash_notes_size.
> 
> Cc: Greg KH <gregkh@linuxfoundation.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>

Assuming that patch 1 of this series is accepted:

Acked-by: Simon Horman <horms@verge.net.au>

> ---
>  Documentation/ABI/testing/sysfs-devices-system-cpu |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 9c978dc..2447698 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -173,3 +173,15 @@ Description:	Processor frequency boosting control
>  		Boosting allows the CPU and the firmware to run at a frequency
>  		beyound it's nominal limit.
>  		More details can be found in Documentation/cpu-freq/boost.txt
> +
> +
> +What:		/sys/devices/system/cpu/cpu#/crash_notes
> +		/sys/devices/system/cpu/cpu#/crash_notes_size
> +Date:		April 2013
> +Contact:	kexec@lists.infradead.org
> +Description:	address and size of the percpu note.
> +
> +		crash_notes: the physical address of the memory that holds the
> +		note of cpu#.
> +
> +		crash_notes_size: size of the note of cpu#.
> -- 
> 1.7.1
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
> 

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