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authorZhang Yanfei <zhangyanfei@cn.fujitsu.com>2013-03-28 16:15:35 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-29 09:17:22 -0700
commiteca4549f57a19f8881dcd7b9cef719b3452003c0 (patch)
treee7b156e0d7c9344337263ed81d683d15203b08fa /drivers/base/cpu.c
parent6ae07f27ab202069bd567967a0099070eb7f77d5 (diff)
sysfs: Add crash_notes_size to export percpu note size
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: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/cpu.c')
-rw-r--r--drivers/base/cpu.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index fb10728f6372..a55b5909176f 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;
}