From eca4549f57a19f8881dcd7b9cef719b3452003c0 Mon Sep 17 00:00:00 2001 From: Zhang Yanfei Date: Thu, 28 Mar 2013 16:15:35 +0800 Subject: [PATCH] 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" Cc: Vivek Goyal Signed-off-by: Zhang Yanfei Acked-by: Simon Horman Signed-off-by: Greg Kroah-Hartman --- drivers/base/cpu.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) 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; } -- 2.34.1