[PATCH] ramoops: provide panic data even in suspend

[yangdongdong]

This also enables panic and oops messages which
in suspend context to be logged into ramoops console
buffer where it can be read back at some later point.

Signed-off-by: yangdongdong <yangdongdong@xxxxxxxxxx>
Signed-off-by: gulinghua <gulinghua@xxxxxxxxxx>
---
 fs/pstore/ram.c            | 16 ++++++++++++++++
 include/linux/pstore_ram.h |  1 +
 kernel/printk/printk.c     |  6 ++++++
 3 files changed, 23 insertions(+)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 6c26c4d..3d981a1 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -642,8 +642,23 @@ static void ramoops_register_dummy(void)
 	}
 }
 
+static int ramoops_console_notify(struct notifier_block *this,
+		unsigned long event, void *ptr)
+{
+	pr_emerg("ramoops unlock console ...\n");
+	emergency_unlock_console();
+
+	return 0;
+}
+
+static struct notifier_block ramoop_nb = {
+	.notifier_call = ramoops_console_notify,
+	.priority = INT_MAX,
+};
+
 static int __init ramoops_init(void)
 {
+	atomic_notifier_chain_register(&panic_notifier_list, &ramoop_nb);
 	ramoops_register_dummy();
 	return platform_driver_register(&ramoops_driver);
 }
@@ -654,6 +669,7 @@ static void __exit ramoops_exit(void)
 	platform_driver_unregister(&ramoops_driver);
 	platform_device_unregister(dummy);
 	kfree(dummy_data);
+	atomic_notifier_chain_unregister(&panic_notifier_list, &ramoop_nb);
 }
 module_exit(ramoops_exit);
 
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 9c9d6c1..826a35b 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -52,6 +52,7 @@ struct persistent_ram_zone {
 	size_t old_log_size;
 };
 
+extern void emergency_unlock_console(void);
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
 			unsigned int memtype);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index cf8c242..ece645c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2107,6 +2107,12 @@ void resume_console(void)
 	console_unlock();
 }
 
+void emergency_unlock_console(void)
+{
+	resume_console();
+}
+EXPORT_SYMBOL(emergency_unlock_console);
+
 /**
  * console_cpu_notify - print deferred console messages after CPU hotplug
  * @self: notifier struct
-- 
2.5.0

Thanks,
Andy

-----é?®ä»¶å??件-----
å??件人: Alex Elder [mailto:elder@xxxxxxxxxx]
å??é??æ?¶é?´: 2015å¹´8æ??5æ?¥ 21:23
æ?¶ä»¶äºº: check.kernel@xxxxxxxxx; Anton Vorontsov; Colin Cross; Kees Cook; Tony Luck; Andrew Morton; Petr Mladek; Luis R. Rodriguez; Peter Hurley; Joe Perches; Tejun Heo; æ??æ?§; 顾å??å??
æ??é??: linux-kernel@xxxxxxxxxxxxxxx; æ?¨å?¬ä¸?
主�: Re: [PATCH] fs/pstore: provide panic data even in suspend

On 08/05/2015 08:11 AM, check.kernel@xxxxxxxxx wrote:
> From: yangdongdong <yangdongdong@xxxxxxxxxx>
> 
> This also enables panic and oops messages which in suspend context to 
> be logged into ramoops console buffer where it can be read back at 
> some later point.
> 
> Signed-off-by: yangdongdong <yangdongdong@xxxxxxxxxx>
> Signed-off-by: gulinghua <gulinghua@xxxxxxxxxx>

I have a small comment on the code below.

                                        -Alex

> ---
>  fs/pstore/ram.c            | 21 +++++++++++++++++++++
>  include/linux/pstore_ram.h |  1 +
>  kernel/printk/printk.c     |  6 ++++++
>  3 files changed, 28 insertions(+)
> 
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 6c26c4d..f84c5ab 
> 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -642,8 +642,28 @@ static void ramoops_register_dummy(void)
>        }
>  }
>  
> +static int ramoops_console_notify(struct notifier_block *this,
> +             unsigned long event, void *ptr)
> +{
> +     pr_emerg("ramoops unlock console ...\n");
> +     emergency_unlock_console();
> +
> +     return 0;
> +}
> +
> +static struct notifier_block ramoop_nb = {
> +     .notifier_call = ramoops_console_notify,
> +     .priority = INT_MAX,
> +};
> +
> +static void ramoops_prepare(void)
> +{
> +     atomic_notifier_chain_register(&panic_notifier_list, &ramoop_nb); }
> +
>  static int __init ramoops_init(void)
>  {
> +     ramoops_prepare();
>        ramoops_register_dummy();
>        return platform_driver_register(&ramoops_driver);
>  }
> @@ -654,6 +674,7 @@ static void __exit ramoops_exit(void)
>        platform_driver_unregister(&ramoops_driver);
>        platform_device_unregister(dummy);
>        kfree(dummy_data);
> +     atomic_notifier_chain_unregister(&panic_notifier_list, &ramoop_nb);

I would say either wrap this atomic_notificer_chain_unregister()
call in a trivial function ramoops_unprepare(), or (preferably) get rid of ramoops_prepare().

>  }
>  module_exit(ramoops_exit);
>  
> diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h 
> index 9c9d6c1..826a35b 100644
> --- a/include/linux/pstore_ram.h
> +++ b/include/linux/pstore_ram.h
> @@ -52,6 +52,7 @@ struct persistent_ram_zone {
>        size_t old_log_size;
>  };
>  
> +extern void emergency_unlock_console(void);
>  struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
>                        u32 sig, struct persistent_ram_ecc_info *ecc_info,
>                        unsigned int memtype);
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 
> cf8c242..ece645c 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2107,6 +2107,12 @@ void resume_console(void)
>        console_unlock();
>  }
>  
> +void emergency_unlock_console(void)
> +{
> +     resume_console();
> +}
> +EXPORT_SYMBOL(emergency_unlock_console);
> +
>  /**
>   * console_cpu_notify - print deferred console messages after CPU hotplug
>   * @self: notifier struct
> 

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