Re: [PATCH v2 6/8] remoteproc: Introduce "panic" callback in ops

From: Arnaud POULIQUEN
Date: Thu Jan 30 2020 - 05:07:35 EST


Hi Bjorn,

On 1/10/20 10:23 PM, Mathieu Poirier wrote:
> On Thu, Dec 26, 2019 at 09:32:13PM -0800, Bjorn Andersson wrote:
>> Introduce a "panic" function in the remoteproc ops table, to allow
>> remoteproc instances to perform operations needed in order to aid in
>> post mortem system debugging, such as flushing caches etc, when the
>> kernel panics.
>>
>> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
>> ---
>>
>> Changes since v1:
>> - None
>>
>> drivers/remoteproc/remoteproc_core.c | 17 +++++++++++++++++
>> include/linux/remoteproc.h | 4 ++++
>> 2 files changed, 21 insertions(+)
>>
>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>> index 307df98347ba..779f19d6d8e7 100644
>> --- a/drivers/remoteproc/remoteproc_core.c
>> +++ b/drivers/remoteproc/remoteproc_core.c
>> @@ -1832,6 +1832,17 @@ void rproc_shutdown(struct rproc *rproc)
>> }
>> EXPORT_SYMBOL(rproc_shutdown);
>>
>> +static int rproc_panic_handler(struct notifier_block *nb, unsigned long event,
>> + void *ptr)
>> +{
>> + struct rproc *rproc = container_of(nb, struct rproc, panic_nb);
>> +
>> + if (rproc->state == RPROC_RUNNING)
>> + rproc->ops->panic(rproc);
>> +
>> + return NOTIFY_DONE;
>> +}
>> +
>> /**
>> * rproc_get_by_phandle() - find a remote processor by phandle
>> * @phandle: phandle to the rproc
>> @@ -2057,6 +2068,12 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
>> rproc->ops->get_boot_addr = rproc_elf_get_boot_addr;
>> }
>>
>> + /* Register panic notifier for remoteprocs with "panic" callback */
>> + if (rproc->ops->panic) {
>> + rproc->panic_nb.notifier_call = rproc_panic_handler;
>> + atomic_notifier_chain_register(&panic_notifier_list, &rproc->panic_nb);
>
> Line over 80 characters.
atomic_notifier_chain_unregister should be added in rproc_del.

Regards,
Arnaud
>
>> + }
>> +
>> mutex_init(&rproc->lock);
>>
>> idr_init(&rproc->notifyids);
>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>> index 16ad66683ad0..7836c528d309 100644
>> --- a/include/linux/remoteproc.h
>> +++ b/include/linux/remoteproc.h
>> @@ -369,6 +369,7 @@ enum rsc_handling_status {
>> * expects to find it
>> * @sanity_check: sanity check the fw image
>> * @get_boot_addr: get boot address to entry point specified in firmware
>> + * @panic: optional callback to react to system panic
>> */
>> struct rproc_ops {
>> int (*start)(struct rproc *rproc);
>> @@ -383,6 +384,7 @@ struct rproc_ops {
>> int (*load)(struct rproc *rproc, const struct firmware *fw);
>> int (*sanity_check)(struct rproc *rproc, const struct firmware *fw);
>> u32 (*get_boot_addr)(struct rproc *rproc, const struct firmware *fw);
>> + void (*panic)(struct rproc *rproc);
>> };
>>
>> /**
>> @@ -481,6 +483,7 @@ struct rproc_dump_segment {
>> * @auto_boot: flag to indicate if remote processor should be auto-started
>> * @dump_segments: list of segments in the firmware
>> * @nb_vdev: number of vdev currently handled by rproc
>> + * @panic_nb: notifier_block for remoteproc's panic handler
>> */
>> struct rproc {
>> struct list_head node;
>> @@ -514,6 +517,7 @@ struct rproc {
>> bool auto_boot;
>> struct list_head dump_segments;
>> int nb_vdev;
>> + struct notifier_block panic_nb;
>> };
>>
>> /**
>> --
>> 2.24.0
>>