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Message-ID: <66b4fb4f-35cc-1ebb-1d43-c2f942937670@samsung.com>
Date: Tue, 10 Jan 2023 23:09:11 +0100
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: Rob Barnes <robbarnes@...gle.com>, groeck@...omium.org,
pmalani@...omium.org
Cc: chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org,
dtor@...omium.org
Subject: Re: [PATCH v3 1/2] platform/chrome: cros_ec: Poll EC log on EC
panic
Hi Rob,
On 04.01.2023 02:15, Rob Barnes wrote:
> Add handler for CrOS EC panic events. When a panic is reported,
> immediately poll for EC log.
>
> This should result in the log leading to the EC panic being
> preserved.
>
> ACPI_NOTIFY_CROS_EC_PANIC is defined in coreboot at
> https://review.coreboot.org/plugins/gitiles/coreboot/+/refs/heads/master/src/ec/google/chromeec/acpi/ec.asl
>
> Signed-off-by: Rob Barnes <robbarnes@...gle.com>
This patch landed in today's linux-next as commit d90fa2c64d59
("platform/chrome: cros_ec: Poll EC log on EC panic"). Unfortunately it
introduces the following runtime warning on my test systems:
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 0 PID: 62 Comm: kworker/u16:1 Not tainted
6.2.0-rc3-next-20230110-00037-g7c2b0426386a #6112
Hardware name: Samsung Exynos (Flattened Device Tree)
Workqueue: events_unbound async_run_entry_fn
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x58/0x70
dump_stack_lvl from register_lock_class+0x998/0x9a8
register_lock_class from __lock_acquire+0x6c/0x2a80
__lock_acquire from lock_acquire+0x124/0x3f0
lock_acquire from down_write+0x40/0xd8
down_write from blocking_notifier_chain_register+0x28/0x58
blocking_notifier_chain_register from cros_ec_debugfs_probe+0x324/0x3b4
cros_ec_debugfs_probe from platform_probe+0x5c/0xb8
platform_probe from really_probe+0xe0/0x414
really_probe from __driver_probe_device+0x9c/0x200
__driver_probe_device from driver_probe_device+0x30/0xc0
driver_probe_device from __device_attach_driver+0xa8/0x120
__device_attach_driver from bus_for_each_drv+0x7c/0xc0
bus_for_each_drv from __device_attach_async_helper+0xa0/0xf4
__device_attach_async_helper from async_run_entry_fn+0x40/0x154
async_run_entry_fn from process_one_work+0x288/0x790
process_one_work from worker_thread+0x44/0x504
worker_thread from kthread+0xf0/0x124
kthread from ret_from_fork+0x14/0x2c
Exception stack(0xf0a6dfb0 to 0xf0a6dff8)
...
------------[ cut here ]------------
That's because the panic_notifier entry is not initialized to the sane
value. Adding the following line:
BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->panic_notifier);
to drivers/platform/chrome/cros_ec.c to cros_ec_register() function
fixes the issue. I will send the incremental fix in a few minutes.
> ---
>
> Changelog since v1:
> - Split into two patches
> - Moved panic handle before mkbp loop
> - Switched to dev_emerg message
>
> drivers/platform/chrome/cros_ec_debugfs.c | 23 +++++++++++++++++++++
> drivers/platform/chrome/cros_ec_lpc.c | 7 +++++++
> include/linux/platform_data/cros_ec_proto.h | 9 ++++++++
> 3 files changed, 39 insertions(+)
>
> diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
> index 21d973fc6be2..34f7b46f8761 100644
> --- a/drivers/platform/chrome/cros_ec_debugfs.c
> +++ b/drivers/platform/chrome/cros_ec_debugfs.c
> @@ -49,6 +49,7 @@ struct cros_ec_debugfs {
> struct delayed_work log_poll_work;
> /* EC panicinfo */
> struct debugfs_blob_wrapper panicinfo_blob;
> + struct notifier_block notifier_panic;
> };
>
> /*
> @@ -437,6 +438,22 @@ static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
> return ret;
> }
>
> +static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
> + unsigned long queued_during_suspend, void *_notify)
> +{
> + struct cros_ec_debugfs *debug_info =
> + container_of(nb, struct cros_ec_debugfs, notifier_panic);
> +
> + if (debug_info->log_buffer.buf) {
> + /* Force log poll work to run immediately */
> + mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
> + /* Block until log poll work finishes */
> + flush_delayed_work(&debug_info->log_poll_work);
> + }
> +
> + return NOTIFY_DONE;
> +}
> +
> static int cros_ec_debugfs_probe(struct platform_device *pd)
> {
> struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
> @@ -473,6 +490,12 @@ static int cros_ec_debugfs_probe(struct platform_device *pd)
> debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
> &ec->ec_dev->suspend_timeout_ms);
>
> + debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
> + ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
> + &debug_info->notifier_panic);
> + if (ret)
> + goto remove_debugfs;
> +
> ec->debug_info = debug_info;
>
> dev_set_drvdata(&pd->dev, ec);
> diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
> index 7fc8f82280ac..5738f1d25091 100644
> --- a/drivers/platform/chrome/cros_ec_lpc.c
> +++ b/drivers/platform/chrome/cros_ec_lpc.c
> @@ -320,6 +320,13 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
>
> ec_dev->last_event_time = cros_ec_get_time_ns();
>
> + if (value == ACPI_NOTIFY_CROS_EC_PANIC) {
> + dev_emerg(ec_dev->dev, "CrOS EC Panic Reported. Shutdown is imminent!");
> + blocking_notifier_call_chain(&ec_dev->panic_notifier, 0, ec_dev);
> + /* Do not query for other events after a panic is reported */
> + return;
> + }
> +
> if (ec_dev->mkbp_event_supported)
> do {
> ret = cros_ec_get_next_event(ec_dev, NULL,
> diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
> index e43107e0bee1..7fb2196f99b0 100644
> --- a/include/linux/platform_data/cros_ec_proto.h
> +++ b/include/linux/platform_data/cros_ec_proto.h
> @@ -41,6 +41,13 @@
> #define EC_MAX_REQUEST_OVERHEAD 1
> #define EC_MAX_RESPONSE_OVERHEAD 32
>
> +/*
> + * EC panic is not covered by the standard (0-F) ACPI notify values.
> + * Arbitrarily choosing B0 to notify ec panic, which is in the 84-BF
> + * device specific ACPI notify range.
> + */
> +#define ACPI_NOTIFY_CROS_EC_PANIC 0xB0
> +
> /*
> * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
> */
> @@ -176,6 +183,8 @@ struct cros_ec_device {
> /* The platform devices used by the mfd driver */
> struct platform_device *ec;
> struct platform_device *pd;
> +
> + struct blocking_notifier_head panic_notifier;
> };
>
> /**
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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