linux-kernel - Re: [PATCH] ACPI: APEI: EINJ: warn on invalid argument when explicitly indicated by platform

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Message-ID: <78481cfe-ce74-58c4-20ab-caf6de0c4125@linux.alibaba.com>
Date:   Wed, 22 Mar 2023 10:37:34 +0800
From:   Shuai Xue <xueshuai@...ux.alibaba.com>
To:     "Luck, Tony" <tony.luck@...el.com>
Cc:     "baolin.wang@...ux.alibaba.com" <baolin.wang@...ux.alibaba.com>,
        "benjamin.cheatham@....com" <benjamin.cheatham@....com>,
        "bp@...en8.de" <bp@...en8.de>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        "james.morse@....com" <james.morse@....com>,
        "jaylu102@....com" <jaylu102@....com>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "rafael@...nel.org" <rafael@...nel.org>,
        "zhuo.song@...ux.alibaba.com" <zhuo.song@...ux.alibaba.com>
Subject: Re: [PATCH] ACPI: APEI: EINJ: warn on invalid argument when
 explicitly indicated by platform



On 2023/3/22 AM12:09, Luck, Tony wrote:
>> Actually, firmware will do some platform dependent sanity checks and returns
>> different error codes. In this case, user injects to a invalid device, platform
>> returns "Invalid Access". And user is expected to see:
>>
>> 	# select a invalid core or device to inject
>> 	# echo 1 > error_inject
>> 	echo: write error: Invalid argument
>>
>> Then user is expected to check his injection argument first.
> 
> Thanks. This makes sense. You want EINVAL when the user chose
> bad arguments, and some other code for problem in BIOS.

Yes, exactly.

> 
> If the BIOS has an issue, is it possible, or likely, that it is a temporary
> problem? If so, EBUSY may be OK. The message " Device or resource busy"
> might encourage the user to wait and try again.
> 
> If it is not going to get better by itself, then one of:
> 
> #define EIO              5      /* I/O error */
> #define ENXIO            6      /* No such device or address */
> 
> might be a better choice.

Yes, BIOS may temporarily not complete error injection (ACPI_EINJ_EXECUTE_OPERATION)
on time, in which case, kernel return EIO.

	for (;;) {
		rc = apei_exec_run(&ctx, ACPI_EINJ_CHECK_BUSY_STATUS);
		if (rc)
			return rc;
		val = apei_exec_ctx_get_output(&ctx);
		if (!(val & EINJ_OP_BUSY))
			break;
		if (einj_timedout(&timeout))
			return -EIO;

In summary, you are asking that:

- report -EINVAL for "Invalid Access" case
- keeps reporting -EBUSY for "Unknown Failure" case unchanged.
- and keeps EIO for temporarily time out unchanged.

right? (This patch is doing so)

> 
> -Tony

Thanks.

Best Regards,
Shuai