linux-kernel - Re: [RESEND PATCH v3 1/2] efi/cper: add cper_mem_err_status

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Date:   Mon, 24 Jan 2022 22:16:34 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Shuai Xue <xueshuai@...ux.alibaba.com>
Cc:     rric@...nel.org, mchehab@...nel.org, tony.luck@...el.com,
        james.morse@....com, ardb@...nel.org, linux-edac@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
        zhangliguang@...ux.alibaba.com, zhuo.song@...ux.alibaba.com
Subject: Re: [RESEND PATCH v3 1/2] efi/cper: add cper_mem_err_status_str to
 decode error description

On Mon, Jan 24, 2022 at 10:47:58AM +0800, Shuai Xue wrote:
> Introduce a new helper function cper_mem_err_status_str() which is used to
> decode the description of error status, and the cper_print_mem() will call
> it and report the details of error status.
> 
> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
> ---
>  drivers/firmware/efi/cper.c | 46 ++++++++++++++++++++++++++++++++++++-
>  include/linux/cper.h        |  1 +
>  2 files changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
> index 6ec8edec6329..addafccecd84 100644
> --- a/drivers/firmware/efi/cper.c
> +++ b/drivers/firmware/efi/cper.c
> @@ -211,6 +211,49 @@ const char *cper_mem_err_type_str(unsigned int etype)
>  }
>  EXPORT_SYMBOL_GPL(cper_mem_err_type_str);
>  
> +const char *cper_mem_err_status_str(u64 status)
> +{
> +	switch ((status >> 8) & 0xff) {
> +	case 1:
> +		return "Error detected internal to the component";

You can make that table a lot more compact:

        switch ((status >> 8) & 0xff) {
        case  1:        return "Error detected internal to the component";
        case  4:        return "Storage error in DRAM memory";
        case  5:        return "Storage error in TLB";
        case  6:        return "Storage error in cache";
        case  7:        return "Error in one or more functional units";
        case  8:        return "component failed self test";
        case  9:        return "Overflow or undervalue of internal queue";
        case 16:        return "Error detected in the bus";
	...

> +	case 16:
> +		return "Error detected in the bus";

And yes, that 16 needs to come before 17, ofc.

> @@ -334,7 +377,8 @@ static void cper_print_mem(const char *pfx, const struct cper_sec_mem_err *mem,
>  		return;
>  	}
>  	if (mem->validation_bits & CPER_MEM_VALID_ERROR_STATUS)
> -		printk("%s""error_status: 0x%016llx\n", pfx, mem->error_status);
> +		printk("%s""error_status: 0x%016llx, %s\n", pfx, mem->error_status,
> +				cper_mem_err_status_str(mem->error_status));

Arguments need to be aligned at opening brace, i.e.:

                printk("%s""error_status: 0x%016llx, %s\n",
                        pfx, mem->error_status, cper_mem_err_status_str(mem->error_status));


Also, the naked error status number is not as user-friendly when we have
the decoded string. So the format should be:

                printk("%s error_status: %s (0x%016llx)\n",
                        pfx, cper_mem_err_status_str(mem->error_status), mem->error_status);

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette