linux-kernel - Re: [PATCH 4/9] x86/mce: Move machine_check_poll() status checks to helper functions

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Message-ID: <20240603173727.GOZl3_V9eVbm0184Wi@fat_crate.local>
Date: Mon, 3 Jun 2024 19:37:27 +0200
From: Borislav Petkov <bp@...en8.de>
To: Yazen Ghannam <yazen.ghannam@....com>
Cc: linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
	tony.luck@...el.com, x86@...nel.org, avadhut.naik@....com,
	john.allen@....com
Subject: Re: [PATCH 4/9] x86/mce: Move machine_check_poll() status checks to
 helper functions

On Thu, May 23, 2024 at 10:56:36AM -0500, Yazen Ghannam wrote:
> @@ -709,48 +747,9 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
>  		if (!mca_cfg.cmci_disabled)
>  			mce_track_storm(&m);
>  
> -		/* If this entry is not valid, ignore it */
> -		if (!(m.status & MCI_STATUS_VAL))
> +		if (!log_poll_error(flags, &m))
>  			continue;
>  
> -		/*
> -		 * If we are logging everything (at CPU online) or this
> -		 * is a corrected error, then we must log it.
> -		 */
> -		if ((flags & MCP_UC) || !(m.status & MCI_STATUS_UC))
> -			goto log_it;
> -
> -		/*
> -		 * Newer Intel systems that support software error
> -		 * recovery need to make additional checks. Other
> -		 * CPUs should skip over uncorrected errors, but log
> -		 * everything else.
> -		 */

You lost that comment.

> -		if (!mca_cfg.ser) {
> -			if (m.status & MCI_STATUS_UC)
> -				continue;
> -			goto log_it;
> -		}
> -
> -		/* Log "not enabled" (speculative) errors */
> -		if (!(m.status & MCI_STATUS_EN))
> -			goto log_it;
> -
> -		/*
> -		 * Log UCNA (SDM: 15.6.3 "UCR Error Classification")
> -		 * UC == 1 && PCC == 0 && S == 0
> -		 */
> -		if (!(m.status & MCI_STATUS_PCC) && !(m.status & MCI_STATUS_S))
> -			goto log_it;
> -
> -		/*
> -		 * Skip anything else. Presumption is that our read of this
> -		 * bank is racing with a machine check. Leave the log alone
> -		 * for do_machine_check() to deal with it.
> -		 */
> -		continue;
> -
> -log_it:
>  		if (flags & MCP_DONTLOG)
>  			goto clear_it;

Btw, the code looks really weird now:

                if (!log_poll_error(flags, &m))
                        continue;

                if (flags & MCP_DONTLOG)
                        goto clear_it;

i.e.,

1. Should I log it?

2. Should I not log it?

Oh well, it was like that before logically so...

-- 
Regards/Gruss,
    Boris.

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