linux-kernel - Re: [PATCH v12 16/37] x86/ptrace: Add FRED additional information to the pt

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Message-ID: <20231128085122.GPZWWqCrPYnzB8BqFB@fat_crate.local>
Date:   Tue, 28 Nov 2023 09:51:22 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Xin Li <xin3.li@...el.com>
Cc:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-edac@...r.kernel.org, linux-hyperv@...r.kernel.org,
        kvm@...r.kernel.org, xen-devel@...ts.xenproject.org,
        tglx@...utronix.de, mingo@...hat.com, dave.hansen@...ux.intel.com,
        x86@...nel.org, hpa@...or.com, luto@...nel.org,
        pbonzini@...hat.com, seanjc@...gle.com, peterz@...radead.org,
        jgross@...e.com, ravi.v.shankar@...el.com, mhiramat@...nel.org,
        andrew.cooper3@...rix.com, jiangshanlai@...il.com,
        nik.borisov@...e.com
Subject: Re: [PATCH v12 16/37] x86/ptrace: Add FRED additional information to
 the pt_regs structure

On Mon, Oct 02, 2023 at 11:24:37PM -0700, Xin Li wrote:
> FRED defines additional information in the upper 48 bits of cs/ss
> fields. Therefore add the information definitions into the pt_regs
> structure.
> 
> Specially introduce a new structure fred_ss to denote the FRED flags
> above SS selector, which avoids FRED_SSX_ macros and makes the code
> simpler and easier to read.
> 
> Signed-off-by: H. Peter Anvin (Intel) <hpa@...or.com>

You and hpa need to go through all the patches and figure out who's the
author that's going to land in git.

Because this and others have hpa's SOB first, suggesting he's the
author. However, the mail doesn't start with

From: H. Peter Anvin (Intel) <hpa@...or.com>

and then git will make *you* the author.

> Tested-by: Shan Kang <shan.kang@...el.com>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Xin Li <xin3.li@...el.com>

...

>  	union {
> -		u64	ssx;	// The full 64-bit data slot containing SS
> -		u16	ss;	// SS selector
> +		/* SS selector */
> +		u16		ss;
> +		/* The extended 64-bit data slot containing SS */
> +		u64		ssx;
> +		/* The FRED SS extension */
> +		struct fred_ss	fred_ss;

Aha, sanity about the right comments has come to your mind in this next
patch. :-P

Just do them right in the previous one.

>  	/*
> -	 * Top of stack on IDT systems.
> +	 * Top of stack on IDT systems, while FRED systems have extra fields
> +	 * defined above for storing exception related information, e.g. CR2 or
> +	 * DR6.

Btw, I really appreciate the good commenting - thanks for that!

-- 
Regards/Gruss,
    Boris.

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