linux-kernel - Help with YASM

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Message-ID: <97819315-bdbd-147a-f178-71860f00679b@lwfinger.net>
Date:   Sun, 13 Nov 2022 21:34:27 -0600
From:   Larry Finger <Larry.Finger@...inger.net>
To:     LKML <linux-kernel@...r.kernel.org>
Subject: Help with YASM

Hi,

I am the openSUSE maintainer for VirtualBox. A portion of the code is written in 
yasm assembler. There are two sections of the code that refer to external 
globals that now need to be referenced in a position-independent manner. After 
much web searching, I have not found a method that works.

The first code snippet is a jump to an external location. The original code is

     jmp     NAME(dtrace_probe)

Based on a reference that I found, I changed this to

     jmp     [rel dtrace_probe wrt ..got]

This compiles without error, but I have no idea if it would work.

The second reference to an external variable is

     lea     T2, [NAME(g_afParity) wrt rip]

Trying to emulate the above change, I replaced this with

     lea     T2, [rel NAME(g_afParity) wrt rip ..got]

This one generates a compile error that there is a missing "]".

Thanks for any help, or pointers to reference works that I can read.

Larry