linux-kernel - Re: [PATCH 1/1] arm: mm: Export __sync_icache

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Message-ID: <20190417094137.2gkbtinldiwbkvwy@shell.armlinux.org.uk>
Date:   Wed, 17 Apr 2019 10:41:37 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     Heinrich Schuchardt <xypron.glpk@....de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: Re: [PATCH 1/1] arm: mm: Export __sync_icache_dcache() for
 xen-privcmd

On Sun, Apr 14, 2019 at 10:51:09PM -0700, Christoph Hellwig wrote:
> On Sat, Apr 13, 2019 at 06:30:52PM +0200, Heinrich Schuchardt wrote:
> > This patch avoids
> > ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined!
> > observed when compiling v4.19.34.
> > 
> > The xen-privcmd driver, which can be modular, calls set_pte_at()
> > which in turn may call __sync_icache_dcache().
> 
> Maybe that really is a sign that it should not be modular..

This issue has been discussed several times, and this URL gives a list
of all messages on linux-arm-kernel that mention __sync_icache_dcache:

https://archive.armlinux.org.uk/lurker/search/20380101.000000.00000000@ml:linux-arm-kernel,sb:__sync_icache_dcache.en.html

At the beginning of March, Boris Ostrovsky pointed that another solution
is available that does not need architecture private symbols to be
exported.

Since I've already said in a previous thread that I don't want this
function exported, it seems the way forward is pretty obvious.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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