Re: [PATCH 1/1] arm: mm: Export __sync_icache_dcache() for xen-privcmd

From: Russell King - ARM Linux admin
Date: Wed Apr 17 2019 - 05:41:47 EST


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/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up