linux-kernel - Re: [PATCH] riscv: export flush_icache

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Message-ID: <alpine.DEB.2.21.9999.1912200302290.3767@viisi.sifive.com>
Date:   Fri, 20 Dec 2019 03:05:04 -0800 (PST)
From:   Paul Walmsley <paul.walmsley@...ive.com>
To:     Olof Johansson <olof@...om.net>
cc:     Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        hch@....de
Subject: Re: [PATCH] riscv: export flush_icache_all to modules

On Mon, 16 Dec 2019, Olof Johansson wrote:

> This is needed by LKDTM (crash dump test module), it calls
> flush_icache_range(), which on RISC-V turns into flush_icache_all(). On
> other architectures, the actual implementation is exported, so follow
> that precedence and export it here too.
> 
> Fixes build of CONFIG_LKDTM that fails with:
> ERROR: "flush_icache_all" [drivers/misc/lkdtm/lkdtm.ko] undefined!

In the past we've resisted doing this; see 

https://lore.kernel.org/linux-riscv/20190611134945.GA28532@lst.de/

under the principle that we don't want modules to be able to flush the I$ 
directly via this interface.  But maybe, like moving the L2 related code 
out of arch/riscv, we should just do it.


- Paul