Re: [PATCH v8] RISC-V: enable XIP

From: Guenter Roeck <linux@roeck-us.net>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	Vitaly Wool <vitaly.wool@konsulko.com>
Subject: Re: [PATCH v8] RISC-V: enable XIP
Date: Tue, 27 Apr 2021 20:08:24 -0700	[thread overview]
Message-ID: <20210428030824.GA196954@roeck-us.net> (raw)
In-Reply-To: <20210413063514.23105-1-alex@ghiti.fr>

On Tue, Apr 13, 2021 at 02:35:14AM -0400, Alexandre Ghiti wrote:
> From: Vitaly Wool <vitaly.wool@konsulko.com>
> 
> Introduce XIP (eXecute In Place) support for RISC-V platforms.
> It allows code to be executed directly from non-volatile storage
> directly addressable by the CPU, such as QSPI NOR flash which can
> be found on many RISC-V platforms. This makes way for significant
> optimization of RAM footprint. The XIP kernel is not compressed
> since it has to run directly from flash, so it will occupy more
> space on the non-volatile storage. The physical flash address used
> to link the kernel object files and for storing it has to be known
> at compile time and is represented by a Kconfig option.
> 
> XIP on RISC-V will for the time being only work on MMU-enabled
> kernels.
> 
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> [ Rebase on top of "Move
> kernel mapping outside the linear mapping" ]
> Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>

In next-20210426, when building riscv:allnoconfig or riscv:tinyconfig:

arch/riscv/kernel/setup.c: In function 'setup_arch':
arch/riscv/kernel/setup.c:284:32: error: implicit declaration of function 'XIP_FIXUP'

Guenter