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Date:   Wed, 2 Nov 2022 12:21:23 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     William Breathitt Gray <william.gray@linaro.org>,
        linux-iio@vger.kernel.org,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Sami Tolvanen <samitolvanen@google.com>, llvm@lists.linux.dev,
        linux-kernel@vger.kernel.org, patches@lists.linux.dev,
        Patrick Havelange <patrick.havelange@essensium.com>,
        Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Oleksij Rempel <linux@rempel-privat.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Julien Panis <jpanis@baylibre.com>,
        David Lechner <david@lechnology.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-omap@vger.kernel.org
Subject: Re: [PATCH 1/4] counter: Adjust final parameter type in function and
 signal callbacks
Message-ID: <202211021216.FF49E84C69@keescook>
References: <20221102172217.2860740-1-nathan@kernel.org>
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On Wed, Nov 02, 2022 at 10:22:14AM -0700, Nathan Chancellor wrote:
> The ->signal_u32_read(), ->count_u32_read(), and ->count_u32_write()
> callbacks in 'struct counter_comp' expect the final parameter to have a
> type of 'u32' or 'u32 *' but the ops functions that are being assigned
> to those callbacks have an enumerated type as the final parameter. While
> these are compatible from an ABI perspective, they will fail the
> aforementioned CFI checks.
> 
> Adjust the type of the final parameter in the ->signal_read(),
> ->function_read(), and ->function_write() callbacks in 'struct
> counter_ops' and their implementations to match the prototypes in
> 'struct counter_comp' to clear up these warnings and CFI failures.

I don't understand these changes. Where do 'struct counter_comp'
and 'struct counter_ops' get confused? I can only find matching
ops/assignments/calls, so I must be missing something. This looks like
a loss of CFI granularity instead of having wrappers added if there is
an enum/u32 conversion needed somewhere.

-- 
Kees Cook