From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: linux-renesas-soc@vger.kernel.org,
Mark Brown <broonie@kernel.org>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] spi: sh-msiof: avoid integer overflow in constants
Date: Tue, 30 Jan 2024 11:14:05 +0100 [thread overview]
Message-ID: <CAMuHMdUMeHCCiAkNyJMHTGUSTqewt=AWPUy+beA_kR26vcS8_Q@mail.gmail.com> (raw)
In-Reply-To: <20240130094053.10672-1-wsa+renesas@sang-engineering.com>
Hi Wolfram,
On Tue, Jan 30, 2024 at 10:42 AM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> cppcheck rightfully warned:
>
> drivers/spi/spi-sh-msiof.c:792:28: warning: Signed integer overflow for expression '7<<29'. [integerOverflow]
> sh_msiof_write(p, SIFCTR, SIFCTR_TFWM_1 | SIFCTR_RFWM_1);
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> --- a/drivers/spi/spi-sh-msiof.c
> +++ b/drivers/spi/spi-sh-msiof.c
> @@ -136,14 +136,14 @@ struct sh_msiof_spi_priv {
>
> /* SIFCTR */
> #define SIFCTR_TFWM_MASK GENMASK(31, 29) /* Transmit FIFO Watermark */
> -#define SIFCTR_TFWM_64 (0 << 29) /* Transfer Request when 64 empty stages */
> -#define SIFCTR_TFWM_32 (1 << 29) /* Transfer Request when 32 empty stages */
> -#define SIFCTR_TFWM_24 (2 << 29) /* Transfer Request when 24 empty stages */
> -#define SIFCTR_TFWM_16 (3 << 29) /* Transfer Request when 16 empty stages */
> -#define SIFCTR_TFWM_12 (4 << 29) /* Transfer Request when 12 empty stages */
> -#define SIFCTR_TFWM_8 (5 << 29) /* Transfer Request when 8 empty stages */
> -#define SIFCTR_TFWM_4 (6 << 29) /* Transfer Request when 4 empty stages */
> -#define SIFCTR_TFWM_1 (7 << 29) /* Transfer Request when 1 empty stage */
> +#define SIFCTR_TFWM_64 (0UL << 29) /* Transfer Request when 64 empty stages */
> +#define SIFCTR_TFWM_32 (1UL << 29) /* Transfer Request when 32 empty stages */
> +#define SIFCTR_TFWM_24 (2UL << 29) /* Transfer Request when 24 empty stages */
> +#define SIFCTR_TFWM_16 (3UL << 29) /* Transfer Request when 16 empty stages */
> +#define SIFCTR_TFWM_12 (4UL << 29) /* Transfer Request when 12 empty stages */
> +#define SIFCTR_TFWM_8 (5UL << 29) /* Transfer Request when 8 empty stages */
> +#define SIFCTR_TFWM_4 (6UL << 29) /* Transfer Request when 4 empty stages */
> +#define SIFCTR_TFWM_1 (7UL << 29) /* Transfer Request when 1 empty stage */
> #define SIFCTR_TFUA_MASK GENMASK(26, 20) /* Transmit FIFO Usable Area */
> #define SIFCTR_TFUA_SHIFT 20
> #define SIFCTR_TFUA(i) ((i) << SIFCTR_TFUA_SHIFT)
There is a similar issue with the SIFCTR_RFWM_* definitions below,
but these don't trigger, as no data is shifted into the sign bit.
What about unifying the individual SIFCTR_?FWM_[0-9]* definitions
into SIFCTR_xFWM_[0-9]* instead, and using the bitfield helpers in its
sole user?
- sh_msiof_write(p, SIFCTR, SIFCTR_TFWM_1 | SIFCTR_RFWM_1);
+ sh_msiof_write(p, SIFCTR,
+ FIELD_PREP(SIFCTR_TFWM_MASK, SIFCTR_xFWM_1) |
+ FIELD_PREP(SIFCTR_RFWM_MASK, SIFCTR_xFWM_1);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2024-01-30 10:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 9:40 [PATCH] spi: sh-msiof: avoid integer overflow in constants Wolfram Sang
2024-01-30 10:14 ` Geert Uytterhoeven [this message]
2024-01-30 11:26 ` Wolfram Sang
2024-01-30 11:39 ` Geert Uytterhoeven
2024-01-30 13:40 ` Wolfram Sang
2024-01-30 14:09 ` Geert Uytterhoeven
2024-01-30 19:38 ` Mark Brown
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