2022-07-21 08:35:39

by Srinivas Neeli

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Subject: [PATCH] gpio: gpio-xilinx: Fix integer overflow

Current implementation is not able to configure more than 32 pins
due to incorrect data type. So type casting with unsigned long
to avoid it.

Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")
Signed-off-by: Srinivas Neeli <[email protected]>
---
drivers/gpio/gpio-xilinx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index b6d3a57e27ed..7f8e2fed2988 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);

map[index] &= ~(0xFFFFFFFFul << offset);
- map[index] |= v << offset;
+ map[index] |= (unsigned long)v << offset;
}

static inline int xgpio_regoffset(struct xgpio_instance *chip, int ch)
--
2.17.1


2022-07-22 07:32:06

by Bartosz Golaszewski

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Subject: Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
<[email protected]> wrote:
>
> Current implementation is not able to configure more than 32 pins
> due to incorrect data type. So type casting with unsigned long
> to avoid it.
>
> Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")
> Signed-off-by: Srinivas Neeli <[email protected]>
> ---
> drivers/gpio/gpio-xilinx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index b6d3a57e27ed..7f8e2fed2988 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
> const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);
>
> map[index] &= ~(0xFFFFFFFFul << offset);
> - map[index] |= v << offset;
> + map[index] |= (unsigned long)v << offset;
> }
>
> static inline int xgpio_regoffset(struct xgpio_instance *chip, int ch)
> --
> 2.17.1
>

Applied, thanks!

Bart

2022-07-25 20:13:12

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

On Fri, Jul 22, 2022 at 9:19 AM Bartosz Golaszewski <[email protected]> wrote:
> On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
> <[email protected]> wrote:
> >
> > Current implementation is not able to configure more than 32 pins
> > due to incorrect data type. So type casting with unsigned long
> > to avoid it.

> > Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")

It doesn't fix anything, I already reject one such "fix" during
development of this patch. Thanks!

...

> > @@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
> > const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);
> >
> > map[index] &= ~(0xFFFFFFFFul << offset);
> > - map[index] |= v << offset;
> > + map[index] |= (unsigned long)v << offset;
> > }

> Applied, thanks!

False positive.

--
With Best Regards,
Andy Shevchenko

2022-07-25 20:35:59

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

On Mon, Jul 25, 2022 at 10:04 PM Andy Shevchenko
<[email protected]> wrote:
> On Fri, Jul 22, 2022 at 9:19 AM Bartosz Golaszewski <[email protected]> wrote:
> > On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
> > <[email protected]> wrote:
> > >
> > > Current implementation is not able to configure more than 32 pins
> > > due to incorrect data type. So type casting with unsigned long
> > > to avoid it.
>
> > > Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")
>
> It doesn't fix anything, I already reject one such "fix" during
> development of this patch. Thanks!

Sorry, not my day, it was something else that time... See below.

> ...
>
> > > @@ -99,7 +99,7 @@ c
>
> > Applied, thanks!
>
> False positive.

Reading again... You mean that

unsigned long x = y << 32;

wouldn't work?



--
With Best Regards,
Andy Shevchenko

2022-07-25 20:38:28

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

On Mon, Jul 25, 2022 at 10:21 PM Andy Shevchenko
<[email protected]> wrote:
> On Mon, Jul 25, 2022 at 10:04 PM Andy Shevchenko
> <[email protected]> wrote:
> > On Fri, Jul 22, 2022 at 9:19 AM Bartosz Golaszewski <[email protected]> wrote:
> > > On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
> > > <[email protected]> wrote:

...

> Reading again... You mean that
>
> unsigned long x = y << 32;
>
> wouldn't work?

Yeah, I even checked this in asm, and indeed it doesn't work. Don't
know what was that about me...


Thanks for the fix,
Reviewed-by: Andy Shevchenko <[email protected]>


--
With Best Regards,
Andy Shevchenko