Hi All,
The purpose of this patchset is to suppress the compiler warning (-Wtype-limits).
In function bitmap_set_value(), add explicit check to see if the value being
written into the bitmap does not fall outside the bitmap.
The situation that it is falling outside is never possible in the code
because the boundaries are required to be correct before the function is
called. The responsibility is on the caller for ensuring the boundaries
are correct.
The code change is simply to silence the GCC warning messages
because GCC is not aware that the boundaries have already been checked.
As such, we're better off using __builtin_unreachable() here because we
can avoid the latency of the conditional check entirely.
Michal,
What do you think of [PATCH 4/4]? Is the conditional check needed, and also whether
returning -EINVAL looks good?
Syed Nayyar Waris (4):
bitmap: Modify bitmap_set_value() to check bitmap length
lib/test_bitmap.c: Modify for_each_set_clump test
gpio: xilinx: Modify bitmap_set_value() calls
gpio: xilinx: Add extra check if sum of widths exceed 64
drivers/gpio/gpio-xilinx.c | 18 ++++++++++++------
include/linux/bitmap.h | 35 +++++++++++++++++++++--------------
lib/test_bitmap.c | 4 ++--
3 files changed, 35 insertions(+), 22 deletions(-)
base-commit: b640c4e12bbe1f0b6383c3ef788a89e5427c763f
--
2.29.0
Add explicit check to see if the value being written into the bitmap
does not fall outside the bitmap.
The situation that it is falling outside would never be possible in the
code because the boundaries are required to be correct before the function
is called. The responsibility is on the caller for ensuring the boundaries
are correct.
This is just to suppress the GCC -Wtype-limits warnings.
Cc: Arnd Bergmann <[email protected]>
Signed-off-by: Syed Nayyar Waris <[email protected]>
Acked-by: William Breathitt Gray <[email protected]>
---
include/linux/bitmap.h | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 386d08777342..efb6199ea1e7 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -78,8 +78,9 @@
* bitmap_get_value(map, start, nbits) Get bit value of size
* 'nbits' from map at start
* bitmap_set_value8(map, value, start) Set 8bit value to map at start
- * bitmap_set_value(map, value, start, nbits) Set bit value of size 'nbits'
- * of map at start
+ * bitmap_set_value(map, nbits, value, value_width, start)
+ * Set bit value of size value_width
+ * to map at start
*
* Note, bitmap_zero() and bitmap_fill() operate over the region of
* unsigned longs, that is, bits behind bitmap till the unsigned long
@@ -610,30 +611,36 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
}
/**
- * bitmap_set_value - set n-bit value within a memory region
+ * bitmap_set_value - set value within a memory region
* @map: address to the bitmap memory region
- * @value: value of nbits
- * @start: bit offset of the n-bit value
- * @nbits: size of value in bits (must be between 1 and BITS_PER_LONG inclusive).
+ * @nbits: size of map in bits
+ * @value: value of clump
+ * @value_width: size of value in bits (must be between 1 and BITS_PER_LONG inclusive)
+ * @start: bit offset of the value
*/
-static inline void bitmap_set_value(unsigned long *map,
- unsigned long value,
- unsigned long start, unsigned long nbits)
+static inline void bitmap_set_value(unsigned long *map, unsigned long nbits,
+ unsigned long value, unsigned long value_width,
+ unsigned long start)
{
- const size_t index = BIT_WORD(start);
+ const unsigned long index = BIT_WORD(start);
+ const unsigned long length = BIT_WORD(nbits);
const unsigned long offset = start % BITS_PER_LONG;
const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG);
const unsigned long space = ceiling - start;
- value &= GENMASK(nbits - 1, 0);
+ value &= GENMASK(value_width - 1, 0);
- if (space >= nbits) {
- map[index] &= ~(GENMASK(nbits - 1, 0) << offset);
+ if (space >= value_width) {
+ map[index] &= ~(GENMASK(value_width - 1, 0) << offset);
map[index] |= value << offset;
} else {
map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start);
map[index + 0] |= value << offset;
- map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits);
+
+ if (index + 1 >= length)
+ __builtin_unreachable();
+
+ map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + value_width);
map[index + 1] |= value >> space;
}
}
--
2.29.0
Modify the bitmap_set_value() calls. bitmap_set_value()
now takes an extra bitmap width as second argument and the width of
value is now present as the fourth argument.
Cc: Michal Simek <[email protected]>
Signed-off-by: Syed Nayyar Waris <[email protected]>
---
drivers/gpio/gpio-xilinx.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index ad4ee4145db4..05dae086c4d0 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -151,16 +151,16 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
spin_lock_irqsave(&chip->gpio_lock[0], flags);
spin_lock(&chip->gpio_lock[1]);
- bitmap_set_value(old, state[0], 0, width[0]);
- bitmap_set_value(old, state[1], width[0], width[1]);
+ bitmap_set_value(old, 64, state[0], width[0], 0);
+ bitmap_set_value(old, 64, state[1], width[1], width[0]);
bitmap_replace(new, old, bits, mask, gc->ngpio);
- bitmap_set_value(old, state[0], 0, 32);
- bitmap_set_value(old, state[1], 32, 32);
+ bitmap_set_value(old, 64, state[0], 32, 0);
+ bitmap_set_value(old, 64, state[1], 32, 32);
state[0] = bitmap_get_value(new, 0, width[0]);
state[1] = bitmap_get_value(new, width[0], width[1]);
- bitmap_set_value(new, state[0], 0, 32);
- bitmap_set_value(new, state[1], 32, 32);
+ bitmap_set_value(new, 64, state[0], 32, 0);
+ bitmap_set_value(new, 64, state[1], 32, 32);
bitmap_xor(changed, old, new, 64);
if (((u32 *)changed)[0])
--
2.29.0
Modify the test where bitmap_set_value() is called. bitmap_set_value()
now takes an extra bitmap-width as second argument and the width of
value is now present as the fourth argument.
Signed-off-by: Syed Nayyar Waris <[email protected]>
---
lib/test_bitmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 1c5791ff02cb..7fafe6a0bc08 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -656,8 +656,8 @@ static void __init prepare_test_data(unsigned int index)
unsigned long width = 0;
for (i = 0; i < clump_test_data[index].count; i++) {
- bitmap_set_value(clump_test_data[index].data,
- clump_bitmap_data[(clump_test_data[index].offset)++], width, 32);
+ bitmap_set_value(clump_test_data[index].data, 256,
+ clump_bitmap_data[(clump_test_data[index].offset)++], 32, width);
width += 32;
}
}
--
2.29.0
Add extra check to see if sum of widths does not exceed 64. If it
exceeds then return -EINVAL alongwith appropriate error message.
Cc: Michal Simek <[email protected]>
Signed-off-by: Syed Nayyar Waris <[email protected]>
---
drivers/gpio/gpio-xilinx.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index 05dae086c4d0..a2e92a1cf50b 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -340,6 +340,12 @@ static int xgpio_probe(struct platform_device *pdev)
chip->gc.base = -1;
chip->gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
+
+ if (chip->gc.ngpio > 64) {
+ dev_err(&pdev->dev, "invalid configuration: number of GPIO is greater than 64");
+ return -EINVAL;
+ }
+
chip->gc.parent = &pdev->dev;
chip->gc.direction_input = xgpio_dir_in;
chip->gc.direction_output = xgpio_dir_out;
--
2.29.0
On Fri, Nov 20, 2020 at 11:14:16PM +0530, Syed Nayyar Waris wrote:
> Add explicit check to see if the value being written into the bitmap
> does not fall outside the bitmap.
> The situation that it is falling outside would never be possible in the
> code because the boundaries are required to be correct before the function
> is called. The responsibility is on the caller for ensuring the boundaries
> are correct.
> This is just to suppress the GCC -Wtype-limits warnings.
Hi Syed,
This commit message sounds a bit strange without the context of our
earlier discussion thread. Would you be able to reword the commit
message to explain the motivation for using __builtin_unreachable()?
Thanks,
William Breathitt Gray
>
> Cc: Arnd Bergmann <[email protected]>
> Signed-off-by: Syed Nayyar Waris <[email protected]>
> Acked-by: William Breathitt Gray <[email protected]>
> ---
> include/linux/bitmap.h | 35 +++++++++++++++++++++--------------
> 1 file changed, 21 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> index 386d08777342..efb6199ea1e7 100644
> --- a/include/linux/bitmap.h
> +++ b/include/linux/bitmap.h
> @@ -78,8 +78,9 @@
> * bitmap_get_value(map, start, nbits) Get bit value of size
> * 'nbits' from map at start
> * bitmap_set_value8(map, value, start) Set 8bit value to map at start
> - * bitmap_set_value(map, value, start, nbits) Set bit value of size 'nbits'
> - * of map at start
> + * bitmap_set_value(map, nbits, value, value_width, start)
> + * Set bit value of size value_width
> + * to map at start
> *
> * Note, bitmap_zero() and bitmap_fill() operate over the region of
> * unsigned longs, that is, bits behind bitmap till the unsigned long
> @@ -610,30 +611,36 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
> }
>
> /**
> - * bitmap_set_value - set n-bit value within a memory region
> + * bitmap_set_value - set value within a memory region
> * @map: address to the bitmap memory region
> - * @value: value of nbits
> - * @start: bit offset of the n-bit value
> - * @nbits: size of value in bits (must be between 1 and BITS_PER_LONG inclusive).
> + * @nbits: size of map in bits
> + * @value: value of clump
> + * @value_width: size of value in bits (must be between 1 and BITS_PER_LONG inclusive)
> + * @start: bit offset of the value
> */
> -static inline void bitmap_set_value(unsigned long *map,
> - unsigned long value,
> - unsigned long start, unsigned long nbits)
> +static inline void bitmap_set_value(unsigned long *map, unsigned long nbits,
> + unsigned long value, unsigned long value_width,
> + unsigned long start)
> {
> - const size_t index = BIT_WORD(start);
> + const unsigned long index = BIT_WORD(start);
> + const unsigned long length = BIT_WORD(nbits);
> const unsigned long offset = start % BITS_PER_LONG;
> const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG);
> const unsigned long space = ceiling - start;
>
> - value &= GENMASK(nbits - 1, 0);
> + value &= GENMASK(value_width - 1, 0);
>
> - if (space >= nbits) {
> - map[index] &= ~(GENMASK(nbits - 1, 0) << offset);
> + if (space >= value_width) {
> + map[index] &= ~(GENMASK(value_width - 1, 0) << offset);
> map[index] |= value << offset;
> } else {
> map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start);
> map[index + 0] |= value << offset;
> - map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits);
> +
> + if (index + 1 >= length)
> + __builtin_unreachable();
> +
> + map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + value_width);
> map[index + 1] |= value >> space;
> }
> }
> --
> 2.29.0
>
On Fri, Nov 20, 2020 at 11:29 PM William Breathitt Gray
<[email protected]> wrote:
>
> On Fri, Nov 20, 2020 at 11:14:16PM +0530, Syed Nayyar Waris wrote:
> > Add explicit check to see if the value being written into the bitmap
> > does not fall outside the bitmap.
> > The situation that it is falling outside would never be possible in the
> > code because the boundaries are required to be correct before the function
> > is called. The responsibility is on the caller for ensuring the boundaries
> > are correct.
> > This is just to suppress the GCC -Wtype-limits warnings.
>
> Hi Syed,
>
> This commit message sounds a bit strange without the context of our
> earlier discussion thread. Would you be able to reword the commit
> message to explain the motivation for using __builtin_unreachable()?
>
> Thanks,
>
> William Breathitt Gray
Hi William,
Actually I explained the motivation for using __builtin_unreachable()
in the cover letter.
So, left it here in this patch.
I am sending this patch again updating the commit message.
Regards
Syed Nayyar Waris
>
> >
> > Cc: Arnd Bergmann <[email protected]>
> > Signed-off-by: Syed Nayyar Waris <[email protected]>
> > Acked-by: William Breathitt Gray <[email protected]>
> > ---
> > include/linux/bitmap.h | 35 +++++++++++++++++++++--------------
> > 1 file changed, 21 insertions(+), 14 deletions(-)
> >
> > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> > index 386d08777342..efb6199ea1e7 100644
> > --- a/include/linux/bitmap.h
> > +++ b/include/linux/bitmap.h
> > @@ -78,8 +78,9 @@
> > * bitmap_get_value(map, start, nbits) Get bit value of size
> > * 'nbits' from map at start
> > * bitmap_set_value8(map, value, start) Set 8bit value to map at start
> > - * bitmap_set_value(map, value, start, nbits) Set bit value of size 'nbits'
> > - * of map at start
> > + * bitmap_set_value(map, nbits, value, value_width, start)
> > + * Set bit value of size value_width
> > + * to map at start
> > *
> > * Note, bitmap_zero() and bitmap_fill() operate over the region of
> > * unsigned longs, that is, bits behind bitmap till the unsigned long
> > @@ -610,30 +611,36 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
> > }
> >
> > /**
> > - * bitmap_set_value - set n-bit value within a memory region
> > + * bitmap_set_value - set value within a memory region
> > * @map: address to the bitmap memory region
> > - * @value: value of nbits
> > - * @start: bit offset of the n-bit value
> > - * @nbits: size of value in bits (must be between 1 and BITS_PER_LONG inclusive).
> > + * @nbits: size of map in bits
> > + * @value: value of clump
> > + * @value_width: size of value in bits (must be between 1 and BITS_PER_LONG inclusive)
> > + * @start: bit offset of the value
> > */
> > -static inline void bitmap_set_value(unsigned long *map,
> > - unsigned long value,
> > - unsigned long start, unsigned long nbits)
> > +static inline void bitmap_set_value(unsigned long *map, unsigned long nbits,
> > + unsigned long value, unsigned long value_width,
> > + unsigned long start)
> > {
> > - const size_t index = BIT_WORD(start);
> > + const unsigned long index = BIT_WORD(start);
> > + const unsigned long length = BIT_WORD(nbits);
> > const unsigned long offset = start % BITS_PER_LONG;
> > const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG);
> > const unsigned long space = ceiling - start;
> >
> > - value &= GENMASK(nbits - 1, 0);
> > + value &= GENMASK(value_width - 1, 0);
> >
> > - if (space >= nbits) {
> > - map[index] &= ~(GENMASK(nbits - 1, 0) << offset);
> > + if (space >= value_width) {
> > + map[index] &= ~(GENMASK(value_width - 1, 0) << offset);
> > map[index] |= value << offset;
> > } else {
> > map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start);
> > map[index + 0] |= value << offset;
> > - map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits);
> > +
> > + if (index + 1 >= length)
> > + __builtin_unreachable();
> > +
> > + map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + value_width);
> > map[index + 1] |= value >> space;
> > }
> > }
> > --
> > 2.29.0
> >
On Fri, Nov 20, 2020 at 7:46 PM Syed Nayyar Waris <[email protected]> wrote:
>
> Modify the bitmap_set_value() calls. bitmap_set_value()
> now takes an extra bitmap width as second argument and the width of
> value is now present as the fourth argument.
>
> Cc: Michal Simek <[email protected]>
> Signed-off-by: Syed Nayyar Waris <[email protected]>
> ---
> drivers/gpio/gpio-xilinx.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index ad4ee4145db4..05dae086c4d0 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -151,16 +151,16 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
> spin_lock_irqsave(&chip->gpio_lock[0], flags);
> spin_lock(&chip->gpio_lock[1]);
>
> - bitmap_set_value(old, state[0], 0, width[0]);
> - bitmap_set_value(old, state[1], width[0], width[1]);
> + bitmap_set_value(old, 64, state[0], width[0], 0);
> + bitmap_set_value(old, 64, state[1], width[1], width[0]);
> bitmap_replace(new, old, bits, mask, gc->ngpio);
>
> - bitmap_set_value(old, state[0], 0, 32);
> - bitmap_set_value(old, state[1], 32, 32);
> + bitmap_set_value(old, 64, state[0], 32, 0);
> + bitmap_set_value(old, 64, state[1], 32, 32);
> state[0] = bitmap_get_value(new, 0, width[0]);
> state[1] = bitmap_get_value(new, width[0], width[1]);
> - bitmap_set_value(new, state[0], 0, 32);
> - bitmap_set_value(new, state[1], 32, 32);
> + bitmap_set_value(new, 64, state[0], 32, 0);
> + bitmap_set_value(new, 64, state[1], 32, 32);
> bitmap_xor(changed, old, new, 64);
>
> if (((u32 *)changed)[0])
> --
> 2.29.0
>
This series is not bisectable because you modify the interface -
breaking existing users - and you only fix them later. Please squash
those changes into a single commit.
Bartosz
On Tue, Dec 1, 2020 at 9:03 PM Bartosz Golaszewski
<[email protected]> wrote:
>
> On Fri, Nov 20, 2020 at 7:46 PM Syed Nayyar Waris <[email protected]> wrote:
> >
> > Modify the bitmap_set_value() calls. bitmap_set_value()
> > now takes an extra bitmap width as second argument and the width of
> > value is now present as the fourth argument.
> >
> > Cc: Michal Simek <[email protected]>
> > Signed-off-by: Syed Nayyar Waris <[email protected]>
> > ---
> > drivers/gpio/gpio-xilinx.c | 12 ++++++------
> > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> > index ad4ee4145db4..05dae086c4d0 100644
> > --- a/drivers/gpio/gpio-xilinx.c
> > +++ b/drivers/gpio/gpio-xilinx.c
> > @@ -151,16 +151,16 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
> > spin_lock_irqsave(&chip->gpio_lock[0], flags);
> > spin_lock(&chip->gpio_lock[1]);
> >
> > - bitmap_set_value(old, state[0], 0, width[0]);
> > - bitmap_set_value(old, state[1], width[0], width[1]);
> > + bitmap_set_value(old, 64, state[0], width[0], 0);
> > + bitmap_set_value(old, 64, state[1], width[1], width[0]);
> > bitmap_replace(new, old, bits, mask, gc->ngpio);
> >
> > - bitmap_set_value(old, state[0], 0, 32);
> > - bitmap_set_value(old, state[1], 32, 32);
> > + bitmap_set_value(old, 64, state[0], 32, 0);
> > + bitmap_set_value(old, 64, state[1], 32, 32);
> > state[0] = bitmap_get_value(new, 0, width[0]);
> > state[1] = bitmap_get_value(new, width[0], width[1]);
> > - bitmap_set_value(new, state[0], 0, 32);
> > - bitmap_set_value(new, state[1], 32, 32);
> > + bitmap_set_value(new, 64, state[0], 32, 0);
> > + bitmap_set_value(new, 64, state[1], 32, 32);
> > bitmap_xor(changed, old, new, 64);
> >
> > if (((u32 *)changed)[0])
> > --
> > 2.29.0
> >
>
> This series is not bisectable because you modify the interface -
> breaking existing users - and you only fix them later. Please squash
> those changes into a single commit.
>
> Bartosz
Hi Bartosz,
I have squashed the changes and have sent a new patchset v2.
Regards
Syed Nayyar Waris