Introduce the for_each_set_clump macro
Subsystems (8)
v10 cover Introduce the for_each_set_clump macro
Hello Linus,
Since this patchset primarily affects GPIO drivers, would you like to pick it up through your GPIO tree?
This patchset introduces a new generic version of for_each_set_clump. The previous version of for_each_set_clump8 used a fixed size 8-bit clump, but the new generic version can work with clump of any size but less than or equal to BITS_PER_LONG. The patchset utilizes the new macro in several GPIO drivers.
The earlier 8-bit for_each_set_clump8 facilitated a
for-loop syntax that iterates over a memory region entire groups of set bits at a time.
For example, suppose you would like to iterate over a 32-bit integer 8 bits at a time, skipping over 8-bit groups with no set bit, where XXXXXXXX represents the current 8-bit group:
Example: 10111110 00000000 11111111 00110011
First loop: 10111110 00000000 11111111 XXXXXXXX
Second loop: 10111110 00000000 XXXXXXXX 00110011
Third loop: XXXXXXXX 00000000 11111111 00110011Each iteration of the loop returns the next 8-bit group that has at least one set bit.
But with the new for_each_set_clump the clump size can be different from 8 bits. Moreover, the clump can be split at word boundary in situations where word size is not multiple of clump size. Following are examples showing the working of new macro for clump sizes of 24 bits and 6 bits.
Example 1:
clump size: 24 bits, Number of clumps (or ports): 10
bitmap stores the bit information from where successive clumps are retrieved.
/* bitmap memory region */
0x00aa0000ff000000; /* Most significant bits */
0xaaaaaa0000ff0000;
0x000000aa000000aa;
0xbbbbabcdeffedcba; /* Least significant bits */Different iterations of for_each_set_clump:-
'offset' is the bit position and 'clump' is the 24 bit clump from the above bitmap.
Iteration first: offset: 0 clump: 0xfedcba Iteration second: offset: 24 clump: 0xabcdef Iteration third: offset: 48 clump: 0xaabbbb Iteration fourth: offset: 96 clump: 0xaa Iteration fifth: offset: 144 clump: 0xff Iteration sixth: offset: 168 clump: 0xaaaaaa Iteration seventh: offset: 216 clump: 0xff
Loop breaks because in the end the remaining bits (0x00aa) size was less than clump size of 24 bits.
In above example it can be seen that in iteration third, the 24 bit clump that was retrieved was split between bitmap[0] and bitmap[1]. This example also shows that 24 bit zeroes if present in between, were skipped (preserving the previous for_each_set_macro8 behaviour).
Example 2:
clump size = 6 bits, Number of clumps (or ports) = 3.
/* bitmap memory region */
0x00aa0000ff000000; /* Most significant bits */
0xaaaaaa0000ff0000;
0x0f00000000000000;
0x0000000000000ac0; /* Least significant bits */Different iterations of for_each_set_clump:
'offset' is the bit position and 'clump' is the 6 bit clump from the above bitmap.
Iteration first: offset: 6 clump: 0x2b
Loop breaks because 6 * 3 = 18 bits traversed in bitmap. Here 6 * 3 is clump size * no. of clumps.
Changes in v10:
- Patchset based on v5.9-rc1.
Changes in v9:
- [Patch 4/4]: Remove looping of 'for_each_set_clump' and instead process two halves of a 64-bit bitmap separately or individually. Use normal spin_lock call for second inner lock. And take the spin_lock_init call outside the 'if' condition in the probe function of driver.
Changes in v8:
- [Patch 2/4]: Minor change: Use '__initdata' for correct section mismatch in 'clump_test_data' array.
Changes in v7:
- [Patch 2/4]: Minor changes: Use macro 'DECLARE_BITMAP()' and split 'struct' definition and test data.
Changes in v6:
- [Patch 2/4]: Make 'for loop' inside test_for_each_set_clump more succinct.
Changes in v5:
- [Patch 4/4]: Minor change: Hardcode value for better code readability.
Changes in v4:
- [Patch 2/4]: Use 'for' loop in test function of for_each_set_clump.
- [Patch 3/4]: Minor change: Inline value for better code readability.
- [Patch 4/4]: Minor change: Inline value for better code readability.
Changes in v3:
- [Patch 3/4]: Change datatype of some variables from u64 to unsigned long in function thunderx_gpio_set_multiple.
CHanges in v2:
- [Patch 2/4]: Unify different tests for 'for_each_set_clump'. Pass test data as function parameters.
- [Patch 2/4]: Remove unnecessary bitmap_zero calls.
Syed Nayyar Waris (4):
bitops: Introduce the for_each_set_clump macro lib/test_bitmap.c: Add for_each_set_clump test cases
gpio: thunderx: Utilize for_each_set_clump macro
gpio: xilinx: Utilize generic bitmap_get_value and _set_value
drivers/gpio/gpio-thunderx.c | 11 ++- drivers/gpio/gpio-xilinx.c | 66 +++++++------- include/asm-generic/bitops/find.h | 19 ++++ include/linux/bitmap.h | 61 +++++++++++++ include/linux/bitops.h | 13 +++ lib/find_bit.c | 14 +++ lib/test_bitmap.c | 144 ++++++++++++++++++++++++++++++ 7 files changed, 291 insertions(+), 37 deletions(-)
base-commit: 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5
Signature · 1 line
2.26.2
PATCH v10 1/4 bitops: Introduce the for_each_set_clump macro
This macro iterates for each group of bits (clump) with set bits, within a bitmap memory region. For each iteration, "start" is set to the bit offset of the found clump, while the respective clump value is stored to the location pointed by "clump". Additionally, the bitmap_get_value and bitmap_set_value functions are introduced to respectively get and set a value of n-bits in a bitmap memory region. The n-bits can have any size less than or equal to BITS_PER_LONG. Moreover, during setting value of n-bit in bitmap, if a situation arise that the width of next n-bit is exceeding the word boundary, then it will divide itself such that some portion of it is stored in that word, while the remaining portion is stored in the next higher word. Similar situation occurs while retrieving value of n-bits from bitmap.
---
Changes in v10:
- No change.
Changes in v9:
- No change.
Changes in v8:
- No change.
Changes in v7:
- No change.
Changes in v6:
- No change.
Changes in v5:
- No change.
Changes in v4:
- No change.
Changes in v3:
- No change.
Changes in v2:
- No change.
include/asm-generic/bitops/find.h | 19 ++++++++++ include/linux/bitmap.h | 61 +++++++++++++++++++++++++++++++ include/linux/bitops.h | 13 +++++++ lib/find_bit.c | 14 +++++++ 4 files changed, 107 insertions(+)
include/asm-generic/bitops/find.h +19 -0
@@ -97,4 +97,23 @@ extern unsigned long find_next_clump8(unsigned long *clump,#define find_first_clump8 (clump, bits, size) \ find_next_clump8((clump), (bits), (size), 0) +/** +* find_next_clump - find next clump with set bits in a memory region +* @clump: location to store copy of found clump +* @addr: address to base the search on +* @size: bitmap size in number of bits +* @offset: bit offset at which to start searching +* @clump_size: clump size in bits +* +* Returns the bit offset for the next set clump; the found clump value is +* copied to the location pointed by @clump. If no bits are set, returns @size. +*/ +extern unsigned long find_next_clump (unsigned long *clump, +const unsigned long *addr, +unsigned long size,unsigned long offset, +unsigned long clump_size); + +#define find_first_clump (clump, bits, size, clump_size) \ + find_next_clump((clump), (bits), (size), 0, (clump_size)) +#endif /*_ASM_GENERIC_BITOPS_FIND_H_ */
include/linux/bitmap.h +61 -0
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include/linux/bitops.h +13 -0
@@ -62,6 +62,19 @@ extern unsigned long __sw_hweight64(__u64 w); (start) < (size); \ (start) = find_next_clump8(&(clump), (bits), (size), (start) + 8)) +/** +* for_each_set_clump - iterate over bitmap for each clump with set bits +* @start: bit offset to start search and to store the current iteration offset +* @clump: location to store copy of current 8-bit clump +* @bits: bitmap address to base the search on +* @size: bitmap size in number of bits +* @clump_size: clump size in bits +*/ +#define for_each_set_clump (start, clump, bits, size, clump_size) \ + for ((start) = find_first_clump(&(clump), (bits), (size), (clump_size)); \ + (start) < (size); \ + (start) = find_next_clump(&(clump), (bits), (size), (start) + (clump_size), (clump_size))) +static inline int get_bitmask_order (unsigned int count) {int order;
lib/find_bit.c +14 -0
@@ -190,3 +190,17 @@ unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,return offset; }EXPORT_SYMBOL (find_next_clump8); + +unsigned long find_next_clump (unsigned long *clump,const unsigned long *addr, +unsigned long size,unsigned long offset, +unsigned long clump_size) +{ + offset =find_next_bit (addr, size, offset); +if (offset == size) +return size; + + offset =rounddown (offset, clump_size); + *clump =bitmap_get_value (addr, offset, clump_size); +return offset; +} +EXPORT_SYMBOL (find_next_clump);
Signature · 1 line
2.26.2
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
On Sat, Oct 3, 2020 at 2:51 AM Syed Nayyar Waris <[email protected]> wrote:
Now I remember...
This needs to be revisited.
Quoted 5 lines
This macro iterates for each group of bits (clump) with set bits, within a bitmap memory region. For each iteration, "start" is set to the bit offset of the found clump, while the respective clump value is stored to the location pointed by "clump". Additionally, the
bitmap_get_valueandbitmap_set_valuefunctions are introduced to
Mark functions like func() in the text as well.
Quoted 7 lines
respectively get and set a value of n-bits in a bitmap memory region. The n-bits can have any size less than or equal to
BITS_PER_LONG. Moreover, during setting value of n-bit in bitmap, if a situation arise that the width of next n-bit is exceeding the word boundary, then it will divide itself such that some portion of it is stored in that word, while the remaining portion is stored in the next higher word. Similar situation occurs while retrieving value of n-bits from bitmap.
retrieving the value
from a bitmap
...
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include/linux/bitmap.h +11
-0+/** +* bitmap_get_value - get a value of n-bits from the memory region +* @map: address to the bitmap memory region +* @start: bit offset of the n-bit value +* @nbits: size of value in bits +* +* Returns value of nbits located at the @start bit offset within the @map +* memory region. +*/ +static inline unsigned long bitmap_get_value(const unsigned long *map, + unsigned long start,
include/linux/bitmap.h static inline unsigned long bitmap_get_value8(const unsigned long *map, · line 590
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include/linux/bitmap.h +10
-0+ unsigned long nbits) +{ +const size_t index =BIT_WORD (start); +const unsigned long offset = start %BITS_PER_LONG ; +const unsigned long ceiling =roundup (start +1 ,BITS_PER_LONG ); +const unsigned long space = ceiling - start; +unsigned long value_low, value_high; + +if (space >= nbits) +return (map[index] >> offset) &GENMASK (nbits -1 ,0 );
This is UB in GENMASK() when nbits == 0.
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include/linux/bitmap.h +6
-0+else { + value_low = map[index] &BITMAP_FIRST_WORD_MASK (start); + value_high = map[index +1 ] &BITMAP_LAST_WORD_MASK (start + nbits); +return (value_low >> offset) | (value_high << space); + } +}
...
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include/linux/bitmap.h +7
-0+/** +* bitmap_set_value - set n-bit 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 +*/
include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
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include/linux/bitmap.h +9
-0+static inline void bitmap_set_value (unsigned long *map, +unsigned long value, +unsigned long start,unsigned long nbits) +{ +const size_t index =BIT_WORD (start); +const unsigned long offset = start %BITS_PER_LONG ; +const unsigned long ceiling =roundup (start +1 ,BITS_PER_LONG ); +const unsigned long space = ceiling - start; + value &=GENMASK (nbits -1 ,0 );
This is UB when nbits == 0.
include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 633
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include/linux/bitmap.h +2
-0+if (space >= nbits) { + map[index] &= ~(GENMASK (nbits + offset -1 , offset));
UB when nbits == 0 and start == 0.
include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 639
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include/linux/bitmap.h +6
-0+ map[index] |= value << offset; + }else { + map[index] &= ~BITMAP_FIRST_WORD_MASK (start); + map[index] |= value << offset; + map[index +1 ] &= ~BITMAP_LAST_WORD_MASK (start + nbits); + map[index +1 ] |= (value >> space);
And another LKP finding was among these lines, but I don't remember the details.
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include/linux/bitmap.h +3
-0+ } +} +#endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ include/linux/bitops.h +13
-0@@ -62,6 +62,19 @@ extern unsigned long __sw_hweight64(__u64 w); (start) < (size); \ (start) = find_next_clump8(&(clump), (bits), (size), (start) + 8)) +/** +* for_each_set_clump - iterate over bitmap for each clump with set bits +* @start: bit offset to start search and to store the current iteration offset +* @clump: location to store copy of current 8-bit clump +* @bits: bitmap address to base the search on +* @size: bitmap size in number of bits +* @clump_size: clump size in bits +*/ +#define for_each_set_clump (start, clump, bits, size, clump_size) \ + for ((start) = find_first_clump(&(clump), (bits), (size), (clump_size)); \ + (start) < (size); \ + (start) = find_next_clump(&(clump), (bits), (size), (start) + (clump_size), (clump_size))) +static inline int get_bitmask_order (unsigned int count) {int order;lib/find_bit.c +14
-1@@ -190,3 +190,17 @@ unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,return offset; }EXPORT_SYMBOL (find_next_clump8); + +unsigned long find_next_clump (unsigned long *clump,const unsigned long *addr, +unsigned long size,unsigned long offset, +unsigned long clump_size) +{ + offset =find_next_bit (addr, size, offset); +if (offset == size) +return size; + + offset =rounddown (offset, clump_size); + *clump =bitmap_get_value (addr, offset, clump_size); +return offset; +} +EXPORT_SYMBOL (find_next_clump); --2.26.2
Signature · 2 lines
With Best Regards, Andy Shevchenko
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
Quoted 6 lines · Andy Shevchenko
On Sat, Oct 3, 2020 at 2:51 AM Syed Nayyar Waris <[email protected]> wrote:
Now I remember...
This needs to be revisited.
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This macro iterates for each group of bits (clump) with set bits, within a bitmap memory region. For each iteration, "start" is set to the bit offset of the found clump, while the respective clump value is stored to the location pointed by "clump". Additionally, the
bitmap_get_valueandbitmap_set_valuefunctions are introduced toMark functions like
func()in the text as well.
Okay
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respectively get and set a value of n-bits in a bitmap memory region. The n-bits can have any size less than or equal to
BITS_PER_LONG. Moreover, during setting value of n-bit in bitmap, if a situation arise that the width of next n-bit is exceeding the word boundary, then it will divide itself such that some portion of it is stored in that word, while the remaining portion is stored in the next higher word. Similar situation occurs while retrieving value of n-bits from bitmap.retrieving the value
from a bitmap
Okay
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...
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include/linux/bitmap.h +15
-0+/** +* bitmap_get_value - get a value of n-bits from the memory region +* @map: address to the bitmap memory region +* @start: bit offset of the n-bit value +* @nbits: size of value in bits +* +* Returns value of nbits located at the @start bit offset within the @map +* memory region. +*/ +static inline unsigned long bitmap_get_value (const unsigned long *map, +unsigned long start, +unsigned long nbits) +{ +const size_t index =BIT_WORD (start); +const unsigned long offset = start %BITS_PER_LONG ;
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include/linux/bitmap.h static inline unsigned long bitmap_get_value8(const unsigned long *map, · line 590
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include/linux/bitmap.h +6
-0+const unsigned long ceiling =roundup (start +1 ,BITS_PER_LONG ); +const unsigned long space = ceiling - start; +unsigned long value_low, value_high; + +if (space >= nbits) +return (map[index] >> offset) &GENMASK (nbits -1 ,0 );This is UB in
GENMASK()when nbits == 0.
'nbits' actually specifies the width of clump value. Basically 'nbits' denotes how-many-bits wide the clump value is.
'nbits' having a value of '0' means zero-width-sized clump, meaning nothing. 'nbits' can take valid values from '1' to BITS_PER_LONG. The minimum value the 'nbits' can have is 1 because the smallest sized clump can be 1-bit-wide. It can't be smaller than that.
Let me know if I have misunderstood something?
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include/linux/bitmap.h +6
-0+else { + value_low = map[index] &BITMAP_FIRST_WORD_MASK (start); + value_high = map[index +1 ] &BITMAP_LAST_WORD_MASK (start + nbits); +return (value_low >> offset) | (value_high << space); + } +}...
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include/linux/bitmap.h +15
-0+/** +* bitmap_set_value - set n-bit 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 +*/ +static inline void bitmap_set_value (unsigned long *map, +unsigned long value, +unsigned long start,unsigned long nbits) +{ +const size_t index =BIT_WORD (start); +const unsigned long offset = start %BITS_PER_LONG ; +const unsigned long ceiling =roundup (start +1 ,BITS_PER_LONG ); +const unsigned long space = ceiling - start;
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+ value &=
GENMASK(nbits - 1, 0);This is UB when nbits == 0.
Same as above.
'nbits' actually specifies the width of clump value. Basically 'nbits' denotes how-many-bits wide the clump value is.
'nbits' having a value of '0' means zero-width-sized clump, meaning nothing. 'nbits' can take valid values from '1' to BITS_PER_LONG. The minimum value the 'nbits' can have is 1 because the smallest sized clump can be 1-bit-wide. It can't be smaller than that.
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 633
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include/linux/bitmap.h +2
-0+if (space >= nbits) { + map[index] &= ~(GENMASK (nbits + offset -1 , offset));UB when nbits == 0 and start == 0.
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 639
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include/linux/bitmap.h +6
-0+ map[index] |= value << offset; + }else { + map[index] &= ~BITMAP_FIRST_WORD_MASK (start); + map[index] |= value << offset; + map[index +1 ] &= ~BITMAP_LAST_WORD_MASK (start + nbits); + map[index +1 ] |= (value >> space);And another LKP finding was among these lines, but I don't remember the details.
Yes you are right. There was sparse warning reported for this.
sparse: shift too big (64) for type unsigned long
The warning was reported in patch [4/4] referring to this patch [1/4].
Later it was clarified by the sparse-check maintainer that this warning is to be ignored and no code fix is required.
https://www.mail-archive.com/[email protected]/msg2202377.html
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include/linux/bitmap.h +3
-0+ } +} +#endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ include/linux/bitops.h +13
-0@@ -62,6 +62,19 @@ extern unsigned long __sw_hweight64(__u64 w); (start) < (size); \ (start) = find_next_clump8(&(clump), (bits), (size), (start) + 8)) +/** +* for_each_set_clump - iterate over bitmap for each clump with set bits +* @start: bit offset to start search and to store the current iteration offset +* @clump: location to store copy of current 8-bit clump +* @bits: bitmap address to base the search on +* @size: bitmap size in number of bits +* @clump_size: clump size in bits +*/ +#define for_each_set_clump (start, clump, bits, size, clump_size) \ + for ((start) = find_first_clump(&(clump), (bits), (size), (clump_size)); \ + (start) < (size); \ + (start) = find_next_clump(&(clump), (bits), (size), (start) + (clump_size), (clump_size))) +static inline int get_bitmask_order (unsigned int count) {int order;lib/find_bit.c +14
-1@@ -190,3 +190,17 @@ unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,return offset; }EXPORT_SYMBOL (find_next_clump8); + +unsigned long find_next_clump (unsigned long *clump,const unsigned long *addr, +unsigned long size,unsigned long offset, +unsigned long clump_size) +{ + offset =find_next_bit (addr, size, offset); +if (offset == size) +return size; + + offset =rounddown (offset, clump_size); + *clump =bitmap_get_value (addr, offset, clump_size); +return offset; +} +EXPORT_SYMBOL (find_next_clump); --Quoted 2 lines
2.26.2
--
With Best Regards,
Andy Shevchenko
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
Quoted 3 lines · Syed Nayyar Waris
Quoted 1 line · Andy Shevchenko
On Sat, Oct 3, 2020 at 2:51 AM Syed Nayyar Waris <[email protected]> wrote:
...
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+/**
+ *bitmap_get_value- get a value of n-bits from the memory region
+ * @map: address to the bitmap memory region
+ * @start: bit offset of the n-bit value
+ * @nbits: size of value in bits
+ *
+ * Returns value of nbits located at the @start bit offset within the @map
+ * memory region.
+ */
...
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+ return (map[index] >> offset) &
GENMASK(nbits - 1, 0);This is UB in
GENMASK()when nbits == 0.
Quoted 8 lines
'nbits' actually specifies the width of clump value. Basically 'nbits' denotes how-many-bits wide the clump value is.
'nbits' having a value of '0' means zero-width-sized clump, meaning nothing. 'nbits' can take valid values from '1' toBITS_PER_LONG. The minimum value the 'nbits' can have is 1 because the smallest sized clump can be 1-bit-wide. It can't be smaller than that.Let me know if I have misunderstood something?
It's still possible to call with an nbits parameter be equal to 0. If code is optimized to allow it, it should be documented that 0 parameter is not valid and behaviour is undefined.
...
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+/**
+ *bitmap_set_value- set n-bit 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
+ */
...
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+ value &=
GENMASK(nbits - 1, 0);This is UB when nbits == 0.
Same as above.
'nbits' actually specifies the width of clump value. Basically 'nbits' denotes how-many-bits wide the clump value is.
'nbits' having a value of '0' means zero-width-sized clump, meaning nothing. 'nbits' can take valid values from '1' toBITS_PER_LONG. The minimum value the 'nbits' can have is 1 because the smallest sized clump can be 1-bit-wide. It can't be smaller than that.
Same as above.
...
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 637
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include/linux/bitmap.h +2
-0+ map[index] &= ~BITMAP_FIRST_WORD_MASK (start); + map[index] |= value << offset;
Side note: I would prefer + 0 here and there, but it's up to you.
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 639
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include/linux/bitmap.h +2
-0+ map[index +1 ] &= ~BITMAP_LAST_WORD_MASK (start + nbits); + map[index +1 ] |= (value >> space);
By the way, what about this in the case of start=0, nbits > 64? space == 64 -> UB.
(And btw parentheses are redundant here)
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And another LKP finding was among these lines, but I don't remember the details.
Yes you are right. There was sparse warning reported for this.
sparse: shift too big (64) for type unsigned long
The warning was reported in patch [4/4] referring to this patch [1/4].Later it was clarified by the sparse-check maintainer that this warning is to be ignored and no code fix is required.
https://www.mail-archive.com/[email protected]/msg2202377.html
Ah, okay!
--
With Best Regards,
Andy Shevchenko
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
Quoted 30 lines · Andy Shevchenko
Quoted 3 lines · Syed Nayyar Waris
Quoted 1 line · Andy Shevchenko
On Sat, Oct 3, 2020 at 2:51 AM Syed Nayyar Waris <[email protected]> wrote:
...
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+/**
+ *bitmap_get_value- get a value of n-bits from the memory region
+ * @map: address to the bitmap memory region
+ * @start: bit offset of the n-bit value
+ * @nbits: size of value in bits
+ *
+ * Returns value of nbits located at the @start bit offset within the @map
+ * memory region.
+ */...
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+ return (map[index] >> offset) &
GENMASK(nbits - 1, 0);This is UB in
GENMASK()when nbits == 0.'nbits' actually specifies the width of clump value. Basically 'nbits' denotes how-many-bits wide the clump value is.
'nbits' having a value of '0' means zero-width-sized clump, meaning nothing. 'nbits' can take valid values from '1' toBITS_PER_LONG. The minimum value the 'nbits' can have is 1 because the smallest sized clump can be 1-bit-wide. It can't be smaller than that.
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Let me know if I have misunderstood something?
It's still possible to call with an nbits parameter be equal to 0. If code is optimized to allow it, it should be documented that 0 parameter is not valid and behaviour is undefined.
Documenting that 0 is not valid would be preferred because an additional conditional check in the code could add a significant latency in a loop. So perhaps change the documentation line to:
@nbits: size of value in bits (must be between 1 and BITS_PER_LONG)
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+/**
+ *bitmap_set_value- set n-bit 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
+ */...
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+ value &=
GENMASK(nbits - 1, 0);This is UB when nbits == 0.
Same as above.
'nbits' actually specifies the width of clump value. Basically 'nbits' denotes how-many-bits wide the clump value is.
'nbits' having a value of '0' means zero-width-sized clump, meaning nothing. 'nbits' can take valid values from '1' toBITS_PER_LONG. The minimum value the 'nbits' can have is 1 because the smallest sized clump can be 1-bit-wide. It can't be smaller than that.Same as above.
...
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 637
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include/linux/bitmap.h +2
-0+ map[index] &= ~BITMAP_FIRST_WORD_MASK (start); + map[index] |= value << offset;Side note: I would prefer + 0 here and there, but it's up to you.
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 639
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include/linux/bitmap.h +2
-0+ map[index +1 ] &= ~BITMAP_LAST_WORD_MASK (start + nbits); + map[index +1 ] |= (value >> space);By the way, what about this in the case of start=0, nbits > 64? space == 64 -> UB.
(And btw parentheses are redundant here)
I think this is the same situation as before: we should document that nbits must be between 1 and BITS_PER_LONG.
William Breathitt Gray
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And another LKP finding was among these lines, but I don't remember the details.
Yes you are right. There was sparse warning reported for this.
sparse: shift too big (64) for type unsigned long
The warning was reported in patch [4/4] referring to this patch [1/4].Later it was clarified by the sparse-check maintainer that this warning is to be ignored and no code fix is required.
https://www.mail-archive.com/[email protected]/msg2202377.html
Ah, okay!
--
With Best Regards,
Andy Shevchenko
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
Quoted 5 lines · William Breathitt Gray
Quoted 4 lines · Andy Shevchenko
Quoted 3 lines · Syed Nayyar Waris
Quoted 1 line · Andy Shevchenko
On Sat, Oct 3, 2020 at 2:51 AM Syed Nayyar Waris <[email protected]> wrote:
...
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 637
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include/linux/bitmap.h +2
-0+ map[index] &= ~BITMAP_FIRST_WORD_MASK (start); + map[index] |= value << offset;Side note: I would prefer + 0 here and there, but it's up to you.
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include/linux/bitmap.h +2
-0+ map[index +1 ] &= ~BITMAP_LAST_WORD_MASK (start + nbits); + map[index +1 ] |= (value >> space);
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By the way, what about this in the case of start=0, nbits > 64? space == 64 -> UB.
(And btw parentheses are redundant here)
I think this is the same situation as before: we should document that nbits must be between 1 and
BITS_PER_LONG.
At least documented, yes.
Signature · 2 lines
With Best Regards, Andy Shevchenko
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
Quoted 7 lines · Andy Shevchenko
Quoted 4 lines · William Breathitt Gray
Quoted 3 lines · Andy Shevchenko
Quoted 2 lines · Syed Nayyar Waris
On Sat, Oct 3, 2020 at 2:14 PM Andy Shevchenko
<[email protected]> wrote:
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 637
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include/linux/bitmap.h +2
-0+ map[index] &= ~BITMAP_FIRST_WORD_MASK (start); + map[index] |= value << offset;Side note: I would prefer + 0 here and there, but it's up to you.
Andy what do you mean by the above statement, can you please clarify? Can you please elaborate on the above statement.
Thanks
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include/linux/bitmap.h static inline void bitmap_set_value8(unsigned long *map, unsigned long value, · line 639
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include/linux/bitmap.h +2
-0+ map[index +1 ] &= ~BITMAP_LAST_WORD_MASK (start + nbits); + map[index +1 ] |= (value >> space);By the way, what about this in the case of start=0, nbits > 64? space == 64 -> UB.
(And btw parentheses are redundant here)
I think this is the same situation as before: we should document that nbits must be between 1 and
BITS_PER_LONG.At least documented, yes.
--
With Best Regards,
Andy Shevchenko
Re: [PATCH v10 1/4] bitops: Introduce the for_each_set_clump macro
Quoted 9 lines · Syed Nayyar Waris
Quoted 7 lines · Andy Shevchenko
Quoted 5 lines · William Breathitt Gray
Quoted 4 lines · Andy Shevchenko
Quoted 3 lines · Syed Nayyar Waris
Quoted 1 line · Andy Shevchenko
On Sat, Oct 3, 2020 at 2:51 AM Syed Nayyar Waris <[email protected]> wrote:
...
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Review
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(quoted diff) +2
-0+ map[index] &= ~BITMAP_FIRST_WORD_MASK(start); + map[index] |= value << offset;Side note: I would prefer + 0 here and there, but it's up to you.
Andy what do you mean by the above statement, can you please clarify? Can you please elaborate on the above statement.
Sure. I meant something like
map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start);
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-0+ map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits); + map[index + 1] |= (value >> space);
Signature · 2 lines
With Best Regards, Andy Shevchenko
PATCH v10 2/4 lib/test_bitmap.c: Add for_each_set_clump test cases
In reply to Syed Nayyar WarisThe introduction of the generic for_each_set_clump macro need test cases to verify the implementation. This patch adds test cases for scenarios in which clump sizes are 8 bits, 24 bits, 30 bits and 6 bits. The cases contain situations where clump is getting split at the word boundary and also when zeroes are present in the start and middle of bitmap.
---
Changes in v10:
- No change.
Changes in v9:
- No change.
Changes in v8:
- [Patch 2/4]: Minor change: Use '__initdata' for correct section mismatch in 'clump_test_data' array.
Changes in v7:
- Minor changes: Use macro 'DECLARE_BITMAP()' and split 'struct' definition and test data.
Changes in v6:
- Make 'for loop' inside 'test_for_each_set_clump' more succinct.
Changes in v5:
- No change.
Changes in v4:
- Use 'for' loop in test function of 'for_each_set_clump'.
Changes in v3:
- No Change.
Changes in v2:
- Unify different tests for 'for_each_set_clump'. Pass test data as function parameters.
- Remove unnecessary bitmap_zero calls.
lib/test_bitmap.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+)
lib/test_bitmap.c +144 -0
@@ -155,6 +155,37 @@ static bool __init __check_eq_clump8(const char *srcfile, unsigned int line,return true; } +static bool __init __check_eq_clump (const char *srcfile,unsigned int line, +const unsigned int offset, +const unsigned int size, +const unsigned long *const clump_exp, +const unsigned long *const clump, +const unsigned long clump_size) +{ +unsigned long exp; + +if (offset >= size) { +pr_warn ("[%s:%u] bit offset for clump out-of-bounds: expected less than %u, got %u\n" , + srcfile, line, size, offset); +return false; + } + + exp = clump_exp[offset / clump_size]; +if (!exp) { +pr_warn ("[%s:%u] bit offset for zero clump: expected nonzero clump, got bit offset %u with clump value 0" , + srcfile, line, offset); +return false; + } + +if (*clump != exp) { +pr_warn ("[%s:%u] expected clump value of 0x%lX, got clump value of 0x%lX" , + srcfile, line, exp, *clump); +return false; + } + +return true; +} +#define __expect_eq (suffix, ...) \ ({ \ int result = 0; \
@@ -172,6 +203,7 @@ static bool __init __check_eq_clump8(const char *srcfile, unsigned int line,#define expect_eq_pbl (...) __expect_eq(pbl, ##__VA_ARGS__)#define expect_eq_u32_array (...) __expect_eq(u32_array, ##__VA_ARGS__)#define expect_eq_clump8 (...) __expect_eq(clump8, ##__VA_ARGS__) +#define expect_eq_clump (...) __expect_eq(clump, ##__VA_ARGS__)static void __init test_zero_clear (void ) {
@@ -577,6 +609,28 @@ static void noinline __init test_mem_optimisations(void) } } +static const unsigned long clump_bitmap_data[]__initconst = { +0x38000201 , +0x05ff0f38 , +0xeffedcba , +0xbbbbabcd , +0x000000aa , +0x000000aa , +0x00ff0000 , +0xaaaaaa00 , +0xff000000 , +0x00aa0000 , +0x00000000 , +0x00000000 , +0x00000000 , +0x0f000000 , +0x00ff0000 , +0xaaaaaa00 , +0xff000000 , +0x00aa0000 , +0x00000ac0 , +}; +static const unsigned char clump_exp[]__initconst = {0x01 ,/* 1 bit set */ 0x02 ,/* non-edge 1 bit set */
@@ -588,6 +642,95 @@ static const unsigned char clump_exp[] __initconst = { 0x05, /* non-adjacent 2 bits set */ }; +static const unsigned long clump_exp1[]__initconst = { +0x01 ,/* 1 bit set */ +0x02 ,/* non-edge 1 bit set */ +0x00 ,/* zero bits set */ +0x38 ,/* 3 bits set across 4-bit boundary */ +0x38 ,/* Repeated clump */ +0x0F ,/* 4 bits set */ +0xFF ,/* all bits set */ +0x05 ,/* non-adjacent 2 bits set */ +}; + +static const unsigned long clump_exp2[]__initconst = { +0xfedcba ,/* 24 bits */ +0xabcdef , +0xaabbbb ,/* Clump split between 2 words */ +0x000000 ,/* zeroes in between */ +0x0000aa , +0x000000 , +0x0000ff , +0xaaaaaa , +0x000000 , +0x0000ff , +}; + +static const unsigned long clump_exp3[]__initconst = { +0x00000000 ,/* starting with 0s*/ +0x00000000 ,/* All 0s */ +0x00000000 , +0x00000000 , +0x3f00000f ,/* Non zero set */ +0x2aa80003 , +0x00000aaa , +0x00003fc0 , +}; + +static const unsigned long clump_exp4[]__initconst = { +0x00 , +0x2b , +}; + +struct clump_test_data_params { + DECLARE_BITMAP(data, 256); +unsigned long count; +unsigned long offset; +unsigned long limit; +unsigned long clump_size; +unsigned long const *exp; +}; + +static struct clump_test_data_params clump_test_data[]__initdata = + { {{0 },2 ,0 ,64 ,8 , clump_exp1}, + {{0 },8 ,2 ,240 ,24 , clump_exp2}, + {{0 },8 ,10 ,240 ,30 , clump_exp3}, + {{0 },1 ,18 ,18 ,6 , clump_exp4} }; + +static void __init prepare_test_data (unsigned int index) +{ +int i; +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 ); + width +=32 ; + } +} + +static void __init execute_for_each_set_clump_test (unsigned int index) +{ +unsigned long start, clump; + +for_each_set_clump (start, clump, clump_test_data[index].data, + clump_test_data[index].limit, + clump_test_data[index].clump_size) +expect_eq_clump (start, clump_test_data[index].limit, clump_test_data[index].exp, + &clump, clump_test_data[index].clump_size); +} + +static void __init test_for_each_set_clump (void ) +{ +unsigned int i; + +for (i =0 ; i <ARRAY_SIZE (clump_test_data); i++) { +prepare_test_data (i); +execute_for_each_set_clump_test (i); + } +} +static void __init test_for_each_set_clump8 (void ) {#define CLUMP_EXP_NUMBITS 64
@@ -680,6 +823,7 @@ static void __init selftest(void)test_bitmap_parselist_user ();test_mem_optimisations (); test_for_each_set_clump8(); + test_for_each_set_clump();test_bitmap_cut (); }
Signature · 1 line
2.26.2
PATCH v10 3/4 gpio: thunderx: Utilize for_each_set_clump macro
In reply to Syed Nayyar WarisThis patch reimplements the thunderx_gpio_set_multiple function in drivers/gpio/gpio-thunderx.c to use the new for_each_set_clump macro. Instead of looping for each bank in thunderx_gpio_set_multiple function, now we can skip bank which is not set and save cycles.
---
Changes in v10:
- No change.
Changes in v9:
- No change.
Changes in v8:
- No change.
Changes in v7:
- No change.
Changes in v6:
- No change.
Changes in v5:
- No change.
Changes in v4:
- Minor change: Inline value '64' in code for better code readability.
Changes in v3:
- Change datatype of some variables from u64 to unsigned long in function thunderx_gpio_set_multiple.
Changes in v2:
- No change.
drivers/gpio/gpio-thunderx.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
drivers/gpio/gpio-thunderx.c +7 -4
@@ -275,12 +275,15 @@ static void thunderx_gpio_set_multiple(struct gpio_chip *chip, unsigned long *bits) {int bank; -u64 set_bits, clear_bits; +unsigned long set_bits, clear_bits, gpio_mask; +unsigned long offset; +struct thunderx_gpio *txgpio =gpiochip_get_data (chip); -for (bank =0 ; bank <= chip->ngpio /64 ; bank++) { - set_bits = bits[bank] & mask[bank]; - clear_bits = ~bits[bank] & mask[bank]; +for_each_set_clump (offset, gpio_mask, mask, chip->ngpio,64 ) { + bank = offset /64 ; + set_bits = bits[bank] & gpio_mask; + clear_bits = ~bits[bank] & gpio_mask;writeq (set_bits, txgpio->register_base + (bank *GPIO_2ND_BANK ) +GPIO_TX_SET );writeq (clear_bits, txgpio->register_base + (bank *GPIO_2ND_BANK ) +GPIO_TX_CLR ); }
Signature · 1 line
2.26.2
PATCH v10 4/4 gpio: xilinx: Utilize generic bitmap_get_value and _set_value
In reply to Syed Nayyar WarisThis patch reimplements the xgpio_set_multiple function in drivers/gpio/gpio-xilinx.c to use the new generic functions:bitmap_get_value and bitmap_set_value. The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple function, now we can check each channel at a time and save cycles.
---
Changes in v10:
- No change.
Changes in v9:
- Remove looping of 'for_each_set_clump' and instead process two halves of a 64-bit bitmap separately or individually. Use normal spin_lock call for second inner lock. And take the spin_lock_init call outside the 'if' condition in the 'probe' function of driver.
Changes in v8:
- No change.
Changes in v7:
- No change.
Changes in v6:
- No change.
Changes in v5:
- Minor change: Inline values '32' and '64' in code for better code readability.
Changes in v4:
- Minor change: Inline values '32' and '64' in code for better code readability.
Changes in v3:
- No change.
Changes in v2:
- No change
drivers/gpio/gpio-xilinx.c | 66 +++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 33 deletions(-)
drivers/gpio/gpio-xilinx.c +33 -33
@@ -136,39 +136,39 @@ static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)static void xgpio_set_multiple (struct gpio_chip *gc,unsigned long *mask,unsigned long *bits) { -unsigned long flags; +unsigned long flag;struct xgpio_instance *chip =gpiochip_get_data (gc); -int index =xgpio_index (chip,0 ); -int offset, i; - -spin_lock_irqsave (&chip->gpio_lock[index], flags); - -/* Write to GPIO signals */ -for (i =0 ; i < gc->ngpio; i++) { -if (*mask ==0 ) -break ; -/* Once finished with an index write it out to the register */ -if (index !=xgpio_index (chip, i)) { -xgpio_writereg (chip->regs +XGPIO_DATA_OFFSET + - index *XGPIO_CHANNEL_OFFSET , - chip->gpio_state[index]); -spin_unlock_irqrestore (&chip->gpio_lock[index], flags); - index =xgpio_index (chip, i); -spin_lock_irqsave (&chip->gpio_lock[index], flags); - } -if (__test_and_clear_bit (i, mask)) { - offset =xgpio_offset (chip, i); -if (test_bit (i, bits)) - chip->gpio_state[index] |=BIT (offset); -else - chip->gpio_state[index] &= ~BIT (offset); - } - } - -xgpio_writereg (chip->regs +XGPIO_DATA_OFFSET + - index *XGPIO_CHANNEL_OFFSET , chip->gpio_state[index]); - -spin_unlock_irqrestore (&chip->gpio_lock[index], flags); +u32 *const state = chip->gpio_state; +unsigned int *const width = chip->gpio_width; + +DECLARE_BITMAP (old,64 ); +DECLARE_BITMAP (new,64 ); +DECLARE_BITMAP (changed,64 ); + +spin_lock_irqsave (&chip->gpio_lock[0 ], flag); +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_replace (new, old, bits, mask, gc->ngpio); + +bitmap_set_value (old, state[0 ],0 ,32 ); +bitmap_set_value (old, 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_xor (changed, old, new,64 ); + +if (((u32 *)changed)[0 ]) +xgpio_writereg (chip->regs +XGPIO_DATA_OFFSET , + state[0 ]); +if (((u32 *)changed)[1 ]) +xgpio_writereg (chip->regs +XGPIO_DATA_OFFSET + +XGPIO_CHANNEL_OFFSET , state[1 ]); + +spin_unlock (&chip->gpio_lock[1 ]); +spin_unlock_irqrestore (&chip->gpio_lock[0 ], flag); }/**
@@ -292,6 +292,7 @@ static int xgpio_probe(struct platform_device *pdev) chip->gpio_width[0 ] =32 ;spin_lock_init (&chip->gpio_lock[0 ]); +spin_lock_init (&chip->gpio_lock[1 ]);if (of_property_read_u32 (np,"xlnx,is-dual" , &is_dual)) is_dual =0 ;
@@ -314,7 +315,6 @@ static int xgpio_probe(struct platform_device *pdev) &chip->gpio_width[1])) chip->gpio_width[1 ] =32 ; -spin_lock_init (&chip->gpio_lock[1 ]); } chip->gc.base =-1 ;
Signature · 1 line
2.26.2
kernel test robot
build botRe: [PATCH v10 4/4] gpio: xilinx: Utilize generic bitmap_get_value and _set_value
I love your patch! Perhaps something to improve:
Hi Syed,
I love your patch! Perhaps something to improve:
[auto build test WARNING on 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5]
url: https://github.com/0day-ci/linux/commits/Syed-Nayyar-Waris/Introduce-the-for_each_set_clump-macro/20201003-075413 base: 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5
:::::: branch date: 3 hours ago
:::::: commit date: 3 hours ago
config: arm64-randconfig-s031-20201002 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.2-201-g24bdaac6-dirty
# https://github.com/0day-ci/linux/commit/d8b00c69c075459dadbdbcd8966b5b885a08a1bd
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Syed-Nayyar-Waris/Introduce-the-for_each_set_clump-macro/20201003-075413 git checkout d8b00c69c075459dadbdbcd8966b5b885a08a1bd
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64
If you fix the issue, kindly add following tag as appropriate
echo
echo "sparse warnings: (new ones prefixed by >>)"
echo
drivers/gpio/gpio-xilinx.c: note: in included file (through include/linux/cpumask.h, include/linux/smp.h, arch/arm64/include/asm/arch_timer.h, ...):
>> include/linux/bitmap.h:593:30: sparse: sparse: invalid access past the end of 'new' (8 8) >> include/linux/bitmap.h:638:17: sparse: sparse: invalid access past the end of 'old' (8 8) >> include/linux/bitmap.h:639:45: sparse: sparse: shift too big (64) for type unsigned long
include/linux/bitmap.h:594:63: sparse: sparse: shift too big (64) for type unsigned long
vim +/new +593 include/linux/bitmap.h
169c474fb22d8a5 William Breathitt Gray 2019-12-04 569
66845ead81685a8 Syed Nayyar Waris 2020-10-03 570 /**
66845ead81685a8 Syed Nayyar Waris 2020-10-03 571 * bitmap_get_value - get a value of n-bits from the memory region
66845ead81685a8 Syed Nayyar Waris 2020-10-03 572 * @map: address to the bitmap memory region
66845ead81685a8 Syed Nayyar Waris 2020-10-03 573 * @start: bit offset of the n-bit value
66845ead81685a8 Syed Nayyar Waris 2020-10-03 574 * @nbits: size of value in bits
66845ead81685a8 Syed Nayyar Waris 2020-10-03 575 *
66845ead81685a8 Syed Nayyar Waris 2020-10-03 576 * Returns value of nbits located at the @start bit offset within the @map
66845ead81685a8 Syed Nayyar Waris 2020-10-03 577 * memory region.
66845ead81685a8 Syed Nayyar Waris 2020-10-03 578 */
66845ead81685a8 Syed Nayyar Waris 2020-10-03 579 static inline unsigned long bitmap_get_value(const unsigned long *map,
66845ead81685a8 Syed Nayyar Waris 2020-10-03 580 unsigned long start,
66845ead81685a8 Syed Nayyar Waris 2020-10-03 581 unsigned long nbits)
66845ead81685a8 Syed Nayyar Waris 2020-10-03 582 {
66845ead81685a8 Syed Nayyar Waris 2020-10-03 583 const size_t index = BIT_WORD(start);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 584 const unsigned long offset = start % BITS_PER_LONG;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 585 const unsigned long ceiling = roundup(start + 1, BITS_PER_LONG);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 586 const unsigned long space = ceiling - start;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 587 unsigned long value_low, value_high;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 588
66845ead81685a8 Syed Nayyar Waris 2020-10-03 589 if (space >= nbits)
66845ead81685a8 Syed Nayyar Waris 2020-10-03 590 return (map[index] >> offset) & GENMASK(nbits - 1, 0);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 591 else {
66845ead81685a8 Syed Nayyar Waris 2020-10-03 592 value_low = map[index] & BITMAP_FIRST_WORD_MASK(start);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 @593 value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 594 return (value_low >> offset) | (value_high << space);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 595 }
66845ead81685a8 Syed Nayyar Waris 2020-10-03 596 }
66845ead81685a8 Syed Nayyar Waris 2020-10-03 597
169c474fb22d8a5 William Breathitt Gray 2019-12-04 598 /**
169c474fb22d8a5 William Breathitt Gray 2019-12-04 599 * bitmap_set_value8 - set an 8-bit value within a memory region
169c474fb22d8a5 William Breathitt Gray 2019-12-04 600 * @map: address to the bitmap memory region
169c474fb22d8a5 William Breathitt Gray 2019-12-04 601 * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
169c474fb22d8a5 William Breathitt Gray 2019-12-04 602 * @start: bit offset of the 8-bit value; must be a multiple of 8
169c474fb22d8a5 William Breathitt Gray 2019-12-04 603 */
169c474fb22d8a5 William Breathitt Gray 2019-12-04 604 static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
169c474fb22d8a5 William Breathitt Gray 2019-12-04 605 unsigned long start)
169c474fb22d8a5 William Breathitt Gray 2019-12-04 606 {
169c474fb22d8a5 William Breathitt Gray 2019-12-04 607 const size_t index = BIT_WORD(start);
169c474fb22d8a5 William Breathitt Gray 2019-12-04 608 const unsigned long offset = start % BITS_PER_LONG;
169c474fb22d8a5 William Breathitt Gray 2019-12-04 609
169c474fb22d8a5 William Breathitt Gray 2019-12-04 610 map[index] &= ~(0xFFUL << offset);
169c474fb22d8a5 William Breathitt Gray 2019-12-04 611 map[index] |= value << offset;
169c474fb22d8a5 William Breathitt Gray 2019-12-04 612 }
169c474fb22d8a5 William Breathitt Gray 2019-12-04 613
66845ead81685a8 Syed Nayyar Waris 2020-10-03 614 /**
66845ead81685a8 Syed Nayyar Waris 2020-10-03 615 * bitmap_set_value - set n-bit value within a memory region
66845ead81685a8 Syed Nayyar Waris 2020-10-03 616 * @map: address to the bitmap memory region
66845ead81685a8 Syed Nayyar Waris 2020-10-03 617 * @value: value of nbits
66845ead81685a8 Syed Nayyar Waris 2020-10-03 618 * @start: bit offset of the n-bit value
66845ead81685a8 Syed Nayyar Waris 2020-10-03 619 * @nbits: size of value in bits
66845ead81685a8 Syed Nayyar Waris 2020-10-03 620 */
66845ead81685a8 Syed Nayyar Waris 2020-10-03 621 static inline void bitmap_set_value(unsigned long *map,
66845ead81685a8 Syed Nayyar Waris 2020-10-03 622 unsigned long value,
66845ead81685a8 Syed Nayyar Waris 2020-10-03 623 unsigned long start, unsigned long nbits)
66845ead81685a8 Syed Nayyar Waris 2020-10-03 624 {
66845ead81685a8 Syed Nayyar Waris 2020-10-03 625 const size_t index = BIT_WORD(start);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 626 const unsigned long offset = start % BITS_PER_LONG;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 627 const unsigned long ceiling = roundup(start + 1, BITS_PER_LONG);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 628 const unsigned long space = ceiling - start;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 629
66845ead81685a8 Syed Nayyar Waris 2020-10-03 630 value &= GENMASK(nbits - 1, 0);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 631
66845ead81685a8 Syed Nayyar Waris 2020-10-03 632 if (space >= nbits) {
66845ead81685a8 Syed Nayyar Waris 2020-10-03 633 map[index] &= ~(GENMASK(nbits + offset - 1, offset));
66845ead81685a8 Syed Nayyar Waris 2020-10-03 634 map[index] |= value << offset;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 635 } else {
66845ead81685a8 Syed Nayyar Waris 2020-10-03 636 map[index] &= ~BITMAP_FIRST_WORD_MASK(start);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 637 map[index] |= value << offset;
66845ead81685a8 Syed Nayyar Waris 2020-10-03 @638 map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 @639 map[index + 1] |= (value >> space);
66845ead81685a8 Syed Nayyar Waris 2020-10-03 640 }
66845ead81685a8 Syed Nayyar Waris 2020-10-03 641 }
66845ead81685a8 Syed Nayyar Waris 2020-10-03 642 ---
0-DAY CI Kernel Test Service, Intel Corporation
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