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lib: packing: duplicate pack() and unpack() implementations
packing() is now used in some hot paths, and it would be good to get rid of some ifs and buts that depend on "op", to speed things up a little bit. With the main implementations now taking size_t endbit, we no longer have to check for negative values. Update the local integer variables to also be size_t to match. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://patch.msgid.link/20241002-packing-kunit-tests-and-split-pack-unpack-v2-5-8373e551eae3@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean
Jakub Kicinski
parent
7263f64e16
commit
28aec9ca29
@ -20,8 +20,8 @@ enum packing_op {
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int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
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enum packing_op op, u8 quirks);
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int pack(void *pbuf, const u64 *uval, size_t startbit, size_t endbit,
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size_t pbuflen, u8 quirks);
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int pack(void *pbuf, u64 uval, size_t startbit, size_t endbit, size_t pbuflen,
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u8 quirks);
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int unpack(const void *pbuf, u64 *uval, size_t startbit, size_t endbit,
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size_t pbuflen, u8 quirks);
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243
lib/packing.c
243
lib/packing.c
@ -9,11 +9,11 @@
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#include <linux/types.h>
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#include <linux/bitrev.h>
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static void adjust_for_msb_right_quirk(u64 *to_write, int *box_start_bit,
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int *box_end_bit, u8 *box_mask)
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static void adjust_for_msb_right_quirk(u64 *to_write, size_t *box_start_bit,
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size_t *box_end_bit, u8 *box_mask)
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{
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int box_bit_width = *box_start_bit - *box_end_bit + 1;
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int new_box_start_bit, new_box_end_bit;
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size_t box_bit_width = *box_start_bit - *box_end_bit + 1;
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size_t new_box_start_bit, new_box_end_bit;
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*to_write >>= *box_end_bit;
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*to_write = bitrev8(*to_write) >> (8 - box_bit_width);
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@ -48,7 +48,7 @@ static void adjust_for_msb_right_quirk(u64 *to_write, int *box_start_bit,
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*
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* Return: the physical offset into the buffer corresponding to the logical box.
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*/
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static int calculate_box_addr(int box, size_t len, u8 quirks)
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static size_t calculate_box_addr(size_t box, size_t len, u8 quirks)
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{
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size_t offset_of_group, offset_in_group, this_group = box / 4;
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size_t group_size;
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@ -69,13 +69,10 @@ static int calculate_box_addr(int box, size_t len, u8 quirks)
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}
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/**
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* packing - Convert numbers (currently u64) between a packed and an unpacked
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* format. Unpacked means laid out in memory in the CPU's native
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* understanding of integers, while packed means anything else that
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* requires translation.
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* pack - Pack u64 number into bitfield of buffer.
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*
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* @pbuf: Pointer to a buffer holding the packed value.
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* @uval: Pointer to an u64 holding the unpacked value.
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* @uval: CPU-readable unpacked value to pack.
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* @startbit: The index (in logical notation, compensated for quirks) where
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* the packed value starts within pbuf. Must be larger than, or
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* equal to, endbit.
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@ -83,58 +80,45 @@ static int calculate_box_addr(int box, size_t len, u8 quirks)
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* the packed value ends within pbuf. Must be smaller than, or equal
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* to, startbit.
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* @pbuflen: The length in bytes of the packed buffer pointed to by @pbuf.
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* @op: If PACK, then uval will be treated as const pointer and copied (packed)
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* into pbuf, between startbit and endbit.
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* If UNPACK, then pbuf will be treated as const pointer and the logical
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* value between startbit and endbit will be copied (unpacked) to uval.
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* @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and
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* QUIRK_MSB_ON_THE_RIGHT.
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*
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* Note: this is deprecated, prefer to use pack() or unpack() in new code.
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*
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* Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming
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* correct usage, return code may be discarded.
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* If op is PACK, pbuf is modified.
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* If op is UNPACK, uval is modified.
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* correct usage, return code may be discarded. The @pbuf memory will
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* be modified on success.
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*/
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int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
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enum packing_op op, u8 quirks)
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int pack(void *pbuf, u64 uval, size_t startbit, size_t endbit, size_t pbuflen,
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u8 quirks)
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{
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/* Number of bits for storing "uval"
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* also width of the field to access in the pbuf
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*/
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u64 value_width;
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/* Logical byte indices corresponding to the
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* start and end of the field.
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*/
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int plogical_first_u8, plogical_last_u8, box;
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/* width of the field to access in the pbuf */
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u64 value_width;
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/* startbit is expected to be larger than endbit, and both are
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* expected to be within the logically addressable range of the buffer.
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*/
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if (unlikely(startbit < endbit || startbit >= 8 * pbuflen || endbit < 0))
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if (unlikely(startbit < endbit || startbit >= 8 * pbuflen))
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/* Invalid function call */
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return -EINVAL;
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value_width = startbit - endbit + 1;
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if (value_width > 64)
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if (unlikely(value_width > 64))
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return -ERANGE;
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/* Check if "uval" fits in "value_width" bits.
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* If value_width is 64, the check will fail, but any
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* 64-bit uval will surely fit.
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*/
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if (op == PACK && value_width < 64 && (*uval >= (1ull << value_width)))
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if (unlikely(value_width < 64 && uval >= (1ull << value_width)))
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/* Cannot store "uval" inside "value_width" bits.
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* Truncating "uval" is most certainly not desirable,
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* so simply erroring out is appropriate.
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*/
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return -ERANGE;
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/* Initialize parameter */
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if (op == UNPACK)
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*uval = 0;
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/* Iterate through an idealistic view of the pbuf as an u64 with
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* no quirks, u8 by u8 (aligned at u8 boundaries), from high to low
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* logical bit significance. "box" denotes the current logical u8.
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@ -144,11 +128,12 @@ int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
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for (box = plogical_first_u8; box >= plogical_last_u8; box--) {
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/* Bit indices into the currently accessed 8-bit box */
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int box_start_bit, box_end_bit, box_addr;
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size_t box_start_bit, box_end_bit, box_addr;
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u8 box_mask;
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/* Corresponding bits from the unpacked u64 parameter */
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int proj_start_bit, proj_end_bit;
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size_t proj_start_bit, proj_end_bit;
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u64 proj_mask;
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u64 pval;
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/* This u8 may need to be accessed in its entirety
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* (from bit 7 to bit 0), or not, depending on the
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@ -182,66 +167,21 @@ int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
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*/
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box_addr = calculate_box_addr(box, pbuflen, quirks);
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if (op == UNPACK) {
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u64 pval;
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/* Write to pbuf, read from uval */
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pval = uval & proj_mask;
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pval >>= proj_end_bit;
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if (quirks & QUIRK_MSB_ON_THE_RIGHT)
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adjust_for_msb_right_quirk(&pval,
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&box_start_bit,
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&box_end_bit,
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&box_mask);
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/* Read from pbuf, write to uval */
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pval = ((u8 *)pbuf)[box_addr] & box_mask;
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if (quirks & QUIRK_MSB_ON_THE_RIGHT)
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adjust_for_msb_right_quirk(&pval,
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&box_start_bit,
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&box_end_bit,
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&box_mask);
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pval >>= box_end_bit;
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pval <<= proj_end_bit;
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*uval &= ~proj_mask;
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*uval |= pval;
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} else {
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u64 pval;
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/* Write to pbuf, read from uval */
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pval = (*uval) & proj_mask;
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pval >>= proj_end_bit;
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if (quirks & QUIRK_MSB_ON_THE_RIGHT)
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adjust_for_msb_right_quirk(&pval,
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&box_start_bit,
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&box_end_bit,
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&box_mask);
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pval <<= box_end_bit;
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((u8 *)pbuf)[box_addr] &= ~box_mask;
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((u8 *)pbuf)[box_addr] |= pval;
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}
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pval <<= box_end_bit;
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((u8 *)pbuf)[box_addr] &= ~box_mask;
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((u8 *)pbuf)[box_addr] |= pval;
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}
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return 0;
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}
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EXPORT_SYMBOL(packing);
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/**
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* pack - Pack u64 number into bitfield of buffer.
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*
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* @pbuf: Pointer to a buffer holding the packed value.
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* @uval: Pointer to an u64 holding the unpacked value.
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* @startbit: The index (in logical notation, compensated for quirks) where
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* the packed value starts within pbuf. Must be larger than, or
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* equal to, endbit.
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* @endbit: The index (in logical notation, compensated for quirks) where
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* the packed value ends within pbuf. Must be smaller than, or equal
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* to, startbit.
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* @pbuflen: The length in bytes of the packed buffer pointed to by @pbuf.
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* @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and
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* QUIRK_MSB_ON_THE_RIGHT.
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*
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* Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming
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* correct usage, return code may be discarded. The @pbuf memory will
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* be modified on success.
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*/
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int pack(void *pbuf, const u64 *uval, size_t startbit, size_t endbit,
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size_t pbuflen, u8 quirks)
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{
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return packing(pbuf, (u64 *)uval, startbit, endbit, pbuflen, PACK, quirks);
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}
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EXPORT_SYMBOL(pack);
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/**
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@ -266,8 +206,129 @@ EXPORT_SYMBOL(pack);
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int unpack(const void *pbuf, u64 *uval, size_t startbit, size_t endbit,
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size_t pbuflen, u8 quirks)
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{
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return packing((void *)pbuf, uval, startbit, endbit, pbuflen, UNPACK, quirks);
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/* Logical byte indices corresponding to the
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* start and end of the field.
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*/
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int plogical_first_u8, plogical_last_u8, box;
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/* width of the field to access in the pbuf */
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u64 value_width;
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/* startbit is expected to be larger than endbit, and both are
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* expected to be within the logically addressable range of the buffer.
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*/
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if (unlikely(startbit < endbit || startbit >= 8 * pbuflen))
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/* Invalid function call */
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return -EINVAL;
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value_width = startbit - endbit + 1;
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if (unlikely(value_width > 64))
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return -ERANGE;
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/* Initialize parameter */
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*uval = 0;
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/* Iterate through an idealistic view of the pbuf as an u64 with
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* no quirks, u8 by u8 (aligned at u8 boundaries), from high to low
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* logical bit significance. "box" denotes the current logical u8.
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*/
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plogical_first_u8 = startbit / 8;
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plogical_last_u8 = endbit / 8;
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for (box = plogical_first_u8; box >= plogical_last_u8; box--) {
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/* Bit indices into the currently accessed 8-bit box */
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size_t box_start_bit, box_end_bit, box_addr;
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u8 box_mask;
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/* Corresponding bits from the unpacked u64 parameter */
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size_t proj_start_bit, proj_end_bit;
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u64 proj_mask;
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u64 pval;
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/* This u8 may need to be accessed in its entirety
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* (from bit 7 to bit 0), or not, depending on the
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* input arguments startbit and endbit.
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*/
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if (box == plogical_first_u8)
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box_start_bit = startbit % 8;
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else
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box_start_bit = 7;
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if (box == plogical_last_u8)
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box_end_bit = endbit % 8;
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else
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box_end_bit = 0;
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/* We have determined the box bit start and end.
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* Now we calculate where this (masked) u8 box would fit
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* in the unpacked (CPU-readable) u64 - the u8 box's
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* projection onto the unpacked u64. Though the
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* box is u8, the projection is u64 because it may fall
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* anywhere within the unpacked u64.
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*/
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proj_start_bit = ((box * 8) + box_start_bit) - endbit;
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proj_end_bit = ((box * 8) + box_end_bit) - endbit;
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proj_mask = GENMASK_ULL(proj_start_bit, proj_end_bit);
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box_mask = GENMASK_ULL(box_start_bit, box_end_bit);
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/* Determine the offset of the u8 box inside the pbuf,
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* adjusted for quirks. The adjusted box_addr will be used for
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* effective addressing inside the pbuf (so it's not
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* logical any longer).
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*/
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box_addr = calculate_box_addr(box, pbuflen, quirks);
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/* Read from pbuf, write to uval */
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pval = ((u8 *)pbuf)[box_addr] & box_mask;
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if (quirks & QUIRK_MSB_ON_THE_RIGHT)
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adjust_for_msb_right_quirk(&pval,
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&box_start_bit,
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&box_end_bit,
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&box_mask);
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pval >>= box_end_bit;
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pval <<= proj_end_bit;
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*uval &= ~proj_mask;
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*uval |= pval;
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}
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return 0;
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}
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EXPORT_SYMBOL(unpack);
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/**
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* packing - Convert numbers (currently u64) between a packed and an unpacked
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* format. Unpacked means laid out in memory in the CPU's native
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* understanding of integers, while packed means anything else that
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* requires translation.
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*
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* @pbuf: Pointer to a buffer holding the packed value.
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* @uval: Pointer to an u64 holding the unpacked value.
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* @startbit: The index (in logical notation, compensated for quirks) where
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* the packed value starts within pbuf. Must be larger than, or
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* equal to, endbit.
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* @endbit: The index (in logical notation, compensated for quirks) where
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* the packed value ends within pbuf. Must be smaller than, or equal
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* to, startbit.
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* @pbuflen: The length in bytes of the packed buffer pointed to by @pbuf.
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* @op: If PACK, then uval will be treated as const pointer and copied (packed)
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* into pbuf, between startbit and endbit.
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* If UNPACK, then pbuf will be treated as const pointer and the logical
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* value between startbit and endbit will be copied (unpacked) to uval.
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* @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and
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* QUIRK_MSB_ON_THE_RIGHT.
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*
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* Note: this is deprecated, prefer to use pack() or unpack() in new code.
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*
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* Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming
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* correct usage, return code may be discarded.
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* If op is PACK, pbuf is modified.
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* If op is UNPACK, uval is modified.
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*/
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int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
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enum packing_op op, u8 quirks)
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{
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if (op == PACK)
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return pack(pbuf, *uval, startbit, endbit, pbuflen, quirks);
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return unpack(pbuf, uval, startbit, endbit, pbuflen, quirks);
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}
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EXPORT_SYMBOL(packing);
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MODULE_DESCRIPTION("Generic bitfield packing and unpacking");
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