Add an arena-based word-aligned bitmap data struture. The structure is useful as a building block, e.g., sched-ext uses it to represent cpumask structures. Signed-off-by: Emil Tsalapatis --- .../bpf/libarena/include/libarena/bitmap.h | 34 +++ .../selftests/bpf/libarena/src/bitmap.bpf.c | 245 ++++++++++++++++++ 2 files changed, 279 insertions(+) create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/bitmap.h create mode 100644 tools/testing/selftests/bpf/libarena/src/bitmap.bpf.c diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/bitmap.h b/tools/testing/selftests/bpf/libarena/include/libarena/bitmap.h new file mode 100644 index 000000000000..cf6b63f5d9a4 --- /dev/null +++ b/tools/testing/selftests/bpf/libarena/include/libarena/bitmap.h @@ -0,0 +1,34 @@ +#pragma once + +#define BITS_PER_BYTE 8 +#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_BYTE) + +#define BITS_PER_LONG_LONG (sizeof(long long) * BITS_PER_BYTE) +#define BITS_TO_LONG_LONGS(nr) (((nr) + BITS_PER_LONG_LONG - 1) / BITS_PER_LONG_LONG) +#define BIT_MASK(nr) (1ULL << ((nr) % BITS_PER_LONG_LONG)) +#define BIT_WORD(nr) ((nr) / BITS_PER_LONG_LONG) + +struct bitmap { + u64 bits[0]; +}; + +struct bitmap __arena *bmp_alloc(size_t bits); +void bmp_free(struct bitmap __arena *bmp); + +void __bmp_set_bit(u32 bit, struct bitmap __arena *bmp); +void __bmp_clear_bit(u32 bit, struct bitmap __arena *bmp); +void bmp_set_bit(u32 bit, struct bitmap __arena *bmp); +void bmp_clear_bit(u32 bit, struct bitmap __arena *bmp); +bool bmp_test_bit(u32 bit, struct bitmap __arena *bmp); +bool bmp_test_and_clear_bit(u32 bit, struct bitmap __arena *bmp); +bool bmp_test_and_set_bit(u32 bit, struct bitmap __arena *bmp); + +void bmp_clear(size_t bits, struct bitmap __arena *bmp); +void bmp_and(size_t bits, struct bitmap __arena *dst, struct bitmap __arena *src1, struct bitmap __arena *src2); +void bmp_or(size_t bits, struct bitmap __arena *dst, struct bitmap __arena *src1, struct bitmap __arena *src2); +bool bmp_empty(size_t bits, struct bitmap __arena *bmp); +void bmp_copy(size_t bits, struct bitmap __arena *dst, struct bitmap __arena *src); + +bool bmp_intersects(size_t bits, struct bitmap __arena *arg1, struct bitmap __arena *arg2); +bool bmp_subset(size_t bits, struct bitmap __arena *big, struct bitmap __arena *small); +void bmp_print(size_t bits, struct bitmap __arena *bmp); diff --git a/tools/testing/selftests/bpf/libarena/src/bitmap.bpf.c b/tools/testing/selftests/bpf/libarena/src/bitmap.bpf.c new file mode 100644 index 000000000000..80e814401fb9 --- /dev/null +++ b/tools/testing/selftests/bpf/libarena/src/bitmap.bpf.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause +/* + * Copyright (c) 2025-2026 Meta Platforms, Inc. and affiliates. + * Copyright (c) 2025-2026 Emil Tsalapatis + */ + +#include + +#include +#include + +__weak +struct bitmap __arena *bmp_alloc(size_t bits) +{ + struct bitmap __arena *bmp; + size_t size = BITS_TO_LONG_LONGS(bits) * sizeof(bmp->bits[0]); + + /* Assume long-aligned masks. */ + if (bits % BITS_PER_LONG_LONG) + return NULL; + + bmp = (struct bitmap __arena *)arena_malloc(size); + if (!bmp) + return NULL; + + bmp_clear(bits, bmp); + + return bmp; +} + +__weak +void bmp_free(struct bitmap __arena *bmp) +{ + arena_free(bmp); +} + +__weak +void __bmp_set_bit(u32 bit, struct bitmap __arena *bmp) +{ + bmp->bits[BIT_WORD(bit)] |= BIT_MASK(bit); +} + +__weak +void __bmp_clear_bit(u32 bit, struct bitmap __arena *bmp) +{ + bmp->bits[BIT_WORD(bit)] &= ~BIT_MASK(bit); +} + +__weak +bool bmp_test_bit(u32 bit, struct bitmap __arena *bmp) +{ + return bmp->bits[BIT_WORD(bit)] & BIT_MASK(bit); +} + +__weak +bool bmp_test_and_clear_bit(u32 bit, struct bitmap __arena *bmp) +{ + u64 val = BIT_MASK(bit); + u32 idx = BIT_WORD(bit); + u64 old, new, actual; + + do { + old = bmp->bits[idx]; + + if (!(old & val)) + return false; + + new = old & ~val; + actual = cmpxchg(&bmp->bits[idx], old, new); + + if (actual == old) + return true; + + } while (can_loop); + + return false; +} + +__weak +bool bmp_test_and_set_bit(u32 bit, struct bitmap __arena *bmp) +{ + u64 val = BIT_MASK(bit); + u32 idx = BIT_WORD(bit); + u64 old, new, actual; + + do { + old = bmp->bits[idx]; + + if ((old & val)) + return true; + + new = old | val; + actual = cmpxchg(&bmp->bits[idx], old, new); + + if (actual == old) + return false; + + } while (can_loop); + + return false; +} + +__weak +void bmp_clear_bit(u32 bit, struct bitmap __arena *bmp) +{ + u64 val = BIT_MASK(bit); + u32 idx = BIT_WORD(bit); + u64 old, new, actual; + + do { + old = bmp->bits[idx]; + new = old & ~val; + actual = cmpxchg(&bmp->bits[idx], old, new); + + } while (actual != old && can_loop); +} + +__weak +void bmp_set_bit(u32 bit, struct bitmap __arena *bmp) +{ + u64 val = BIT_MASK(bit); + u32 idx = BIT_WORD(bit); + u64 old, new, actual; + + do { + old = bmp->bits[idx]; + new = old | val; + actual = cmpxchg(&bmp->bits[idx], old, new); + + } while (actual != old && can_loop); +} + +__weak +void bmp_clear(size_t bits, struct bitmap __arena *bmp) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) + bmp->bits[i] = 0; +} + +static __always_inline u64 bmp_last_word_mask(size_t bits) +{ + u32 rem = bits % BITS_PER_LONG_LONG; + + return rem ? (1ULL << rem) - 1 : ~0ULL; +} + +__weak +void bmp_and(size_t bits, struct bitmap __arena *dst, struct bitmap __arena *src1, struct bitmap __arena *src2) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) + dst->bits[i] = src1->bits[i] & src2->bits[i]; + + if (nwords && bits % BITS_PER_LONG_LONG) + dst->bits[nwords - 1] &= bmp_last_word_mask(bits); +} + +__weak +void bmp_or(size_t bits, struct bitmap __arena *dst, struct bitmap __arena *src1, struct bitmap __arena *src2) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) + dst->bits[i] = src1->bits[i] | src2->bits[i]; + + if (nwords && bits % BITS_PER_LONG_LONG) + dst->bits[nwords - 1] &= bmp_last_word_mask(bits); +} + +__weak +bool bmp_empty(size_t bits, struct bitmap __arena *bmp) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) { + u64 mask = (i == nwords - 1) ? bmp_last_word_mask(bits) : ~0ULL; + + if (bmp->bits[i] & mask) + return false; + } + + return true; +} + +__weak +void bmp_copy(size_t bits, struct bitmap __arena *dst, struct bitmap __arena *src) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) + dst->bits[i] = src->bits[i]; + + if (nwords && bits % BITS_PER_LONG_LONG) + dst->bits[nwords - 1] &= bmp_last_word_mask(bits); +} + +__weak +bool bmp_subset(size_t bits, struct bitmap __arena *big, struct bitmap __arena *small) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) { + u64 mask = (i == nwords - 1) ? bmp_last_word_mask(bits) : ~0ULL; + + if (~big->bits[i] & small->bits[i] & mask) + return false; + } + + return true; +} + +__weak +bool bmp_intersects(size_t bits, struct bitmap __arena *arg1, struct bitmap __arena *arg2) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) { + u64 mask = (i == nwords - 1) ? bmp_last_word_mask(bits) : ~0ULL; + + if (arg1->bits[i] & arg2->bits[i] & mask) + return true; + } + + return false; +} + +__weak +void bmp_print(size_t bits, struct bitmap __arena *bmp) +{ + size_t nwords = BITS_TO_LONG_LONGS(bits); + volatile u32 i; + + for (i = zero; i < nwords && can_loop; i++) + arena_stderr("%016llx ", bmp->bits[i]); +} -- 2.54.0