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-rw-r--r--kernel/bpf/cpumask.c476
1 files changed, 476 insertions, 0 deletions
diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
new file mode 100644
index 000000000000..25355a0a367a
--- /dev/null
+++ b/kernel/bpf/cpumask.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2023 Meta, Inc */
+#include <linux/bpf.h>
+#include <linux/bpf_mem_alloc.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
+#include <linux/cpumask.h>
+
+/**
+ * struct bpf_cpumask - refcounted BPF cpumask wrapper structure
+ * @cpumask: The actual cpumask embedded in the struct.
+ * @usage: Object reference counter. When the refcount goes to 0, the
+ * memory is released back to the BPF allocator, which provides
+ * RCU safety.
+ *
+ * Note that we explicitly embed a cpumask_t rather than a cpumask_var_t. This
+ * is done to avoid confusing the verifier due to the typedef of cpumask_var_t
+ * changing depending on whether CONFIG_CPUMASK_OFFSTACK is defined or not. See
+ * the details in <linux/cpumask.h>. The consequence is that this structure is
+ * likely a bit larger than it needs to be when CONFIG_CPUMASK_OFFSTACK is
+ * defined due to embedding the whole NR_CPUS-size bitmap, but the extra memory
+ * overhead is minimal. For the more typical case of CONFIG_CPUMASK_OFFSTACK
+ * not being defined, the structure is the same size regardless.
+ */
+struct bpf_cpumask {
+ cpumask_t cpumask;
+ refcount_t usage;
+};
+
+static struct bpf_mem_alloc bpf_cpumask_ma;
+
+static bool cpu_valid(u32 cpu)
+{
+ return cpu < nr_cpu_ids;
+}
+
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+ "Global kfuncs as their definitions will be in BTF");
+
+/**
+ * bpf_cpumask_create() - Create a mutable BPF cpumask.
+ *
+ * Allocates a cpumask that can be queried, mutated, acquired, and released by
+ * a BPF program. The cpumask returned by this function must either be embedded
+ * in a map as a kptr, or freed with bpf_cpumask_release().
+ *
+ * bpf_cpumask_create() allocates memory using the BPF memory allocator, and
+ * will not block. It may return NULL if no memory is available.
+ */
+struct bpf_cpumask *bpf_cpumask_create(void)
+{
+ struct bpf_cpumask *cpumask;
+
+ cpumask = bpf_mem_alloc(&bpf_cpumask_ma, sizeof(*cpumask));
+ if (!cpumask)
+ return NULL;
+
+ memset(cpumask, 0, sizeof(*cpumask));
+ refcount_set(&cpumask->usage, 1);
+
+ return cpumask;
+}
+
+/**
+ * bpf_cpumask_acquire() - Acquire a reference to a BPF cpumask.
+ * @cpumask: The BPF cpumask being acquired. The cpumask must be a trusted
+ * pointer.
+ *
+ * Acquires a reference to a BPF cpumask. The cpumask returned by this function
+ * must either be embedded in a map as a kptr, or freed with
+ * bpf_cpumask_release().
+ */
+struct bpf_cpumask *bpf_cpumask_acquire(struct bpf_cpumask *cpumask)
+{
+ refcount_inc(&cpumask->usage);
+ return cpumask;
+}
+
+/**
+ * bpf_cpumask_kptr_get() - Attempt to acquire a reference to a BPF cpumask
+ * stored in a map.
+ * @cpumaskp: A pointer to a BPF cpumask map value.
+ *
+ * Attempts to acquire a reference to a BPF cpumask stored in a map value. The
+ * cpumask returned by this function must either be embedded in a map as a
+ * kptr, or freed with bpf_cpumask_release(). This function may return NULL if
+ * no BPF cpumask was found in the specified map value.
+ */
+struct bpf_cpumask *bpf_cpumask_kptr_get(struct bpf_cpumask **cpumaskp)
+{
+ struct bpf_cpumask *cpumask;
+
+ /* The BPF memory allocator frees memory backing its caches in an RCU
+ * callback. Thus, we can safely use RCU to ensure that the cpumask is
+ * safe to read.
+ */
+ rcu_read_lock();
+
+ cpumask = READ_ONCE(*cpumaskp);
+ if (cpumask && !refcount_inc_not_zero(&cpumask->usage))
+ cpumask = NULL;
+
+ rcu_read_unlock();
+ return cpumask;
+}
+
+/**
+ * bpf_cpumask_release() - Release a previously acquired BPF cpumask.
+ * @cpumask: The cpumask being released.
+ *
+ * Releases a previously acquired reference to a BPF cpumask. When the final
+ * reference of the BPF cpumask has been released, it is subsequently freed in
+ * an RCU callback in the BPF memory allocator.
+ */
+void bpf_cpumask_release(struct bpf_cpumask *cpumask)
+{
+ if (!cpumask)
+ return;
+
+ if (refcount_dec_and_test(&cpumask->usage)) {
+ migrate_disable();
+ bpf_mem_free(&bpf_cpumask_ma, cpumask);
+ migrate_enable();
+ }
+}
+
+/**
+ * bpf_cpumask_first() - Get the index of the first nonzero bit in the cpumask.
+ * @cpumask: The cpumask being queried.
+ *
+ * Find the index of the first nonzero bit of the cpumask. A struct bpf_cpumask
+ * pointer may be safely passed to this function.
+ */
+u32 bpf_cpumask_first(const struct cpumask *cpumask)
+{
+ return cpumask_first(cpumask);
+}
+
+/**
+ * bpf_cpumask_first_zero() - Get the index of the first unset bit in the
+ * cpumask.
+ * @cpumask: The cpumask being queried.
+ *
+ * Find the index of the first unset bit of the cpumask. A struct bpf_cpumask
+ * pointer may be safely passed to this function.
+ */
+u32 bpf_cpumask_first_zero(const struct cpumask *cpumask)
+{
+ return cpumask_first_zero(cpumask);
+}
+
+/**
+ * bpf_cpumask_set_cpu() - Set a bit for a CPU in a BPF cpumask.
+ * @cpu: The CPU to be set in the cpumask.
+ * @cpumask: The BPF cpumask in which a bit is being set.
+ */
+void bpf_cpumask_set_cpu(u32 cpu, struct bpf_cpumask *cpumask)
+{
+ if (!cpu_valid(cpu))
+ return;
+
+ cpumask_set_cpu(cpu, (struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_clear_cpu() - Clear a bit for a CPU in a BPF cpumask.
+ * @cpu: The CPU to be cleared from the cpumask.
+ * @cpumask: The BPF cpumask in which a bit is being cleared.
+ */
+void bpf_cpumask_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask)
+{
+ if (!cpu_valid(cpu))
+ return;
+
+ cpumask_clear_cpu(cpu, (struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_test_cpu() - Test whether a CPU is set in a cpumask.
+ * @cpu: The CPU being queried for.
+ * @cpumask: The cpumask being queried for containing a CPU.
+ *
+ * Return:
+ * * true - @cpu is set in the cpumask
+ * * false - @cpu was not set in the cpumask, or @cpu is an invalid cpu.
+ */
+bool bpf_cpumask_test_cpu(u32 cpu, const struct cpumask *cpumask)
+{
+ if (!cpu_valid(cpu))
+ return false;
+
+ return cpumask_test_cpu(cpu, (struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_test_and_set_cpu() - Atomically test and set a CPU in a BPF cpumask.
+ * @cpu: The CPU being set and queried for.
+ * @cpumask: The BPF cpumask being set and queried for containing a CPU.
+ *
+ * Return:
+ * * true - @cpu is set in the cpumask
+ * * false - @cpu was not set in the cpumask, or @cpu is invalid.
+ */
+bool bpf_cpumask_test_and_set_cpu(u32 cpu, struct bpf_cpumask *cpumask)
+{
+ if (!cpu_valid(cpu))
+ return false;
+
+ return cpumask_test_and_set_cpu(cpu, (struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_test_and_clear_cpu() - Atomically test and clear a CPU in a BPF
+ * cpumask.
+ * @cpu: The CPU being cleared and queried for.
+ * @cpumask: The BPF cpumask being cleared and queried for containing a CPU.
+ *
+ * Return:
+ * * true - @cpu is set in the cpumask
+ * * false - @cpu was not set in the cpumask, or @cpu is invalid.
+ */
+bool bpf_cpumask_test_and_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask)
+{
+ if (!cpu_valid(cpu))
+ return false;
+
+ return cpumask_test_and_clear_cpu(cpu, (struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_setall() - Set all of the bits in a BPF cpumask.
+ * @cpumask: The BPF cpumask having all of its bits set.
+ */
+void bpf_cpumask_setall(struct bpf_cpumask *cpumask)
+{
+ cpumask_setall((struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_clear() - Clear all of the bits in a BPF cpumask.
+ * @cpumask: The BPF cpumask being cleared.
+ */
+void bpf_cpumask_clear(struct bpf_cpumask *cpumask)
+{
+ cpumask_clear((struct cpumask *)cpumask);
+}
+
+/**
+ * bpf_cpumask_and() - AND two cpumasks and store the result.
+ * @dst: The BPF cpumask where the result is being stored.
+ * @src1: The first input.
+ * @src2: The second input.
+ *
+ * Return:
+ * * true - @dst has at least one bit set following the operation
+ * * false - @dst is empty following the operation
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+bool bpf_cpumask_and(struct bpf_cpumask *dst,
+ const struct cpumask *src1,
+ const struct cpumask *src2)
+{
+ return cpumask_and((struct cpumask *)dst, src1, src2);
+}
+
+/**
+ * bpf_cpumask_or() - OR two cpumasks and store the result.
+ * @dst: The BPF cpumask where the result is being stored.
+ * @src1: The first input.
+ * @src2: The second input.
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+void bpf_cpumask_or(struct bpf_cpumask *dst,
+ const struct cpumask *src1,
+ const struct cpumask *src2)
+{
+ cpumask_or((struct cpumask *)dst, src1, src2);
+}
+
+/**
+ * bpf_cpumask_xor() - XOR two cpumasks and store the result.
+ * @dst: The BPF cpumask where the result is being stored.
+ * @src1: The first input.
+ * @src2: The second input.
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+void bpf_cpumask_xor(struct bpf_cpumask *dst,
+ const struct cpumask *src1,
+ const struct cpumask *src2)
+{
+ cpumask_xor((struct cpumask *)dst, src1, src2);
+}
+
+/**
+ * bpf_cpumask_equal() - Check two cpumasks for equality.
+ * @src1: The first input.
+ * @src2: The second input.
+ *
+ * Return:
+ * * true - @src1 and @src2 have the same bits set.
+ * * false - @src1 and @src2 differ in at least one bit.
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+bool bpf_cpumask_equal(const struct cpumask *src1, const struct cpumask *src2)
+{
+ return cpumask_equal(src1, src2);
+}
+
+/**
+ * bpf_cpumask_intersects() - Check two cpumasks for overlap.
+ * @src1: The first input.
+ * @src2: The second input.
+ *
+ * Return:
+ * * true - @src1 and @src2 have at least one of the same bits set.
+ * * false - @src1 and @src2 don't have any of the same bits set.
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+bool bpf_cpumask_intersects(const struct cpumask *src1, const struct cpumask *src2)
+{
+ return cpumask_intersects(src1, src2);
+}
+
+/**
+ * bpf_cpumask_subset() - Check if a cpumask is a subset of another.
+ * @src1: The first cpumask being checked as a subset.
+ * @src2: The second cpumask being checked as a superset.
+ *
+ * Return:
+ * * true - All of the bits of @src1 are set in @src2.
+ * * false - At least one bit in @src1 is not set in @src2.
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+bool bpf_cpumask_subset(const struct cpumask *src1, const struct cpumask *src2)
+{
+ return cpumask_subset(src1, src2);
+}
+
+/**
+ * bpf_cpumask_empty() - Check if a cpumask is empty.
+ * @cpumask: The cpumask being checked.
+ *
+ * Return:
+ * * true - None of the bits in @cpumask are set.
+ * * false - At least one bit in @cpumask is set.
+ *
+ * A struct bpf_cpumask pointer may be safely passed to @cpumask.
+ */
+bool bpf_cpumask_empty(const struct cpumask *cpumask)
+{
+ return cpumask_empty(cpumask);
+}
+
+/**
+ * bpf_cpumask_full() - Check if a cpumask has all bits set.
+ * @cpumask: The cpumask being checked.
+ *
+ * Return:
+ * * true - All of the bits in @cpumask are set.
+ * * false - At least one bit in @cpumask is cleared.
+ *
+ * A struct bpf_cpumask pointer may be safely passed to @cpumask.
+ */
+bool bpf_cpumask_full(const struct cpumask *cpumask)
+{
+ return cpumask_full(cpumask);
+}
+
+/**
+ * bpf_cpumask_copy() - Copy the contents of a cpumask into a BPF cpumask.
+ * @dst: The BPF cpumask being copied into.
+ * @src: The cpumask being copied.
+ *
+ * A struct bpf_cpumask pointer may be safely passed to @src.
+ */
+void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src)
+{
+ cpumask_copy((struct cpumask *)dst, src);
+}
+
+/**
+ * bpf_cpumask_any() - Return a random set CPU from a cpumask.
+ * @cpumask: The cpumask being queried.
+ *
+ * Return:
+ * * A random set bit within [0, num_cpus) if at least one bit is set.
+ * * >= num_cpus if no bit is set.
+ *
+ * A struct bpf_cpumask pointer may be safely passed to @src.
+ */
+u32 bpf_cpumask_any(const struct cpumask *cpumask)
+{
+ return cpumask_any(cpumask);
+}
+
+/**
+ * bpf_cpumask_any_and() - Return a random set CPU from the AND of two
+ * cpumasks.
+ * @src1: The first cpumask.
+ * @src2: The second cpumask.
+ *
+ * Return:
+ * * A random set bit within [0, num_cpus) if at least one bit is set.
+ * * >= num_cpus if no bit is set.
+ *
+ * struct bpf_cpumask pointers may be safely passed to @src1 and @src2.
+ */
+u32 bpf_cpumask_any_and(const struct cpumask *src1, const struct cpumask *src2)
+{
+ return cpumask_any_and(src1, src2);
+}
+
+__diag_pop();
+
+BTF_SET8_START(cpumask_kfunc_btf_ids)
+BTF_ID_FLAGS(func, bpf_cpumask_create, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_cpumask_release, KF_RELEASE | KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_cpumask_first, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_first_zero, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_set_cpu, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_clear_cpu, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_test_cpu, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_test_and_set_cpu, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_test_and_clear_cpu, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_setall, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_clear, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_and, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_or, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_xor, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_equal, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_intersects, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_subset, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_empty, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_full, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_copy, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_any, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_any_and, KF_TRUSTED_ARGS)
+BTF_SET8_END(cpumask_kfunc_btf_ids)
+
+static const struct btf_kfunc_id_set cpumask_kfunc_set = {
+ .owner = THIS_MODULE,
+ .set = &cpumask_kfunc_btf_ids,
+};
+
+BTF_ID_LIST(cpumask_dtor_ids)
+BTF_ID(struct, bpf_cpumask)
+BTF_ID(func, bpf_cpumask_release)
+
+static int __init cpumask_kfunc_init(void)
+{
+ int ret;
+ const struct btf_id_dtor_kfunc cpumask_dtors[] = {
+ {
+ .btf_id = cpumask_dtor_ids[0],
+ .kfunc_btf_id = cpumask_dtor_ids[1]
+ },
+ };
+
+ ret = bpf_mem_alloc_init(&bpf_cpumask_ma, 0, false);
+ ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &cpumask_kfunc_set);
+ ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &cpumask_kfunc_set);
+ return ret ?: register_btf_id_dtor_kfuncs(cpumask_dtors,
+ ARRAY_SIZE(cpumask_dtors),
+ THIS_MODULE);
+}
+
+late_initcall(cpumask_kfunc_init);