From 33a154a96e71a34a1bcca9f40da343dbbf7b38b4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 1 Oct 2026 14:52:55 +0000 Subject: selftests/bpf: Test packet range of pointers sharing an id Add tests where two packet pointers share an id and tightening one pointer's umax from its var_off would put it less than their constant distance from the other's umax: with an index & 0x38 capped at 50, the base pointer keeps umax 50, so the pointer 8 bytes further on must keep umax 58, even though its known bits allow at most 56. These refused a valid program or accepted an out-of-bounds access before the fix: - check the advanced copy, load through the base: valid, was refused; - check the base, load the byte at base + 1 through a copy advanced by 8: was accepted; - check base + 4, load 4 bytes at base + 2 through base + 8: reads two bytes past the checked range, was accepted; - the same as the second with data_meta pointers checked against data: was accepted. These pass with and without the fix and cover nearby paths: - subtract an unknown scalar from a checked pointer and load below it (the range is kept across a new id); - reach a load through two paths whose checks cover 8 and 7 bytes after the loaded pointer; the second path must not be pruned by the first; - spill a copy of a pointer, check the pointer, fill the copy and load one byte past the checked range: the load is refused, and the copy has the range of the check. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- lib/cache_maint.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 lib/cache_maint.c (limited to 'lib/cache_maint.c') diff --git a/lib/cache_maint.c b/lib/cache_maint.c new file mode 100644 index 000000000..9256a9ffc --- /dev/null +++ b/lib/cache_maint.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic support for Memory System Cache Maintenance operations. + * + * Coherency maintenance drivers register with this simple framework that will + * iterate over each registered instance to first kick off invalidation and + * then to wait until it is complete. + * + * If no implementations are registered yet cpu_cache_has_invalidate_memregion() + * will return false. If this runs concurrently with unregistration then a + * race exists but this is no worse than the case where the operations instance + * responsible for a given memory region has not yet registered. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static LIST_HEAD(cache_ops_instance_list); +static DECLARE_RWSEM(cache_ops_instance_list_lock); + +static void __cache_coherency_ops_instance_free(struct kref *kref) +{ + struct cache_coherency_ops_inst *cci = + container_of(kref, struct cache_coherency_ops_inst, kref); + kfree(cci); +} + +void cache_coherency_ops_instance_put(struct cache_coherency_ops_inst *cci) +{ + kref_put(&cci->kref, __cache_coherency_ops_instance_free); +} +EXPORT_SYMBOL_GPL(cache_coherency_ops_instance_put); + +static int cache_inval_one(struct cache_coherency_ops_inst *cci, void *data) +{ + if (!cci->ops) + return -EINVAL; + + return cci->ops->wbinv(cci, data); +} + +static int cache_inval_done_one(struct cache_coherency_ops_inst *cci) +{ + if (!cci->ops) + return -EINVAL; + + if (!cci->ops->done) + return 0; + + return cci->ops->done(cci); +} + +static int cache_invalidate_memregion(phys_addr_t addr, size_t size) +{ + int ret; + struct cache_coherency_ops_inst *cci; + struct cc_inval_params params = { + .addr = addr, + .size = size, + }; + + guard(rwsem_read)(&cache_ops_instance_list_lock); + list_for_each_entry(cci, &cache_ops_instance_list, node) { + ret = cache_inval_one(cci, ¶ms); + if (ret) + return ret; + } + list_for_each_entry(cci, &cache_ops_instance_list, node) { + ret = cache_inval_done_one(cci); + if (ret) + return ret; + } + + return 0; +} + +struct cache_coherency_ops_inst * +_cache_coherency_ops_instance_alloc(const struct cache_coherency_ops *ops, + size_t size) +{ + struct cache_coherency_ops_inst *cci; + + if (!ops || !ops->wbinv) + return NULL; + + cci = kzalloc(size, GFP_KERNEL); + if (!cci) + return NULL; + + cci->ops = ops; + INIT_LIST_HEAD(&cci->node); + kref_init(&cci->kref); + + return cci; +} +EXPORT_SYMBOL_NS_GPL(_cache_coherency_ops_instance_alloc, "CACHE_COHERENCY"); + +int cache_coherency_ops_instance_register(struct cache_coherency_ops_inst *cci) +{ + guard(rwsem_write)(&cache_ops_instance_list_lock); + list_add(&cci->node, &cache_ops_instance_list); + + return 0; +} +EXPORT_SYMBOL_NS_GPL(cache_coherency_ops_instance_register, "CACHE_COHERENCY"); + +void cache_coherency_ops_instance_unregister(struct cache_coherency_ops_inst *cci) +{ + guard(rwsem_write)(&cache_ops_instance_list_lock); + list_del(&cci->node); +} +EXPORT_SYMBOL_NS_GPL(cache_coherency_ops_instance_unregister, "CACHE_COHERENCY"); + +int cpu_cache_invalidate_memregion(phys_addr_t start, size_t len) +{ + return cache_invalidate_memregion(start, len); +} +EXPORT_SYMBOL_NS_GPL(cpu_cache_invalidate_memregion, "DEVMEM"); + +/* + * Used for optimization / debug purposes only as removal can race + * + * Machines that do not support invalidation, e.g. VMs, will not have any + * operations instance to register and so this will always return false. + */ +bool cpu_cache_has_invalidate_memregion(void) +{ + guard(rwsem_read)(&cache_ops_instance_list_lock); + return !list_empty(&cache_ops_instance_list); +} +EXPORT_SYMBOL_NS_GPL(cpu_cache_has_invalidate_memregion, "DEVMEM"); -- cgit v1.3.1