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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2024-04-24 05:13:14 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-04-24 18:47:49 +0200 |
| commit | fc7566ad0a826cdc8886c5dbbb39ce72a0dc6333 (patch) | |
| tree | 141b3fc7a2c4174e8d6d685a20229ffedea61846 /kernel/bpf/helpers.c | |
| parent | bpf: Don't check for recursion in bpf_wq_work. (diff) | |
| download | linux-fc7566ad0a826cdc8886c5dbbb39ce72a0dc6333.tar.xz linux-fc7566ad0a826cdc8886c5dbbb39ce72a0dc6333.zip | |
bpf: Introduce bpf_preempt_[disable,enable] kfuncs
Introduce two new BPF kfuncs, bpf_preempt_disable and
bpf_preempt_enable. These kfuncs allow disabling preemption in BPF
programs. Nesting is allowed, since the intended use cases includes
building native BPF spin locks without kernel helper involvement. Apart
from that, this can be used to per-CPU data structures for cases where
programs (or userspace) may preempt one or the other. Currently, while
per-CPU access is stable, whether it will be consistent is not
guaranteed, as only migration is disabled for BPF programs.
Global functions are disallowed from being called, but support for them
will be added as a follow up not just preempt kfuncs, but rcu_read_lock
kfuncs as well. Static subprog calls are permitted. Sleepable helpers
and kfuncs are disallowed in non-preemptible regions.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240424031315.2757363-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/helpers.c')
| -rw-r--r-- | kernel/bpf/helpers.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 5f61ffa7505a..14c401b78e12 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2734,6 +2734,16 @@ __bpf_kfunc int bpf_wq_set_callback_impl(struct bpf_wq *wq, return __bpf_async_set_callback(async, callback_fn, aux, flags, BPF_ASYNC_TYPE_WQ); } +__bpf_kfunc void bpf_preempt_disable(void) +{ + preempt_disable(); +} + +__bpf_kfunc void bpf_preempt_enable(void) +{ + preempt_enable(); +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -2814,6 +2824,8 @@ BTF_ID_FLAGS(func, bpf_modify_return_test_tp) BTF_ID_FLAGS(func, bpf_wq_init) BTF_ID_FLAGS(func, bpf_wq_set_callback_impl) BTF_ID_FLAGS(func, bpf_wq_start) +BTF_ID_FLAGS(func, bpf_preempt_disable) +BTF_ID_FLAGS(func, bpf_preempt_enable) BTF_KFUNCS_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { |