diff options
| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2026-02-17 17:05:08 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-03-03 08:35:07 -0800 |
| commit | 6fe54677bcc2e7a42f5fcaa3c66600232ba54d44 (patch) | |
| tree | ba956500a3e669fa3fd6e355cbccdb64f28d221d | |
| parent | 309d8808eef93d29b65ae69241a4475b2c8bd6fe (diff) | |
s390: Introduce bpf_get_lowcore() kfunc
Implementing BPF version of preempt_count() requires accessing lowcore
from BPF. Since lowcore can be relocated, open-coding
(struct lowcore *)0 does not work, so add a kfunc.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20260217160813.100855-2-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | arch/s390/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/bpf.c | 12 | ||||
| -rw-r--r-- | kernel/bpf/helpers.c | 3 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/bpf_experimental.h | 4 |
4 files changed, 21 insertions, 0 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile index 42c83d60d6fa..b522c6649fcc 100644 --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -80,5 +80,7 @@ obj-$(CONFIG_PERF_EVENTS) += perf_pai.o obj-$(CONFIG_TRACEPOINTS) += trace.o +obj-$(CONFIG_BPF_SYSCALL) += bpf.o + # vdso obj-y += vdso/ diff --git a/arch/s390/kernel/bpf.c b/arch/s390/kernel/bpf.c new file mode 100644 index 000000000000..713337fae626 --- /dev/null +++ b/arch/s390/kernel/bpf.c @@ -0,0 +1,12 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <asm/lowcore.h> +#include <linux/btf.h> + +__bpf_kfunc_start_defs(); + +__bpf_kfunc struct lowcore *bpf_get_lowcore(void) +{ + return get_lowcore(); +} + +__bpf_kfunc_end_defs(); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 6eb6c82ed2ee..cb6d242bd093 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4578,6 +4578,9 @@ BTF_ID_FLAGS(func, bpf_key_put, KF_RELEASE) BTF_ID_FLAGS(func, bpf_verify_pkcs7_signature, KF_SLEEPABLE) #endif #endif +#ifdef CONFIG_S390 +BTF_ID_FLAGS(func, bpf_get_lowcore) +#endif BTF_KFUNCS_END(generic_btf_ids) static const struct btf_kfunc_id_set generic_kfunc_set = { diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index 9df77e59d4f5..4453ad27b2ef 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -627,6 +627,10 @@ struct task_struct___preempt_rt { int softirq_disable_cnt; } __attribute__((preserve_access_index)); +#ifdef bpf_target_s390 +extern struct lowcore *bpf_get_lowcore(void) __weak __ksym; +#endif + static inline int get_preempt_count(void) { #if defined(bpf_target_x86) |