bpf/s390: Implement get_preempt_count()

exe_ctx test fails on s390, because get_preempt_count() is not
implemented and its fallback path always returns 0. Implement it
using the new bpf_get_lowcore() kfunc.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20260217160813.100855-3-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 4453ad27b2ef71b081a1e8b8814fc4a4fde0f5ae..44466acf808384fa641ab96e73f42bc531159125 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -651,6 +651,8 @@ static inline int get_preempt_count(void)
        return bpf_get_current_task_btf()->thread_info.preempt.count;
 #elif defined(bpf_target_powerpc)
        return bpf_get_current_task_btf()->thread_info.preempt_count;
+#elif defined(bpf_target_s390)
+       return bpf_get_lowcore()->preempt_count;
 #endif
        return 0;
 }
@@ -660,6 +662,7 @@ static inline int get_preempt_count(void)
  *     * x86
  *     * arm64
  *     * powerpc64
+ *     * s390x
  */
 static inline int bpf_in_interrupt(void)
 {
@@ -680,6 +683,7 @@ static inline int bpf_in_interrupt(void)
  *     * x86
  *     * arm64
  *     * powerpc64
+ *     * s390x
  */
 static inline int bpf_in_nmi(void)
 {
@@ -691,6 +695,7 @@ static inline int bpf_in_nmi(void)
  *     * x86
  *     * arm64
  *     * powerpc64
+ *     * s390x
  */
 static inline int bpf_in_hardirq(void)
 {
@@ -702,6 +707,7 @@ static inline int bpf_in_hardirq(void)
  *     * x86
  *     * arm64
  *     * powerpc64
+ *     * s390x
  */
 static inline int bpf_in_serving_softirq(void)
 {
@@ -721,6 +727,7 @@ static inline int bpf_in_serving_softirq(void)
  *     * x86
  *     * arm64
  *     * powerpc64
+ *     * s390x
  */
 static inline int bpf_in_task(void)
 {