Re: [PATCH v2 3/5] selftests/bpf: Use the new NMI_BITS definition

[Leon Hwang <leon.hwang@linux.dev>]

On 1/10/26 21:13, Boqun Feng wrote:
> On Thu, Oct 01, 2026 at 10:25:17AM +0200, Boqun Feng wrote:
>> The definition of NMI_BITS was out of sync after the introduction of
>> HAS_SEPARATE_PREEMPT_RESCHED_BITS, hence adjust it.
>>
>> Reported-by: Shrikanth Hegde <sshegde@linux.ibm.com>
>> Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
>> Signed-off-by: Boqun Feng <boqun@kernel.org>
>> ---
>>  tools/testing/selftests/bpf/bpf_experimental.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
>> index 2893bf06ff25..4bf7390994bf 100644
>> --- a/tools/testing/selftests/bpf/bpf_experimental.h
>> +++ b/tools/testing/selftests/bpf/bpf_experimental.h
> 
> Per sashiko's report, seems I need the following to make it work:

Sashiko is correct.

BPF compilation context is different from kernel compilation context. It
cannot directly use
IS_ENABLED(CONFIG_HAS_SEPARATE_PREEMPT_RESCHED_BITS)) when compiling BPF
objects.

> 
> diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
> index 4bf7390994bf..94143cf0ab0d 100644
> --- a/tools/testing/selftests/bpf/bpf_experimental.h
> +++ b/tools/testing/selftests/bpf/bpf_experimental.h
> @@ -367,6 +367,9 @@ extern int bpf_cgroup_read_xattr(struct cgroup *cgroup, const char *name__str,
>  extern int bpf_sock_read_xattr(struct socket *sock, const char *name__str,
>                                struct bpf_dynptr *value_p) __weak __ksym;
> 
> +extern bool CONFIG_HAS_SEPARATE_PREEMPT_RESCHED_BITS __kconfig __weak;
> +#define IS_ENABLED(cfg) (cfg)

Correct.

IS_ENABLED is unnecessary here.

The below patch passed the BPF ci [1].

[1] https://github.com/kernel-patches/bpf/pull/14197

> +
>  #define PREEMPT_BITS   8
>  #define SOFTIRQ_BITS   8
>  #define HARDIRQ_DISABLE_BITS   8
> 
> ?
> 
> [Cc Leon and Alexi]

Please cc BPF list, BPF maintainers, and me when respinning.

Thanks,
Leon

> 
> Regards,
> Boqun
> 
---

From 4c1b9a6f6404aa25d1d300465dba4bee9a139668 Mon Sep 17 00:00:00 2001
From: Boqun Feng <boqun@kernel.org>
Date: Thu, 1 Oct 2026 10:25:17 +0200
Subject: [PATCH 1/3] selftests/bpf: Use the new NMI_BITS definition

The definition of NMI_BITS was out of sync after the introduction of
HAS_SEPARATE_PREEMPT_RESCHED_BITS, hence adjust it.

Reported-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
---
 tools/testing/selftests/bpf/bpf_experimental.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/bpf_experimental.h
b/tools/testing/selftests/bpf/bpf_experimental.h
index 2893bf06ff25..b567a48f1dce 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -367,11 +367,13 @@ extern int bpf_cgroup_read_xattr(struct cgroup
*cgroup, const char *name__str,
 extern int bpf_sock_read_xattr(struct socket *sock, const char *name__str,
 			       struct bpf_dynptr *value_p) __weak __ksym;

+extern bool CONFIG_HAS_SEPARATE_PREEMPT_RESCHED_BITS __weak __kconfig;
+
 #define PREEMPT_BITS	8
 #define SOFTIRQ_BITS	8
 #define HARDIRQ_DISABLE_BITS	8
 #define HARDIRQ_BITS	4
-#define NMI_BITS	1
+#define NMI_BITS	(1 + 3*CONFIG_HAS_SEPARATE_PREEMPT_RESCHED_BITS)

 #define PREEMPT_SHIFT	0
 #define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
-- 
2.55.0