From:   Gregory Price <gourry.memverge@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kselftest@vger.kernel.org, krisman@collabora.com,
        tglx@linutronix.de, luto@kernel.org, oleg@redhat.com,
        peterz@infradead.org, ebiederm@xmission.com,
        akpm@linux-foundation.org, adobriyan@gmail.com, corbet@lwn.net,
        shuah@kernel.org, Gregory Price <gregory.price@memverge.com>
Subject: [PATCH 2/3] fs/proc/array: Add Syscall User Dispatch to proc status
Date:   Sun, 22 Jan 2023 22:29:41 -0500
Message-Id: <20230123032942.18263-3-gregory.price@memverge.com>
In-Reply-To: <20230123032942.18263-1-gregory.price@memverge.com>
References: <20230123032942.18263-1-gregory.price@memverge.com>
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Report the value of test_syscall_work(SYSCALL_USER_DISPATCH)) in
proc/status if GENERIC_ENTRY is enabled or the arch has implemented it.

This provides an indicator to userland checkpoint/restore software that
it must manage special signal conditions (similar to SECCOMP)

Signed-off-by: Gregory Price <gregory.price@memverge.com>
---
 fs/proc/array.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 49283b8103c7..d4e4ee2409c6 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -428,6 +428,15 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
 	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
 }
 
+static inline void task_syscall_user_dispatch(struct seq_file *m,
+						struct task_struct *p)
+{
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_USER_DISPATCH)
+	seq_put_decimal_ull(m, "\nSyscall_user_dispatch:\t",
+			    test_task_syscall_work(p, SYSCALL_USER_DISPATCH));
+#endif
+}
+
 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 			struct pid *pid, struct task_struct *task)
 {
@@ -451,6 +460,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 	task_cpus_allowed(m, task);
 	cpuset_task_status_allowed(m, task);
 	task_context_switch_counts(m, task);
+	task_syscall_user_dispatch(m, task);
 	return 0;
 }
 
-- 
2.39.0