[tip: core/entry] syscall_user_dispatch: Make it configurable in Kconfig
From: tip-bot2 for Gregory Price
Date: Wed Jul 08 2026 - 04:28:47 EST
The following commit has been merged into the core/entry branch of tip:
Commit-ID: ee935e8dc757614006ac29a7d98a15882cdcaeb2
Gitweb: https://git.kernel.org/tip/ee935e8dc757614006ac29a7d98a15882cdcaeb2
Author: Gregory Price <gourry@xxxxxxxxxx>
AuthorDate: Mon, 06 Jul 2026 10:00:18 -04:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxx>
CommitterDate: Wed, 08 Jul 2026 10:22:00 +02:00
syscall_user_dispatch: Make it configurable in Kconfig
Syscall User Dispatch is presently built under CONFIG_GENERIC_SYSCALL and
cannot be disabled independently.
Add CONFIG_SYSCALL_USER_DISPATCH to make it an optional feature.
Signed-off-by: Gregory Price <gourry@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Link: https://patch.msgid.link/20260706140020.873735-2-gourry@xxxxxxxxxx
---
arch/Kconfig | 10 ++++-
include/linux/entry-common.h | 6 +--
include/linux/syscall_user_dispatch.h | 28 ++++++++++-
include/linux/syscall_user_dispatch_types.h | 2 +-
kernel/entry/Makefile | 3 +-
tools/testing/selftests/syscall_user_dispatch/config | 2 +-
6 files changed, 42 insertions(+), 9 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index fa7507a..0c01521 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -114,6 +114,16 @@ config GENERIC_ENTRY
select GENERIC_IRQ_ENTRY
select GENERIC_SYSCALL
+config SYSCALL_USER_DISPATCH
+ bool "Syscall User Dispatch"
+ depends on GENERIC_ENTRY
+ default y
+ help
+ Syscall User Dispatch lets a thread have its own system calls
+ intercepted and redirected to a userspace signal handler based
+ on a prctl() configured instruction pointer range.
+ If unsure, say Y.
+
config KPROBES
bool "Kprobes"
depends on HAVE_KPROBES
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 416a335..9336516 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -9,6 +9,7 @@
#include <linux/resume_user_mode.h>
#include <linux/seccomp.h>
#include <linux/sched.h>
+#include <linux/syscall_user_dispatch.h>
#include <asm/entry-common.h>
#include <asm/syscall.h>
@@ -55,7 +56,6 @@ static __always_inline int arch_ptrace_report_syscall_entry(struct pt_regs *regs
}
#endif
-bool syscall_user_dispatch(struct pt_regs *regs);
long trace_syscall_enter(struct pt_regs *regs, long syscall);
void trace_syscall_exit(struct pt_regs *regs, long ret);
@@ -232,10 +232,8 @@ static __always_inline void syscall_exit_work(struct pt_regs *regs, unsigned lon
* of these syscalls is unknown.
*/
if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
- if (unlikely(current->syscall_dispatch.on_dispatch)) {
- current->syscall_dispatch.on_dispatch = false;
+ if (syscall_user_dispatch_clear_on_dispatch())
return;
- }
}
audit_syscall_exit(regs);
diff --git a/include/linux/syscall_user_dispatch.h b/include/linux/syscall_user_dispatch.h
index 3858a6f..3dd30f4 100644
--- a/include/linux/syscall_user_dispatch.h
+++ b/include/linux/syscall_user_dispatch.h
@@ -6,9 +6,23 @@
#define _SYSCALL_USER_DISPATCH_H
#include <linux/thread_info.h>
+#include <linux/sched.h>
#include <linux/syscall_user_dispatch_types.h>
-#ifdef CONFIG_GENERIC_ENTRY
+struct pt_regs;
+
+#ifdef CONFIG_SYSCALL_USER_DISPATCH
+
+bool syscall_user_dispatch(struct pt_regs *regs);
+
+static __always_inline bool syscall_user_dispatch_clear_on_dispatch(void)
+{
+ if (likely(!current->syscall_dispatch.on_dispatch))
+ return false;
+
+ current->syscall_dispatch.on_dispatch = false;
+ return true;
+}
int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
unsigned long len, char __user *selector);
@@ -24,6 +38,16 @@ int syscall_user_dispatch_set_config(struct task_struct *task, unsigned long siz
#else
+static __always_inline bool syscall_user_dispatch(struct pt_regs *regs)
+{
+ return false;
+}
+
+static __always_inline bool syscall_user_dispatch_clear_on_dispatch(void)
+{
+ return false;
+}
+
static inline int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
unsigned long len, char __user *selector)
{
@@ -46,6 +70,6 @@ static inline int syscall_user_dispatch_set_config(struct task_struct *task,
return -EINVAL;
}
-#endif /* CONFIG_GENERIC_ENTRY */
+#endif /* CONFIG_SYSCALL_USER_DISPATCH */
#endif /* _SYSCALL_USER_DISPATCH_H */
diff --git a/include/linux/syscall_user_dispatch_types.h b/include/linux/syscall_user_dispatch_types.h
index 3be36b0..c0bdd4f 100644
--- a/include/linux/syscall_user_dispatch_types.h
+++ b/include/linux/syscall_user_dispatch_types.h
@@ -4,7 +4,7 @@
#include <linux/types.h>
-#ifdef CONFIG_GENERIC_ENTRY
+#ifdef CONFIG_SYSCALL_USER_DISPATCH
struct syscall_user_dispatch {
char __user *selector;
diff --git a/kernel/entry/Makefile b/kernel/entry/Makefile
index 2333d70..f220bae 100644
--- a/kernel/entry/Makefile
+++ b/kernel/entry/Makefile
@@ -13,5 +13,6 @@ CFLAGS_REMOVE_common.o = -fstack-protector -fstack-protector-strong
CFLAGS_common.o += -fno-stack-protector
obj-$(CONFIG_GENERIC_IRQ_ENTRY) += common.o
-obj-$(CONFIG_GENERIC_SYSCALL) += syscall-common.o syscall_user_dispatch.o
+obj-$(CONFIG_GENERIC_SYSCALL) += syscall-common.o
+obj-$(CONFIG_SYSCALL_USER_DISPATCH) += syscall_user_dispatch.o
obj-$(CONFIG_VIRT_XFER_TO_GUEST_WORK) += virt.o
diff --git a/tools/testing/selftests/syscall_user_dispatch/config b/tools/testing/selftests/syscall_user_dispatch/config
index 039e303..22c4dfe 100644
--- a/tools/testing/selftests/syscall_user_dispatch/config
+++ b/tools/testing/selftests/syscall_user_dispatch/config
@@ -1 +1 @@
-CONFIG_GENERIC_ENTRY=y
+CONFIG_SYSCALL_USER_DISPATCH=y