From ee935e8dc757614006ac29a7d98a15882cdcaeb2 Mon Sep 17 00:00:00 2001 From: Gregory Price Date: Mon, 6 Jul 2026 10:00:18 -0400 Subject: 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 Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260706140020.873735-2-gourry@gourry.net --- include/linux/entry-common.h | 6 ++---- include/linux/syscall_user_dispatch.h | 28 ++++++++++++++++++++++++++-- include/linux/syscall_user_dispatch_types.h | 2 +- 3 files changed, 29 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 416a3352261f..9336516430a1 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -9,6 +9,7 @@ #include #include #include +#include #include #include @@ -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 3858a6ffdd5c..3dd30f4b2799 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 +#include #include -#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 3be36b06c7d7..c0bdd4f760d3 100644 --- a/include/linux/syscall_user_dispatch_types.h +++ b/include/linux/syscall_user_dispatch_types.h @@ -4,7 +4,7 @@ #include -#ifdef CONFIG_GENERIC_ENTRY +#ifdef CONFIG_SYSCALL_USER_DISPATCH struct syscall_user_dispatch { char __user *selector; -- cgit v1.2.3