Currently, only x86 genuinely implements and supports Syscall User Dispatch (SUD). Multiple architectures provide a stub arch_syscall_is_vdso_sigreturn() returning 'false' simply to satisfy GENERIC_ENTRY compilation, which creates a false impression of feature support.
Introduce ARCH_SUPPORTS_SYSCALL_USER_DISPATCH to decouple this mechanism from GENERIC_ENTRY. Select it exclusively on x86 and remove the redundant stub functions from other architectures. Link: https://lore.kernel.org/linux-arm-kernel/[email protected]/ Cc: Thomas Gleixner <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Ada Couprie Diaz <[email protected]> Cc: Thomas Weißschuh <[email protected]> Suggested-by: Mark Rutland <[email protected]> Signed-off-by: Jinjie Ruan <[email protected]> --- arch/Kconfig | 1 + arch/loongarch/include/asm/syscall.h | 6 ------ arch/powerpc/include/asm/syscall.h | 5 ----- arch/riscv/include/asm/syscall.h | 5 ----- arch/s390/include/asm/syscall.h | 5 ----- arch/x86/Kconfig | 1 + 6 files changed, 2 insertions(+), 21 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 0c01521c2f3f..393d0fb75eac 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -116,6 +116,7 @@ config GENERIC_ENTRY config SYSCALL_USER_DISPATCH bool "Syscall User Dispatch" + depends on ARCH_SUPPORTS_SYSCALL_USER_DISPATCH depends on GENERIC_ENTRY default y help diff --git a/arch/loongarch/include/asm/syscall.h b/arch/loongarch/include/asm/syscall.h index df8ea223c77b..d9275010f548 100644 --- a/arch/loongarch/include/asm/syscall.h +++ b/arch/loongarch/include/asm/syscall.h @@ -84,10 +84,4 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_LOONGARCH64; #endif } - -static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) -{ - return false; -} - #endif /* __ASM_LOONGARCH_SYSCALL_H */ diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h index 834fcc4f7b54..4b3c52ed6e9d 100644 --- a/arch/powerpc/include/asm/syscall.h +++ b/arch/powerpc/include/asm/syscall.h @@ -139,9 +139,4 @@ static inline int syscall_get_arch(struct task_struct *task) else return AUDIT_ARCH_PPC64; } - -static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) -{ - return false; -} #endif /* _ASM_SYSCALL_H */ diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h index 8067e666a4ca..987c9a78806f 100644 --- a/arch/riscv/include/asm/syscall.h +++ b/arch/riscv/include/asm/syscall.h @@ -112,11 +112,6 @@ static inline void syscall_handler(struct pt_regs *regs, ulong syscall) regs->a0 = fn(regs); } -static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) -{ - return false; -} - asmlinkage long sys_riscv_flush_icache(uintptr_t, uintptr_t, uintptr_t); asmlinkage long sys_riscv_hwprobe(struct riscv_hwprobe *, size_t, size_t, diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h index 4271e4169f45..5f310caad1fc 100644 --- a/arch/s390/include/asm/syscall.h +++ b/arch/s390/include/asm/syscall.h @@ -89,11 +89,6 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_S390X; } -static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) -{ - return false; -} - #define SYSCALL_FMT_0 #define SYSCALL_FMT_1 , "0" (r2) #define SYSCALL_FMT_2 , "d" (r3) SYSCALL_FMT_1 diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index bdad90f210e4..f3f8ad107eeb 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -335,6 +335,7 @@ config X86 select SCHED_SMT if SMP select ARCH_SUPPORTS_SCHED_CLUSTER if SMP select ARCH_SUPPORTS_SCHED_MC if SMP + select ARCH_SUPPORTS_SYSCALL_USER_DISPATCH select HAVE_SINGLE_FTRACE_DIRECT_OPS if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS config INSTRUCTION_DECODER -- 2.34.1
