On Thu, Jul 09, 2026 at 03:28:03PM +0800, Jinjie Ruan wrote: > 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.
Nice, this confused me before. > 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 ARCH_SUPPORTS_SYSCALL_USER_DISPATCH is not declared as a config option, so the 'select' will not do anything. Needs this: config ARCH_SUPPORTS_SYSCALL_USER_DISPATCH bool > depends on GENERIC_ENTRY > default y > help (...)
