From 94f9c00f6460c0b175226c8fe6fd137547b239bd Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Jul 2021 12:24:42 +0100 Subject: arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores The scheduler now knows enough about these braindead systems to place 32-bit tasks accordingly, so throw out the safety checks and allow the ret-to-user path to avoid do_notify_resume() if there is nothing to do. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20210730112443.23245-16-will@kernel.org --- arch/arm64/kernel/signal.c | 26 -------------------------- 1 file changed, 26 deletions(-) (limited to 'arch/arm64/kernel/signal.c') diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 23036334f4dc..22899c86711a 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -912,19 +912,6 @@ static void do_signal(struct pt_regs *regs) restore_saved_sigmask(); } -static bool cpu_affinity_invalid(struct pt_regs *regs) -{ - if (!compat_user_mode(regs)) - return false; - - /* - * We're preemptible, but a reschedule will cause us to check the - * affinity again. - */ - return !cpumask_test_cpu(raw_smp_processor_id(), - system_32bit_el0_cpumask()); -} - asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) { @@ -952,19 +939,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, if (thread_flags & _TIF_NOTIFY_RESUME) { tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); - - /* - * If we reschedule after checking the affinity - * then we must ensure that TIF_NOTIFY_RESUME - * is set so that we check the affinity again. - * Since tracehook_notify_resume() clears the - * flag, ensure that the compiler doesn't move - * it after the affinity check. - */ - barrier(); - - if (cpu_affinity_invalid(regs)) - force_sig(SIGKILL); } if (thread_flags & _TIF_FOREIGN_FPSTATE) -- cgit v1.2.3