add xenomai

hc

2024-11-01 2f529f9b558ca1c1bd74be7437a84e4711743404

 kernel/arch/arm64/kernel/signal.c
..
..
@@ -11,6 +11,7 @@
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 #include <linux/errno.h>
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 #include <linux/kernel.h>
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 #include <linux/signal.h>
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+#include <linux/irq_pipeline.h>
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 #include <linux/personality.h>
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 #include <linux/freezer.h>
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 #include <linux/stddef.h>
..
..
@@ -914,19 +915,36 @@
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 	restore_saved_sigmask();
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 }
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+static inline void do_retuser(void)
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+{
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+	unsigned long thread_flags;
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+
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+	if (dovetailing()) {
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+		thread_flags = current_thread_info()->flags;
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+		if (thread_flags & _TIF_RETUSER)
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+			inband_retuser_notify();
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+	}
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+}
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+
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 asmlinkage void do_notify_resume(struct pt_regs *regs,
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 				 unsigned long thread_flags)
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 {
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+	WARN_ON_ONCE(irq_pipeline_debug() && running_oob());
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+
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+	stall_inband();
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+
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 	do {
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 		/* Check valid user FS if needed */
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 		addr_limit_user_check();
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 		if (thread_flags & _TIF_NEED_RESCHED) {
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 			/* Unmask Debug and SError for the next task */
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-			local_daif_restore(DAIF_PROCCTX_NOIRQ);
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+			local_daif_restore(irqs_pipelined() ? DAIF_PROCCTX :
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+					DAIF_PROCCTX_NOIRQ);
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 			schedule();
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 		} else {
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+			unstall_inband();
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 			local_daif_restore(DAIF_PROCCTX);
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 			if (thread_flags & _TIF_UPROBE)
..
..
@@ -948,11 +966,29 @@
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 			if (thread_flags & _TIF_FOREIGN_FPSTATE)
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 				fpsimd_restore_current_state();
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+
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+			do_retuser();
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+			/* RETUSER might have switched oob */
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+			if (running_oob()) {
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+				local_daif_mask();
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+				return;
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+			}
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 		}
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+		/*
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+		 * Dovetail: we may have restored the fpsimd state for
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+		 * current with no other opportunity to check for
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+		 * _TIF_FOREIGN_FPSTATE until we are back running on
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+		 * el0, so we must not take any interrupt until then,
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+		 * otherwise we may end up resuming with some OOB
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+		 * thread's fpsimd state.
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+		 */
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 		local_daif_mask();
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+		stall_inband();
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 		thread_flags = READ_ONCE(current_thread_info()->flags);
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 	} while (thread_flags & _TIF_WORK_MASK);
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+
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+	unstall_inband();
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 }
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 unsigned long __ro_after_init signal_minsigstksz;