hardirq/nmi: Allow nested nmi_enter() (69ea03b5) · Commits · 戴 / test

arch/arm64/kernel/sdei.c

+2 −12

Original line number	Diff line number	Diff line
		@@ -251,21 +251,11 @@ asmlinkage __kprobes notrace unsigned long
		__sdei_handler(struct pt_regs regs, struct sdei_registered_event arg)
		{
		unsigned long ret;
		bool do_nmi_exit = false;

		/*
		* nmi_enter() deals with printk() re-entrance and use of RCU when
		* RCU believed this CPU was idle. Because critical events can
		* interrupt normal events, we may already be in_nmi().
		*/
		if (!in_nmi()) {
		nmi_enter();
		do_nmi_exit = true;
		}

		ret = _sdei_handler(regs, arg);

		if (do_nmi_exit)
		nmi_exit();

		return ret;

+2 −6

Original line number	Diff line number	Diff line
		@@ -906,16 +906,12 @@ bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)

		asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
		{
		const bool was_in_nmi = in_nmi();

		if (!was_in_nmi)
		nmi_enter();

		/* non-RAS errors are not containable */
		if (!arm64_is_ras_serror(esr) \|\| arm64_is_fatal_ras_serror(regs, esr))
		arm64_serror_panic(regs, esr);

		if (!was_in_nmi)
		nmi_exit();
		}

+6 −16

Original line number	Diff line number	Diff line
		@@ -441,14 +441,8 @@ nonrecoverable:
		void system_reset_exception(struct pt_regs *regs)
		{
		unsigned long hsrr0, hsrr1;
		bool nested = in_nmi();
		bool saved_hsrrs = false;

		/*
		* Avoid crashes in case of nested NMI exceptions. Recoverability
		* is determined by RI and in_nmi
		*/
		if (!nested)
		nmi_enter();

		/*
		@@ -521,7 +515,6 @@ out:
		mtspr(SPRN_HSRR1, hsrr1);
		}

		if (!nested)
		nmi_exit();

		/* What should we do here? We could issue a shutdown or hard reset. */
		@@ -823,8 +816,7 @@ int machine_check_generic(struct pt_regs *regs)
		void machine_check_exception(struct pt_regs *regs)
		{
		int recover = 0;
		bool nested = in_nmi();
		if (!nested)

		nmi_enter();

		__this_cpu_inc(irq_stat.mce_exceptions);
		@@ -851,7 +843,6 @@ void machine_check_exception(struct pt_regs *regs)
		if (check_io_access(regs))
		goto bail;

		if (!nested)
		nmi_exit();

		die("Machine check", regs, SIGBUS);
		@@ -863,7 +854,6 @@ void machine_check_exception(struct pt_regs *regs)
		return;

		bail:
		if (!nested)
		nmi_exit();
		}

+4 −1

Original line number	Diff line number	Diff line
		@@ -65,13 +65,16 @@ extern void irq_exit(void);
		#define arch_nmi_exit() do { } while (0)
		#endif

		/*
		* nmi_enter() can nest up to 15 times; see NMI_BITS.
		*/
		#define nmi_enter() \
		do { \
		arch_nmi_enter(); \
		printk_nmi_enter(); \
		lockdep_off(); \
		ftrace_nmi_enter(); \
		BUG_ON(in_nmi()); \
		BUG_ON(in_nmi() == NMI_MASK); \
		preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \
		rcu_nmi_enter(); \
		lockdep_hardirq_enter(); \

+2 −2

Original line number	Diff line number	Diff line
		@@ -26,13 +26,13 @@
		* PREEMPT_MASK: 0x000000ff
		* SOFTIRQ_MASK: 0x0000ff00
		* HARDIRQ_MASK: 0x000f0000
		* NMI_MASK: 0x00100000
		* NMI_MASK: 0x00f00000
		* PREEMPT_NEED_RESCHED: 0x80000000
		*/
		#define PREEMPT_BITS 8
		#define SOFTIRQ_BITS 8
		#define HARDIRQ_BITS 4
		#define NMI_BITS 1
		#define NMI_BITS 4

		#define PREEMPT_SHIFT 0
		#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)