Commit 118178e6 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: move NMI entry/exit code into wrapper 



This moves the common NMI entry and exit code into the interrupt handler
wrappers.

This changes the behaviour of soft-NMI (watchdog) and HMI interrupts, and
also MCE interrupts on 64e, by adding missing parts of the NMI entry to
them.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-40-npiggin@gmail.com
parent 74c3354b

arch/powerpc/include/asm/interrupt.h

+28 −0
Original line number Diff line number Diff line
@@ -94,14 +94,42 @@ static inline void interrupt_async_exit_prepare(struct pt_regs *regs, struct int 
}



struct interrupt_nmi_state {

#ifdef CONFIG_PPC64

	u8 ftrace_enabled;

#endif

};



static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)

{

#ifdef CONFIG_PPC64

	/* Allow DEC and PMI to be traced when they are soft-NMI */

	if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260) {

		state->ftrace_enabled = this_cpu_get_ftrace_enabled();

		this_cpu_set_ftrace_enabled(0);

	}

#endif



	/*

	 * Do not use nmi_enter() for pseries hash guest taking a real-mode

	 * NMI because not everything it touches is within the RMA limit.

	 */

	if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64) ||

			!firmware_has_feature(FW_FEATURE_LPAR) ||

			radix_enabled() || (mfmsr() & MSR_DR))

		nmi_enter();

}



static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)

{

	if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64) ||

			!firmware_has_feature(FW_FEATURE_LPAR) ||

			radix_enabled() || (mfmsr() & MSR_DR))

		nmi_exit();



#ifdef CONFIG_PPC64

	if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260)

		this_cpu_set_ftrace_enabled(state->ftrace_enabled);

#endif

}



/**

arch/powerpc/kernel/mce.c

+0 −11
Original line number Diff line number Diff line
@@ -587,12 +587,6 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info); 
DEFINE_INTERRUPT_HANDLER_NMI(machine_check_early)

{

	long handled = 0;

	u8 ftrace_enabled = this_cpu_get_ftrace_enabled();



	this_cpu_set_ftrace_enabled(0);

	/* Do not use nmi_enter/exit for pseries hpte guest */

	if (radix_enabled() || !firmware_has_feature(FW_FEATURE_LPAR))

		nmi_enter();



	hv_nmi_check_nonrecoverable(regs);
@@ -602,11 +596,6 @@ DEFINE_INTERRUPT_HANDLER_NMI(machine_check_early) 
	if (ppc_md.machine_check_early)

		handled = ppc_md.machine_check_early(regs);



	if (radix_enabled() || !firmware_has_feature(FW_FEATURE_LPAR))

		nmi_exit();



	this_cpu_set_ftrace_enabled(ftrace_enabled);



	return handled;

}

arch/powerpc/kernel/traps.c

+6 −29
Original line number Diff line number Diff line
@@ -435,11 +435,6 @@ DEFINE_INTERRUPT_HANDLER_NMI(system_reset_exception) 
{

	unsigned long hsrr0, hsrr1;

	bool saved_hsrrs = false;

	u8 ftrace_enabled = this_cpu_get_ftrace_enabled();



	this_cpu_set_ftrace_enabled(0);



	nmi_enter();



	/*

	 * System reset can interrupt code where HSRRs are live and MSR[RI]=1.
@@ -514,10 +509,6 @@ DEFINE_INTERRUPT_HANDLER_NMI(system_reset_exception) 
		mtspr(SPRN_HSRR1, hsrr1);

	}



	nmi_exit();



	this_cpu_set_ftrace_enabled(ftrace_enabled);



	/* What should we do here? We could issue a shutdown or hard reset. */



	return 0;
@@ -809,6 +800,12 @@ void die_mce(const char *str, struct pt_regs *regs, long err) 
}

NOKPROBE_SYMBOL(die_mce);



/*

 * BOOK3S_64 does not call this handler as a non-maskable interrupt

 * (it uses its own early real-mode handler to handle the MCE proper

 * and then raises irq_work to call this handler when interrupts are

 * enabled).

 */

#ifdef CONFIG_PPC_BOOK3S_64

DEFINE_INTERRUPT_HANDLER_ASYNC(machine_check_exception)

#else
@@ -817,20 +814,6 @@ DEFINE_INTERRUPT_HANDLER_NMI(machine_check_exception) 
{

	int recover = 0;



	/*

	 * BOOK3S_64 does not call this handler as a non-maskable interrupt

	 * (it uses its own early real-mode handler to handle the MCE proper

	 * and then raises irq_work to call this handler when interrupts are

	 * enabled).

	 *

	 * This is silly. The BOOK3S_64 should just call a different function

	 * rather than expecting semantics to magically change. Something

	 * like 'non_nmi_machine_check_exception()', perhaps?

	 */

	const bool nmi = !IS_ENABLED(CONFIG_PPC_BOOK3S_64);



	if (nmi) nmi_enter();



	__this_cpu_inc(irq_stat.mce_exceptions);



	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
@@ -862,8 +845,6 @@ DEFINE_INTERRUPT_HANDLER_NMI(machine_check_exception) 
	if (!(regs->msr & MSR_RI))

		die_mce("Unrecoverable Machine check", regs, SIGBUS);



	if (nmi) nmi_exit();



#ifdef CONFIG_PPC_BOOK3S_64

	return;

#else
@@ -1892,14 +1873,10 @@ DEFINE_INTERRUPT_HANDLER(vsx_unavailable_tm) 
DECLARE_INTERRUPT_HANDLER_NMI(performance_monitor_exception_nmi);

DEFINE_INTERRUPT_HANDLER_NMI(performance_monitor_exception_nmi)

{

	nmi_enter();



	__this_cpu_inc(irq_stat.pmu_irqs);



	perf_irq(regs);



	nmi_exit();



	return 0;

}

#endif

arch/powerpc/kernel/watchdog.c

+4 −6
Original line number Diff line number Diff line
@@ -255,11 +255,12 @@ DEFINE_INTERRUPT_HANDLER_NMI(soft_nmi_interrupt) 
	int cpu = raw_smp_processor_id();

	u64 tb;



	/* should only arrive from kernel, with irqs disabled */

	WARN_ON_ONCE(!arch_irq_disabled_regs(regs));



	if (!cpumask_test_cpu(cpu, &wd_cpus_enabled))

		return 0;



	nmi_enter();



	__this_cpu_inc(irq_stat.soft_nmi_irqs);



	tb = get_tb();
@@ -267,7 +268,7 @@ DEFINE_INTERRUPT_HANDLER_NMI(soft_nmi_interrupt) 
		wd_smp_lock(&flags);

		if (cpumask_test_cpu(cpu, &wd_smp_cpus_stuck)) {

			wd_smp_unlock(&flags);

			goto out;

			return 0;

		}

		set_cpu_stuck(cpu, tb);
@@ -291,9 +292,6 @@ DEFINE_INTERRUPT_HANDLER_NMI(soft_nmi_interrupt) 
	if (wd_panic_timeout_tb < 0x7fffffff)

		mtspr(SPRN_DEC, wd_panic_timeout_tb);



out:

	nmi_exit();



	return 0;

}