Commit 3db8aa10 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/64e/interrupt: NMI save irq soft-mask state in C 



64e non-maskable interrupts save the state of the irq soft-mask in
asm. This can be done in C in interrupt wrappers as 64s does.

I haven't been able to test this with qemu because it doesn't seem
to cause FSL bookE WDT interrupts.

This makes WatchdogException an NMI interrupt, which affects 32-bit
as well (okay, or create a new handler?)

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/20210316104206.407354-6-npiggin@gmail.com
parent 0c2472de

arch/powerpc/include/asm/interrupt.h

+22 −10
Original line number Diff line number Diff line
@@ -149,18 +149,32 @@ static inline void interrupt_async_exit_prepare(struct pt_regs *regs, struct int 


struct interrupt_nmi_state {

#ifdef CONFIG_PPC64

#ifdef CONFIG_PPC_BOOK3S_64

	u8 irq_soft_mask;

	u8 irq_happened;

#endif

	u8 ftrace_enabled;

#endif

};



static inline bool nmi_disables_ftrace(struct pt_regs *regs)

{

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

	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64)) {

		if (TRAP(regs) == 0x900)

		       return false;

		if (TRAP(regs) == 0xf00)

		       return false;

	}

	if (IS_ENABLED(CONFIG_PPC_BOOK3E)) {

		if (TRAP(regs) == 0x260)

			return false;

	}



	return true;

}



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

{

#ifdef CONFIG_PPC64

#ifdef CONFIG_PPC_BOOK3S_64

	state->irq_soft_mask = local_paca->irq_soft_mask;

	state->irq_happened = local_paca->irq_happened;
@@ -173,9 +187,8 @@ static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct inte 
	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;



	/* Don't do any per-CPU operations until interrupt state is fixed */

#endif

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

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



	if (nmi_disables_ftrace(regs)) {

		state->ftrace_enabled = this_cpu_get_ftrace_enabled();

		this_cpu_set_ftrace_enabled(0);

	}
@@ -204,16 +217,14 @@ static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct inter 
	 */



#ifdef CONFIG_PPC64

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

	if (nmi_disables_ftrace(regs))

		this_cpu_set_ftrace_enabled(state->ftrace_enabled);



#ifdef CONFIG_PPC_BOOK3S_64

	/* Check we didn't change the pending interrupt mask. */

	WARN_ON_ONCE((state->irq_happened | PACA_IRQ_HARD_DIS) != local_paca->irq_happened);

	local_paca->irq_happened = state->irq_happened;

	local_paca->irq_soft_mask = state->irq_soft_mask;

#endif

#endif

}



/*
@@ -426,6 +437,7 @@ DECLARE_INTERRUPT_HANDLER(SMIException); 
DECLARE_INTERRUPT_HANDLER(handle_hmi_exception);

DECLARE_INTERRUPT_HANDLER(unknown_exception);

DECLARE_INTERRUPT_HANDLER_ASYNC(unknown_async_exception);

DECLARE_INTERRUPT_HANDLER_NMI(unknown_nmi_exception);

DECLARE_INTERRUPT_HANDLER(instruction_breakpoint_exception);

DECLARE_INTERRUPT_HANDLER(RunModeException);

DECLARE_INTERRUPT_HANDLER(single_step_exception);
@@ -449,7 +461,7 @@ DECLARE_INTERRUPT_HANDLER(altivec_assist_exception); 
DECLARE_INTERRUPT_HANDLER(CacheLockingException);

DECLARE_INTERRUPT_HANDLER(SPEFloatingPointException);

DECLARE_INTERRUPT_HANDLER(SPEFloatingPointRoundException);

DECLARE_INTERRUPT_HANDLER(WatchdogException);

DECLARE_INTERRUPT_HANDLER_NMI(WatchdogException);

DECLARE_INTERRUPT_HANDLER(kernel_bad_stack);



/* slb.c */

arch/powerpc/kernel/exceptions-64e.S

+4 −32
Original line number Diff line number Diff line
@@ -63,9 +63,6 @@ 
	ld	reg, (SPECIAL_EXC_##name * 8 + SPECIAL_EXC_FRAME_OFFS)(r1)



special_reg_save:

	lbz	r9,PACAIRQHAPPENED(r13)

	RECONCILE_IRQ_STATE(r3,r4)



	/*

	 * We only need (or have stack space) to save this stuff if

	 * we interrupted the kernel.
@@ -119,15 +116,11 @@ BEGIN_FTR_SECTION 
	mtspr	SPRN_MAS5,r10

	mtspr	SPRN_MAS8,r10

END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)

	SPECIAL_EXC_STORE(r9,IRQHAPPENED)



	mfspr	r10,SPRN_DEAR

	SPECIAL_EXC_STORE(r10,DEAR)

	mfspr	r10,SPRN_ESR

	SPECIAL_EXC_STORE(r10,ESR)



	lbz	r10,PACAIRQSOFTMASK(r13)

	SPECIAL_EXC_STORE(r10,SOFTE)

	ld	r10,_NIP(r1)

	SPECIAL_EXC_STORE(r10,CSRR0)

	ld	r10,_MSR(r1)
@@ -194,27 +187,6 @@ BEGIN_FTR_SECTION 
	mtspr	SPRN_MAS8,r10

END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)



	lbz	r6,PACAIRQSOFTMASK(r13)

	ld	r5,SOFTE(r1)



	/* Interrupts had better not already be enabled... */

	tweqi	r6,IRQS_ENABLED



	andi.	r6,r5,IRQS_DISABLED

	bne	1f



	TRACE_ENABLE_INTS

	stb	r5,PACAIRQSOFTMASK(r13)

1:

	/*

	 * Restore PACAIRQHAPPENED rather than setting it based on

	 * the return MSR[EE], since we could have interrupted

	 * interrupt replay or other inconsistent transitory

	 * states that must remain that way.

	 */

	SPECIAL_EXC_LOAD(r10,IRQHAPPENED)

	stb	r10,PACAIRQHAPPENED(r13)



	SPECIAL_EXC_LOAD(r10,DEAR)

	mtspr	SPRN_DEAR,r10

	SPECIAL_EXC_LOAD(r10,ESR)
@@ -566,7 +538,7 @@ __end_interrupts: 
	bl	special_reg_save

	CHECK_NAPPING();

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	unknown_exception

	bl	unknown_nmi_exception

	b	ret_from_crit_except



/* Machine Check Interrupt */
@@ -702,7 +674,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) 
#ifdef CONFIG_BOOKE_WDT

	bl	WatchdogException

#else

	bl	unknown_exception

	bl	unknown_nmi_exception

#endif

	b	ret_from_crit_except
@@ -886,7 +858,7 @@ kernel_dbg_exc: 
	bl	special_reg_save

	CHECK_NAPPING();

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	unknown_exception

	bl	unknown_nmi_exception

	b	ret_from_crit_except



/*
@@ -910,7 +882,7 @@ kernel_dbg_exc: 
	bl	special_reg_save

	CHECK_NAPPING();

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	unknown_exception

	bl	unknown_nmi_exception

	b	ret_from_crit_except



/* Hypervisor call */

arch/powerpc/kernel/traps.c

+12 −1
Original line number Diff line number Diff line
@@ -1078,6 +1078,16 @@ DEFINE_INTERRUPT_HANDLER_ASYNC(unknown_async_exception) 
	_exception(SIGTRAP, regs, TRAP_UNK, 0);

}



DEFINE_INTERRUPT_HANDLER_NMI(unknown_nmi_exception)

{

	printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",

	       regs->nip, regs->msr, regs->trap);



	_exception(SIGTRAP, regs, TRAP_UNK, 0);



	return 0;

}



DEFINE_INTERRUPT_HANDLER(instruction_breakpoint_exception)

{

	if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
@@ -2181,10 +2191,11 @@ void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs) 
	return;

}



DEFINE_INTERRUPT_HANDLER(WatchdogException) /* XXX NMI? async? */

DEFINE_INTERRUPT_HANDLER_NMI(WatchdogException)

{

	printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");

	WatchdogHandler(regs);

	return 0;

}

#endif