powerpc/64s/exception: Soft NMI interrupt should not use ret_from_except (71c3b05a) · Commits · 戴 / test

The soft NMI handler does not reconcile interrupt state, so it should not return via the normal ret_from_except path. Return like other NMIs, using the EXCEPTION_RESTORE_REGS macro. This becomes important when the scv interrupt is implemented, which must handle soft-masked interrupts that have r13 set to something other than the PACA -- returning to kernel in this case must restore r13. Signed-off-by:

Nicholas Piggin <npiggin@gmail.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-23-npiggin@gmail.com

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

+29 −1

Original line number	Diff line number	Diff line
		@@ -2731,6 +2731,7 @@ EXC_VIRT_NONE(0x5800, 0x100)
		INT_DEFINE_BEGIN(soft_nmi)
		IVEC=0x900
		ISTACK=0
		IRECONCILE=0 /* Soft-NMI may fire under local_irq_disable */
		INT_DEFINE_END(soft_nmi)

		/*
		@@ -2749,9 +2750,36 @@ EXC_COMMON_BEGIN(soft_nmi_common)
		subi r1,r1,INT_FRAME_SIZE
		__GEN_COMMON_BODY soft_nmi
		bl save_nvgprs

		/*
		* Set IRQS_ALL_DISABLED and save PACAIRQHAPPENED (see
		* system_reset_common)
		*/
		li r10,IRQS_ALL_DISABLED
		stb r10,PACAIRQSOFTMASK(r13)
		lbz r10,PACAIRQHAPPENED(r13)
		std r10,_DAR(r1)
		ori r10,r10,PACA_IRQ_HARD_DIS
		stb r10,PACAIRQHAPPENED(r13)

		addi r3,r1,STACK_FRAME_OVERHEAD
		bl soft_nmi_interrupt
		b ret_from_except

		/* Clear MSR_RI before setting SRR0 and SRR1. */
		li r9,0
		mtmsrd r9,1

		/*
		* Restore soft mask settings.
		*/
		ld r10,_DAR(r1)
		stb r10,PACAIRQHAPPENED(r13)
		ld r10,SOFTE(r1)
		stb r10,PACAIRQSOFTMASK(r13)

		kuap_restore_amr r10
		EXCEPTION_RESTORE_REGS hsrr=0
		RFI_TO_KERNEL

		#endif /* CONFIG_PPC_WATCHDOG */

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