[FSL P50xx] IRQ issues

[Nicholas Piggin]

Excerpts from Christian Zigotzky's message of July 6, 2021 4:49 am:
> Hi All,
> 
> Our FSL P50xx machines don't boot anymore because of IRQ issues. [1]
> 
> Please check the IRQ changes in the latest PowerPC updates 5.14-1. [2]
> 
> Thanks,
> Christian
> 
> [1] 
> https://forum.hyperion-entertainment.com/download/file.php?id=2592&mode=view
> [2] 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=019b3fd94ba73d3ac615f0537440b81f129821f6

This looks like mtmsrd in the 64e code. I think this should fix it.

QEMU does not seem to trap on this, maybe something to improve.

Thanks,
Nick
--

diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S
index 4063e8a3f704..d4212d2ff0b5 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -311,9 +311,13 @@ END_BTB_FLUSH_SECTION
 	 * trace_hardirqs_off().
 	 */
 	li	r11,IRQS_ALL_DISABLED
-	li	r12,-1 /* Set MSR_EE and MSR_RI */
 	stb	r11,PACAIRQSOFTMASK(r13)
+#ifdef CONFIG_PPC_BOOK3S
+	li	r12,-1 /* Set MSR_EE and MSR_RI */
 	mtmsrd	r12,1
+#else
+	wrteei	1
+#endif
 
 	/* Calling convention has r9 = orig r0, r10 = regs */
 	mr	r9,r0