powerpc: Disable DAWR on POWER9 via CPU feature quirk

mikey · mpe · commit 622aa35e8f6a · 2018-03-27T23:55:33.000+11:00
This disables the DAWR on all POWER9 CPUs via cpu feature quirk.

Using the DAWR on POWER9 can cause xstops, hence we need to disable
it.

Signed-off-by: Michael Neuling &lt;mikey@neuling.org&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -713,6 +713,9 @@ static __init void cpufeatures_cpu_quirks(void)
 	else if ((version & 0xffffefff) == 0x004e0202)
 		cur_cpu_spec->cpu_features |= CPU_FTR_P9_TM_HV_ASSIST |
 			CPU_FTR_P9_TM_XER_SO_BUG;
+
+	if ((version & 0xffff0000) == 0x004e0000)
+		cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
 }
 
 static void __init cpufeatures_setup_finished(void)

Original file line number	Diff line number	Diff line change
`@@ -713,6 +713,9 @@ static __init void cpufeatures_cpu_quirks(void)`
`713`	`713`	`else if ((version & 0xffffefff) == 0x004e0202)`
`714`	`714`	`cur_cpu_spec->cpu_features \|= CPU_FTR_P9_TM_HV_ASSIST \|`
`715`	`715`	`CPU_FTR_P9_TM_XER_SO_BUG;`
	`716`	`+`
	`717`	`+ if ((version & 0xffff0000) == 0x004e0000)`
	`718`	`+ cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);`
`716`	`719`	`}`
`717`	`720`
`718`	`721`	`static void __init cpufeatures_setup_finished(void)`