From 783771fdbfd7f58d704c26c360a3130208772f26 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Fri, 18 May 2018 11:37:42 +1000 Subject: [PATCH] powerpc/64s: Clear PCR on boot commit faf37c44a105f3608115785f17cbbf3500f8bc71 upstream. Clear the PCR (Processor Compatibility Register) on boot to ensure we are not running in a compatibility mode. We've seen this cause problems when a crash (and kdump) occurs while running compat mode guests. The kdump kernel then runs with the PCR set and causes problems. The symptom in the kdump kernel (also seen in petitboot after fast-reboot) is early userspace programs taking sigills on newer instructions (seen in libc). Signed-off-by: Michael Neuling Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/cpu_setup_power.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S index 9c9b7411b28b..55eb3b752ca0 100644 --- a/arch/powerpc/kernel/cpu_setup_power.S +++ b/arch/powerpc/kernel/cpu_setup_power.S @@ -27,6 +27,7 @@ _GLOBAL(__setup_cpu_power7) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR bl __init_LPCR bl __init_tlb_power7 @@ -40,6 +41,7 @@ _GLOBAL(__restore_cpu_power7) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR bl __init_LPCR bl __init_tlb_power7 @@ -55,6 +57,7 @@ _GLOBAL(__setup_cpu_power8) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR ori r3, r3, LPCR_PECEDH bl __init_LPCR @@ -74,6 +77,7 @@ _GLOBAL(__restore_cpu_power8) beqlr li r0,0 mtspr SPRN_LPID,r0 + mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR ori r3, r3, LPCR_PECEDH bl __init_LPCR