From 4bb3219837a3dcf58bce96c27db6e0cd48f3d9b2 Mon Sep 17 00:00:00 2001 From: Jordan Niethe Date: Mon, 7 Dec 2020 12:05:18 +1100 Subject: [PATCH] powerpc/book3s64/kexec: Clear CIABR on kexec The value in CIABR persists across kexec which can lead to unintended results when the new kernel hits the old kernel's breakpoint. For example: 0:mon> bi $loadavg_proc_show 0:mon> b type address 1 inst c000000000519060 loadavg_proc_show+0x0/0x130 0:mon> x $ kexec -l /mnt/vmlinux --initrd=/mnt/rootfs.cpio.gz --append='xmon=off' $ kexec -e $ cat /proc/loadavg Trace/breakpoint trap Make sure CIABR is cleared so this does not happen. Signed-off-by: Jordan Niethe Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201207010519.15597-1-jniethe5@gmail.com --- arch/powerpc/include/asm/book3s/64/kexec.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/powerpc/include/asm/book3s/64/kexec.h b/arch/powerpc/include/asm/book3s/64/kexec.h index 6b5c3a248ba2f..d4b9d476ecba2 100644 --- a/arch/powerpc/include/asm/book3s/64/kexec.h +++ b/arch/powerpc/include/asm/book3s/64/kexec.h @@ -3,6 +3,7 @@ #ifndef _ASM_POWERPC_BOOK3S_64_KEXEC_H_ #define _ASM_POWERPC_BOOK3S_64_KEXEC_H_ +#include #define reset_sprs reset_sprs static inline void reset_sprs(void) @@ -14,6 +15,10 @@ static inline void reset_sprs(void) if (cpu_has_feature(CPU_FTR_ARCH_207S)) { mtspr(SPRN_IAMR, 0); + if (cpu_has_feature(CPU_FTR_HVMODE)) + mtspr(SPRN_CIABR, 0); + else + plpar_set_ciabr(0); } /* Do we need isync()? We are going via a kexec reset */