From: Ganesh Goudar Date: Fri, 9 Oct 2020 06:40:04 +0000 (+0530) Subject: powerpc/mce: Avoid nmi_enter/exit in real mode on pseries hash X-Git-Tag: Ubuntu-5.13.0-19.19~4746^2~10 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=8d0e2101274358d9b6b1f27232b40253ca48bab5;p=mirror_ubuntu-jammy-kernel.git powerpc/mce: Avoid nmi_enter/exit in real mode on pseries hash Use of nmi_enter/exit in real mode handler causes the kernel to panic and reboot on injecting SLB mutihit on pseries machine running in hash MMU mode, because these calls try to accesses memory outside RMO region in real mode handler where translation is disabled. Add check to not to use these calls on pseries machine running in hash MMU mode. Fixes: 116ac378bb3f ("powerpc/64s: machine check interrupt update NMI accounting") Cc: stable@vger.kernel.org # v5.8+ Signed-off-by: Ganesh Goudar Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201009064005.19777-2-ganeshgr@linux.ibm.com --- diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c index ada59f6c4298..63702c0badb9 100644 --- a/arch/powerpc/kernel/mce.c +++ b/arch/powerpc/kernel/mce.c @@ -591,12 +591,11 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info); long notrace machine_check_early(struct pt_regs *regs) { long handled = 0; - bool nested = in_nmi(); u8 ftrace_enabled = this_cpu_get_ftrace_enabled(); this_cpu_set_ftrace_enabled(0); - - if (!nested) + /* Do not use nmi_enter/exit for pseries hpte guest */ + if (radix_enabled() || !firmware_has_feature(FW_FEATURE_LPAR)) nmi_enter(); hv_nmi_check_nonrecoverable(regs); @@ -607,7 +606,7 @@ long notrace machine_check_early(struct pt_regs *regs) if (ppc_md.machine_check_early) handled = ppc_md.machine_check_early(regs); - if (!nested) + if (radix_enabled() || !firmware_has_feature(FW_FEATURE_LPAR)) nmi_exit(); this_cpu_set_ftrace_enabled(ftrace_enabled);