From 895e3dceeb97855dc9990136cbb80a842fe581aa Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Tue, 20 Aug 2019 13:43:50 +0530 Subject: [PATCH] powerpc/mce: Handle UE event for memcpy_mcsafe If we take a UE on one of the instructions with a fixup entry, set nip to continue execution at the fixup entry. Stop processing the event further or print it. Co-developed-by: Reza Arbab Signed-off-by: Reza Arbab Signed-off-by: Balbir Singh Reviewed-by: Mahesh Salgaonkar Reviewed-by: Nicholas Piggin Signed-off-by: Santosh Sivaraj Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190820081352.8641-6-santosh@fossix.org --- arch/powerpc/include/asm/mce.h | 4 +++- arch/powerpc/kernel/mce.c | 16 ++++++++++++++++ arch/powerpc/kernel/mce_power.c | 15 +++++++++++++-- 3 files changed, 32 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h index a4c6a74ad2fb..19a33707d5ef 100644 --- a/arch/powerpc/include/asm/mce.h +++ b/arch/powerpc/include/asm/mce.h @@ -122,7 +122,8 @@ struct machine_check_event { enum MCE_UeErrorType ue_error_type:8; u8 effective_address_provided; u8 physical_address_provided; - u8 reserved_1[5]; + u8 ignore_event; + u8 reserved_1[4]; u64 effective_address; u64 physical_address; u8 reserved_2[8]; @@ -193,6 +194,7 @@ struct mce_error_info { enum MCE_Initiator initiator:8; enum MCE_ErrorClass error_class:8; bool sync_error; + bool ignore_event; }; #define MAX_MC_EVT 100 diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c index a3b122a685a5..ec4b3e1087be 100644 --- a/arch/powerpc/kernel/mce.c +++ b/arch/powerpc/kernel/mce.c @@ -149,6 +149,7 @@ void save_mce_event(struct pt_regs *regs, long handled, if (phys_addr != ULONG_MAX) { mce->u.ue_error.physical_address_provided = true; mce->u.ue_error.physical_address = phys_addr; + mce->u.ue_error.ignore_event = mce_err->ignore_event; machine_check_ue_event(mce); } } @@ -266,8 +267,17 @@ static void machine_process_ue_event(struct work_struct *work) /* * This should probably queued elsewhere, but * oh! well + * + * Don't report this machine check because the caller has a + * asked us to ignore the event, it has a fixup handler which + * will do the appropriate error handling and reporting. */ if (evt->error_type == MCE_ERROR_TYPE_UE) { + if (evt->u.ue_error.ignore_event) { + __this_cpu_dec(mce_ue_count); + continue; + } + if (evt->u.ue_error.physical_address_provided) { unsigned long pfn; @@ -301,6 +311,12 @@ static void machine_check_process_queued_event(struct irq_work *work) while (__this_cpu_read(mce_queue_count) > 0) { index = __this_cpu_read(mce_queue_count) - 1; evt = this_cpu_ptr(&mce_event_queue[index]); + + if (evt->error_type == MCE_ERROR_TYPE_UE && + evt->u.ue_error.ignore_event) { + __this_cpu_dec(mce_queue_count); + continue; + } machine_check_print_event_info(evt, false, false); __this_cpu_dec(mce_queue_count); } diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c index 714a98e0927f..b6cbe3449358 100644 --- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -11,6 +11,7 @@ #include #include +#include #include #include #include @@ -18,6 +19,7 @@ #include #include #include +#include /* * Convert an address related to an mm to a PFN. NOTE: we are in real @@ -565,9 +567,18 @@ static int mce_handle_derror(struct pt_regs *regs, return 0; } -static long mce_handle_ue_error(struct pt_regs *regs) +static long mce_handle_ue_error(struct pt_regs *regs, + struct mce_error_info *mce_err) { long handled = 0; + const struct exception_table_entry *entry; + + entry = search_kernel_exception_table(regs->nip); + if (entry) { + mce_err->ignore_event = true; + regs->nip = extable_fixup(entry); + return 1; + } /* * On specific SCOM read via MMIO we may get a machine check @@ -600,7 +611,7 @@ static long mce_handle_error(struct pt_regs *regs, &phys_addr); if (!handled && mce_err.error_type == MCE_ERROR_TYPE_UE) - handled = mce_handle_ue_error(regs); + handled = mce_handle_ue_error(regs, &mce_err); save_mce_event(regs, handled, &mce_err, regs->nip, addr, phys_addr);