From 8051f4d16ef1d037e7b12abab79c3e0b960f4d36 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 31 May 2016 12:07:47 +0100 Subject: [PATCH] arm64: report CPU number in bad_mode If we take an exception we don't expect (e.g. SError), we report this in the bad_mode handler with pr_crit. Depending on the configured log level, we may or may not log additional information in functions called subsequently. Notably, the messages in dump_stack (including the CPU number) are printed with KERN_DEFAULT and may not appear. Some exceptions have an IMPLEMENTATION DEFINED ESR_ELx.ISS encoding, and knowing the CPU number is crucial to correctly decode them. To ensure that this is always possible, we should log the CPU number along with the ESR_ELx value, so we are not reliant on subsequent logs or additional printk configuration options. This patch logs the CPU number in bad_mode such that it is possible for a developer to decode these exceptions, provided access to sufficient documentation. Signed-off-by: Mark Rutland Reported-by: Al Grant Cc: Catalin Marinas Cc: Dave Martin Cc: Robin Murphy Cc: Will Deacon Signed-off-by: Will Deacon --- arch/arm64/kernel/traps.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index c5392081b49b..f7cf463107df 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -477,8 +477,9 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) void __user *pc = (void __user *)instruction_pointer(regs); console_verbose(); - pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n", - handler[reason], esr, esr_get_class_string(esr)); + pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n", + handler[reason], smp_processor_id(), esr, + esr_get_class_string(esr)); __show_regs(regs); info.si_signo = SIGILL; -- 2.20.1