From 55d2d0ad2fb4325f615d1950486fbc5e6fba1769 Mon Sep 17 00:00:00 2001 From: Chunyu Hu Date: Mon, 27 Nov 2017 22:21:39 +0800 Subject: [PATCH] x86/idt: Load idt early in start_secondary On a secondary, idt is first loaded in cpu_init() with load_current_idt(), i.e. no exceptions can be handled before that point. The conversion of WARN() to use UD requires the IDT being loaded earlier as any warning between start_secondary() and load_curren_idt() in cpu_init() will result in an unhandled @UD exception and therefore fail the bringup of the CPU. Install the IDT handlers right in start_secondary() before calling cpu_init(). [ tglx: Massaged changelog ] Fixes: 9a93848fe787 ("x86/debug: Implement __WARN() using UD0") Signed-off-by: Chunyu Hu Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Cc: peterz@infradead.org Cc: bp@alien8.de Cc: rostedt@goodmis.org Cc: luto@kernel.org Link: https://lkml.kernel.org/r/1511792499-4073-1-git-send-email-chuhu@redhat.com --- arch/x86/kernel/smpboot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 3d01df7d7cf6..05a97d5fe298 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -237,7 +237,7 @@ static void notrace start_secondary(void *unused) load_cr3(swapper_pg_dir); __flush_tlb_all(); #endif - + load_current_idt(); cpu_init(); x86_cpuinit.early_percpu_clock_init(); preempt_disable();