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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 3d01df7d7cf60cdbe1342fe84006405712394663..05a97d5fe29840e387a66aa00f5041d8c749ad17 100644 (file)
--- 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();