Commit-ID:  55d2d0ad2fb4325f615d1950486fbc5e6fba1769
Gitweb:     https://git.kernel.org/tip/55d2d0ad2fb4325f615d1950486fbc5e6fba1769
Author:     Chunyu Hu <ch...@redhat.com>
AuthorDate: Mon, 27 Nov 2017 22:21:39 +0800
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Tue, 28 Nov 2017 08:15:40 +0100

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 <ch...@redhat.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: sta...@vger.kernel.org
Cc: pet...@infradead.org
Cc: b...@alien8.de
Cc: rost...@goodmis.org
Cc: l...@kernel.org
Link: 
https://lkml.kernel.org/r/1511792499-4073-1-git-send-email-ch...@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 3d01df7..05a97d5 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();

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