x86/mm/32: Initialize the CR4 shadow before __flush_tlb_all()
authorZhenzhong Duan <zhenzhong.duan@oracle.com>
Tue, 3 Jul 2018 06:49:54 +0000 (23:49 -0700)
committerIngo Molnar <mingo@kernel.org>
Tue, 3 Jul 2018 07:26:10 +0000 (09:26 +0200)
commit4fb5f58e8d191f7c81637ad81284e4848afb4244
treef2b0d0f92b021ee79e4ec4cf44c4c2697958096b
parent021c91791a5e7e85c567452f1be3e4c2c6cb6063
x86/mm/32: Initialize the CR4 shadow before __flush_tlb_all()

On 32-bit kernels, __flush_tlb_all() may have read the CR4 shadow before the
initialization of CR4 shadow in cpu_init().

Fix it by adding an explicit cr4_init_shadow() call into start_secondary()
which is the first function called on non-boot SMP CPUs - ahead of the
__flush_tlb_all() call.

( This is somewhat of a layering violation, but start_secondary() does
  CR4 bootstrap in the PCID case anyway. )

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: http://lkml.kernel.org/r/b07b6ae9-4b57-4b40-b9bc-50c2c67f1d91@default
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/smpboot.c