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| author | Zhenzhong Duan <zhenzhong.duan@oracle.com> | 2018-07-03 08:49:54 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-07-03 09:26:10 +0200 |
| commit | 4fb5f58e8d191f7c81637ad81284e4848afb4244 (patch) | |
| tree | f2b0d0f92b021ee79e4ec4cf44c4c2697958096b /arch | |
| parent | Linux 4.18-rc3 (diff) | |
| download | linux-4fb5f58e8d191f7c81637ad81284e4848afb4244.tar.xz linux-4fb5f58e8d191f7c81637ad81284e4848afb4244.zip | |
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index c2f7d1d2a5c3..db9656e13ea0 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -221,6 +221,11 @@ static void notrace start_secondary(void *unused) #ifdef CONFIG_X86_32 /* switch away from the initial page table */ load_cr3(swapper_pg_dir); + /* + * Initialize the CR4 shadow before doing anything that could + * try to read it. + */ + cr4_init_shadow(); __flush_tlb_all(); #endif load_current_idt(); |