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x86/mm: Split read_cr3() into read_cr3_pa() and __read_cr3()

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The kernel has several code paths that read CR3.  Most of them assume that
CR3 contains the PGD's physical address, whereas some of them awkwardly
use PHYSICAL_PAGE_MASK to mask off low bits.

Add explicit mask macros for CR3 and convert all of the CR3 readers.
This will keep them from breaking when PCID is enabled.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: xen-devel <xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/883f8fb121f4616c1c1427ad87350bb2f5ffeca1.1497288170.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski
2017-06-12 10:26:14 -07:00
committed by Ingo Molnar
parent 3f365cf304
commit 6c690ee103
20 changed files with 79 additions and 29 deletions
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4
arch/x86/include/asm/mmu_context.h
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@@ -269,7 +269,7 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
/*
* This can be used from process context to figure out what the value of
* CR3 is without needing to do a (slow) read_cr3().
* CR3 is without needing to do a (slow) __read_cr3().
*
* It's intended to be used for code like KVM that sneakily changes CR3
* and needs to restore it. It needs to be used very carefully.
@@ -281,7 +281,7 @@ static inline unsigned long __get_current_cr3_fast(void)
/* For now, be very restrictive about when this can be called. */
VM_WARN_ON(in_nmi() || !in_atomic());
VM_BUG_ON(cr3 != read_cr3());
VM_BUG_ON(cr3 != __read_cr3());
return cr3;
}