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author | Andy Lutomirski <luto@kernel.org> | 2017-06-12 10:26:14 -0700 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-06-13 08:48:09 +0200 |
commit | 6c690ee1039b251e583fc65b28da30e97d6a7385 (patch) | |
tree | 44898545622f632411caf72c54cd3ffd1ff107b3 /arch/x86/include/asm/processor-flags.h | |
parent | 3f365cf304ba3d316b3df2474af8d7df6edd2455 (diff) | |
download | linux-stable-6c690ee1039b251e583fc65b28da30e97d6a7385.tar.gz linux-stable-6c690ee1039b251e583fc65b28da30e97d6a7385.tar.bz2 linux-stable-6c690ee1039b251e583fc65b28da30e97d6a7385.zip |
x86/mm: Split read_cr3() into read_cr3_pa() and __read_cr3()
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>
Diffstat (limited to 'arch/x86/include/asm/processor-flags.h')
-rw-r--r-- | arch/x86/include/asm/processor-flags.h | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/x86/include/asm/processor-flags.h b/arch/x86/include/asm/processor-flags.h index 39fb618e2211..79aa2f98398d 100644 --- a/arch/x86/include/asm/processor-flags.h +++ b/arch/x86/include/asm/processor-flags.h @@ -8,4 +8,40 @@ #else #define X86_VM_MASK 0 /* No VM86 support */ #endif + +/* + * CR3's layout varies depending on several things. + * + * If CR4.PCIDE is set (64-bit only), then CR3[11:0] is the address space ID. + * If PAE is enabled, then CR3[11:5] is part of the PDPT address + * (i.e. it's 32-byte aligned, not page-aligned) and CR3[4:0] is ignored. + * Otherwise (non-PAE, non-PCID), CR3[3] is PWT, CR3[4] is PCD, and + * CR3[2:0] and CR3[11:5] are ignored. + * + * In all cases, Linux puts zeros in the low ignored bits and in PWT and PCD. + * + * CR3[63] is always read as zero. If CR4.PCIDE is set, then CR3[63] may be + * written as 1 to prevent the write to CR3 from flushing the TLB. + * + * On systems with SME, one bit (in a variable position!) is stolen to indicate + * that the top-level paging structure is encrypted. + * + * All of the remaining bits indicate the physical address of the top-level + * paging structure. + * + * CR3_ADDR_MASK is the mask used by read_cr3_pa(). + */ +#ifdef CONFIG_X86_64 +/* Mask off the address space ID bits. */ +#define CR3_ADDR_MASK 0x7FFFFFFFFFFFF000ull +#define CR3_PCID_MASK 0xFFFull +#else +/* + * CR3_ADDR_MASK needs at least bits 31:5 set on PAE systems, and we save + * a tiny bit of code size by setting all the bits. + */ +#define CR3_ADDR_MASK 0xFFFFFFFFull +#define CR3_PCID_MASK 0ull +#endif + #endif /* _ASM_X86_PROCESSOR_FLAGS_H */ |