xref: /linux/arch/x86/include/asm/processor-flags.h (revision 3d886aa3be15439e05784ac1cbd4acc2f13c0048)
1 #ifndef _ASM_X86_PROCESSOR_FLAGS_H
2 #define _ASM_X86_PROCESSOR_FLAGS_H
3 
4 #include <uapi/asm/processor-flags.h>
5 
6 #ifdef CONFIG_VM86
7 #define X86_VM_MASK	X86_EFLAGS_VM
8 #else
9 #define X86_VM_MASK	0 /* No VM86 support */
10 #endif
11 
12 /*
13  * CR3's layout varies depending on several things.
14  *
15  * If CR4.PCIDE is set (64-bit only), then CR3[11:0] is the address space ID.
16  * If PAE is enabled, then CR3[11:5] is part of the PDPT address
17  * (i.e. it's 32-byte aligned, not page-aligned) and CR3[4:0] is ignored.
18  * Otherwise (non-PAE, non-PCID), CR3[3] is PWT, CR3[4] is PCD, and
19  * CR3[2:0] and CR3[11:5] are ignored.
20  *
21  * In all cases, Linux puts zeros in the low ignored bits and in PWT and PCD.
22  *
23  * CR3[63] is always read as zero.  If CR4.PCIDE is set, then CR3[63] may be
24  * written as 1 to prevent the write to CR3 from flushing the TLB.
25  *
26  * On systems with SME, one bit (in a variable position!) is stolen to indicate
27  * that the top-level paging structure is encrypted.
28  *
29  * All of the remaining bits indicate the physical address of the top-level
30  * paging structure.
31  *
32  * CR3_ADDR_MASK is the mask used by read_cr3_pa().
33  */
34 #ifdef CONFIG_X86_64
35 /* Mask off the address space ID bits. */
36 #define CR3_ADDR_MASK 0x7FFFFFFFFFFFF000ull
37 #define CR3_PCID_MASK 0xFFFull
38 #else
39 /*
40  * CR3_ADDR_MASK needs at least bits 31:5 set on PAE systems, and we save
41  * a tiny bit of code size by setting all the bits.
42  */
43 #define CR3_ADDR_MASK 0xFFFFFFFFull
44 #define CR3_PCID_MASK 0ull
45 #endif
46 
47 #endif /* _ASM_X86_PROCESSOR_FLAGS_H */
48