xref: /linux/arch/x86/include/asm/processor-flags.h (revision 6a4aee277740d04ac0fd54cfa17cc28261932ddc)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_PROCESSOR_FLAGS_H
3 #define _ASM_X86_PROCESSOR_FLAGS_H
4 
5 #include <uapi/asm/processor-flags.h>
6 #include <linux/mem_encrypt.h>
7 
8 #ifdef CONFIG_VM86
9 #define X86_VM_MASK	X86_EFLAGS_VM
10 #else
11 #define X86_VM_MASK	0 /* No VM86 support */
12 #endif
13 
14 /*
15  * CR3's layout varies depending on several things.
16  *
17  * If CR4.PCIDE is set (64-bit only), then CR3[11:0] is the address space ID.
18  * If PAE is enabled, then CR3[11:5] is part of the PDPT address
19  * (i.e. it's 32-byte aligned, not page-aligned) and CR3[4:0] is ignored.
20  * Otherwise (non-PAE, non-PCID), CR3[3] is PWT, CR3[4] is PCD, and
21  * CR3[2:0] and CR3[11:5] are ignored.
22  *
23  * In all cases, Linux puts zeros in the low ignored bits and in PWT and PCD.
24  *
25  * CR3[63] is always read as zero.  If CR4.PCIDE is set, then CR3[63] may be
26  * written as 1 to prevent the write to CR3 from flushing the TLB.
27  *
28  * On systems with SME, one bit (in a variable position!) is stolen to indicate
29  * that the top-level paging structure is encrypted.
30  *
31  * On systemms with LAM, bits 61 and 62 are used to indicate LAM mode.
32  *
33  * All of the remaining bits indicate the physical address of the top-level
34  * paging structure.
35  *
36  * CR3_ADDR_MASK is the mask used by read_cr3_pa().
37  */
38 #ifdef CONFIG_X86_64
39 /* Mask off the address space ID and SME encryption bits. */
40 #define CR3_ADDR_MASK	__sme_clr(PHYSICAL_PAGE_MASK)
41 #define CR3_PCID_MASK	0xFFFull
42 #define CR3_NOFLUSH	BIT_ULL(63)
43 
44 #else
45 /*
46  * CR3_ADDR_MASK needs at least bits 31:5 set on PAE systems, and we save
47  * a tiny bit of code size by setting all the bits.
48  */
49 #define CR3_ADDR_MASK	0xFFFFFFFFull
50 #define CR3_PCID_MASK	0ull
51 #define CR3_NOFLUSH	0
52 #endif
53 
54 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
55 # define X86_CR3_PTI_PCID_USER_BIT	11
56 #endif
57 
58 #endif /* _ASM_X86_PROCESSOR_FLAGS_H */
59