| Andi Kleen | 33182fe | 2018-06-13 15:48:24 -0700 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _ASM_PGTABLE_INVERT_H |
| 3 | #define _ASM_PGTABLE_INVERT_H 1 |
| 4 | |
| 5 | #ifndef __ASSEMBLY__ |
| 6 | |
| 7 | static inline bool __pte_needs_invert(u64 val) |
| 8 | { |
| 9 | return (val & (_PAGE_PRESENT|_PAGE_PROTNONE)) == _PAGE_PROTNONE; |
| 10 | } |
| 11 | |
| 12 | /* Get a mask to xor with the page table entry to get the correct pfn. */ |
| 13 | static inline u64 protnone_mask(u64 val) |
| 14 | { |
| 15 | return __pte_needs_invert(val) ? ~0ull : 0; |
| 16 | } |
| 17 | |
| 18 | static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask) |
| 19 | { |
| 20 | /* |
| 21 | * When a PTE transitions from NONE to !NONE or vice-versa |
| 22 | * invert the PFN part to stop speculation. |
| 23 | * pte_pfn undoes this when needed. |
| 24 | */ |
| 25 | if (__pte_needs_invert(oldval) != __pte_needs_invert(val)) |
| 26 | val = (val & ~mask) | (~val & mask); |
| 27 | return val; |
| 28 | } |
| 29 | |
| 30 | #endif /* __ASSEMBLY__ */ |
| 31 | |
| 32 | #endif |