diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/pgtable.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index cdd68ed3ae1a..b5739bb99fc1 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1036,6 +1036,31 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres } #endif +#ifndef ptep_try_set +/** + * ptep_try_set - atomically set an empty kernel PTE + * @ptep: page table entry + * @new_pte: value to install + * + * Atomically set *@ptep to @new_pte iff *@ptep is pte_none(). Return true on + * success, false if the slot was already populated or the arch has no + * implementation. + * + * For special kernel page tables only - never user page tables. The caller must + * prevent concurrent teardown of @ptep and must accept that other writers may + * race. Concurrent clearers must use ptep_get_and_clear() so racing accesses + * agree on the outcome. + * + * Architectures opt in by providing a cmpxchg-based override and defining + * ptep_try_set as an identity macro. The generic stub returns false, which is + * correct for callers that fall through to oops on failure. + */ +static inline bool ptep_try_set(pte_t *ptep, pte_t new_pte) +{ + return false; +} +#endif + #ifndef wrprotect_ptes /** * wrprotect_ptes - Write-protect PTEs that map consecutive pages of the same |