diff options
| author | David Hildenbrand <david@redhat.com> | 2023-01-13 18:10:02 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-02-02 22:33:06 -0800 |
| commit | a172d5128706028ac07b8db709728379ecc72f6e (patch) | |
| tree | 7eb8fb408708ec3ab4afc9ce054abb2072e3bcf8 | |
| parent | 2321ba3e3733f513e46e29b9c70512ecddbf1085 (diff) | |
alpha/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type. Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.
While at it, mask the type in mk_swap_pte() as well.
Link: https://lkml.kernel.org/r/20230113171026.582290-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | arch/alpha/include/asm/pgtable.h | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h index 9e45f6735d5d..970abf511b13 100644 --- a/arch/alpha/include/asm/pgtable.h +++ b/arch/alpha/include/asm/pgtable.h @@ -74,6 +74,9 @@ struct vm_area_struct; #define _PAGE_DIRTY 0x20000 #define _PAGE_ACCESSED 0x40000 +/* We borrow bit 39 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE 0x8000000000UL + /* * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it. @@ -301,18 +304,48 @@ extern inline void update_mmu_cache(struct vm_area_struct * vma, } /* - * Non-present pages: high 24 bits are offset, next 8 bits type, - * low 32 bits zero. + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * + * Format of swap PTEs: + * + * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 + * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 + * <------------------- offset ------------------> E <--- type --> + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * <--------------------------- zeroes --------------------------> + * + * E is the exclusive marker that is not stored in swap entries. */ extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset) -{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; } +{ pte_t pte; pte_val(pte) = ((type & 0x7f) << 32) | (offset << 40); return pte; } -#define __swp_type(x) (((x).val >> 32) & 0xff) +#define __swp_type(x) (((x).val >> 32) & 0x7f) #define __swp_offset(x) ((x).val >> 40) #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE +static inline int pte_swp_exclusive(pte_t pte) +{ + return pte_val(pte) & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + pte_val(pte) |= _PAGE_SWP_EXCLUSIVE; + return pte; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE; + return pte; +} + #define pte_ERROR(e) \ printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e)) #define pmd_ERROR(e) \ |