From 3151cc26565ea864c51a78900101ad68b864f405 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 13 Jan 2023 18:10:07 +0100 Subject: ia64/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, also mask the type in __swp_entry(). Link: https://lkml.kernel.org/r/20230113171026.582290-8-david@redhat.com Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton --- arch/ia64/include/asm/pgtable.h | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) (limited to 'arch/ia64/include') diff --git a/arch/ia64/include/asm/pgtable.h b/arch/ia64/include/asm/pgtable.h index 01517a5e6778..e4b8ab931399 100644 --- a/arch/ia64/include/asm/pgtable.h +++ b/arch/ia64/include/asm/pgtable.h @@ -58,6 +58,9 @@ #define _PAGE_ED (__IA64_UL(1) << 52) /* exception deferral */ #define _PAGE_PROTNONE (__IA64_UL(1) << 63) +/* We borrow bit 7 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1 << 7) + #define _PFN_MASK _PAGE_PPN_MASK /* Mask of bits which may be changed by pte_modify(); the odd bits are there for _PAGE_PROTNONE */ #define _PAGE_CHG_MASK (_PAGE_P | _PAGE_PROTNONE | _PAGE_PL_MASK | _PAGE_AR_MASK | _PAGE_ED) @@ -399,6 +402,9 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; extern void paging_init (void); /* + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * * Note: The macros below rely on the fact that MAX_SWAPFILES_SHIFT <= number of * bits in the swap-type field of the swap pte. It would be nice to * enforce that, but we can't easily include here. @@ -406,16 +412,36 @@ extern void paging_init (void); * * Format of swap pte: * bit 0 : present bit (must be zero) - * bits 1- 7: swap-type + * bits 1- 6: swap type + * bit 7 : exclusive marker * bits 8-62: swap offset * bit 63 : _PAGE_PROTNONE bit */ -#define __swp_type(entry) (((entry).val >> 1) & 0x7f) +#define __swp_type(entry) (((entry).val >> 1) & 0x3f) #define __swp_offset(entry) (((entry).val << 1) >> 9) -#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 1) | ((long) (offset) << 8) }) +#define __swp_entry(type, offset) ((swp_entry_t) { ((type & 0x3f) << 1) | \ + ((long) (offset) << 8) }) #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; +} + /* * ZERO_PAGE is a global shared page that is always zero: used * for zero-mapped memory areas etc.. -- cgit