[PATCH mm-unstable v1 03/26] arc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
From: David Hildenbrand <hidden>
Date: 2023-01-13 17:13:12
Also in:
linux-alpha, linux-arm-kernel, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, lkml, loongarch, sparclinux
Subsystem:
synopsys arc architecture, the rest · Maintainers:
Vineet Gupta, Linus Torvalds
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using bit 5, which is yet unused. The only important parts seems to be to not use _PAGE_PRESENT (bit 9). Cc: Vineet Gupta <vgupta@kernel.org> Signed-off-by: David Hildenbrand <redacted> --- arch/arc/include/asm/pgtable-bits-arcv2.h | 27 ++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/arc/include/asm/pgtable-bits-arcv2.h b/arch/arc/include/asm/pgtable-bits-arcv2.h
index 515e82db519f..611f412713b9 100644
--- a/arch/arc/include/asm/pgtable-bits-arcv2.h
+++ b/arch/arc/include/asm/pgtable-bits-arcv2.h@@ -26,6 +26,9 @@ #define _PAGE_GLOBAL (1 << 8) /* ASID agnostic (H) */ #define _PAGE_PRESENT (1 << 9) /* PTE/TLB Valid (H) */ +/* We borrow bit 5 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE _PAGE_DIRTY + #ifdef CONFIG_ARC_MMU_V4 #define _PAGE_HW_SZ (1 << 10) /* Normal/super (H) */ #else
@@ -106,9 +109,18 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep); -/* Encode swap {type,off} tuple into PTE - * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that - * PAGE_PRESENT is zero in a PTE holding swap "identifier" +/* + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * + * Format of swap PTEs: + * + * 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 + * <-------------- offset -------------> <--- zero --> E < type -> + * + * E is the exclusive marker that is not stored in swap entries. + * The zero'ed bits include _PAGE_PRESENT. */ #define __swp_entry(type, off) ((swp_entry_t) \ { ((type) & 0x1f) | ((off) << 13) })
@@ -120,6 +132,15 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, #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; +} + +PTE_BIT_FUNC(swp_mkexclusive, |= (_PAGE_SWP_EXCLUSIVE)); +PTE_BIT_FUNC(swp_clear_exclusive, &= ~(_PAGE_SWP_EXCLUSIVE)); + #ifdef CONFIG_TRANSPARENT_HUGEPAGE #include <asm/hugepage.h> #endif
--
2.39.0