arch/riscv/include/asm/pgtable-bits.h

Source file repositories/reference/linux-study-clean/arch/riscv/include/asm/pgtable-bits.h

File Facts

System
Linux kernel
Corpus path
arch/riscv/include/asm/pgtable-bits.h
Extension
.h
Size
2334 bytes
Lines
79
Domain
Architecture Layer
Bucket
arch/riscv
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_RISCV_PGTABLE_BITS_H
#define _ASM_RISCV_PGTABLE_BITS_H

#define _PAGE_ACCESSED_OFFSET 6

#define _PAGE_PRESENT   (1 << 0)
#define _PAGE_READ      (1 << 1)    /* Readable */
#define _PAGE_WRITE     (1 << 2)    /* Writable */
#define _PAGE_EXEC      (1 << 3)    /* Executable */
#define _PAGE_USER      (1 << 4)    /* User */
#define _PAGE_GLOBAL    (1 << 5)    /* Global */
#define _PAGE_ACCESSED  (1 << 6)    /* Set by hardware on any access */
#define _PAGE_DIRTY     (1 << 7)    /* Set by hardware on any write */
#define _PAGE_SOFT      (3 << 8)    /* Reserved for software */

#define _PAGE_SPECIAL   (1 << 8)    /* RSW: 0x1 */

#ifdef CONFIG_MEM_SOFT_DIRTY

/* ext_svrsw60t59b: bit 59 for soft-dirty tracking */
#define _PAGE_SOFT_DIRTY						\
	((riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B)) ?	\
	 (1UL << 59) : 0)
/*
 * Bit 3 is always zero for swap entry computation, so we
 * can borrow it for swap page soft-dirty tracking.
 */
#define _PAGE_SWP_SOFT_DIRTY						\
	((riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B)) ?	\
	 _PAGE_EXEC : 0)
#else
#define _PAGE_SOFT_DIRTY	0
#define _PAGE_SWP_SOFT_DIRTY	0
#endif /* CONFIG_MEM_SOFT_DIRTY */

#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP

/* ext_svrsw60t59b: Bit(60) for uffd-wp tracking */
#define _PAGE_UFFD_WP							\
	((riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B)) ?	\
	 (1UL << 60) : 0)
/*
 * Bit 4 is not involved into swap entry computation, so we
 * can borrow it for swap page uffd-wp tracking.
 */
#define _PAGE_SWP_UFFD_WP						\
	((riscv_has_extension_unlikely(RISCV_ISA_EXT_SVRSW60T59B)) ?	\
	 _PAGE_USER : 0)
#else
#define _PAGE_UFFD_WP		0
#define _PAGE_SWP_UFFD_WP	0
#endif

#define _PAGE_TABLE     _PAGE_PRESENT

/*
 * _PAGE_PROT_NONE is set on not-present pages (and ignored by the hardware) to
 * distinguish them from swapped out pages
 */
#define _PAGE_PROT_NONE _PAGE_GLOBAL

/* Used for swap PTEs only. */
#define _PAGE_SWP_EXCLUSIVE _PAGE_ACCESSED

#define _PAGE_PFN_SHIFT 10

/*
 * when all of R/W/X are zero, the PTE is a pointer to the next level
 * of the page table; otherwise, it is a leaf PTE.
 */
#define _PAGE_LEAF (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)

#endif /* _ASM_RISCV_PGTABLE_BITS_H */

Annotation

Implementation Notes