From 2a20e3596a446df55cfe4b34b45b4cd8eae594db Mon Sep 17 00:00:00 2001 From: stefan Date: Sat, 29 Apr 2023 17:37:05 -0400 Subject: some work on paging --- sys/include/vm.h | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 65 insertions(+), 1 deletion(-) (limited to 'sys/include/vm.h') diff --git a/sys/include/vm.h b/sys/include/vm.h index 1883ea7..4378552 100644 --- a/sys/include/vm.h +++ b/sys/include/vm.h @@ -1,6 +1,70 @@ #ifndef _VM_H #define _VM_H -void vminit(void); +#include + +#define PAGEBITS_VALID (1 << 0) +#define PAGEBITS_R (1 << 1) +#define PAGEBITS_W (1 << 2) +#define PAGEBITS_X (1 << 3) +#define PAGEBITS_USER (1 << 4) +#define PAGEBITS_GLOBAL (1 << 5) +#define PAGEBITS_ACCESSED (1 << 6) +#define PAGEBITS_DIRTY (1 << 7) + +#define PAGEBITS_RO PAGEBITS_R +#define PAGEBITS_XO PAGEBITS_X +#define PAGEBITS_RW (PAGEBITS_R | PAGEBITS_W) +#define PAGEPITS_RX (PAGEBITS_R | PAGEBITS_X) +#define PAGEBITS_RWX (PAGEBITS_R | PAGEBITS_W | PAGEBITS_X) + +#define MODE_SV39 (8L << 60) + +typedef uint64_t pt_entry_t; +typedef struct _pagetable { + pt_entry_t entries[512]; +} pagetable_t; + +/* allocate kernel pagetable */ +void kptinit(void); +void kptinithart(void); +//void kptinitharts(uintptr_t mask); + +/* maps virtual address to physical address for @pt. */ +void vmap(pagetable_t *root, uintptr_t vaddr, uintptr_t paddr, int bits, int level); + +/* returns address of page table entry for @vaddr. if @alloc, next level page tables will be allocated */ +pt_entry_t *walkpt(pagetable_t *root, uintptr_t vaddr, int alloc); + +/* helper functions */ +static inline void write_satp(uintptr_t mode, uintptr_t ppn); +static inline int pte_is_branch(pt_entry_t); +static inline int pte_is_valid(pt_entry_t); + +#define PA2PTE(pa) ((uintptr_t)pa >> 2) +#define PTE2PA(pa) ((uintptr_t)pa << 2) +#define FLUSH_TLB() asm volatile("sfence.vma zero, zero") + +static inline void +write_satp(uintptr_t mode, uintptr_t ppn) +{ + FLUSH_TLB(); + asm volatile("csrw satp, %0" : : "r"((ppn >> 12) | mode)); + FLUSH_TLB(); +} + +static inline int +pte_is_branch(pt_entry_t e) +{ + return ((e & PAGEBITS_RWX) == 0); +} +#define pte_is_leaf(e) (!pte_is_branch(e)) + +static inline int +pte_is_valid(pt_entry_t e) +{ + return (e & PAGEBITS_VALID); +} + #endif /* _VM_H */ -- cgit v1.2.3