diff options
Diffstat (limited to 'arch/riscv64/kernel/vmem.c')
| -rw-r--r-- | arch/riscv64/kernel/vmem.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/arch/riscv64/kernel/vmem.c b/arch/riscv64/kernel/vmem.c new file mode 100644 index 0000000..bc1a74e --- /dev/null +++ b/arch/riscv64/kernel/vmem.c @@ -0,0 +1,182 @@ +#include <apos/string.h> +#include <apos/pmem.h> +#include <apos/vmem.h> +#include <apos/mem.h> +#include <apos/debug.h> +#include <apos/cpu.h> +#include <pages.h> +#include <vmem.h> +#include <csr.h> + +#define pte_ppn(pte) (((pm_t)(pte)) >> 10) +#define pte_flags(pte) (((pm_t)(pte)) & 0xff) +#define to_pte(p, f) ((pm_to_pnum(p) << 10) | (f)) +#define pte_addr(pte) __va(pnum_to_paddr(pte_ppn(pte))) +#define pte_paddr(pte) (pnum_to_paddr(pte_ppn(pte))) +#define vm_to_index(a, o) (pm_to_index(a, o)) +#define is_active(pte) (pte_flags(pte) & VM_V) +#define is_leaf(pte) (is_active(pte) && (pte_flags(pte) & ~VM_V)) +#define is_branch(pte) (is_active(pte) && !(pte_flags(pte) & ~VM_V)) + +static pm_t *__find_vmem(struct vm_branch *b, vm_t v, enum mm_order *o) +{ + enum mm_order top = __mm_max_order; + if(o) + *o = MM_O0; + do { + size_t idx = vm_to_index(v, top); + pm_t pte = (pm_t)b->leaf[idx]; + + if(!pte) + return 0; + + if(is_leaf(pte)){ + if(o) + *o = top; + + return (pm_t *)&b->leaf[idx]; + } + + b = (struct vm_branch *)pte_addr(pte); + } while (top--); + + return 0; +} + +int mod_vmem(struct vm_branch *branch, vm_t vaddr, pm_t paddr, uint8_t flags) +{ + pm_t *pte = __find_vmem(branch, vaddr, 0); + if(pte){ + *pte = to_pte((pm_t)__pa(paddr), flags); + return 0; + } + + return -1; +} + +/* huh, should probably add status flags etc. to all my API functions. Damn, I'm + * lazy. */ +int stat_vmem(struct vm_branch *branch, vm_t vaddr, pm_t *paddr, + enum mm_order *order, uint8_t *flags) +{ + pm_t *pte = __find_vmem(branch, vaddr, order); + if(pte){ + if(paddr) + *paddr = (pm_t)pte_addr(*pte); + + if(flags) + *flags = pte_flags(*pte); + + return 0; + } + + return -1; +} + +static struct vm_branch *__create_leaf() +{ + pm_t new_leaf = alloc_page(MM_KPAGE, 0); + memset((void *)new_leaf, 0, sizeof(struct vm_branch)); + return (struct vm_branch *)to_pte((pm_t)__pa(new_leaf), VM_V); +} + +static void __destroy_branch(struct vm_branch *b) +{ + if(!b) + return; + + for(size_t i = 0; i < BASE_PAGE_SIZE / sizeof(pm_t); ++i){ + if(is_branch(b->leaf[i])) + __destroy_branch((struct vm_branch *)pte_addr(b->leaf[i])); + + free_page(MM_KPAGE, (pm_t)pte_addr(b->leaf[i])); + } +} + +void map_vmem(struct vm_branch *branch, + pm_t paddr, vm_t vaddr, uint8_t flags, enum mm_order order) +{ + enum mm_order top = __mm_max_order; + while (top != order) { + size_t idx = vm_to_index(vaddr, top); + + if (!branch->leaf[idx]) + branch->leaf[idx] = __create_leaf(); + + + branch = (struct vm_branch *)pte_addr(branch->leaf[idx]); + top--; + } + + size_t idx = vm_to_index(vaddr, top); + if (is_branch(branch->leaf[idx])) /* something has gone terribly wrong */ + __destroy_branch(branch->leaf[idx]); + + branch->leaf[idx] = (struct vm_branch *)to_pte((pm_t)__pa(paddr), flags); +} + +void unmap_vmem(struct vm_branch *branch, vm_t vaddr) +{ + + pm_t *pte = __find_vmem(branch, vaddr, 0); + if(pte) + *pte = 0; +} + +void flush_tlb() +{ + __asm__ volatile ("sfence.vma %0\n" :: "r" (cpu_id()) : "memory"); +} + +void flush_tlb_all() +{ + __asm__ volatile ("sfence.vma\n" ::: "memory"); +} + +static void start_vmem(struct vm_branch *branch, enum mm_mode m) +{ + branch = (struct vm_branch *)__pa(branch); + + if(m == Sv32) + csr_write(CSR_SATP, SATP_MODE_Sv32 | pm_to_pnum((pm_t)(branch))); + else if (m == Sv39) + csr_write(CSR_SATP, SATP_MODE_Sv39 | pm_to_pnum((pm_t)(branch))); + else + csr_write(CSR_SATP, SATP_MODE_Sv48 | pm_to_pnum((pm_t)(branch))); + + flush_tlb_all(); + /* Sv57 && Sv64 in the future? */ +} + +struct vm_branch *init_vmem(void *fdt) +{ + UNUSED(fdt); + struct vm_branch *b = (struct vm_branch *)alloc_page(MM_KPAGE, 0); + memset(b, 0, MM_KPAGE_SIZE); + + populate_root_branch(b); + /* update which memory branch to use */ + start_vmem(b, Sv39); + return b; +} + +void populate_root_branch(struct vm_branch *b) +{ + size_t flags = VM_V | VM_R | VM_W | VM_X | VM_G; + for(size_t i = KSTART_PAGE; i < IO_PAGE; ++i) + b->leaf[i] = (struct vm_branch *)to_pte(RAM_BASE + SZ_1G * (i - KSTART_PAGE), flags); + + /* map kernel IO to zero for now, this will be overridden later + * (if at all) */ + b->leaf[IO_PAGE] = (struct vm_branch *)to_pte(0, flags); +} + +#ifdef DEBUG +int setup_kernel_io(struct vm_branch *b, vm_t paddr) +{ + /* assume Sv39 for now */ + pm_t gigapage = paddr / MM_GPAGE_SIZE; + b->leaf[IO_PAGE] = (struct vm_branch *)to_pte(gigapage, VM_V | VM_R | VM_W); + return -SZ_1G + paddr - (gigapage * MM_GPAGE_SIZE); +} +#endif |