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/**
* @file vmem.c
* riscv64 implementation of arch-specific virtual memory handling.
*/
#include <apos/string.h>
#include <apos/pmem.h>
#include <apos/vmem.h>
#include <apos/mem.h>
#include <apos/debug.h>
#include <arch/cpu.h>
#include <pages.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 vmem *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 vmem *)pte_addr(pte);
} while (top--);
return 0;
}
stat_t mod_vpage(struct vmem *branch, vm_t vaddr, pm_t paddr, vmflags_t flags)
{
enum mm_order order;
pm_t *pte = __find_vmem(branch, vaddr, &order);
if (pte) {
*pte = to_pte((pm_t)__pa(paddr), vp_flags(flags));
/* if we're modifying a top level mapping, we will have to
* update the same one for all the other threads in this process
* */
if (order == __mm_max_order)
return INFO_SEFF;
else
return OK;
}
return ERR_NF;
}
/* huh, should probably add status flags etc. to all my API functions. Damn, I'm
* lazy. */
stat_t stat_vpage(struct vmem *branch, vm_t vaddr, pm_t *paddr,
enum mm_order *order, vmflags_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 OK;
}
return ERR_NF;
}
static struct vmem *__create_leaf()
{
pm_t new_leaf = alloc_page(MM_KPAGE, 0);
memset((void *)new_leaf, 0, sizeof(struct vmem));
return (struct vmem *)to_pte((pm_t)__pa(new_leaf), VM_V);
}
static void __destroy_branch(struct vmem *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 vmem *)pte_addr(b->leaf[i]));
free_page(MM_KPAGE, (pm_t)pte_addr(b->leaf[i]));
}
}
stat_t map_vpage(struct vmem *branch, pm_t paddr, vm_t vaddr, vmflags_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 vmem *)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 vmem *)to_pte((pm_t)__pa(paddr), vp_flags(flags));
return top == __mm_max_order ? INFO_SEFF : OK;
}
stat_t unmap_vpage(struct vmem *branch, vm_t vaddr)
{
pm_t *pte = __find_vmem(branch, vaddr, 0);
if (pte) {
*pte = 0;
return OK;
}
return ERR_NF;
}
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 vmem *branch, enum mm_mode m)
{
branch = (struct vmem *)__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 vmem *init_vmem(void *fdt)
{
UNUSED(fdt);
struct vmem *b = create_vmem();
/* update which memory branch to use */
__start_vmem(b, Sv39);
return b;
}
struct vmem *create_vmem()
{
struct vmem *b = (struct vmem *)alloc_page(MM_KPAGE, 0);
memset(b, 0, MM_KPAGE_SIZE);
populate_kvmem(b);
return b;
}
stat_t destroy_vmem(struct vmem *b)
{
free_page(MM_KPAGE, (pm_t)b);
return OK;
}
stat_t populate_kvmem(struct vmem *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 vmem *)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 vmem *)to_pte(0, flags);
return OK;
}
#if defined(DEBUG)
vm_t setup_kernel_io(struct vmem *b, vm_t paddr)
{
/* assume Sv39 for now */
pm_t gigapage = paddr / MM_GPAGE_SIZE;
b->leaf[IO_PAGE] = (struct vmem *)to_pte(gigapage, VM_V | VM_R | VM_W);
return -SZ_1G + paddr - (gigapage * MM_GPAGE_SIZE);
}
#endif
stat_t clone_uvmem(struct vmem *r, struct vmem *b)
{
/* TODO: error checking? */
for (size_t i = 0; i <= CSTACK_PAGE; ++i)
b->leaf[i] = r->leaf[i];
return OK;
}
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