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#include <apos/string.h>
#include <apos/pmem.h>
#include <apos/vmem.h>
#include <apos/mem.h>
#include <apos/debug.h>
#include <pages.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) (pnum_to_paddr(pte_ppn(pte)))
#define vm_to_index(a, o) (pm_to_index(a, o))
#if defined(KERNEL)
static vm_t *tmp_pte = 0;
void arch_init_vmem(struct vm_branch_t *branch, vm_t pte)
{
(void)branch;
tmp_pte = (vm_t *)pte;
}
/* this seems like an awful idea, should probably try to come up with a smarter
* approach? flushing the cache every time is probably pretty slow and also
* this code doesn't take into account the cpu ASID, although that's probably
* not relevant here */
/* what I probably should do is something like Linux, where the kernel has a
* direct (or linear, I suppose?) so that all direct memory accesses are also
* accessible from virtual memory. Not entirely sure how I should do that,
* wouldn't there be situations where the RAM is larger than the allocated
* memory region?
*
* Or maybe some kind of walker, where I maintain a virtual page table that
* mirrors the physical page table? Not sure yet, but this seems to work for
* _now_.
*/
#define QUOTE2(x) #x
#define QUOTE(x) QUOTE2(x)
static void *set_vptr(uint8_t flags, pm_t a)
{
*tmp_pte = to_pte(a, flags);
__asm__ ("sfence.vma %0, %1"
:: "rk" (0), "rK" (TMP_PTE)
: "memory");
return (void *)TMP_PTE;
}
#else
struct vm_branch_t *arch_get_tmp_pte(struct vm_branch_t *branch)
{
enum mm_order_t top = __mm_max_order;
while(top){
size_t idx = vm_to_index(TMP_PTE, top);
branch = (struct vm_branch_t *)pte_addr(branch->leaf[idx]);
top--;
}
return branch;
}
#define set_vptr(flags, a) (a)
#endif
void map_vmem(struct vm_branch_t *branch,
pm_t paddr, vm_t vaddr, uint8_t flags, enum mm_order_t order)
{
enum mm_order_t top = __mm_max_order;
while (top != order) {
size_t idx = vm_to_index(vaddr, top);
if (!branch->leaf[idx]) {
pm_t new_leaf = alloc_page(MM_KPAGE, 0);
branch->leaf[idx] =
(struct vm_branch_t *)to_pte(new_leaf, VM_V);
void *leaf_ptr = (void *)set_vptr(VM_R | VM_W | VM_V, new_leaf);
memset(leaf_ptr, 0, sizeof(struct vm_branch_t));
}
pm_t pte = (pm_t)branch->leaf[idx];
pm_t branch_pptr = (pm_t)pte_addr(pte);
branch = (struct vm_branch_t *)set_vptr(VM_R | VM_W | VM_V, branch_pptr);
top--;
}
size_t idx = vm_to_index(vaddr, top);
branch->leaf[idx] = (struct vm_branch_t *)to_pte(paddr, flags);
}
void unmap_vmem(struct vm_branch_t *branch, vm_t vaddr, enum mm_order_t order)
{
while (order) {
size_t idx = pm_to_index(vaddr, order);
branch = (struct vm_branch_t *)pte_addr(branch->leaf[idx]);
}
size_t idx = pm_to_index(vaddr, order);
if (branch->leaf[idx])
free_page(order, pte_addr(branch->leaf[idx]));
branch->leaf[idx] = 0;
}
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