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x86_64: pmap: implement pmap_remove

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max 🍓
2026-03-15 14:38:32 +00:00
parent cef4af53c9
commit 399742cabf
1 changed files with 99 additions and 1 deletions
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100
arch/x86_64/pmap.c
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@@ -241,6 +241,104 @@ static kern_status_t do_pmap_add(
return KERN_OK;
}
static kern_status_t do_pmap_remove(
pmap_t pmap,
virt_addr_t pv,
enum page_size size)
{
unsigned int pml4t_index = BAD_INDEX, pdpt_index = BAD_INDEX,
pd_index = BAD_INDEX, pt_index = BAD_INDEX;
switch (size) {
case PS_4K:
pml4t_index = (pv >> 39) & 0x1FF;
pdpt_index = (pv >> 30) & 0x1FF;
pd_index = (pv >> 21) & 0x1FF;
pt_index = (pv >> 12) & 0x1FF;
break;
case PS_2M:
pml4t_index = (pv >> 39) & 0x1FF;
pdpt_index = (pv >> 30) & 0x1FF;
pd_index = (pv >> 21) & 0x1FF;
break;
case PS_1G:
if (!can_use_gbpages) {
return KERN_UNSUPPORTED;
}
pml4t_index = (pv >> 39) & 0x1FF;
pdpt_index = (pv >> 30) & 0x1FF;
break;
default:
return KERN_INVALID_ARGUMENT;
}
/* 1. get PML4T (mandatory) */
struct pml4t *pml4t = vm_phys_to_virt(ENTRY_TO_PTR(pmap));
if (!pml4t) {
return KERN_OK;
}
/* 2. traverse PML4T, get PDPT (mandatory) */
struct pdpt *pdpt = NULL;
if (!pml4t->p_entries[pml4t_index]) {
return KERN_OK;
} else {
pdpt = vm_phys_to_virt(
ENTRY_TO_PTR(pml4t->p_entries[pml4t_index]));
}
/* if we're mapping a 1GiB page, we stop here */
if (size == PS_1G) {
if (pdpt->p_entries[pdpt_index] != 0) {
/* this slot points to a pdir, delete it.
if this slot points to a hugepage, this does nothing
*/
delete_pdir(pdpt->p_entries[pdpt_index]);
}
pdpt->p_pages[pdpt_index] = 0;
return KERN_OK;
}
/* 3. traverse PDPT, get PDIR (optional, 4K and 2M only) */
struct pdir *pdir = NULL;
if (!pdpt->p_entries[pdpt_index]
|| pdpt->p_pages[pdpt_index] & PTE_PAGESIZE) {
/* entry is null, or points to a hugepage */
return KERN_OK;
} else {
pdir = vm_phys_to_virt(
ENTRY_TO_PTR(pdpt->p_entries[pdpt_index]));
}
/* if we're mapping a 2MiB page, we stop here */
if (size == PS_2M) {
if (pdir->p_entries[pd_index] != 0) {
/* this slot points to a ptab, delete it.
if this slot points to a hugepage, this does nothing
*/
delete_ptab(pdir->p_entries[pd_index]);
}
pdir->p_pages[pd_index] = 0;
return KERN_OK;
}
/* 4. traverse PDIR, get PTAB (optional, 4K only) */
struct ptab *ptab = NULL;
if (!pdir->p_entries[pd_index]
|| pdir->p_pages[pd_index] & PTE_PAGESIZE) {
/* entry is null, or points to a hugepage */
return KERN_OK;
} else {
ptab = vm_phys_to_virt(ENTRY_TO_PTR(pdir->p_entries[pd_index]));
}
ptab->p_pages[pt_index] = 0;
return KERN_OK;
}
pmap_t get_kernel_pmap(void)
{
return kernel_pmap;
@@ -404,7 +502,7 @@ kern_status_t pmap_add_block(
kern_status_t pmap_remove(pmap_t pmap, virt_addr_t p)
{
return KERN_OK;
return do_pmap_remove(pmap, p, PS_4K);
}
kern_status_t pmap_remove_range(pmap_t pmap, virt_addr_t p, size_t len)