bool km_page_create(struct km *mem_dst, unsigned long address, page_prot_t prot)
{
pte_t entry;
unsigned long page = 0;
struct km_walk_ctx dst_ctx;
KM_WALK_INIT(mem_dst, &dst_ctx);
if (unlikely(km_walk_to(&dst_ctx, address) == false))
goto err;
/* Create 模式应该看不到任何内容，否则可以理解被别人刚刚处理成功 */
if (km_pte_read(&dst_ctx))
goto err;
page = km_page_alloc();
if (!page)
goto err;
entry = page | km_arch_get_flags(prot);
km_pte_write(&dst_ctx, entry);
/* 不需要flush tlb，因为新的page在tlb中是不存在的 */
return true;
err:
if (page)
km_page_dealloc(page);
return false;
}
static uintptr_t
km_map_aligned(uintptr_t paddr, size_t size, unsigned int flags)
{
uintptr_t vaddr;
size_t align;
uintptr_t offs;
ASSERT(ALIGN_DOWN(paddr, FRAME_SIZE) == paddr);
ASSERT(ALIGN_UP(size, FRAME_SIZE) == size);
/* Enforce natural or at least PAGE_SIZE alignment. */
align = ispwr2(size) ? size : (1U << (fnzb(size) + 1));
vaddr = km_page_alloc(size, max(PAGE_SIZE, align));
page_table_lock(AS_KERNEL, true);
for (offs = 0; offs < size; offs += PAGE_SIZE) {
page_mapping_insert(AS_KERNEL, vaddr + offs, paddr + offs,
flags);
}
page_table_unlock(AS_KERNEL, true);
return vaddr;
}
bool km_page_create_cow(struct km *mem_dst, unsigned long address)
{
pte_t entry;
unsigned long page = 0;
struct km_walk_ctx dst_ctx;
KM_WALK_INIT(mem_dst, &dst_ctx);
if (unlikely(km_walk_to(&dst_ctx, address) == false))
goto err;
/* 必须有内容，否则就不应该Cow */
if (!km_pte_read(&dst_ctx))
goto err;
page = km_page_alloc();
if (!page)
goto err;
//TODO: Non identical map
if (page >= CONFIG_HAL_KERNEL_MEM_LEN)
goto err;
memcpy((void*)HAL_GET_BASIC_KADDRESS(page), (void*)KM_PAGE_ROUND_ALIGN(address), PAGE_SIZE);
entry = page | km_arch_get_flags(KM_PROT_READ | KM_PROT_WRITE);
km_pte_write_force(&dst_ctx, entry);
/* Must flush, because we are changing the entry */
km_arch_flush_page(mem_dst, address);
return true;
err:
if (page)
km_page_dealloc(page);
return false;
}