/* Locates and clears a region for a new top level page table. */
void initialize_identity_maps(void)
{
/* Init mapping_info with run-time function/buffer pointers. */
mapping_info.alloc_pgt_page = alloc_pgt_page;
mapping_info.context = &pgt_data;
/*
* It should be impossible for this not to already be true,
* but since calling this a second time would rewind the other
* counters, let's just make sure this is reset too.
*/
pgt_data.pgt_buf_offset = 0;
/*
* If we came here via startup_32(), cr3 will be _pgtable already
* and we must append to the existing area instead of entirely
* overwriting it.
*/
level4p = read_cr3();
if (level4p == (unsigned long)_pgtable) {
debug_putstr("booted via startup_32()\n");
pgt_data.pgt_buf = _pgtable + BOOT_INIT_PGT_SIZE;
pgt_data.pgt_buf_size = BOOT_PGT_SIZE - BOOT_INIT_PGT_SIZE;
memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
} else {
debug_putstr("booted via startup_64()\n");
pgt_data.pgt_buf = _pgtable;
pgt_data.pgt_buf_size = BOOT_PGT_SIZE;
memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
level4p = (unsigned long)alloc_pgt_page(&pgt_data);
}
}
/* Locates and clears a region for a new top level page table. */
void initialize_identity_maps(void)
{
unsigned long sev_me_mask = get_sev_encryption_mask();
/* Init mapping_info with run-time function/buffer pointers. */
mapping_info.alloc_pgt_page = alloc_pgt_page;
mapping_info.context = &pgt_data;
mapping_info.page_flag = __PAGE_KERNEL_LARGE_EXEC | sev_me_mask;
mapping_info.kernpg_flag = _KERNPG_TABLE | sev_me_mask;
/*
* It should be impossible for this not to already be true,
* but since calling this a second time would rewind the other
* counters, let's just make sure this is reset too.
*/
pgt_data.pgt_buf_offset = 0;
/*
* If we came here via startup_32(), cr3 will be _pgtable already
* and we must append to the existing area instead of entirely
* overwriting it.
*
* With 5-level paging, we use '_pgtable' to allocate the p4d page table,
* the top-level page table is allocated separately.
*
* p4d_offset(top_level_pgt, 0) would cover both the 4- and 5-level
* cases. On 4-level paging it's equal to 'top_level_pgt'.
*/
top_level_pgt = read_cr3_pa();
if (p4d_offset((pgd_t *)top_level_pgt, 0) == (p4d_t *)_pgtable) {
debug_putstr("booted via startup_32()\n");
pgt_data.pgt_buf = _pgtable + BOOT_INIT_PGT_SIZE;
pgt_data.pgt_buf_size = BOOT_PGT_SIZE - BOOT_INIT_PGT_SIZE;
memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
} else {
debug_putstr("booted via startup_64()\n");
pgt_data.pgt_buf = _pgtable;
pgt_data.pgt_buf_size = BOOT_PGT_SIZE;
memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
top_level_pgt = (unsigned long)alloc_pgt_page(&pgt_data);
}
}
