| // SPDX-License-Identifier: GPL-2.0 |
| |
| /* |
| * MMU-generic set_memory implementation for powerpc |
| * |
| * Copyright 2019-2021, IBM Corporation. |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/vmalloc.h> |
| #include <linux/set_memory.h> |
| |
| #include <asm/mmu.h> |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| |
| |
| static pte_basic_t pte_update_delta(pte_t *ptep, unsigned long addr, |
| unsigned long old, unsigned long new) |
| { |
| return pte_update(&init_mm, addr, ptep, old & ~new, new & ~old, 0); |
| } |
| |
| /* |
| * Updates the attributes of a page atomically. |
| * |
| * This sequence is safe against concurrent updates, and also allows updating the |
| * attributes of a page currently being executed or accessed. |
| */ |
| static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) |
| { |
| long action = (long)data; |
| |
| addr &= PAGE_MASK; |
| /* modify the PTE bits as desired */ |
| switch (action) { |
| case SET_MEMORY_RO: |
| /* Don't clear DIRTY bit */ |
| pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, _PAGE_KERNEL_RO); |
| break; |
| case SET_MEMORY_RW: |
| pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_RW); |
| break; |
| case SET_MEMORY_NX: |
| pte_update_delta(ptep, addr, _PAGE_KERNEL_ROX, _PAGE_KERNEL_RO); |
| break; |
| case SET_MEMORY_X: |
| pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_ROX); |
| break; |
| case SET_MEMORY_NP: |
| pte_update(&init_mm, addr, ptep, _PAGE_PRESENT, 0, 0); |
| break; |
| case SET_MEMORY_P: |
| pte_update(&init_mm, addr, ptep, 0, _PAGE_PRESENT, 0); |
| break; |
| default: |
| WARN_ON_ONCE(1); |
| break; |
| } |
| |
| /* See ptesync comment in radix__set_pte_at() */ |
| if (radix_enabled()) |
| asm volatile("ptesync": : :"memory"); |
| |
| flush_tlb_kernel_range(addr, addr + PAGE_SIZE); |
| |
| return 0; |
| } |
| |
| int change_memory_attr(unsigned long addr, int numpages, long action) |
| { |
| unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE); |
| unsigned long size = numpages * PAGE_SIZE; |
| |
| if (!numpages) |
| return 0; |
| |
| if (WARN_ON_ONCE(is_vmalloc_or_module_addr((void *)addr) && |
| is_vm_area_hugepages((void *)addr))) |
| return -EINVAL; |
| |
| #ifdef CONFIG_PPC_BOOK3S_64 |
| /* |
| * On hash, the linear mapping is not in the Linux page table so |
| * apply_to_existing_page_range() will have no effect. If in the future |
| * the set_memory_* functions are used on the linear map this will need |
| * to be updated. |
| */ |
| if (!radix_enabled()) { |
| int region = get_region_id(addr); |
| |
| if (WARN_ON_ONCE(region != VMALLOC_REGION_ID && region != IO_REGION_ID)) |
| return -EINVAL; |
| } |
| #endif |
| |
| return apply_to_existing_page_range(&init_mm, start, size, |
| change_page_attr, (void *)action); |
| } |