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- // 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);
- }
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