11f9ad21cSRussell Currey // SPDX-License-Identifier: GPL-2.0 21f9ad21cSRussell Currey 31f9ad21cSRussell Currey /* 41f9ad21cSRussell Currey * MMU-generic set_memory implementation for powerpc 51f9ad21cSRussell Currey * 61f9ad21cSRussell Currey * Copyright 2019-2021, IBM Corporation. 71f9ad21cSRussell Currey */ 81f9ad21cSRussell Currey 91f9ad21cSRussell Currey #include <linux/mm.h> 101f9ad21cSRussell Currey #include <linux/vmalloc.h> 111f9ad21cSRussell Currey #include <linux/set_memory.h> 121f9ad21cSRussell Currey 131f9ad21cSRussell Currey #include <asm/mmu.h> 141f9ad21cSRussell Currey #include <asm/page.h> 151f9ad21cSRussell Currey #include <asm/pgtable.h> 161f9ad21cSRussell Currey 171f9ad21cSRussell Currey 181f9ad21cSRussell Currey /* 191f9ad21cSRussell Currey * Updates the attributes of a page in three steps: 201f9ad21cSRussell Currey * 21*9f7853d7SMichael Ellerman * 1. take the page_table_lock 22*9f7853d7SMichael Ellerman * 2. install the new entry with the updated attributes 23*9f7853d7SMichael Ellerman * 3. flush the TLB 241f9ad21cSRussell Currey * 25*9f7853d7SMichael Ellerman * This sequence is safe against concurrent updates, and also allows updating the 26*9f7853d7SMichael Ellerman * attributes of a page currently being executed or accessed. 271f9ad21cSRussell Currey */ 281f9ad21cSRussell Currey static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) 291f9ad21cSRussell Currey { 301f9ad21cSRussell Currey long action = (long)data; 311f9ad21cSRussell Currey pte_t pte; 321f9ad21cSRussell Currey 331f9ad21cSRussell Currey spin_lock(&init_mm.page_table_lock); 341f9ad21cSRussell Currey 35*9f7853d7SMichael Ellerman pte = ptep_get(ptep); 361f9ad21cSRussell Currey 371f9ad21cSRussell Currey /* modify the PTE bits as desired, then apply */ 381f9ad21cSRussell Currey switch (action) { 391f9ad21cSRussell Currey case SET_MEMORY_RO: 401f9ad21cSRussell Currey pte = pte_wrprotect(pte); 411f9ad21cSRussell Currey break; 421f9ad21cSRussell Currey case SET_MEMORY_RW: 431f9ad21cSRussell Currey pte = pte_mkwrite(pte_mkdirty(pte)); 441f9ad21cSRussell Currey break; 451f9ad21cSRussell Currey case SET_MEMORY_NX: 461f9ad21cSRussell Currey pte = pte_exprotect(pte); 471f9ad21cSRussell Currey break; 481f9ad21cSRussell Currey case SET_MEMORY_X: 491f9ad21cSRussell Currey pte = pte_mkexec(pte); 501f9ad21cSRussell Currey break; 511f9ad21cSRussell Currey default: 521f9ad21cSRussell Currey WARN_ON_ONCE(1); 531f9ad21cSRussell Currey break; 541f9ad21cSRussell Currey } 551f9ad21cSRussell Currey 56*9f7853d7SMichael Ellerman pte_update(&init_mm, addr, ptep, ~0UL, pte_val(pte), 0); 571f9ad21cSRussell Currey 581f9ad21cSRussell Currey /* See ptesync comment in radix__set_pte_at() */ 591f9ad21cSRussell Currey if (radix_enabled()) 601f9ad21cSRussell Currey asm volatile("ptesync": : :"memory"); 61*9f7853d7SMichael Ellerman 62*9f7853d7SMichael Ellerman flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 63*9f7853d7SMichael Ellerman 641f9ad21cSRussell Currey spin_unlock(&init_mm.page_table_lock); 651f9ad21cSRussell Currey 661f9ad21cSRussell Currey return 0; 671f9ad21cSRussell Currey } 681f9ad21cSRussell Currey 691f9ad21cSRussell Currey int change_memory_attr(unsigned long addr, int numpages, long action) 701f9ad21cSRussell Currey { 711f9ad21cSRussell Currey unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE); 721f9ad21cSRussell Currey unsigned long size = numpages * PAGE_SIZE; 731f9ad21cSRussell Currey 741f9ad21cSRussell Currey if (!numpages) 751f9ad21cSRussell Currey return 0; 761f9ad21cSRussell Currey 771f9ad21cSRussell Currey if (WARN_ON_ONCE(is_vmalloc_or_module_addr((void *)addr) && 781f9ad21cSRussell Currey is_vm_area_hugepages((void *)addr))) 791f9ad21cSRussell Currey return -EINVAL; 801f9ad21cSRussell Currey 811f9ad21cSRussell Currey #ifdef CONFIG_PPC_BOOK3S_64 821f9ad21cSRussell Currey /* 831f9ad21cSRussell Currey * On hash, the linear mapping is not in the Linux page table so 841f9ad21cSRussell Currey * apply_to_existing_page_range() will have no effect. If in the future 851f9ad21cSRussell Currey * the set_memory_* functions are used on the linear map this will need 861f9ad21cSRussell Currey * to be updated. 871f9ad21cSRussell Currey */ 881f9ad21cSRussell Currey if (!radix_enabled()) { 891f9ad21cSRussell Currey int region = get_region_id(addr); 901f9ad21cSRussell Currey 911f9ad21cSRussell Currey if (WARN_ON_ONCE(region != VMALLOC_REGION_ID && region != IO_REGION_ID)) 921f9ad21cSRussell Currey return -EINVAL; 931f9ad21cSRussell Currey } 941f9ad21cSRussell Currey #endif 951f9ad21cSRussell Currey 961f9ad21cSRussell Currey return apply_to_existing_page_range(&init_mm, start, size, 971f9ad21cSRussell Currey change_page_attr, (void *)action); 981f9ad21cSRussell Currey } 994d1755b6SChristophe Leroy 1004d1755b6SChristophe Leroy /* 1014d1755b6SChristophe Leroy * Set the attributes of a page: 1024d1755b6SChristophe Leroy * 1034d1755b6SChristophe Leroy * This function is used by PPC32 at the end of init to set final kernel memory 1044d1755b6SChristophe Leroy * protection. It includes changing the maping of the page it is executing from 1054d1755b6SChristophe Leroy * and data pages it is using. 1064d1755b6SChristophe Leroy */ 1074d1755b6SChristophe Leroy static int set_page_attr(pte_t *ptep, unsigned long addr, void *data) 1084d1755b6SChristophe Leroy { 1094d1755b6SChristophe Leroy pgprot_t prot = __pgprot((unsigned long)data); 1104d1755b6SChristophe Leroy 1114d1755b6SChristophe Leroy spin_lock(&init_mm.page_table_lock); 1124d1755b6SChristophe Leroy 1134d1755b6SChristophe Leroy set_pte_at(&init_mm, addr, ptep, pte_modify(*ptep, prot)); 1144d1755b6SChristophe Leroy flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 1154d1755b6SChristophe Leroy 1164d1755b6SChristophe Leroy spin_unlock(&init_mm.page_table_lock); 1174d1755b6SChristophe Leroy 1184d1755b6SChristophe Leroy return 0; 1194d1755b6SChristophe Leroy } 1204d1755b6SChristophe Leroy 1214d1755b6SChristophe Leroy int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot) 1224d1755b6SChristophe Leroy { 1234d1755b6SChristophe Leroy unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE); 1244d1755b6SChristophe Leroy unsigned long sz = numpages * PAGE_SIZE; 1254d1755b6SChristophe Leroy 1264d1755b6SChristophe Leroy if (numpages <= 0) 1274d1755b6SChristophe Leroy return 0; 1284d1755b6SChristophe Leroy 1294d1755b6SChristophe Leroy return apply_to_existing_page_range(&init_mm, start, sz, set_page_attr, 1304d1755b6SChristophe Leroy (void *)pgprot_val(prot)); 1314d1755b6SChristophe Leroy } 132