1 | // SPDX-License-Identifier: GPL-2.0 |
2 | |
3 | /* |
4 | * MMU-generic set_memory implementation for powerpc |
5 | * |
6 | * Copyright 2019-2021, IBM Corporation. |
7 | */ |
8 | |
9 | #include <linux/mm.h> |
10 | #include <linux/vmalloc.h> |
11 | #include <linux/set_memory.h> |
12 | |
13 | #include <asm/mmu.h> |
14 | #include <asm/page.h> |
15 | #include <asm/pgtable.h> |
16 | |
17 | #include <mm/mmu_decl.h> |
18 | |
19 | static pte_basic_t pte_update_delta(pte_t *ptep, unsigned long addr, |
20 | unsigned long old, unsigned long new) |
21 | { |
22 | return pte_update(&init_mm, addr, ptep, old & ~new, new & ~old, 0); |
23 | } |
24 | |
25 | /* |
26 | * Updates the attributes of a page atomically. |
27 | * |
28 | * This sequence is safe against concurrent updates, and also allows updating the |
29 | * attributes of a page currently being executed or accessed. |
30 | */ |
31 | static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) |
32 | { |
33 | long action = (long)data; |
34 | |
35 | addr &= PAGE_MASK; |
36 | /* modify the PTE bits as desired */ |
37 | switch (action) { |
38 | case SET_MEMORY_RO: |
39 | /* Don't clear DIRTY bit */ |
40 | pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, _PAGE_KERNEL_RO); |
41 | break; |
42 | case SET_MEMORY_ROX: |
43 | /* Don't clear DIRTY bit */ |
44 | pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, _PAGE_KERNEL_ROX); |
45 | break; |
46 | case SET_MEMORY_RW: |
47 | pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_RW); |
48 | break; |
49 | case SET_MEMORY_NX: |
50 | pte_update_delta(ptep, addr, _PAGE_KERNEL_ROX, _PAGE_KERNEL_RO); |
51 | break; |
52 | case SET_MEMORY_X: |
53 | pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_ROX); |
54 | break; |
55 | case SET_MEMORY_NP: |
56 | pte_update(&init_mm, addr, ptep, _PAGE_PRESENT, 0, 0); |
57 | break; |
58 | case SET_MEMORY_P: |
59 | pte_update(&init_mm, addr, ptep, 0, _PAGE_PRESENT, 0); |
60 | break; |
61 | default: |
62 | WARN_ON_ONCE(1); |
63 | break; |
64 | } |
65 | |
66 | /* See ptesync comment in radix__set_pte_at() */ |
67 | if (radix_enabled()) |
68 | asm volatile("ptesync" : : :"memory" ); |
69 | |
70 | flush_tlb_kernel_range(start: addr, end: addr + PAGE_SIZE); |
71 | |
72 | return 0; |
73 | } |
74 | |
75 | int change_memory_attr(unsigned long addr, int numpages, long action) |
76 | { |
77 | unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE); |
78 | unsigned long size = numpages * PAGE_SIZE; |
79 | |
80 | if (!numpages) |
81 | return 0; |
82 | |
83 | if (WARN_ON_ONCE(is_vmalloc_or_module_addr((void *)addr) && |
84 | is_vm_area_hugepages((void *)addr))) |
85 | return -EINVAL; |
86 | |
87 | #ifdef CONFIG_PPC_BOOK3S_64 |
88 | /* |
89 | * On hash, the linear mapping is not in the Linux page table so |
90 | * apply_to_existing_page_range() will have no effect. If in the future |
91 | * the set_memory_* functions are used on the linear map this will need |
92 | * to be updated. |
93 | */ |
94 | if (!radix_enabled()) { |
95 | int region = get_region_id(addr); |
96 | |
97 | if (WARN_ON_ONCE(region != VMALLOC_REGION_ID && region != IO_REGION_ID)) |
98 | return -EINVAL; |
99 | } |
100 | #endif |
101 | |
102 | return apply_to_existing_page_range(mm: &init_mm, address: start, size, |
103 | fn: change_page_attr, data: (void *)action); |
104 | } |
105 | |
106 | #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) |
107 | #ifdef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC |
108 | void __kernel_map_pages(struct page *page, int numpages, int enable) |
109 | { |
110 | int err; |
111 | unsigned long addr = (unsigned long)page_address(page); |
112 | |
113 | if (PageHighMem(page)) |
114 | return; |
115 | |
116 | if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled()) |
117 | err = hash__kernel_map_pages(page, numpages, enable); |
118 | else if (enable) |
119 | err = set_memory_p(addr, numpages); |
120 | else |
121 | err = set_memory_np(addr, numpages); |
122 | |
123 | if (err) |
124 | panic(fmt: "%s: changing memory protections failed\n" , __func__); |
125 | } |
126 | #endif |
127 | #endif |
128 | |