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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 | /* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2020 ARM Ltd. */ #include <linux/linkage.h> #include <asm/alternative.h> #include <asm/assembler.h> #include <asm/mte.h> #include <asm/page.h> #include <asm/sysreg.h> .arch armv8.5-a+memtag /* * multitag_transfer_size - set \reg to the block size that is accessed by the * LDGM/STGM instructions. */ .macro multitag_transfer_size, reg, tmp mrs_s \reg, SYS_GMID_EL1 ubfx \reg, \reg, #SYS_GMID_EL1_BS_SHIFT, #SYS_GMID_EL1_BS_SIZE mov \tmp, #4 lsl \reg, \tmp, \reg .endm /* * Clear the tags in a page * x0 - address of the page to be cleared */ SYM_FUNC_START(mte_clear_page_tags) multitag_transfer_size x1, x2 1: stgm xzr, [x0] add x0, x0, x1 tst x0, #(PAGE_SIZE - 1) b.ne 1b ret SYM_FUNC_END(mte_clear_page_tags) /* * Copy the tags from the source page to the destination one * x0 - address of the destination page * x1 - address of the source page */ SYM_FUNC_START(mte_copy_page_tags) mov x2, x0 mov x3, x1 multitag_transfer_size x5, x6 1: ldgm x4, [x3] stgm x4, [x2] add x2, x2, x5 add x3, x3, x5 tst x2, #(PAGE_SIZE - 1) b.ne 1b ret SYM_FUNC_END(mte_copy_page_tags) /* * Read tags from a user buffer (one tag per byte) and set the corresponding * tags at the given kernel address. Used by PTRACE_POKEMTETAGS. * x0 - kernel address (to) * x1 - user buffer (from) * x2 - number of tags/bytes (n) * Returns: * x0 - number of tags read/set */ SYM_FUNC_START(mte_copy_tags_from_user) mov x3, x1 cbz x2, 2f 1: uao_user_alternative 2f, ldrb, ldtrb, w4, x1, 0 lsl x4, x4, #MTE_TAG_SHIFT stg x4, [x0], #MTE_GRANULE_SIZE add x1, x1, #1 subs x2, x2, #1 b.ne 1b // exception handling and function return 2: sub x0, x1, x3 // update the number of tags set ret SYM_FUNC_END(mte_copy_tags_from_user) /* * Get the tags from a kernel address range and write the tag values to the * given user buffer (one tag per byte). Used by PTRACE_PEEKMTETAGS. * x0 - user buffer (to) * x1 - kernel address (from) * x2 - number of tags/bytes (n) * Returns: * x0 - number of tags read/set */ SYM_FUNC_START(mte_copy_tags_to_user) mov x3, x0 cbz x2, 2f 1: ldg x4, [x1] ubfx x4, x4, #MTE_TAG_SHIFT, #MTE_TAG_SIZE uao_user_alternative 2f, strb, sttrb, w4, x0, 0 add x0, x0, #1 add x1, x1, #MTE_GRANULE_SIZE subs x2, x2, #1 b.ne 1b // exception handling and function return 2: sub x0, x0, x3 // update the number of tags copied ret SYM_FUNC_END(mte_copy_tags_to_user) /* * Save the tags in a page * x0 - page address * x1 - tag storage */ SYM_FUNC_START(mte_save_page_tags) multitag_transfer_size x7, x5 1: mov x2, #0 2: ldgm x5, [x0] orr x2, x2, x5 add x0, x0, x7 tst x0, #0xFF // 16 tag values fit in a register, b.ne 2b // which is 16*16=256 bytes str x2, [x1], #8 tst x0, #(PAGE_SIZE - 1) b.ne 1b ret SYM_FUNC_END(mte_save_page_tags) /* * Restore the tags in a page * x0 - page address * x1 - tag storage */ SYM_FUNC_START(mte_restore_page_tags) multitag_transfer_size x7, x5 1: ldr x2, [x1], #8 2: stgm x2, [x0] add x0, x0, x7 tst x0, #0xFF b.ne 2b tst x0, #(PAGE_SIZE - 1) b.ne 1b ret SYM_FUNC_END(mte_restore_page_tags) |