1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (C) 2020 ARM Ltd.
5 #include <linux/linkage.h>
7 #include <asm/asm-uaccess.h>
8 #include <asm/assembler.h>
11 #include <asm/sysreg.h>
13 .arch armv8.5-a+memtag
16 * multitag_transfer_size - set \reg to the block size that is accessed by the
17 * LDGM/STGM instructions.
19 .macro multitag_transfer_size, reg, tmp
20 mrs_s \reg, SYS_GMID_EL1
21 ubfx \reg, \reg, #SYS_GMID_EL1_BS_SHIFT, #SYS_GMID_EL1_BS_SIZE
27 * Clear the tags in a page
28 * x0 - address of the page to be cleared
30 SYM_FUNC_START(mte_clear_page_tags)
31 multitag_transfer_size x1, x2
34 tst x0, #(PAGE_SIZE - 1)
37 SYM_FUNC_END(mte_clear_page_tags)
40 * Zero the page and tags at the same time
43 * x0 - address to the beginning of the page
45 SYM_FUNC_START(mte_zero_clear_page_tags)
50 and x0, x0, #(1 << MTE_TAG_SHIFT) - 1 // clear the tag
54 tst x0, #(PAGE_SIZE - 1)
57 SYM_FUNC_END(mte_zero_clear_page_tags)
60 * Copy the tags from the source page to the destination one
61 * x0 - address of the destination page
62 * x1 - address of the source page
64 SYM_FUNC_START(mte_copy_page_tags)
67 multitag_transfer_size x5, x6
72 tst x2, #(PAGE_SIZE - 1)
75 SYM_FUNC_END(mte_copy_page_tags)
78 * Read tags from a user buffer (one tag per byte) and set the corresponding
79 * tags at the given kernel address. Used by PTRACE_POKEMTETAGS.
80 * x0 - kernel address (to)
81 * x1 - user buffer (from)
82 * x2 - number of tags/bytes (n)
84 * x0 - number of tags read/set
86 SYM_FUNC_START(mte_copy_tags_from_user)
90 user_ldst 2f, ldtrb, w4, x1, 0
91 lsl x4, x4, #MTE_TAG_SHIFT
92 stg x4, [x0], #MTE_GRANULE_SIZE
97 // exception handling and function return
98 2: sub x0, x1, x3 // update the number of tags set
100 SYM_FUNC_END(mte_copy_tags_from_user)
103 * Get the tags from a kernel address range and write the tag values to the
104 * given user buffer (one tag per byte). Used by PTRACE_PEEKMTETAGS.
105 * x0 - user buffer (to)
106 * x1 - kernel address (from)
107 * x2 - number of tags/bytes (n)
109 * x0 - number of tags read/set
111 SYM_FUNC_START(mte_copy_tags_to_user)
116 ubfx x4, x4, #MTE_TAG_SHIFT, #MTE_TAG_SIZE
117 user_ldst 2f, sttrb, w4, x0, 0
119 add x1, x1, #MTE_GRANULE_SIZE
123 // exception handling and function return
124 2: sub x0, x0, x3 // update the number of tags copied
126 SYM_FUNC_END(mte_copy_tags_to_user)
129 * Save the tags in a page
133 SYM_FUNC_START(mte_save_page_tags)
134 multitag_transfer_size x7, x5
141 tst x0, #0xFF // 16 tag values fit in a register,
142 b.ne 2b // which is 16*16=256 bytes
146 tst x0, #(PAGE_SIZE - 1)
150 SYM_FUNC_END(mte_save_page_tags)
153 * Restore the tags in a page
157 SYM_FUNC_START(mte_restore_page_tags)
158 multitag_transfer_size x7, x5
167 tst x0, #(PAGE_SIZE - 1)
171 SYM_FUNC_END(mte_restore_page_tags)