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151 lines
3.1 KiB
151 lines
3.1 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Copyright (C) 2020 ARM Ltd. |
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*/ |
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#include <linux/linkage.h> |
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#include <asm/asm-uaccess.h> |
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#include <asm/assembler.h> |
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#include <asm/mte.h> |
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#include <asm/page.h> |
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#include <asm/sysreg.h> |
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.arch armv8.5-a+memtag |
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/* |
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* multitag_transfer_size - set \reg to the block size that is accessed by the |
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* LDGM/STGM instructions. |
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*/ |
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.macro multitag_transfer_size, reg, tmp |
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mrs_s \reg, SYS_GMID_EL1 |
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ubfx \reg, \reg, #SYS_GMID_EL1_BS_SHIFT, #SYS_GMID_EL1_BS_SIZE |
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mov \tmp, #4 |
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lsl \reg, \tmp, \reg |
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.endm |
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/* |
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* Clear the tags in a page |
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* x0 - address of the page to be cleared |
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*/ |
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SYM_FUNC_START(mte_clear_page_tags) |
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multitag_transfer_size x1, x2 |
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1: stgm xzr, [x0] |
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add x0, x0, x1 |
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tst x0, #(PAGE_SIZE - 1) |
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b.ne 1b |
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ret |
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SYM_FUNC_END(mte_clear_page_tags) |
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/* |
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* Copy the tags from the source page to the destination one |
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* x0 - address of the destination page |
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* x1 - address of the source page |
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*/ |
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SYM_FUNC_START(mte_copy_page_tags) |
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mov x2, x0 |
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mov x3, x1 |
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multitag_transfer_size x5, x6 |
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1: ldgm x4, [x3] |
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stgm x4, [x2] |
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add x2, x2, x5 |
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add x3, x3, x5 |
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tst x2, #(PAGE_SIZE - 1) |
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b.ne 1b |
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ret |
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SYM_FUNC_END(mte_copy_page_tags) |
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/* |
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* Read tags from a user buffer (one tag per byte) and set the corresponding |
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* tags at the given kernel address. Used by PTRACE_POKEMTETAGS. |
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* x0 - kernel address (to) |
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* x1 - user buffer (from) |
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* x2 - number of tags/bytes (n) |
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* Returns: |
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* x0 - number of tags read/set |
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*/ |
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SYM_FUNC_START(mte_copy_tags_from_user) |
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mov x3, x1 |
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cbz x2, 2f |
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1: |
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user_ldst 2f, ldtrb, w4, x1, 0 |
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lsl x4, x4, #MTE_TAG_SHIFT |
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stg x4, [x0], #MTE_GRANULE_SIZE |
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add x1, x1, #1 |
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subs x2, x2, #1 |
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b.ne 1b |
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// exception handling and function return |
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2: sub x0, x1, x3 // update the number of tags set |
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ret |
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SYM_FUNC_END(mte_copy_tags_from_user) |
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/* |
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* Get the tags from a kernel address range and write the tag values to the |
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* given user buffer (one tag per byte). Used by PTRACE_PEEKMTETAGS. |
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* x0 - user buffer (to) |
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* x1 - kernel address (from) |
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* x2 - number of tags/bytes (n) |
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* Returns: |
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* x0 - number of tags read/set |
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*/ |
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SYM_FUNC_START(mte_copy_tags_to_user) |
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mov x3, x0 |
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cbz x2, 2f |
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1: |
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ldg x4, [x1] |
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ubfx x4, x4, #MTE_TAG_SHIFT, #MTE_TAG_SIZE |
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user_ldst 2f, sttrb, w4, x0, 0 |
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add x0, x0, #1 |
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add x1, x1, #MTE_GRANULE_SIZE |
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subs x2, x2, #1 |
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b.ne 1b |
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// exception handling and function return |
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2: sub x0, x0, x3 // update the number of tags copied |
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ret |
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SYM_FUNC_END(mte_copy_tags_to_user) |
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/* |
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* Save the tags in a page |
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* x0 - page address |
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* x1 - tag storage |
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*/ |
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SYM_FUNC_START(mte_save_page_tags) |
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multitag_transfer_size x7, x5 |
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1: |
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mov x2, #0 |
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2: |
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ldgm x5, [x0] |
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orr x2, x2, x5 |
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add x0, x0, x7 |
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tst x0, #0xFF // 16 tag values fit in a register, |
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b.ne 2b // which is 16*16=256 bytes |
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str x2, [x1], #8 |
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tst x0, #(PAGE_SIZE - 1) |
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b.ne 1b |
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ret |
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SYM_FUNC_END(mte_save_page_tags) |
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/* |
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* Restore the tags in a page |
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* x0 - page address |
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* x1 - tag storage |
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*/ |
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SYM_FUNC_START(mte_restore_page_tags) |
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multitag_transfer_size x7, x5 |
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1: |
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ldr x2, [x1], #8 |
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2: |
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stgm x2, [x0] |
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add x0, x0, x7 |
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tst x0, #0xFF |
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b.ne 2b |
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tst x0, #(PAGE_SIZE - 1) |
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b.ne 1b |
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ret |
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SYM_FUNC_END(mte_restore_page_tags)
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