40 lines
1.2 KiB
ArmAsm
40 lines
1.2 KiB
ArmAsm
|
/* SPDX-License-Identifier: GPL-2.0 */
|
||
|
|
/*
|
||
|
|
* The ARM LDRD and Thumb LDRSB instructions use bit 20/11 (ARM/Thumb)
|
||
|
|
* differently than every other instruction, so it is set to 0 (write)
|
||
|
|
* even though the instructions are read instructions. This means that
|
||
|
|
* during an abort the instructions will be treated as a write and the
|
||
|
|
* handler will raise a signal from unwriteable locations if they
|
||
|
|
* fault. We have to specifically check for these instructions
|
||
|
|
* from the abort handlers to treat them properly.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
.macro do_thumb_abort, fsr, pc, psr, tmp
|
||
|
|
tst \psr, #PSR_T_BIT
|
||
|
|
beq not_thumb
|
||
|
|
ldrh \tmp, [\pc] @ Read aborted Thumb instruction
|
||
|
|
uaccess_disable ip @ disable userspace access
|
||
|
|
and \tmp, \tmp, # 0xfe00 @ Mask opcode field
|
||
|
|
cmp \tmp, # 0x5600 @ Is it ldrsb?
|
||
|
|
orreq \tmp, \tmp, #1 << 11 @ Set L-bit if yes
|
||
|
|
tst \tmp, #1 << 11 @ L = 0 -> write
|
||
|
|
orreq \fsr, \fsr, #1 << 11 @ yes.
|
||
|
|
b do_DataAbort
|
||
|
|
not_thumb:
|
||
|
|
.endm
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We check for the following instruction encoding for LDRD.
|
||
|
|
*
|
||
|
|
* [27:25] == 000
|
||
|
|
* [7:4] == 1101
|
||
|
|
* [20] == 0
|
||
|
|
*/
|
||
|
|
.macro teq_ldrd, tmp, insn
|
||
|
|
mov \tmp, #0x0e100000
|
||
|
|
orr \tmp, #0x000000f0
|
||
|
|
and \tmp, \insn, \tmp
|
||
|
|
teq \tmp, #0x000000d0
|
||
|
|
.endm
|