1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * The ARM LDRD and Thumb LDRSB instructions use bit 20/11 (ARM/Thumb) 4 * differently than every other instruction, so it is set to 0 (write) 5 * even though the instructions are read instructions. This means that 6 * during an abort the instructions will be treated as a write and the 7 * handler will raise a signal from unwriteable locations if they 8 * fault. We have to specifically check for these instructions 9 * from the abort handlers to treat them properly. 10 * 11 */ 12 13 .macro do_thumb_abort, fsr, pc, psr, tmp 14 tst \psr, #PSR_T_BIT 15 beq not_thumb 16 ldrh \tmp, [\pc] @ Read aborted Thumb instruction 17 uaccess_disable ip @ disable userspace access 18 and \tmp, \tmp, # 0xfe00 @ Mask opcode field 19 cmp \tmp, # 0x5600 @ Is it ldrsb? 20 orreq \tmp, \tmp, #1 << 11 @ Set L-bit if yes 21 tst \tmp, #1 << 11 @ L = 0 -> write 22 orreq \fsr, \fsr, #1 << 11 @ yes. 23 b do_DataAbort 24 not_thumb: 25 .endm 26 27 /* 28 * We check for the following instruction encoding for LDRD. 29 * 30 * [27:25] == 000 31 * [7:4] == 1101 32 * [20] == 0 33 */ 34 .macro teq_ldrd, tmp, insn 35 mov \tmp, #0x0e100000 36 orr \tmp, #0x000000f0 37 and \tmp, \insn, \tmp 38 teq \tmp, #0x000000d0 39 .endm 40