/* * 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 tst r3, #PSR_T_BIT beq not_thumb ldrh r3, [r2] @ Read aborted Thumb instruction and r3, r3, # 0xfe00 @ Mask opcode field cmp r3, # 0x5600 @ Is it ldrsb? orreq r3, r3, #1 << 11 @ Set L-bit if yes tst r3, #1 << 11 @ L = 0 -> write orreq r1, r1, #1 << 11 @ yes. mov pc, lr not_thumb: .endm /* * We check for the following insturction encoding for LDRD. * * [27:25] == 0 * [7:4] == 1101 * [20] == 0 */ .macro do_ldrd_abort tst r3, #0x0e000000 @ [27:25] == 0 bne not_ldrd and r2, r3, #0x000000f0 @ [7:4] == 1101 cmp r2, #0x000000d0 bne not_ldrd tst r3, #1 << 20 @ [20] == 0 moveq pc, lr not_ldrd: .endm