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Diffstat (limited to 'kernel/arch/arm/mm/abort-macro.S')
| -rw-r--r-- | kernel/arch/arm/mm/abort-macro.S | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/kernel/arch/arm/mm/abort-macro.S b/kernel/arch/arm/mm/abort-macro.S new file mode 100644 index 000000000..2cbf68ef0 --- /dev/null +++ b/kernel/arch/arm/mm/abort-macro.S @@ -0,0 +1,40 @@ +/* + * 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 + 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 do_ldrd_abort, tmp, insn + tst \insn, #0x0e100000 @ [27:25,20] == 0 + bne not_ldrd + and \tmp, \insn, #0x000000f0 @ [7:4] == 1101 + cmp \tmp, #0x000000d0 + beq do_DataAbort +not_ldrd: + .endm + |