From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/arm/mm/abort-macro.S | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 arch/arm/mm/abort-macro.S (limited to 'arch/arm/mm/abort-macro.S') diff --git a/arch/arm/mm/abort-macro.S b/arch/arm/mm/abort-macro.S new file mode 100644 index 00000000000..d7cb1bfa51a --- /dev/null +++ b/arch/arm/mm/abort-macro.S @@ -0,0 +1,42 @@ +/* + * 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 + -- cgit v1.2.3