|author||Linus Torvalds <firstname.lastname@example.org>||2005-04-16 15:20:36 -0700|
|committer||Linus Torvalds <email@example.com>||2005-04-16 15:20:36 -0700|
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!
Diffstat (limited to 'arch/arm/mm/abort-macro.S')
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/arm/mm/abort-macro.S b/arch/arm/mm/abort-macro.S
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+ * 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
+ * We check for the following insturction encoding for LDRD.
+ * [27:25] == 0
+ * [7:4] == 1101
+ *  == 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 @  == 0
+ moveq pc, lr