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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mm/abort-macro.S | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2v2.6.12-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!
Diffstat (limited to 'arch/arm/mm/abort-macro.S')
-rw-r--r-- | arch/arm/mm/abort-macro.S | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/arm/mm/abort-macro.S b/arch/arm/mm/abort-macro.S new file mode 100644 index 000000000000..d7cb1bfa51a4 --- /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 + |