[PARISC] Make sure use of RFI conforms to PA 2.0 and 1.1 arch docs
2.6.12-rc4-pa3 : first pass at making sure use of RFI conforms to
PA 2.0 arch pages F-4 and F-5, PA 1.1 Arch page 3-19 and 3-20.
The discussion revolves around all the rules for clearing PSW Q-bit.
The hard part is meeting all the rules for "relied upon translation".
.align directive is used to guarantee the critical sequence ends more than
8 instructions (32 bytes) from the end of page.
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/include/asm-parisc/assembly.h b/include/asm-parisc/assembly.h
index 30b0234..b24a99e 100644
--- a/include/asm-parisc/assembly.h
+++ b/include/asm-parisc/assembly.h
@@ -450,5 +450,30 @@
REST_CR (%cr22, PT_PSW (\regs))
.endm
+
+ /* First step to create a "relied upon translation"
+ * See PA 2.0 Arch. page F-4 and F-5.
+ *
+ * The ssm was originally necessary due to a "PCxT bug".
+ * But someone decided it needed to be added to the architecture
+ * and this "feature" went into rev3 of PA-RISC 1.1 Arch Manual.
+ * It's been carried forward into PA 2.0 Arch as well. :^(
+ *
+ * "ssm 0,%r0" is a NOP with side effects (prefetch barrier).
+ * rsm/ssm prevents the ifetch unit from speculatively fetching
+ * instructions past this line in the code stream.
+ * PA 2.0 processor will single step all insn in the same QUAD (4 insn).
+ */
+ .macro pcxt_ssm_bug
+ rsm PSW_SM_I,%r0
+ nop /* 1 */
+ nop /* 2 */
+ nop /* 3 */
+ nop /* 4 */
+ nop /* 5 */
+ nop /* 6 */
+ nop /* 7 */
+ .endm
+
#endif /* __ASSEMBLY__ */
#endif
