[POWERPC] 8xx: Work around CPU15 erratum.
The CPU15 erratum on MPC8xx chips can cause incorrect code execution
under certain circumstances, where there is a conditional or indirect
branch in the last word of a page, with a target in the last cache line
of the next page. This patch implements one of the suggested
workarounds, by forcing a TLB miss whenever execution crosses a page
boundary. This is done by invalidating the pages before and after the
one being loaded into the TLB in the ITLB miss handler.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/8xx/Kconfig b/arch/powerpc/platforms/8xx/Kconfig
index 8ecd01a..322b155 100644
--- a/arch/powerpc/platforms/8xx/Kconfig
+++ b/arch/powerpc/platforms/8xx/Kconfig
@@ -100,6 +100,22 @@
If in doubt, say N here.
+config 8xx_CPU15
+ bool "CPU15 Silicon Errata"
+ default y
+ help
+ This enables a workaround for erratum CPU15 on MPC8xx chips.
+ This bug can cause incorrect code execution under certain
+ circumstances. This workaround adds some overhead (a TLB miss
+ every time execution crosses a page boundary), and you may wish
+ to disable it if you have worked around the bug in the compiler
+ (by not placing conditional branches or branches to LR or CTR
+ in the last word of a page, with a target of the last cache
+ line in the next page), or if you have used some other
+ workaround.
+
+ If in doubt, say Y here.
+
choice
prompt "Microcode patch selection"
default NO_UCODE_PATCH