[ARM] 3967/1: xsc3: make branch predication configurable on xsc3
Remove BTB_ENABLE from proc-xsc3.S
On some early revisions of xsc3 enabling the branch target buffer can cause
crashes, see erratum #42.
Cc: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index c0bfb82..efebd60 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -580,7 +580,7 @@
config CPU_BPREDICT_DISABLE
bool "Disable branch prediction"
- depends on CPU_ARM1020 || CPU_V6
+ depends on CPU_ARM1020 || CPU_V6 || CPU_XSC3
help
Say Y here to disable branch prediction. If unsure, say N.
diff --git a/arch/arm/mm/proc-xsc3.S b/arch/arm/mm/proc-xsc3.S
index 85c3523..1ef564d 100644
--- a/arch/arm/mm/proc-xsc3.S
+++ b/arch/arm/mm/proc-xsc3.S
@@ -57,11 +57,6 @@
#define L2_CACHE_ENABLE 1
/*
- * Enable the Branch Target Buffer (can cause crashes, see erratum #42.)
- */
-#define BTB_ENABLE 0
-
-/*
* This macro is used to wait for a CP15 write and is needed
* when we have to ensure that the last operation to the co-pro
* was completed before continuing with operation.
@@ -434,9 +429,7 @@
mrc p15, 0, r0, c1, c0, 0 @ get control register
bic r0, r0, r5 @ .... .... .... ..A.
orr r0, r0, r6 @ .... .... .... .C.M
-#if BTB_ENABLE
orr r0, r0, #0x00000800 @ ..VI Z..S .... ....
-#endif
#if L2_CACHE_ENABLE
orr r0, r0, #0x04000000 @ L2 enable
#endif