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-rw-r--r--arch/arm/Kconfig9
-rw-r--r--arch/arm/mm/proc-v7.S14
2 files changed, 22 insertions, 1 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 57562f8d1f9..bd2709d5567 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1373,6 +1373,15 @@ config ARM_ERRATA_798181
which sends an IPI to the CPUs that are running the same ASID
as the one being invalidated.
+config ARM_ERRATA_773022
+ bool "ARM errata: incorrect instructions may be executed from loop buffer"
+ depends on CPU_V7
+ help
+ This option enables the workaround for the 773022 Cortex-A15
+ (up to r0p4) erratum. In certain rare sequences of code, the
+ loop buffer may deliver incorrect instructions. This
+ workaround disables the loop buffer to avoid the erratum.
+
endmenu
source "arch/arm/common/Kconfig"
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 5c6d5a3050e..e7d45d529a2 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -329,7 +329,19 @@ __v7_setup:
1:
#endif
-3: mov r10, #0
+ /* Cortex-A15 Errata */
+3: ldr r10, =0x00000c0f @ Cortex-A15 primary part number
+ teq r0, r10
+ bne 4f
+
+#ifdef CONFIG_ARM_ERRATA_773022
+ cmp r6, #0x4 @ only present up to r0p4
+ mrcle p15, 0, r10, c1, c0, 1 @ read aux control register
+ orrle r10, r10, #1 << 1 @ disable loop buffer
+ mcrle p15, 0, r10, c1, c0, 1 @ write aux control register
+#endif
+
+4: mov r10, #0
mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate
dsb
#ifdef CONFIG_MMU