arm64: optionally set CP15BEN in SCTLR

Setting CP15BEN allows legacy applications running in AArch32 mode
that use CP15 DMB as similar instructions to continue running.

Change-Id: If76d3c6ee12865ff8c4b4e7aed01146bead87773
Signed-off-by: Alex Van Brunt <avanbrunt@nvidia.com>
Reviewed-on: http://git-master/r/366096
Reviewed-by: Richard Wiley <rwiley@nvidia.com>
Tested-by: Oskari Jaaskelainen <oskarij@nvidia.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 787cee384e1ce760010d2314680b28c6f9058205..0df94f10cda683659c5d9ca449c55bb9649c70d5 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -218,6 +218,17 @@ config ARMV7_COMPAT
         If you want to execute ARMv7 applications, say Y
 
 
+config ARMV7_COMPAT_CP15_BARRIER
+       bool "Allow applications to use the CP15 barrier operations"
+       depends on ARMV7_COMPAT
+       default y
+       help
+        This option allows applications to use deprecated CP15 barrier
+        instructions. This is useful because this was the only way to create
+        a barrier on older ARM processors.
+
+        If you want to execute ARMv7 applications, say Y
+
 source "mm/Kconfig"
 
 endmenu

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 9428de8a8f3766c6d82c9670453ba3f74f7b871d..48fffb27a7bfa34f3f1efa65562c0fb1460fcdb5 100644 (file)
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -160,6 +160,20 @@ ENTRY(__cpu_setup)
        ret                                     // return to head.S
 ENDPROC(__cpu_setup)
 
+#ifdef CONFIG_ARMV7_COMPAT_CP15_BARRIER
+       /*
+        *                 n n            T
+        *       U E      WT T UD     US IHBS
+        *       CE0      XWHW CZ     ME TEEA S
+        * .... .IEE .... NEAI TE.I ..AD DEN0 ACAM
+        * 0011 0... 1101 ..0. ..0. 10.. .... .... < hardware reserved
+        * .... .100 .... 01.1 11.1 ..01 0011 1101 < software settings
+        */
+       .type   crval, #object
+crval:
+       .word   0x030802e2                      // clear
+       .word   0x0405d13d                      // set
+#else
        /*
         *                 n n            T
         *       U E      WT T UD     US IHBS
@@ -172,3 +186,4 @@ ENDPROC(__cpu_setup)
 crval:
        .word   0x030802e2                      // clear
        .word   0x0405d11d                      // set
+#endif