Add core support for ARMv6/v7 big-endian

Starting with ARMv6, the CPUs support the BE-8 variant of big-endian
(byte-invariant). This patch adds the core support:

- setting of the BE-8 mode via the CPSR.E register for both kernel and
  user threads
- big-endian page table walking
- REV used to rotate instructions read from memory during fault
  processing as they are still little-endian format
- Kconfig and Makefile support for BE-8. The --be8 option must be passed
  to the final linking stage to convert the instructions to
  little-endian

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

2 files changed, 10 insertions, 1 deletions

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index fbe5eef1f6c9..ce39dc540085 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -40,7 +40,7 @@ ifeq ($(CONFIG_PXA_SHARPSL),y)
 OBJS            += head-sharpsl.o
 endif
 
-ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)
+ifeq ($(CONFIG_CPU_ENDIAN_BE32),y)
 ifeq ($(CONFIG_CPU_CP15),y)
 OBJS            += big-endian.o
 else
@@ -78,6 +78,9 @@ EXTRA_AFLAGS  := -Wa,-march=all
 # linker symbols.  We only define initrd_phys and params_phys if the
 # machine class defined the corresponding makefile variable.
 LDFLAGS_vmlinux := --defsym zreladdr=$(ZRELADDR)
+ifeq ($(CONFIG_CPU_ENDIAN_BE8),y)
+LDFLAGS_vmlinux += --be8
+endif
 ifneq ($(INITRD_PHYS),)
 LDFLAGS_vmlinux += --defsym initrd_phys=$(INITRD_PHYS)
 endif
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index b371fba1b954..01d49be3b2ca 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -438,6 +438,9 @@ __armv4_mmu_cache_on:
                 mrc     p15, 0, r0, c1, c0, 0   @ read control reg
                 orr     r0, r0, #0x5000         @ I-cache enable, RR cache replacement
                 orr     r0, r0, #0x0030
+#ifdef CONFIG_CPU_ENDIAN_BE8
+                orr     r0, r0, #1 << 25        @ big-endian page tables
+#endif
                 bl      __common_mmu_cache_on
                 mov     r0, #0
                 mcr     p15, 0, r0, c8, c7, 0   @ flush I,D TLBs
@@ -455,6 +458,9 @@ __armv7_mmu_cache_on:
                 mrc     p15, 0, r0, c1, c0, 0   @ read control reg
                 orr     r0, r0, #0x5000         @ I-cache enable, RR cache replacement
                 orr     r0, r0, #0x003c         @ write buffer
+#ifdef CONFIG_CPU_ENDIAN_BE8
+                orr     r0, r0, #1 << 25        @ big-endian page tables
+#endif
                 orrne   r0, r0, #1              @ MMU enabled
                 movne   r1, #-1
                 mcrne   p15, 0, r3, c2, c0, 0   @ load page table pointer