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>
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index d662a2f..9d7ce43 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -482,6 +482,9 @@
subeq r4, r2, #4 @ ARM instr at LR - 4
subne r4, r2, #2 @ Thumb instr at LR - 2
1: ldreqt r0, [r4]
+#ifdef CONFIG_CPU_ENDIAN_BE8
+ reveq r0, r0 @ little endian instruction
+#endif
beq call_fpe
@ Thumb instruction
#if __LINUX_ARM_ARCH__ >= 7
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index b55cb03..366e509 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -210,6 +210,9 @@
A710( teq ip, #0x0f000000 )
A710( bne .Larm710bug )
#endif
+#ifdef CONFIG_CPU_ENDIAN_BE8
+ rev r10, r10 @ little endian instruction
+#endif
#elif defined(CONFIG_AEABI)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index c3265a2..1585423 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -365,7 +365,7 @@
regs.ARM_r2 = (unsigned long)fn;
regs.ARM_r3 = (unsigned long)do_exit;
regs.ARM_pc = (unsigned long)kernel_thread_helper;
- regs.ARM_cpsr = SVC_MODE;
+ regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE;
return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
}