arm64: compat: correct register concatenation for syscall wrappers
The arm64 port contains wrappers for arm32 syscalls that pass 64-bit
values. These wrappers concatenate the two registers to hold a 64-bit
value in a single X register. On BE, however, the lower and higher
words are swapped.
Create a new assembler macro, regs_to_64, that when on BE systems
swaps the registers in the orr instruction.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 5aceb83..381b935 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -115,3 +115,15 @@
.align 7
b \label
.endm
+/*
+ * Define a macro that constructs a 64-bit value by concatenating two
+ * 32-bit registers. Note that on big endian systems the order of the
+ * registers is swapped.
+ */
+#ifndef CONFIG_CPU_BIG_ENDIAN
+ .macro regs_to_64, rd, lbits, hbits
+#else
+ .macro regs_to_64, rd, hbits, lbits
+#endif
+ orr \rd, \lbits, \hbits, lsl #32
+ .endm