arm64: introduce mov_q macro to move a constant into a 64-bit register

commit 30b5ba5cf333cc650e474eaf2cc1ae91bc7cf89f upstream.

Implement a macro mov_q that can be used to move an immediate constant
into a 64-bit register, using between 2 and 4 movz/movk instructions
(depending on the operand)

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 12eff928ef8b38dd18ae3bd157b12eb918f797a6..83e23093dfd8aa66ef6468783e58d80a8ed0e317 100644 (file)
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -204,4 +204,24 @@ lr .req    x30             // link register
        .size   __pi_##x, . - x;        \
        ENDPROC(x)
 
+       /*
+        * mov_q - move an immediate constant into a 64-bit register using
+        *         between 2 and 4 movz/movk instructions (depending on the
+        *         magnitude and sign of the operand)
+        */
+       .macro  mov_q, reg, val
+       .if (((\val) >> 31) == 0 || ((\val) >> 31) == 0x1ffffffff)
+       movz    \reg, :abs_g1_s:\val
+       .else
+       .if (((\val) >> 47) == 0 || ((\val) >> 47) == 0x1ffff)
+       movz    \reg, :abs_g2_s:\val
+       .else
+       movz    \reg, :abs_g3:\val
+       movk    \reg, :abs_g2_nc:\val
+       .endif
+       movk    \reg, :abs_g1_nc:\val
+       .endif
+       movk    \reg, :abs_g0_nc:\val
+       .endm
+
 #endif /* __ASM_ASSEMBLER_H */