[PATCH 4.19 16/64] lib/raid6: use vdupq_n_u8 to avoid endianness warnings

From: Greg Kroah-Hartman
Date: Wed Apr 22 2020 - 06:15:47 EST


From: ndesaulniers@xxxxxxxxxx <ndesaulniers@xxxxxxxxxx>

commit 1ad3935b39da78a403e7df7a3813f866c731bc64 upstream.

Clang warns: vector initializers are not compatible with NEON intrinsics
in big endian mode [-Wnonportable-vector-initialization]

While this is usually the case, it's not an issue for this case since
we're initializing the uint8x16_t (16x uint8_t's) with the same value.

Instead, use vdupq_n_u8 which both compilers lower into a single movi
instruction: https://godbolt.org/z/vBrgzt

This avoids the static storage for a constant value.

Link: https://github.com/ClangBuiltLinux/linux/issues/214
Suggested-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
lib/raid6/neon.uc | 5 ++---
lib/raid6/recov_neon_inner.c | 7 ++-----
2 files changed, 4 insertions(+), 8 deletions(-)

--- a/lib/raid6/neon.uc
+++ b/lib/raid6/neon.uc
@@ -28,7 +28,6 @@

typedef uint8x16_t unative_t;

-#define NBYTES(x) ((unative_t){x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
#define NSIZE sizeof(unative_t)

/*
@@ -61,7 +60,7 @@ void raid6_neon$#_gen_syndrome_real(int
int d, z, z0;

register unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
- const unative_t x1d = NBYTES(0x1d);
+ const unative_t x1d = vdupq_n_u8(0x1d);

z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
@@ -92,7 +91,7 @@ void raid6_neon$#_xor_syndrome_real(int
int d, z, z0;

register unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
- const unative_t x1d = NBYTES(0x1d);
+ const unative_t x1d = vdupq_n_u8(0x1d);

z0 = stop; /* P/Q right side optimization */
p = dptr[disks-2]; /* XOR parity */
--- a/lib/raid6/recov_neon_inner.c
+++ b/lib/raid6/recov_neon_inner.c
@@ -10,11 +10,6 @@

#include <arm_neon.h>

-static const uint8x16_t x0f = {
- 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
- 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
-};
-
#ifdef CONFIG_ARM
/*
* AArch32 does not provide this intrinsic natively because it does not
@@ -41,6 +36,7 @@ void __raid6_2data_recov_neon(int bytes,
uint8x16_t pm1 = vld1q_u8(pbmul + 16);
uint8x16_t qm0 = vld1q_u8(qmul);
uint8x16_t qm1 = vld1q_u8(qmul + 16);
+ uint8x16_t x0f = vdupq_n_u8(0x0f);

/*
* while ( bytes-- ) {
@@ -87,6 +83,7 @@ void __raid6_datap_recov_neon(int bytes,
{
uint8x16_t qm0 = vld1q_u8(qmul);
uint8x16_t qm1 = vld1q_u8(qmul + 16);
+ uint8x16_t x0f = vdupq_n_u8(0x0f);

/*
* while (bytes--) {