crypto: arm/curve25519 - Move '.fpu' after '.arch'
Subsystems (3)
PATCH 1/1 crypto: arm/curve25519 - Move '.fpu' after '.arch'
Debian's clang carries a patch that makes the default FPU mode 'vfp3-d16' instead of 'neon' for 'armv7-a' to avoid generating NEON instructions on hardware that does not support them:
https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/raw/5a61ca6f21b4ad8c6ac4970e5ea5a7b5b4486d22/debian/patches/clang-arm-default-vfp3-on-armv7a.patch
https://bugs.debian.org/841474
https://bugs.debian.org/842142
https://bugs.debian.org/914268
This results in the following build error when clang's integrated assembler is used because the '.arch' directive overrides the '.fpu' directive:
arch/arm/crypto/curve25519-core.S:25:2: error: instruction requires: NEON
vmov.i32 q0, #1
^arch/arm/crypto/curve25519-core.S:26:2: error: instruction requires: NEON
vshr.u64 q1, q0, #7
^arch/arm/crypto/curve25519-core.S:27:2: error: instruction requires: NEON
vshr.u64 q0, q0, #8
^arch/arm/crypto/curve25519-core.S:28:2: error: instruction requires: NEON
vmov.i32 d4, #19
^
Shuffle the order of the '.arch' and '.fpu' directives so that the code builds regardless of the default FPU mode. This has been tested against both clang with and without Debian's patch and GCC.
--- arch/arm/crypto/curve25519-core.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arm/crypto/curve25519-core.S +1 -1
@@ -10,8 +10,8 @@ #include <linux/linkage.h> .text -.fpu neon .arch armv7-a +.fpu neon .align 4 ENTRY(curve25519_neon)
base-commit: e49d033bddf5b565044e2abe4241353959bc9120
Signature · 1 line
2.31.1.189.g2e36527f23
Seems reasonable to me.
Quoted 9 lines · Nathan Chancellor
Debian's clang carries a patch that makes the default FPU mode 'vfp3-d16' instead of 'neon' for 'armv7-a' to avoid generating NEON instructions on hardware that does not support them:
https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/raw/5a61ca6f21b4ad8c6ac4970e5ea5a7b5b4486d22/debian/patches/clang-arm-default-vfp3-on-armv7a.patch
https://bugs.debian.org/841474
https://bugs.debian.org/842142
https://bugs.debian.org/914268
Another good link would be the one from Jessica describing more precisely what the ARM targets for Debian are:
https://wiki.debian.org/ArchitectureSpecificsMemo#armel
Quoted 22 lines
This results in the following build error when clang's integrated assembler is used because the '.arch' directive overrides the '.fpu' directive:
arch/arm/crypto/curve25519-core.S:25:2: error: instruction requires: NEON
vmov.i32 q0, #1
^arch/arm/crypto/curve25519-core.S:26:2: error: instruction requires: NEON
vshr.u64 q1, q0, #7
^arch/arm/crypto/curve25519-core.S:27:2: error: instruction requires: NEON
vshr.u64 q0, q0, #8
^arch/arm/crypto/curve25519-core.S:28:2: error: instruction requires: NEON
vmov.i32 d4, #19
^Shuffle the order of the '.arch' and '.fpu' directives so that the code builds regardless of the default FPU mode. This has been tested against both clang with and without Debian's patch and GCC.
Quoted 7 lines
Fixes d8f1308a025f ("crypto: arm/curve25519 - wire up NEON implementation")Reported-by Arnd Bergmann <[email protected]>Suggested-by Arnd Bergmann <[email protected]>Suggested-by Jessica Clarke <[email protected]>Signed-off-by Nathan Chancellor <[email protected]>
Great work tracking down that Debian was carrying patches! Thank you! I've run this through the same 3 assemblers.
Quoted 23 lines
--- arch/arm/crypto/curve25519-core.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)arch/arm/crypto/curve25519-core.S +1
-1@@ -10,8 +10,8 @@ #include <linux/linkage.h> .text -.fpu neon .arch armv7-a +.fpu neon .align 4 ENTRY(curve25519_neon)base-commit:
e49d033bddf5b565044e2abe4241353959bc9120--
2.31.1.189.g2e36527f23
Signature · 2 lines
Thanks, ~Nick Desaulniers
Herbert Xu
maintainerQuoted 37 lines · Nathan Chancellor
Debian's clang carries a patch that makes the default FPU mode 'vfp3-d16' instead of 'neon' for 'armv7-a' to avoid generating NEON instructions on hardware that does not support them:
https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/raw/5a61ca6f21b4ad8c6ac4970e5ea5a7b5b4486d22/debian/patches/clang-arm-default-vfp3-on-armv7a.patch
https://bugs.debian.org/841474
https://bugs.debian.org/842142
https://bugs.debian.org/914268This results in the following build error when clang's integrated assembler is used because the '.arch' directive overrides the '.fpu' directive:
arch/arm/crypto/curve25519-core.S:25:2: error: instruction requires: NEON
vmov.i32 q0, #1
^arch/arm/crypto/curve25519-core.S:26:2: error: instruction requires: NEON
vshr.u64 q1, q0, #7
^arch/arm/crypto/curve25519-core.S:27:2: error: instruction requires: NEON
vshr.u64 q0, q0, #8
^arch/arm/crypto/curve25519-core.S:28:2: error: instruction requires: NEON
vmov.i32 d4, #19
^Shuffle the order of the '.arch' and '.fpu' directives so that the code builds regardless of the default FPU mode. This has been tested against both clang with and without Debian's patch and GCC.
Fixes d8f1308a025f ("crypto: arm/curve25519 - wire up NEON implementation")Reported-by Arnd Bergmann <[email protected]>Suggested-by Arnd Bergmann <[email protected]>Suggested-by Jessica Clarke <[email protected]>Signed-off-by Nathan Chancellor <[email protected]>
Quoted 3 lines
--- arch/arm/crypto/curve25519-core.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Patch applied. Thanks.
Signature · 3 lines
Email: Herbert Xu <[email protected]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt