[PATCH] crypto: mips/poly1305 - enable for all MIPS processors

[Maciej W. Rozycki]

The MIPS Poly1305 implementation is generic MIPS code written such as to 
support down to the original MIPS I and MIPS III ISA for the 32-bit and 
64-bit variant respectively.  Lift the current limitation then to enable 
code for MIPSr1 ISA or newer processors only and have it available for 
all MIPS processors.

Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
Fixes: a11d055e7a64 ("crypto: mips/poly1305 - incorporate OpenSSL/CRYPTOGAMS optimized implementation")
Cc: stable@xxxxxxxxxxxxxxx # v5.5+
---
On Wed, 3 Mar 2021, Jason A. Donenfeld wrote:

> >> Would you mind sending this for 5.12 in an rc at some point, rather
> >> than waiting for 5.13? I'd like to see this backported to 5.10 and 5.4
> >> for OpenWRT.
> >
> > why is this so important for OpenWRT ? Just to select CRYPTO_POLY1305_MIPS
> > ?
> 
> Yes. The performance boost on Octeon is significant for WireGuard users.

 But that's the wrong fix for that purpose.  I've skimmed over that module 
and there's nothing MIPS64-specific there.  In fact it's plain generic 
MIPS assembly, with some R2 optimisations enabled where applicable but not 
necessary (and then R6 tweaks, but that's irrelevant here).

 As a matter of interest I have just built it successfully for a MIPS I 
DECstation configuration:

$ file arch/mips/crypto/poly1305-mips.ko
arch/mips/crypto/poly1305-mips.ko: ELF 32-bit LSB relocatable, MIPS, MIPS-I version 1 (SYSV), BuildID[sha1]=d36384d94f60ba7deff638ca8a24500120b45b56, not stripped
$ 

Patch included, please apply.

 So while your change is surely right, what you want is this really.

  Maciej
---
 arch/mips/crypto/Makefile |    4 ++--
 crypto/Kconfig            |    2 +-
 drivers/net/Kconfig       |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

Index: linux/arch/mips/crypto/Makefile
===================================================================
--- linux.orig/arch/mips/crypto/Makefile
+++ linux/arch/mips/crypto/Makefile
@@ -12,8 +12,8 @@ AFLAGS_chacha-core.o += -O2 # needed to
 obj-$(CONFIG_CRYPTO_POLY1305_MIPS) += poly1305-mips.o
 poly1305-mips-y := poly1305-core.o poly1305-glue.o
 
-perlasm-flavour-$(CONFIG_CPU_MIPS32) := o32
-perlasm-flavour-$(CONFIG_CPU_MIPS64) := 64
+perlasm-flavour-$(CONFIG_32BIT) := o32
+perlasm-flavour-$(CONFIG_64BIT) := 64
 
 quiet_cmd_perlasm = PERLASM $@
       cmd_perlasm = $(PERL) $(<) $(perlasm-flavour-y) $(@)
Index: linux/crypto/Kconfig
===================================================================
--- linux.orig/crypto/Kconfig
+++ linux/crypto/Kconfig
@@ -772,7 +772,7 @@ config CRYPTO_POLY1305_X86_64
 
 config CRYPTO_POLY1305_MIPS
 	tristate "Poly1305 authenticator algorithm (MIPS optimized)"
-	depends on CPU_MIPS32 || (CPU_MIPS64 && 64BIT)
+	depends on MIPS
 	select CRYPTO_ARCH_HAVE_LIB_POLY1305
 
 config CRYPTO_MD4
Index: linux/drivers/net/Kconfig
===================================================================
--- linux.orig/drivers/net/Kconfig
+++ linux/drivers/net/Kconfig
@@ -92,7 +92,7 @@ config WIREGUARD
 	select CRYPTO_POLY1305_ARM if ARM
 	select CRYPTO_CURVE25519_NEON if ARM && KERNEL_MODE_NEON
 	select CRYPTO_CHACHA_MIPS if CPU_MIPS32_R2
-	select CRYPTO_POLY1305_MIPS if CPU_MIPS32 || (CPU_MIPS64 && 64BIT)
+	select CRYPTO_POLY1305_MIPS if MIPS
 	help
 	  WireGuard is a secure, fast, and easy to use replacement for IPSec
 	  that uses modern cryptography and clever networking tricks. It's