lib/crypto: poly1305: Consolidate into single module

Consolidate the Poly1305 code into a single module, similar to various
other algorithms (SHA-1, SHA-256, SHA-512, etc.):

- Each arch now provides a header file lib/crypto/$(SRCARCH)/poly1305.h,
  replacing lib/crypto/$(SRCARCH)/poly1305*.c.  The header defines
  poly1305_block_init(), poly1305_blocks(), poly1305_emit(), and
  optionally poly1305_mod_init_arch().  It is included by
  lib/crypto/poly1305.c, and thus the code gets built into the single
  libpoly1305 module, with improved inlining in some cases.

- Whether arch-optimized Poly1305 is buildable is now controlled
  centrally by lib/crypto/Kconfig instead of by
  lib/crypto/$(SRCARCH)/Kconfig.  The conditions for enabling it remain
  the same as before, and it remains enabled by default.  (The PPC64 one
  remains unconditionally disabled due to 'depends on BROKEN'.)

- Any additional arch-specific translation units for the optimized
  Poly1305 code, such as assembly files, are now compiled by
  lib/crypto/Makefile instead of lib/crypto/$(SRCARCH)/Makefile.

A special consideration is needed because the Adiantum code uses the
poly1305_core_*() functions directly.  For now, just carry forward that
approach.  This means retaining the CRYPTO_LIB_POLY1305_GENERIC kconfig
symbol, and keeping the poly1305_core_*() functions in separate
translation units.  So it's not quite as streamlined I've done with the
other hash functions, but we still get a single libpoly1305 module.

Note: to see the diff from the arm, arm64, and x86 .c files to the new
.h files, view this commit with 'git show -M10'.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250829152513.92459-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

1 files changed, 53 insertions, 6 deletions

diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index d362636a22d3..e0536e3b3a04 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -71,13 +71,60 @@ endif # CONFIG_CRYPTO_LIB_MD5_ARCH
 
 ################################################################################
 
-obj-$(CONFIG_CRYPTO_LIB_POLY1305)		+= libpoly1305.o
-libpoly1305-y					+= poly1305.o
+obj-$(CONFIG_CRYPTO_LIB_POLY1305) += libpoly1305.o
+libpoly1305-y := poly1305.o
+ifeq ($(CONFIG_ARCH_SUPPORTS_INT128),y)
+libpoly1305-$(CONFIG_CRYPTO_LIB_POLY1305_GENERIC) += poly1305-donna64.o
+else
+libpoly1305-$(CONFIG_CRYPTO_LIB_POLY1305_GENERIC) += poly1305-donna32.o
+endif
+
+ifeq ($(CONFIG_CRYPTO_LIB_POLY1305_ARCH),y)
+CFLAGS_poly1305.o += -I$(src)/$(SRCARCH)
+
+ifeq ($(CONFIG_ARM),y)
+libpoly1305-y += arm/poly1305-core.o
+$(obj)/arm/poly1305-core.S: $(src)/arm/poly1305-armv4.pl
+	$(call cmd,perlasm)
+# massage the perlasm code a bit so we only get the NEON routine if we need it
+poly1305-aflags-$(CONFIG_CPU_V7) := -U__LINUX_ARM_ARCH__ -D__LINUX_ARM_ARCH__=5
+poly1305-aflags-$(CONFIG_KERNEL_MODE_NEON) := -U__LINUX_ARM_ARCH__ -D__LINUX_ARM_ARCH__=7
+AFLAGS_arm/poly1305-core.o += $(poly1305-aflags-y) $(aflags-thumb2-y)
+endif
+
+ifeq ($(CONFIG_ARM64),y)
+libpoly1305-y += arm64/poly1305-core.o
+$(obj)/arm64/poly1305-core.S: $(src)/arm64/poly1305-armv8.pl
+	$(call cmd,perlasm_with_args)
+endif
+
+ifeq ($(CONFIG_MIPS),y)
+libpoly1305-y += mips/poly1305-core.o
+poly1305-perlasm-flavour-$(CONFIG_32BIT) := o32
+poly1305-perlasm-flavour-$(CONFIG_64BIT) := 64
+quiet_cmd_perlasm_poly1305 = PERLASM $@
+      cmd_perlasm_poly1305 = $(PERL) $< $(poly1305-perlasm-flavour-y) $@
+# Use if_changed instead of cmd, in case the flavour changed.
+$(obj)/mips/poly1305-core.S: $(src)/mips/poly1305-mips.pl FORCE
+	$(call if_changed,perlasm_poly1305)
+targets += mips/poly1305-core.S
+endif
 
-obj-$(CONFIG_CRYPTO_LIB_POLY1305_GENERIC)	+= libpoly1305-generic.o
-libpoly1305-generic-y				:= poly1305-donna32.o
-libpoly1305-generic-$(CONFIG_ARCH_SUPPORTS_INT128) := poly1305-donna64.o
-libpoly1305-generic-y				+= poly1305-generic.o
+libpoly1305-$(CONFIG_PPC) += powerpc/poly1305-p10le_64.o
+
+ifeq ($(CONFIG_X86),y)
+libpoly1305-y += x86/poly1305-x86_64-cryptogams.o
+$(obj)/x86/poly1305-x86_64-cryptogams.S: $(src)/x86/poly1305-x86_64-cryptogams.pl
+	$(call cmd,perlasm)
+endif
+
+endif # CONFIG_CRYPTO_LIB_POLY1305_ARCH
+
+# clean-files must be defined unconditionally
+clean-files += arm/poly1305-core.S \
+	       arm64/poly1305-core.S \
+	       mips/poly1305-core.S \
+	       x86/poly1305-x86_64-cryptogams.S
 
 ################################################################################