lib/crypto: chacha: Consolidate into single module

Consolidate the ChaCha code into a single module (excluding
chacha-block-generic.c which remains always built-in for random.c),
similar to various other algorithms:

- Each arch now provides a header file lib/crypto/$(SRCARCH)/chacha.h,
  replacing lib/crypto/$(SRCARCH)/chacha*.c.  The header defines
  chacha_crypt_arch() and hchacha_block_arch().  It is included by
  lib/crypto/chacha.c, and thus the code gets built into the single
  libchacha module, with improved inlining in some cases.

- Whether arch-optimized ChaCha 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.

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

This removes the last use for the Makefile and Kconfig files in the
arm64, mips, powerpc, riscv, and s390 subdirectories of lib/crypto/.  So
also remove those files and the references to them.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250827151131.27733-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

3 files changed, 7 insertions, 30 deletions

diff --git a/lib/crypto/arm/Kconfig b/lib/crypto/arm/Kconfig
index 0d821e282c64..740341aa35d2 100644
--- a/lib/crypto/arm/Kconfig
+++ b/lib/crypto/arm/Kconfig
@@ -12,8 +12,3 @@ config CRYPTO_BLAKE2S_ARM
 	  BLAKE2b, but slower than the NEON implementation of BLAKE2b.
 	  There is no NEON implementation of BLAKE2s, since NEON doesn't
 	  really help with it.
-
-config CRYPTO_CHACHA20_NEON
-	tristate
-	default CRYPTO_LIB_CHACHA
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA
diff --git a/lib/crypto/arm/Makefile b/lib/crypto/arm/Makefile
index 9f70e61d419e..0574b0e9739e 100644
--- a/lib/crypto/arm/Makefile
+++ b/lib/crypto/arm/Makefile
@@ -2,7 +2,3 @@
 
 obj-$(CONFIG_CRYPTO_BLAKE2S_ARM) += libblake2s-arm.o
 libblake2s-arm-y := blake2s-core.o blake2s-glue.o
-
-obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha-neon.o
-chacha-neon-y := chacha-scalar-core.o chacha-glue.o
-chacha-neon-$(CONFIG_KERNEL_MODE_NEON) += chacha-neon-core.o
diff --git a/lib/crypto/arm/chacha-glue.c b/lib/crypto/arm/chacha.h
index 67ba045cae35..0cae30f8ee5d 100644
--- a/lib/crypto/arm/chacha-glue.c
+++ b/lib/crypto/arm/chacha.h
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * ChaCha and HChaCha functions (ARM optimized)
  *
@@ -6,11 +6,9 @@
  * Copyright (C) 2015 Martin Willi
  */
 
-#include <crypto/chacha.h>
 #include <crypto/internal/simd.h>
 #include <linux/jump_label.h>
 #include <linux/kernel.h>
-#include <linux/module.h>
 
 #include <asm/cputype.h>
 #include <asm/hwcap.h>
@@ -64,8 +62,8 @@ static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
 	}
 }
 
-void hchacha_block_arch(const struct chacha_state *state,
-			u32 out[HCHACHA_OUT_WORDS], int nrounds)
+static void hchacha_block_arch(const struct chacha_state *state,
+			       u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable()) {
 		hchacha_block_arm(state, out, nrounds);
@@ -75,10 +73,9 @@ void hchacha_block_arch(const struct chacha_state *state,
 		kernel_neon_end();
 	}
 }
-EXPORT_SYMBOL(hchacha_block_arch);
 
-void chacha_crypt_arch(struct chacha_state *state, u8 *dst, const u8 *src,
-		       unsigned int bytes, int nrounds)
+static void chacha_crypt_arch(struct chacha_state *state, u8 *dst,
+			      const u8 *src, unsigned int bytes, int nrounds)
 {
 	if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable() ||
 	    bytes <= CHACHA_BLOCK_SIZE) {
@@ -99,9 +96,9 @@ void chacha_crypt_arch(struct chacha_state *state, u8 *dst, const u8 *src,
 		dst += todo;
 	} while (bytes);
 }
-EXPORT_SYMBOL(chacha_crypt_arch);
 
-static int __init chacha_arm_mod_init(void)
+#define chacha_mod_init_arch chacha_mod_init_arch
+static void chacha_mod_init_arch(void)
 {
 	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON)) {
 		switch (read_cpuid_part()) {
@@ -117,15 +114,4 @@ static int __init chacha_arm_mod_init(void)
 			static_branch_enable(&use_neon);
 		}
 	}
-	return 0;
 }
-subsys_initcall(chacha_arm_mod_init);
-
-static void __exit chacha_arm_mod_exit(void)
-{
-}
-module_exit(chacha_arm_mod_exit);
-
-MODULE_DESCRIPTION("ChaCha and HChaCha functions (ARM optimized)");
-MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
-MODULE_LICENSE("GPL v2");