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, 6 insertions, 36 deletions

diff --git a/lib/crypto/powerpc/Kconfig b/lib/crypto/powerpc/Kconfig
deleted file mode 100644
index e41012a61876..000000000000
--- a/lib/crypto/powerpc/Kconfig
+++ /dev/null
@@ -1,8 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-
-config CRYPTO_CHACHA20_P10
-	tristate
-	depends on PPC64 && CPU_LITTLE_ENDIAN && VSX
-	default CRYPTO_LIB_CHACHA
-	select CRYPTO_LIB_CHACHA_GENERIC
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA
diff --git a/lib/crypto/powerpc/Makefile b/lib/crypto/powerpc/Makefile
deleted file mode 100644
index 778a04edd226..000000000000
--- a/lib/crypto/powerpc/Makefile
+++ /dev/null
@@ -1,4 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-
-obj-$(CONFIG_CRYPTO_CHACHA20_P10) += chacha-p10-crypto.o
-chacha-p10-crypto-y := chacha-p10-glue.o chacha-p10le-8x.o
diff --git a/lib/crypto/powerpc/chacha-p10-glue.c b/lib/crypto/powerpc/chacha.h
index 5d3d5506d7f9..1df6e1ce31c4 100644
--- a/lib/crypto/powerpc/chacha-p10-glue.c
+++ b/lib/crypto/powerpc/chacha.h
@@ -1,14 +1,12 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * ChaCha stream cipher (P10 accelerated)
  *
  * Copyright 2023- IBM Corp. All rights reserved.
  */
 
-#include <crypto/chacha.h>
 #include <crypto/internal/simd.h>
 #include <linux/kernel.h>
-#include <linux/module.h>
 #include <linux/cpufeature.h>
 #include <linux/sizes.h>
 #include <asm/simd.h>
@@ -48,15 +46,10 @@ static void chacha_p10_do_8x(struct chacha_state *state, u8 *dst, const u8 *src,
 		chacha_crypt_generic(state, dst, src, bytes, nrounds);
 }
 
-void hchacha_block_arch(const struct chacha_state *state,
-			u32 out[HCHACHA_OUT_WORDS], int nrounds)
-{
-	hchacha_block_generic(state, out, nrounds);
-}
-EXPORT_SYMBOL(hchacha_block_arch);
+#define hchacha_block_arch hchacha_block_generic /* not implemented yet */
 
-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 (!static_branch_likely(&have_p10) || bytes <= CHACHA_BLOCK_SIZE ||
 	    !crypto_simd_usable())
@@ -74,21 +67,10 @@ 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_p10_init(void)
+#define chacha_mod_init_arch chacha_mod_init_arch
+static void chacha_mod_init_arch(void)
 {
 	if (cpu_has_feature(CPU_FTR_ARCH_31))
 		static_branch_enable(&have_p10);
-	return 0;
-}
-subsys_initcall(chacha_p10_init);
-
-static void __exit chacha_p10_exit(void)
-{
 }
-module_exit(chacha_p10_exit);
-
-MODULE_DESCRIPTION("ChaCha stream cipher (P10 accelerated)");
-MODULE_AUTHOR("Danny Tsen <dtsen@linux.ibm.com>");
-MODULE_LICENSE("GPL v2");