Files
linux/lib/crypto/arm/curve25519.h
Eric Biggers 68546e5632 lib/crypto: curve25519: Consolidate into single module
Reorganize the Curve25519 library code:

- Build a single libcurve25519 module, instead of up to three modules:
  libcurve25519, libcurve25519-generic, and an arch-specific module.

- Move the arch-specific Curve25519 code from arch/$(SRCARCH)/crypto/ to
  lib/crypto/$(SRCARCH)/.  Centralize the build rules into
  lib/crypto/Makefile and lib/crypto/Kconfig.

- Include the arch-specific code directly in lib/crypto/curve25519.c via
  a header, rather than using a separate .c file.

- Eliminate the entanglement with CRYPTO.  CRYPTO_LIB_CURVE25519 no
  longer selects CRYPTO, and the arch-specific Curve25519 code no longer
  depends on CRYPTO.

This brings Curve25519 in line with the latest conventions for
lib/crypto/, used by other algorithms.  The exception is that I kept the
generic code in separate translation units for now.  (Some of the
function names collide between the x86 and generic Curve25519 code.  And
the Curve25519 functions are very long anyway, so inlining doesn't
matter as much for Curve25519 as it does for some other algorithms.)

Link: https://lore.kernel.org/r/20250906213523.84915-11-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
2025-09-06 16:32:43 -07:00

48 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* Based on public domain code from Daniel J. Bernstein and Peter Schwabe. This
* began from SUPERCOP's curve25519/neon2/scalarmult.s, but has subsequently been
* manually reworked for use in kernel space.
*/
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
#include <crypto/internal/simd.h>
#include <linux/types.h>
#include <linux/jump_label.h>
asmlinkage void curve25519_neon(u8 mypublic[CURVE25519_KEY_SIZE],
const u8 secret[CURVE25519_KEY_SIZE],
const u8 basepoint[CURVE25519_KEY_SIZE]);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
static void curve25519_arch(u8 out[CURVE25519_KEY_SIZE],
const u8 scalar[CURVE25519_KEY_SIZE],
const u8 point[CURVE25519_KEY_SIZE])
{
if (static_branch_likely(&have_neon) && crypto_simd_usable()) {
kernel_neon_begin();
curve25519_neon(out, scalar, point);
kernel_neon_end();
} else {
curve25519_generic(out, scalar, point);
}
}
static void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],
const u8 secret[CURVE25519_KEY_SIZE])
{
curve25519_arch(pub, secret, curve25519_base_point);
}
#define curve25519_mod_init_arch curve25519_mod_init_arch
static void curve25519_mod_init_arch(void)
{
if (elf_hwcap & HWCAP_NEON)
static_branch_enable(&have_neon);
}