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/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/*
* Copyright (C) 2016-2018 René van Dorst <opensource@vdorst.com>. All Rights Reserved.
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#define MASK_U32 0x3c
#define CHACHA20_BLOCK_SIZE 64
#define STACK_SIZE 32
#define X0 $t0
#define X1 $t1
#define X2 $t2
#define X3 $t3
#define X4 $t4
#define X5 $t5
#define X6 $t6
#define X7 $t7
#define X8 $t8
#define X9 $t9
#define X10 $v1
#define X11 $s6
#define X12 $s5
#define X13 $s4
#define X14 $s3
#define X15 $s2
/* Use regs which are overwritten on exit for Tx so we don't leak clear data. */
#define T0 $s1
#define T1 $s0
#define T(n) T ## n
#define X(n) X ## n
/* Input arguments */
#define STATE $a0
#define OUT $a1
#define IN $a2
#define BYTES $a3
/* Output argument */
/* NONCE[0] is kept in a register and not in memory.
* We don't want to touch original value in memory.
* Must be incremented every loop iteration.
*/
#define NONCE_0 $v0
/* SAVED_X and SAVED_CA are set in the jump table.
* Use regs which are overwritten on exit else we don't leak clear data.
* They are used to handling the last bytes which are not multiple of 4.
*/
#define SAVED_X X15
#define SAVED_CA $s7
#define IS_UNALIGNED $s7
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define MSB 0
#define LSB 3
#define ROTx rotl
#define ROTR(n) rotr n, 24
#define CPU_TO_LE32(n) \
wsbh n; \
rotr n, 16;
#else
#define MSB 3
#define LSB 0
#define ROTx rotr
#define CPU_TO_LE32(n)
#define ROTR(n)
#endif
#define FOR_EACH_WORD(x) \
x( 0); \
x( 1); \
x( 2); \
x( 3); \
x( 4); \
x( 5); \
x( 6); \
x( 7); \
x( 8); \
x( 9); \
x(10); \
x(11); \
x(12); \
x(13); \
x(14); \
x(15);
#define FOR_EACH_WORD_REV(x) \
x(15); \
x(14); \
x(13); \
x(12); \
x(11); \
x(10); \
x( 9); \
x( 8); \
x( 7); \
x( 6); \
x( 5); \
x( 4); \
x( 3); \
x( 2); \
x( 1); \
x( 0);
#define PLUS_ONE_0 1
#define PLUS_ONE_1 2
#define PLUS_ONE_2 3
#define PLUS_ONE_3 4
#define PLUS_ONE_4 5
#define PLUS_ONE_5 6
#define PLUS_ONE_6 7
#define PLUS_ONE_7 8
#define PLUS_ONE_8 9
#define PLUS_ONE_9 10
#define PLUS_ONE_10 11
#define PLUS_ONE_11 12
#define PLUS_ONE_12 13
#define PLUS_ONE_13 14
#define PLUS_ONE_14 15
#define PLUS_ONE_15 16
#define PLUS_ONE(x) PLUS_ONE_ ## x
#define _CONCAT3(a,b,c) a ## b ## c
#define CONCAT3(a,b,c) _CONCAT3(a,b,c)
#define STORE_UNALIGNED(x) \
CONCAT3(.Lchacha20_mips_xor_unaligned_, PLUS_ONE(x), _b: ;) \
.if (x != 12); \
lw T0, (x*4)(STATE); \
.endif; \
lwl T1, (x*4)+MSB ## (IN); \
lwr T1, (x*4)+LSB ## (IN); \
.if (x == 12); \
addu X ## x, NONCE_0; \
.else; \
addu X ## x, T0; \
.endif; \
CPU_TO_LE32(X ## x); \
xor X ## x, T1; \
swl X ## x, (x*4)+MSB ## (OUT); \
swr X ## x, (x*4)+LSB ## (OUT);
#define STORE_ALIGNED(x) \
CONCAT3(.Lchacha20_mips_xor_aligned_, PLUS_ONE(x), _b: ;) \
.if (x != 12); \
lw T0, (x*4)(STATE); \
.endif; \
lw T1, (x*4) ## (IN); \
.if (x == 12); \
addu X ## x, NONCE_0; \
.else; \
addu X ## x, T0; \
.endif; \
CPU_TO_LE32(X ## x); \
xor X ## x, T1; \
sw X ## x, (x*4) ## (OUT);
/* Jump table macro.
* Used for setup and handling the last bytes, which are not multiple of 4.
* X15 is free to store Xn
* Every jumptable entry must be equal in size.
*/
#define JMPTBL_ALIGNED(x) \
.Lchacha20_mips_jmptbl_aligned_ ## x: ; \
.set noreorder; \
b .Lchacha20_mips_xor_aligned_ ## x ## _b; \
.if (x == 12); \
addu SAVED_X, X ## x, NONCE_0; \
.else; \
addu SAVED_X, X ## x, SAVED_CA; \
.endif; \
.set reorder
#define JMPTBL_UNALIGNED(x) \
.Lchacha20_mips_jmptbl_unaligned_ ## x: ; \
.set noreorder; \
b .Lchacha20_mips_xor_unaligned_ ## x ## _b; \
.if (x == 12); \
addu SAVED_X, X ## x, NONCE_0; \
.else; \
addu SAVED_X, X ## x, SAVED_CA; \
.endif; \
.set reorder
#define AXR(A, B, C, D, K, L, M, N, V, W, Y, Z, S) \
addu X(A), X(K); \
addu X(B), X(L); \
addu X(C), X(M); \
addu X(D), X(N); \
xor X(V), X(A); \
xor X(W), X(B); \
xor X(Y), X(C); \
xor X(Z), X(D); \
rotl X(V), S; \
rotl X(W), S; \
rotl X(Y), S; \
rotl X(Z), S;
.text
.set reorder
.set noat
.globl chacha20_mips
.ent chacha20_mips
chacha20_mips:
.frame $sp, STACK_SIZE, $ra
addiu $sp, -STACK_SIZE
/* Return bytes = 0. */
beqz BYTES, .Lchacha20_mips_end
lw NONCE_0, 48(STATE)
/* Save s0-s7 */
sw $s0, 0($sp)
sw $s1, 4($sp)
sw $s2, 8($sp)
sw $s3, 12($sp)
sw $s4, 16($sp)
sw $s5, 20($sp)
sw $s6, 24($sp)
sw $s7, 28($sp)
/* Test IN or OUT is unaligned.
* IS_UNALIGNED = ( IN | OUT ) & 0x00000003
*/
or IS_UNALIGNED, IN, OUT
andi IS_UNALIGNED, 0x3
/* Set number of rounds */
li $at, 20
b .Lchacha20_rounds_start
.align 4
.Loop_chacha20_rounds:
addiu IN, CHACHA20_BLOCK_SIZE
addiu OUT, CHACHA20_BLOCK_SIZE
addiu NONCE_0, 1
.Lchacha20_rounds_start:
lw X0, 0(STATE)
lw X1, 4(STATE)
lw X2, 8(STATE)
lw X3, 12(STATE)
lw X4, 16(STATE)
lw X5, 20(STATE)
lw X6, 24(STATE)
lw X7, 28(STATE)
lw X8, 32(STATE)
lw X9, 36(STATE)
lw X10, 40(STATE)
lw X11, 44(STATE)
move X12, NONCE_0
lw X13, 52(STATE)
lw X14, 56(STATE)
lw X15, 60(STATE)
.Loop_chacha20_xor_rounds:
addiu $at, -2
AXR( 0, 1, 2, 3, 4, 5, 6, 7, 12,13,14,15, 16);
AXR( 8, 9,10,11, 12,13,14,15, 4, 5, 6, 7, 12);
AXR( 0, 1, 2, 3, 4, 5, 6, 7, 12,13,14,15, 8);
AXR( 8, 9,10,11, 12,13,14,15, 4, 5, 6, 7, 7);
AXR( 0, 1, 2, 3, 5, 6, 7, 4, 15,12,13,14, 16);
AXR(10,11, 8, 9, 15,12,13,14, 5, 6, 7, 4, 12);
AXR( 0, 1, 2, 3, 5, 6, 7, 4, 15,12,13,14, 8);
AXR(10,11, 8, 9, 15,12,13,14, 5, 6, 7, 4, 7);
bnez $at, .Loop_chacha20_xor_rounds
addiu BYTES, -(CHACHA20_BLOCK_SIZE)
/* Is data src/dst unaligned? Jump */
bnez IS_UNALIGNED, .Loop_chacha20_unaligned
/* Set number rounds here to fill delayslot. */
li $at, 20
/* BYTES < 0, it has no full block. */
bltz BYTES, .Lchacha20_mips_no_full_block_aligned
FOR_EACH_WORD_REV(STORE_ALIGNED)
/* BYTES > 0? Loop again. */
bgtz BYTES, .Loop_chacha20_rounds
/* Place this here to fill delay slot */
addiu NONCE_0, 1
/* BYTES < 0? Handle last bytes */
bltz BYTES, .Lchacha20_mips_xor_bytes
.Lchacha20_mips_xor_done:
/* Restore used registers */
lw $s0, 0($sp)
lw $s1, 4($sp)
lw $s2, 8($sp)
lw $s3, 12($sp)
lw $s4, 16($sp)
lw $s5, 20($sp)
lw $s6, 24($sp)
lw $s7, 28($sp)
/* Write NONCE_0 back to right location in state */
sw NONCE_0, 48(STATE)
.Lchacha20_mips_end:
addiu $sp, STACK_SIZE
jr $ra
.Lchacha20_mips_no_full_block_aligned:
/* Restore the offset on BYTES */
addiu BYTES, CHACHA20_BLOCK_SIZE
/* Get number of full WORDS */
andi $at, BYTES, MASK_U32
/* Load upper half of jump table addr */
lui T0, %hi(.Lchacha20_mips_jmptbl_aligned_0)
/* Calculate lower half jump table offset */
ins T0, $at, 1, 6
/* Add offset to STATE */
addu T1, STATE, $at
/* Add lower half jump table addr */
addiu T0, %lo(.Lchacha20_mips_jmptbl_aligned_0)
/* Read value from STATE */
lw SAVED_CA, 0(T1)
/* Store remaining bytecounter as negative value */
subu BYTES, $at, BYTES
jr T0
/* Jump table */
FOR_EACH_WORD(JMPTBL_ALIGNED)
.Loop_chacha20_unaligned:
/* Set number rounds here to fill delayslot. */
li $at, 20
/* BYTES > 0, it has no full block. */
bltz BYTES, .Lchacha20_mips_no_full_block_unaligned
FOR_EACH_WORD_REV(STORE_UNALIGNED)
/* BYTES > 0? Loop again. */
bgtz BYTES, .Loop_chacha20_rounds
/* Write NONCE_0 back to right location in state */
sw NONCE_0, 48(STATE)
.set noreorder
/* Fall through to byte handling */
bgez BYTES, .Lchacha20_mips_xor_done
.Lchacha20_mips_xor_unaligned_0_b:
.Lchacha20_mips_xor_aligned_0_b:
/* Place this here to fill delay slot */
addiu NONCE_0, 1
.set reorder
.Lchacha20_mips_xor_bytes:
addu IN, $at
addu OUT, $at
/* First byte */
lbu T1, 0(IN)
addiu $at, BYTES, 1
CPU_TO_LE32(SAVED_X)
ROTR(SAVED_X)
xor T1, SAVED_X
sb T1, 0(OUT)
beqz $at, .Lchacha20_mips_xor_done
/* Second byte */
lbu T1, 1(IN)
addiu $at, BYTES, 2
ROTx SAVED_X, 8
xor T1, SAVED_X
sb T1, 1(OUT)
beqz $at, .Lchacha20_mips_xor_done
/* Third byte */
lbu T1, 2(IN)
ROTx SAVED_X, 8
xor T1, SAVED_X
sb T1, 2(OUT)
b .Lchacha20_mips_xor_done
.Lchacha20_mips_no_full_block_unaligned:
/* Restore the offset on BYTES */
addiu BYTES, CHACHA20_BLOCK_SIZE
/* Get number of full WORDS */
andi $at, BYTES, MASK_U32
/* Load upper half of jump table addr */
lui T0, %hi(.Lchacha20_mips_jmptbl_unaligned_0)
/* Calculate lower half jump table offset */
ins T0, $at, 1, 6
/* Add offset to STATE */
addu T1, STATE, $at
/* Add lower half jump table addr */
addiu T0, %lo(.Lchacha20_mips_jmptbl_unaligned_0)
/* Read value from STATE */
lw SAVED_CA, 0(T1)
/* Store remaining bytecounter as negative value */
subu BYTES, $at, BYTES
jr T0
/* Jump table */
FOR_EACH_WORD(JMPTBL_UNALIGNED)
.end chacha20_mips
.set at
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