[PATCH v1 4/7] AES for PPC/SPE - key handling
Markus Stockhausen
stockhausen at collogia.de
Mon Feb 16 23:45:51 AEDT 2015
[PATCH v1 4/7] AES for PPC/SPE - key handling
Key generation for big endian core routines.
Signed-off-by: Markus Stockhausen <stockhausen at collogia.de>
diff --git a/arch/powerpc/crypto/aes-spe-keys.S b/arch/powerpc/crypto/aes-spe-keys.S
new file mode 100644
index 0000000..55b258c
--- /dev/null
+++ b/arch/powerpc/crypto/aes-spe-keys.S
@@ -0,0 +1,283 @@
+/*
+ * Key handling functions for PPC AES implementation
+ *
+ * Copyright (c) 2015 Markus Stockhausen <stockhausen at collogia.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <asm/ppc_asm.h>
+
+#ifdef __BIG_ENDIAN__
+#define LOAD_KEY(d, s, off) \
+ lwz d,off(s);
+#else
+#define LOAD_KEY(d, s, off) \
+ li r0,off; \
+ lwbrx d,s,r0;
+#endif
+
+#define INITIALIZE_KEY \
+ stwu r1,-32(r1); /* create stack frame */ \
+ stw r14,8(r1); /* save registers */ \
+ stw r15,12(r1); \
+ stw r16,16(r1);
+
+#define FINALIZE_KEY \
+ lwz r14,8(r1); /* restore registers */ \
+ lwz r15,12(r1); \
+ lwz r16,16(r1); \
+ xor r5,r5,r5; /* clear sensitive data */ \
+ xor r6,r6,r6; \
+ xor r7,r7,r7; \
+ xor r8,r8,r8; \
+ xor r9,r9,r9; \
+ xor r10,r10,r10; \
+ xor r11,r11,r11; \
+ xor r12,r12,r12; \
+ addi r1,r1,32; /* cleanup stack */
+
+#define LS_BOX(r, t1, t2) \
+ lis t2,PPC_AES_4K_ENCTAB at h; \
+ ori t2,t2,PPC_AES_4K_ENCTAB at l; \
+ rlwimi t2,r,4,20,27; \
+ lbz t1,8(t2); \
+ rlwimi r,t1,0,24,31; \
+ rlwimi t2,r,28,20,27; \
+ lbz t1,8(t2); \
+ rlwimi r,t1,8,16,23; \
+ rlwimi t2,r,20,20,27; \
+ lbz t1,8(t2); \
+ rlwimi r,t1,16,8,15; \
+ rlwimi t2,r,12,20,27; \
+ lbz t1,8(t2); \
+ rlwimi r,t1,24,0,7;
+
+#define GF8_MUL(out, in, t1, t2) \
+ lis t1,0x8080; /* multiplication in GF8 */ \
+ ori t1,t1,0x8080; \
+ and t1,t1,in; \
+ srwi t1,t1,7; \
+ mulli t1,t1,0x1b; \
+ lis t2,0x7f7f; \
+ ori t2,t2,0x7f7f; \
+ and t2,t2,in; \
+ slwi t2,t2,1; \
+ xor out,t1,t2;
+
+/*
+ * ppc_expand_key_128(u32 *key_enc, const u8 *key)
+ *
+ * Expand 128 bit key into 176 bytes encryption key. It consists of
+ * key itself plus 10 rounds with 16 bytes each
+ *
+ */
+_GLOBAL(ppc_expand_key_128)
+ INITIALIZE_KEY
+ LOAD_KEY(r5,r4,0)
+ LOAD_KEY(r6,r4,4)
+ LOAD_KEY(r7,r4,8)
+ LOAD_KEY(r8,r4,12)
+ stw r5,0(r3) /* key[0..3] = input data */
+ stw r6,4(r3)
+ stw r7,8(r3)
+ stw r8,12(r3)
+ li r16,10 /* 10 expansion rounds */
+ lis r0,0x0100 /* RCO(1) */
+ppc_expand_128_loop:
+ addi r3,r3,16
+ mr r14,r8 /* apply LS_BOX to 4th temp */
+ rotlwi r14,r14,8
+ LS_BOX(r14, r15, r4)
+ xor r14,r14,r0
+ xor r5,r5,r14 /* xor next 4 keys */
+ xor r6,r6,r5
+ xor r7,r7,r6
+ xor r8,r8,r7
+ stw r5,0(r3) /* store next 4 keys */
+ stw r6,4(r3)
+ stw r7,8(r3)
+ stw r8,12(r3)
+ GF8_MUL(r0, r0, r4, r14) /* multiply RCO by 2 in GF */
+ subi r16,r16,1
+ cmpwi r16,0
+ bt eq,ppc_expand_128_end
+ b ppc_expand_128_loop
+ppc_expand_128_end:
+ FINALIZE_KEY
+ blr
+
+/*
+ * ppc_expand_key_192(u32 *key_enc, const u8 *key)
+ *
+ * Expand 192 bit key into 208 bytes encryption key. It consists of key
+ * itself plus 12 rounds with 16 bytes each
+ *
+ */
+_GLOBAL(ppc_expand_key_192)
+ INITIALIZE_KEY
+ LOAD_KEY(r5,r4,0)
+ LOAD_KEY(r6,r4,4)
+ LOAD_KEY(r7,r4,8)
+ LOAD_KEY(r8,r4,12)
+ LOAD_KEY(r9,r4,16)
+ LOAD_KEY(r10,r4,20)
+ stw r5,0(r3)
+ stw r6,4(r3)
+ stw r7,8(r3)
+ stw r8,12(r3)
+ stw r9,16(r3)
+ stw r10,20(r3)
+ li r16,8 /* 8 expansion rounds */
+ lis r0,0x0100 /* RCO(1) */
+ppc_expand_192_loop:
+ addi r3,r3,24
+ mr r14,r10 /* apply LS_BOX to 6th temp */
+ rotlwi r14,r14,8
+ LS_BOX(r14, r15, r4)
+ xor r14,r14,r0
+ xor r5,r5,r14 /* xor next 6 keys */
+ xor r6,r6,r5
+ xor r7,r7,r6
+ xor r8,r8,r7
+ xor r9,r9,r8
+ xor r10,r10,r9
+ stw r5,0(r3)
+ stw r6,4(r3)
+ stw r7,8(r3)
+ stw r8,12(r3)
+ subi r16,r16,1
+ cmpwi r16,0 /* last round early kick out */
+ bt eq,ppc_expand_192_end
+ stw r9,16(r3)
+ stw r10,20(r3)
+ GF8_MUL(r0, r0, r4, r14) /* multiply RCO GF8 */
+ b ppc_expand_192_loop
+ppc_expand_192_end:
+ FINALIZE_KEY
+ blr
+
+/*
+ * ppc_expand_key_256(u32 *key_enc, const u8 *key)
+ *
+ * Expand 256 bit key into 240 bytes encryption key. It consists of key
+ * itself plus 14 rounds with 16 bytes each
+ *
+ */
+_GLOBAL(ppc_expand_key_256)
+ INITIALIZE_KEY
+ LOAD_KEY(r5,r4,0)
+ LOAD_KEY(r6,r4,4)
+ LOAD_KEY(r7,r4,8)
+ LOAD_KEY(r8,r4,12)
+ LOAD_KEY(r9,r4,16)
+ LOAD_KEY(r10,r4,20)
+ LOAD_KEY(r11,r4,24)
+ LOAD_KEY(r12,r4,28)
+ stw r5,0(r3)
+ stw r6,4(r3)
+ stw r7,8(r3)
+ stw r8,12(r3)
+ stw r9,16(r3)
+ stw r10,20(r3)
+ stw r11,24(r3)
+ stw r12,28(r3)
+ li r16,7 /* 7 expansion rounds */
+ lis r0,0x0100 /* RCO(1) */
+ppc_expand_256_loop:
+ addi r3,r3,32
+ mr r14,r12 /* apply LS_BOX to 8th temp */
+ rotlwi r14,r14,8
+ LS_BOX(r14, r15, r4)
+ xor r14,r14,r0
+ xor r5,r5,r14 /* xor 4 keys */
+ xor r6,r6,r5
+ xor r7,r7,r6
+ xor r8,r8,r7
+ mr r14,r8
+ LS_BOX(r14, r15, r4) /* apply LS_BOX to 4th temp */
+ xor r9,r9,r14 /* xor 4 keys */
+ xor r10,r10,r9
+ xor r11,r11,r10
+ xor r12,r12,r11
+ stw r5,0(r3)
+ stw r6,4(r3)
+ stw r7,8(r3)
+ stw r8,12(r3)
+ subi r16,r16,1
+ cmpwi r16,0 /* last round early kick out */
+ bt eq,ppc_expand_256_end
+ stw r9,16(r3)
+ stw r10,20(r3)
+ stw r11,24(r3)
+ stw r12,28(r3)
+ GF8_MUL(r0, r0, r4, r14)
+ b ppc_expand_256_loop
+ppc_expand_256_end:
+ FINALIZE_KEY
+ blr
+
+/*
+ * ppc_generate_decrypt_key: derive decryption key from encryption key
+ * number of bytes to handle are calculated from length of key (16/24/32)
+ *
+ */
+_GLOBAL(ppc_generate_decrypt_key)
+ addi r6,r5,24
+ slwi r6,r6,2
+ lwzx r7,r4,r6 /* first/last 4 words are same */
+ stw r7,0(r3)
+ lwz r7,0(r4)
+ stwx r7,r3,r6
+ addi r6,r6,4
+ lwzx r7,r4,r6
+ stw r7,4(r3)
+ lwz r7,4(r4)
+ stwx r7,r3,r6
+ addi r6,r6,4
+ lwzx r7,r4,r6
+ stw r7,8(r3)
+ lwz r7,8(r4)
+ stwx r7,r3,r6
+ addi r6,r6,4
+ lwzx r7,r4,r6
+ stw r7,12(r3)
+ lwz r7,12(r4)
+ stwx r7,r3,r6
+ addi r3,r3,16
+ add r4,r4,r6
+ subi r4,r4,28
+ addi r5,r5,20
+ srwi r5,r5,2
+ppc_generate_decrypt_block:
+ li r6,4
+ mtctr r6
+ppc_generate_decrypt_word:
+ lwz r6,0(r4)
+ GF8_MUL(r7, r6, r0, r7)
+ GF8_MUL(r8, r7, r0, r8)
+ GF8_MUL(r9, r8, r0, r9)
+ xor r10,r9,r6
+ xor r11,r7,r8
+ xor r11,r11,r9
+ xor r12,r7,r10
+ rotrwi r12,r12,24
+ xor r11,r11,r12
+ xor r12,r8,r10
+ rotrwi r12,r12,16
+ xor r11,r11,r12
+ rotrwi r12,r10,8
+ xor r11,r11,r12
+ stw r11,0(r3)
+ addi r3,r3,4
+ addi r4,r4,4
+ bdnz ppc_generate_decrypt_word
+ subi r4,r4,32
+ subi r5,r5,1
+ cmpwi r5,0
+ bt gt,ppc_generate_decrypt_block
+ blr
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