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author | Markus Stockhausen <stockhausen@collogia.de> | 2015-02-22 09:00:00 (GMT) |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2015-03-01 10:02:28 (GMT) |
commit | f2e2ad2e1bfae66f087f4a33cd14da6d5ffcb79f (patch) | |
tree | a0d52552c395f484b7f8853a10cff272aeb7b828 | |
parent | f98992af419e3b69696e9c418eda664bd5d7ceb2 (diff) | |
download | linux-f2e2ad2e1bfae66f087f4a33cd14da6d5ffcb79f.tar.xz |
crypto: powerpc/aes - ECB/CBC/CTR/XTS modes
The assembler block cipher module that controls the core
AES functions.
Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r-- | arch/powerpc/crypto/aes-spe-modes.S | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/arch/powerpc/crypto/aes-spe-modes.S b/arch/powerpc/crypto/aes-spe-modes.S new file mode 100644 index 0000000..ad48032 --- /dev/null +++ b/arch/powerpc/crypto/aes-spe-modes.S @@ -0,0 +1,630 @@ +/* + * AES modes (ECB/CBC/CTR/XTS) for PPC AES implementation + * + * Copyright (c) 2015 Markus Stockhausen <stockhausen@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> +#include "aes-spe-regs.h" + +#ifdef __BIG_ENDIAN__ /* Macros for big endian builds */ + +#define LOAD_DATA(reg, off) \ + lwz reg,off(rSP); /* load with offset */ +#define SAVE_DATA(reg, off) \ + stw reg,off(rDP); /* save with offset */ +#define NEXT_BLOCK \ + addi rSP,rSP,16; /* increment pointers per bloc */ \ + addi rDP,rDP,16; +#define LOAD_IV(reg, off) \ + lwz reg,off(rIP); /* IV loading with offset */ +#define SAVE_IV(reg, off) \ + stw reg,off(rIP); /* IV saving with offset */ +#define START_IV /* nothing to reset */ +#define CBC_DEC 16 /* CBC decrement per block */ +#define CTR_DEC 1 /* CTR decrement one byte */ + +#else /* Macros for little endian */ + +#define LOAD_DATA(reg, off) \ + lwbrx reg,0,rSP; /* load reversed */ \ + addi rSP,rSP,4; /* and increment pointer */ +#define SAVE_DATA(reg, off) \ + stwbrx reg,0,rDP; /* save reversed */ \ + addi rDP,rDP,4; /* and increment pointer */ +#define NEXT_BLOCK /* nothing todo */ +#define LOAD_IV(reg, off) \ + lwbrx reg,0,rIP; /* load reversed */ \ + addi rIP,rIP,4; /* and increment pointer */ +#define SAVE_IV(reg, off) \ + stwbrx reg,0,rIP; /* load reversed */ \ + addi rIP,rIP,4; /* and increment pointer */ +#define START_IV \ + subi rIP,rIP,16; /* must reset pointer */ +#define CBC_DEC 32 /* 2 blocks because of incs */ +#define CTR_DEC 17 /* 1 block because of incs */ + +#endif + +#define SAVE_0_REGS +#define LOAD_0_REGS + +#define SAVE_4_REGS \ + stw rI0,96(r1); /* save 32 bit registers */ \ + stw rI1,100(r1); \ + stw rI2,104(r1); \ + stw rI3,108(r1); + +#define LOAD_4_REGS \ + lwz rI0,96(r1); /* restore 32 bit registers */ \ + lwz rI1,100(r1); \ + lwz rI2,104(r1); \ + lwz rI3,108(r1); + +#define SAVE_8_REGS \ + SAVE_4_REGS \ + stw rG0,112(r1); /* save 32 bit registers */ \ + stw rG1,116(r1); \ + stw rG2,120(r1); \ + stw rG3,124(r1); + +#define LOAD_8_REGS \ + LOAD_4_REGS \ + lwz rG0,112(r1); /* restore 32 bit registers */ \ + lwz rG1,116(r1); \ + lwz rG2,120(r1); \ + lwz rG3,124(r1); + +#define INITIALIZE_CRYPT(tab,nr32bitregs) \ + mflr r0; \ + stwu r1,-160(r1); /* create stack frame */ \ + lis rT0,tab@h; /* en-/decryption table pointer */ \ + stw r0,8(r1); /* save link register */ \ + ori rT0,rT0,tab@l; \ + evstdw r14,16(r1); \ + mr rKS,rKP; \ + evstdw r15,24(r1); /* We must save non volatile */ \ + evstdw r16,32(r1); /* registers. Take the chance */ \ + evstdw r17,40(r1); /* and save the SPE part too */ \ + evstdw r18,48(r1); \ + evstdw r19,56(r1); \ + evstdw r20,64(r1); \ + evstdw r21,72(r1); \ + evstdw r22,80(r1); \ + evstdw r23,88(r1); \ + SAVE_##nr32bitregs##_REGS + +#define FINALIZE_CRYPT(nr32bitregs) \ + lwz r0,8(r1); \ + evldw r14,16(r1); /* restore SPE registers */ \ + evldw r15,24(r1); \ + evldw r16,32(r1); \ + evldw r17,40(r1); \ + evldw r18,48(r1); \ + evldw r19,56(r1); \ + evldw r20,64(r1); \ + evldw r21,72(r1); \ + evldw r22,80(r1); \ + evldw r23,88(r1); \ + LOAD_##nr32bitregs##_REGS \ + mtlr r0; /* restore link register */ \ + xor r0,r0,r0; \ + stw r0,16(r1); /* delete sensitive data */ \ + stw r0,24(r1); /* that we might have pushed */ \ + stw r0,32(r1); /* from other context that runs */ \ + stw r0,40(r1); /* the same code */ \ + stw r0,48(r1); \ + stw r0,56(r1); \ + stw r0,64(r1); \ + stw r0,72(r1); \ + stw r0,80(r1); \ + stw r0,88(r1); \ + addi r1,r1,160; /* cleanup stack frame */ + +#define ENDIAN_SWAP(t0, t1, s0, s1) \ + rotrwi t0,s0,8; /* swap endianness for 2 GPRs */ \ + rotrwi t1,s1,8; \ + rlwimi t0,s0,8,8,15; \ + rlwimi t1,s1,8,8,15; \ + rlwimi t0,s0,8,24,31; \ + rlwimi t1,s1,8,24,31; + +#define GF128_MUL(d0, d1, d2, d3, t0) \ + li t0,0x87; /* multiplication in GF128 */ \ + cmpwi d3,-1; \ + iselgt t0,0,t0; \ + rlwimi d3,d2,0,0,0; /* propagate "carry" bits */ \ + rotlwi d3,d3,1; \ + rlwimi d2,d1,0,0,0; \ + rotlwi d2,d2,1; \ + rlwimi d1,d0,0,0,0; \ + slwi d0,d0,1; /* shift left 128 bit */ \ + rotlwi d1,d1,1; \ + xor d0,d0,t0; + +#define START_KEY(d0, d1, d2, d3) \ + lwz rW0,0(rKP); \ + mtctr rRR; \ + lwz rW1,4(rKP); \ + lwz rW2,8(rKP); \ + lwz rW3,12(rKP); \ + xor rD0,d0,rW0; \ + xor rD1,d1,rW1; \ + xor rD2,d2,rW2; \ + xor rD3,d3,rW3; + +/* + * ppc_encrypt_aes(u8 *out, const u8 *in, u32 *key_enc, + * u32 rounds) + * + * called from glue layer to encrypt a single 16 byte block + * round values are AES128 = 4, AES192 = 5, AES256 = 6 + * + */ +_GLOBAL(ppc_encrypt_aes) + INITIALIZE_CRYPT(PPC_AES_4K_ENCTAB, 0) + LOAD_DATA(rD0, 0) + LOAD_DATA(rD1, 4) + LOAD_DATA(rD2, 8) + LOAD_DATA(rD3, 12) + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_encrypt_block + xor rD0,rD0,rW0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rW1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rW2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rW3 + SAVE_DATA(rD3, 12) + FINALIZE_CRYPT(0) + blr + +/* + * ppc_decrypt_aes(u8 *out, const u8 *in, u32 *key_dec, + * u32 rounds) + * + * called from glue layer to decrypt a single 16 byte block + * round values are AES128 = 4, AES192 = 5, AES256 = 6 + * + */ +_GLOBAL(ppc_decrypt_aes) + INITIALIZE_CRYPT(PPC_AES_4K_DECTAB,0) + LOAD_DATA(rD0, 0) + addi rT1,rT0,4096 + LOAD_DATA(rD1, 4) + LOAD_DATA(rD2, 8) + LOAD_DATA(rD3, 12) + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_decrypt_block + xor rD0,rD0,rW0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rW1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rW2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rW3 + SAVE_DATA(rD3, 12) + FINALIZE_CRYPT(0) + blr + +/* + * ppc_encrypt_ecb(u8 *out, const u8 *in, u32 *key_enc, + * u32 rounds, u32 bytes); + * + * called from glue layer to encrypt multiple blocks via ECB + * Bytes must be larger or equal 16 and only whole blocks are + * processed. round values are AES128 = 4, AES192 = 5 and + * AES256 = 6 + * + */ +_GLOBAL(ppc_encrypt_ecb) + INITIALIZE_CRYPT(PPC_AES_4K_ENCTAB, 0) +ppc_encrypt_ecb_loop: + LOAD_DATA(rD0, 0) + mr rKP,rKS + LOAD_DATA(rD1, 4) + subi rLN,rLN,16 + LOAD_DATA(rD2, 8) + cmpwi rLN,15 + LOAD_DATA(rD3, 12) + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_encrypt_block + xor rD0,rD0,rW0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rW1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rW2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rW3 + SAVE_DATA(rD3, 12) + NEXT_BLOCK + bt gt,ppc_encrypt_ecb_loop + FINALIZE_CRYPT(0) + blr + +/* + * ppc_decrypt_ecb(u8 *out, const u8 *in, u32 *key_dec, + * u32 rounds, u32 bytes); + * + * called from glue layer to decrypt multiple blocks via ECB + * Bytes must be larger or equal 16 and only whole blocks are + * processed. round values are AES128 = 4, AES192 = 5 and + * AES256 = 6 + * + */ +_GLOBAL(ppc_decrypt_ecb) + INITIALIZE_CRYPT(PPC_AES_4K_DECTAB, 0) + addi rT1,rT0,4096 +ppc_decrypt_ecb_loop: + LOAD_DATA(rD0, 0) + mr rKP,rKS + LOAD_DATA(rD1, 4) + subi rLN,rLN,16 + LOAD_DATA(rD2, 8) + cmpwi rLN,15 + LOAD_DATA(rD3, 12) + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_decrypt_block + xor rD0,rD0,rW0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rW1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rW2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rW3 + SAVE_DATA(rD3, 12) + NEXT_BLOCK + bt gt,ppc_decrypt_ecb_loop + FINALIZE_CRYPT(0) + blr + +/* + * ppc_encrypt_cbc(u8 *out, const u8 *in, u32 *key_enc, + * 32 rounds, u32 bytes, u8 *iv); + * + * called from glue layer to encrypt multiple blocks via CBC + * Bytes must be larger or equal 16 and only whole blocks are + * processed. round values are AES128 = 4, AES192 = 5 and + * AES256 = 6 + * + */ +_GLOBAL(ppc_encrypt_cbc) + INITIALIZE_CRYPT(PPC_AES_4K_ENCTAB, 4) + LOAD_IV(rI0, 0) + LOAD_IV(rI1, 4) + LOAD_IV(rI2, 8) + LOAD_IV(rI3, 12) +ppc_encrypt_cbc_loop: + LOAD_DATA(rD0, 0) + mr rKP,rKS + LOAD_DATA(rD1, 4) + subi rLN,rLN,16 + LOAD_DATA(rD2, 8) + cmpwi rLN,15 + LOAD_DATA(rD3, 12) + xor rD0,rD0,rI0 + xor rD1,rD1,rI1 + xor rD2,rD2,rI2 + xor rD3,rD3,rI3 + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_encrypt_block + xor rI0,rD0,rW0 + SAVE_DATA(rI0, 0) + xor rI1,rD1,rW1 + SAVE_DATA(rI1, 4) + xor rI2,rD2,rW2 + SAVE_DATA(rI2, 8) + xor rI3,rD3,rW3 + SAVE_DATA(rI3, 12) + NEXT_BLOCK + bt gt,ppc_encrypt_cbc_loop + START_IV + SAVE_IV(rI0, 0) + SAVE_IV(rI1, 4) + SAVE_IV(rI2, 8) + SAVE_IV(rI3, 12) + FINALIZE_CRYPT(4) + blr + +/* + * ppc_decrypt_cbc(u8 *out, const u8 *in, u32 *key_dec, + * u32 rounds, u32 bytes, u8 *iv); + * + * called from glue layer to decrypt multiple blocks via CBC + * round values are AES128 = 4, AES192 = 5, AES256 = 6 + * + */ +_GLOBAL(ppc_decrypt_cbc) + INITIALIZE_CRYPT(PPC_AES_4K_DECTAB, 4) + li rT1,15 + LOAD_IV(rI0, 0) + andc rLN,rLN,rT1 + LOAD_IV(rI1, 4) + subi rLN,rLN,16 + LOAD_IV(rI2, 8) + add rSP,rSP,rLN /* reverse processing */ + LOAD_IV(rI3, 12) + add rDP,rDP,rLN + LOAD_DATA(rD0, 0) + addi rT1,rT0,4096 + LOAD_DATA(rD1, 4) + LOAD_DATA(rD2, 8) + LOAD_DATA(rD3, 12) + START_IV + SAVE_IV(rD0, 0) + SAVE_IV(rD1, 4) + SAVE_IV(rD2, 8) + cmpwi rLN,16 + SAVE_IV(rD3, 12) + bt lt,ppc_decrypt_cbc_end +ppc_decrypt_cbc_loop: + mr rKP,rKS + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_decrypt_block + subi rLN,rLN,16 + subi rSP,rSP,CBC_DEC + xor rW0,rD0,rW0 + LOAD_DATA(rD0, 0) + xor rW1,rD1,rW1 + LOAD_DATA(rD1, 4) + xor rW2,rD2,rW2 + LOAD_DATA(rD2, 8) + xor rW3,rD3,rW3 + LOAD_DATA(rD3, 12) + xor rW0,rW0,rD0 + SAVE_DATA(rW0, 0) + xor rW1,rW1,rD1 + SAVE_DATA(rW1, 4) + xor rW2,rW2,rD2 + SAVE_DATA(rW2, 8) + xor rW3,rW3,rD3 + SAVE_DATA(rW3, 12) + cmpwi rLN,15 + subi rDP,rDP,CBC_DEC + bt gt,ppc_decrypt_cbc_loop +ppc_decrypt_cbc_end: + mr rKP,rKS + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_decrypt_block + xor rW0,rW0,rD0 + xor rW1,rW1,rD1 + xor rW2,rW2,rD2 + xor rW3,rW3,rD3 + xor rW0,rW0,rI0 /* decrypt with initial IV */ + SAVE_DATA(rW0, 0) + xor rW1,rW1,rI1 + SAVE_DATA(rW1, 4) + xor rW2,rW2,rI2 + SAVE_DATA(rW2, 8) + xor rW3,rW3,rI3 + SAVE_DATA(rW3, 12) + FINALIZE_CRYPT(4) + blr + +/* + * ppc_crypt_ctr(u8 *out, const u8 *in, u32 *key_enc, + * u32 rounds, u32 bytes, u8 *iv); + * + * called from glue layer to encrypt/decrypt multiple blocks + * via CTR. Number of bytes does not need to be a multiple of + * 16. Round values are AES128 = 4, AES192 = 5, AES256 = 6 + * + */ +_GLOBAL(ppc_crypt_ctr) + INITIALIZE_CRYPT(PPC_AES_4K_ENCTAB, 4) + LOAD_IV(rI0, 0) + LOAD_IV(rI1, 4) + LOAD_IV(rI2, 8) + cmpwi rLN,16 + LOAD_IV(rI3, 12) + START_IV + bt lt,ppc_crypt_ctr_partial +ppc_crypt_ctr_loop: + mr rKP,rKS + START_KEY(rI0, rI1, rI2, rI3) + bl ppc_encrypt_block + xor rW0,rD0,rW0 + xor rW1,rD1,rW1 + xor rW2,rD2,rW2 + xor rW3,rD3,rW3 + LOAD_DATA(rD0, 0) + subi rLN,rLN,16 + LOAD_DATA(rD1, 4) + LOAD_DATA(rD2, 8) + LOAD_DATA(rD3, 12) + xor rD0,rD0,rW0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rW1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rW2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rW3 + SAVE_DATA(rD3, 12) + addic rI3,rI3,1 /* increase counter */ + addze rI2,rI2 + addze rI1,rI1 + addze rI0,rI0 + NEXT_BLOCK + cmpwi rLN,15 + bt gt,ppc_crypt_ctr_loop +ppc_crypt_ctr_partial: + cmpwi rLN,0 + bt eq,ppc_crypt_ctr_end + mr rKP,rKS + START_KEY(rI0, rI1, rI2, rI3) + bl ppc_encrypt_block + xor rW0,rD0,rW0 + SAVE_IV(rW0, 0) + xor rW1,rD1,rW1 + SAVE_IV(rW1, 4) + xor rW2,rD2,rW2 + SAVE_IV(rW2, 8) + xor rW3,rD3,rW3 + SAVE_IV(rW3, 12) + mtctr rLN + subi rIP,rIP,CTR_DEC + subi rSP,rSP,1 + subi rDP,rDP,1 +ppc_crypt_ctr_xorbyte: + lbzu rW4,1(rIP) /* bytewise xor for partial block */ + lbzu rW5,1(rSP) + xor rW4,rW4,rW5 + stbu rW4,1(rDP) + bdnz ppc_crypt_ctr_xorbyte + subf rIP,rLN,rIP + addi rIP,rIP,1 + addic rI3,rI3,1 + addze rI2,rI2 + addze rI1,rI1 + addze rI0,rI0 +ppc_crypt_ctr_end: + SAVE_IV(rI0, 0) + SAVE_IV(rI1, 4) + SAVE_IV(rI2, 8) + SAVE_IV(rI3, 12) + FINALIZE_CRYPT(4) + blr + +/* + * ppc_encrypt_xts(u8 *out, const u8 *in, u32 *key_enc, + * u32 rounds, u32 bytes, u8 *iv, u32 *key_twk); + * + * called from glue layer to encrypt multiple blocks via XTS + * If key_twk is given, the initial IV encryption will be + * processed too. Round values are AES128 = 4, AES192 = 5, + * AES256 = 6 + * + */ +_GLOBAL(ppc_encrypt_xts) + INITIALIZE_CRYPT(PPC_AES_4K_ENCTAB, 8) + LOAD_IV(rI0, 0) + LOAD_IV(rI1, 4) + LOAD_IV(rI2, 8) + cmpwi rKT,0 + LOAD_IV(rI3, 12) + bt eq,ppc_encrypt_xts_notweak + mr rKP,rKT + START_KEY(rI0, rI1, rI2, rI3) + bl ppc_encrypt_block + xor rI0,rD0,rW0 + xor rI1,rD1,rW1 + xor rI2,rD2,rW2 + xor rI3,rD3,rW3 +ppc_encrypt_xts_notweak: + ENDIAN_SWAP(rG0, rG1, rI0, rI1) + ENDIAN_SWAP(rG2, rG3, rI2, rI3) +ppc_encrypt_xts_loop: + LOAD_DATA(rD0, 0) + mr rKP,rKS + LOAD_DATA(rD1, 4) + subi rLN,rLN,16 + LOAD_DATA(rD2, 8) + LOAD_DATA(rD3, 12) + xor rD0,rD0,rI0 + xor rD1,rD1,rI1 + xor rD2,rD2,rI2 + xor rD3,rD3,rI3 + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_encrypt_block + xor rD0,rD0,rW0 + xor rD1,rD1,rW1 + xor rD2,rD2,rW2 + xor rD3,rD3,rW3 + xor rD0,rD0,rI0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rI1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rI2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rI3 + SAVE_DATA(rD3, 12) + GF128_MUL(rG0, rG1, rG2, rG3, rW0) + ENDIAN_SWAP(rI0, rI1, rG0, rG1) + ENDIAN_SWAP(rI2, rI3, rG2, rG3) + cmpwi rLN,0 + NEXT_BLOCK + bt gt,ppc_encrypt_xts_loop + START_IV + SAVE_IV(rI0, 0) + SAVE_IV(rI1, 4) + SAVE_IV(rI2, 8) + SAVE_IV(rI3, 12) + FINALIZE_CRYPT(8) + blr + +/* + * ppc_decrypt_xts(u8 *out, const u8 *in, u32 *key_dec, + * u32 rounds, u32 blocks, u8 *iv, u32 *key_twk); + * + * called from glue layer to decrypt multiple blocks via XTS + * If key_twk is given, the initial IV encryption will be + * processed too. Round values are AES128 = 4, AES192 = 5, + * AES256 = 6 + * + */ +_GLOBAL(ppc_decrypt_xts) + INITIALIZE_CRYPT(PPC_AES_4K_DECTAB, 8) + LOAD_IV(rI0, 0) + addi rT1,rT0,4096 + LOAD_IV(rI1, 4) + LOAD_IV(rI2, 8) + cmpwi rKT,0 + LOAD_IV(rI3, 12) + bt eq,ppc_decrypt_xts_notweak + subi rT0,rT0,4096 + mr rKP,rKT + START_KEY(rI0, rI1, rI2, rI3) + bl ppc_encrypt_block + xor rI0,rD0,rW0 + xor rI1,rD1,rW1 + xor rI2,rD2,rW2 + xor rI3,rD3,rW3 + addi rT0,rT0,4096 +ppc_decrypt_xts_notweak: + ENDIAN_SWAP(rG0, rG1, rI0, rI1) + ENDIAN_SWAP(rG2, rG3, rI2, rI3) +ppc_decrypt_xts_loop: + LOAD_DATA(rD0, 0) + mr rKP,rKS + LOAD_DATA(rD1, 4) + subi rLN,rLN,16 + LOAD_DATA(rD2, 8) + LOAD_DATA(rD3, 12) + xor rD0,rD0,rI0 + xor rD1,rD1,rI1 + xor rD2,rD2,rI2 + xor rD3,rD3,rI3 + START_KEY(rD0, rD1, rD2, rD3) + bl ppc_decrypt_block + xor rD0,rD0,rW0 + xor rD1,rD1,rW1 + xor rD2,rD2,rW2 + xor rD3,rD3,rW3 + xor rD0,rD0,rI0 + SAVE_DATA(rD0, 0) + xor rD1,rD1,rI1 + SAVE_DATA(rD1, 4) + xor rD2,rD2,rI2 + SAVE_DATA(rD2, 8) + xor rD3,rD3,rI3 + SAVE_DATA(rD3, 12) + GF128_MUL(rG0, rG1, rG2, rG3, rW0) + ENDIAN_SWAP(rI0, rI1, rG0, rG1) + ENDIAN_SWAP(rI2, rI3, rG2, rG3) + cmpwi rLN,0 + NEXT_BLOCK + bt gt,ppc_decrypt_xts_loop + START_IV + SAVE_IV(rI0, 0) + SAVE_IV(rI1, 4) + SAVE_IV(rI2, 8) + SAVE_IV(rI3, 12) + FINALIZE_CRYPT(8) + blr |