1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * SHA-1 optimized for PowerPC 4 * 5 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de> 6 */ 7 8 #include <asm/switch_to.h> 9 #include <linux/preempt.h> 10 11 #ifdef CONFIG_SPE 12 /* 13 * MAX_BYTES defines the number of bytes that are allowed to be processed 14 * between preempt_disable() and preempt_enable(). SHA1 takes ~1000 15 * operations per 64 bytes. e500 cores can issue two arithmetic instructions 16 * per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2). 17 * Thus 2KB of input data will need an estimated maximum of 18,000 cycles. 18 * Headroom for cache misses included. Even with the low end model clocked 19 * at 667 MHz this equals to a critical time window of less than 27us. 20 * 21 */ 22 #define MAX_BYTES 2048 23 24 asmlinkage void ppc_spe_sha1_transform(struct sha1_block_state *state, 25 const u8 *data, u32 nblocks); 26 27 static void spe_begin(void) 28 { 29 /* We just start SPE operations and will save SPE registers later. */ 30 preempt_disable(); 31 enable_kernel_spe(); 32 } 33 34 static void spe_end(void) 35 { 36 disable_kernel_spe(); 37 /* reenable preemption */ 38 preempt_enable(); 39 } 40 41 static void sha1_blocks(struct sha1_block_state *state, 42 const u8 *data, size_t nblocks) 43 { 44 do { 45 u32 unit = min_t(size_t, nblocks, MAX_BYTES / SHA1_BLOCK_SIZE); 46 47 spe_begin(); 48 ppc_spe_sha1_transform(state, data, unit); 49 spe_end(); 50 51 data += unit * SHA1_BLOCK_SIZE; 52 nblocks -= unit; 53 } while (nblocks); 54 } 55 #else /* CONFIG_SPE */ 56 asmlinkage void powerpc_sha_transform(struct sha1_block_state *state, 57 const u8 data[SHA1_BLOCK_SIZE]); 58 59 static void sha1_blocks(struct sha1_block_state *state, 60 const u8 *data, size_t nblocks) 61 { 62 do { 63 powerpc_sha_transform(state, data); 64 data += SHA1_BLOCK_SIZE; 65 } while (--nblocks); 66 } 67 #endif /* !CONFIG_SPE */ 68