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| 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 |
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