diff options
Diffstat (limited to '')
-rw-r--r-- | lib/842/842.h | 130 | ||||
-rw-r--r-- | lib/842/842_compress.c | 630 | ||||
-rw-r--r-- | lib/842/842_debugfs.h | 50 | ||||
-rw-r--r-- | lib/842/842_decompress.c | 417 | ||||
-rw-r--r-- | lib/842/Makefile | 3 |
5 files changed, 1230 insertions, 0 deletions
diff --git a/lib/842/842.h b/lib/842/842.h new file mode 100644 index 0000000000..7b1f581a29 --- /dev/null +++ b/lib/842/842.h @@ -0,0 +1,130 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __842_H__ +#define __842_H__ + +/* The 842 compressed format is made up of multiple blocks, each of + * which have the format: + * + * <template>[arg1][arg2][arg3][arg4] + * + * where there are between 0 and 4 template args, depending on the specific + * template operation. For normal operations, each arg is either a specific + * number of data bytes to add to the output buffer, or an index pointing + * to a previously-written number of data bytes to copy to the output buffer. + * + * The template code is a 5-bit value. This code indicates what to do with + * the following data. Template codes from 0 to 0x19 should use the template + * table, the static "decomp_ops" table used in decompress. For each template + * (table row), there are between 1 and 4 actions; each action corresponds to + * an arg following the template code bits. Each action is either a "data" + * type action, or a "index" type action, and each action results in 2, 4, or 8 + * bytes being written to the output buffer. Each template (i.e. all actions + * in the table row) will add up to 8 bytes being written to the output buffer. + * Any row with less than 4 actions is padded with noop actions, indicated by + * N0 (for which there is no corresponding arg in the compressed data buffer). + * + * "Data" actions, indicated in the table by D2, D4, and D8, mean that the + * corresponding arg is 2, 4, or 8 bytes, respectively, in the compressed data + * buffer should be copied directly to the output buffer. + * + * "Index" actions, indicated in the table by I2, I4, and I8, mean the + * corresponding arg is an index parameter that points to, respectively, a 2, + * 4, or 8 byte value already in the output buffer, that should be copied to + * the end of the output buffer. Essentially, the index points to a position + * in a ring buffer that contains the last N bytes of output buffer data. + * The number of bits for each index's arg are: 8 bits for I2, 9 bits for I4, + * and 8 bits for I8. Since each index points to a 2, 4, or 8 byte section, + * this means that I2 can reference 512 bytes ((2^8 bits = 256) * 2 bytes), I4 + * can reference 2048 bytes ((2^9 = 512) * 4 bytes), and I8 can reference 2048 + * bytes ((2^8 = 256) * 8 bytes). Think of it as a kind-of ring buffer for + * each of I2, I4, and I8 that are updated for each byte written to the output + * buffer. In this implementation, the output buffer is directly used for each + * index; there is no additional memory required. Note that the index is into + * a ring buffer, not a sliding window; for example, if there have been 260 + * bytes written to the output buffer, an I2 index of 0 would index to byte 256 + * in the output buffer, while an I2 index of 16 would index to byte 16 in the + * output buffer. + * + * There are also 3 special template codes; 0x1b for "repeat", 0x1c for + * "zeros", and 0x1e for "end". The "repeat" operation is followed by a 6 bit + * arg N indicating how many times to repeat. The last 8 bytes written to the + * output buffer are written again to the output buffer, N + 1 times. The + * "zeros" operation, which has no arg bits, writes 8 zeros to the output + * buffer. The "end" operation, which also has no arg bits, signals the end + * of the compressed data. There may be some number of padding (don't care, + * but usually 0) bits after the "end" operation bits, to fill the buffer + * length to a specific byte multiple (usually a multiple of 8, 16, or 32 + * bytes). + * + * This software implementation also uses one of the undefined template values, + * 0x1d as a special "short data" template code, to represent less than 8 bytes + * of uncompressed data. It is followed by a 3 bit arg N indicating how many + * data bytes will follow, and then N bytes of data, which should be copied to + * the output buffer. This allows the software 842 compressor to accept input + * buffers that are not an exact multiple of 8 bytes long. However, those + * compressed buffers containing this sw-only template will be rejected by + * the 842 hardware decompressor, and must be decompressed with this software + * library. The 842 software compression module includes a parameter to + * disable using this sw-only "short data" template, and instead simply + * reject any input buffer that is not a multiple of 8 bytes long. + * + * After all actions for each operation code are processed, another template + * code is in the next 5 bits. The decompression ends once the "end" template + * code is detected. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/bitops.h> +#include <linux/crc32.h> +#include <asm/unaligned.h> + +#include <linux/sw842.h> + +/* special templates */ +#define OP_REPEAT (0x1B) +#define OP_ZEROS (0x1C) +#define OP_END (0x1E) + +/* sw only template - this is not in the hw design; it's used only by this + * software compressor and decompressor, to allow input buffers that aren't + * a multiple of 8. + */ +#define OP_SHORT_DATA (0x1D) + +/* additional bits of each op param */ +#define OP_BITS (5) +#define REPEAT_BITS (6) +#define SHORT_DATA_BITS (3) +#define I2_BITS (8) +#define I4_BITS (9) +#define I8_BITS (8) +#define CRC_BITS (32) + +#define REPEAT_BITS_MAX (0x3f) +#define SHORT_DATA_BITS_MAX (0x7) + +/* Arbitrary values used to indicate action */ +#define OP_ACTION (0x70) +#define OP_ACTION_INDEX (0x10) +#define OP_ACTION_DATA (0x20) +#define OP_ACTION_NOOP (0x40) +#define OP_AMOUNT (0x0f) +#define OP_AMOUNT_0 (0x00) +#define OP_AMOUNT_2 (0x02) +#define OP_AMOUNT_4 (0x04) +#define OP_AMOUNT_8 (0x08) + +#define D2 (OP_ACTION_DATA | OP_AMOUNT_2) +#define D4 (OP_ACTION_DATA | OP_AMOUNT_4) +#define D8 (OP_ACTION_DATA | OP_AMOUNT_8) +#define I2 (OP_ACTION_INDEX | OP_AMOUNT_2) +#define I4 (OP_ACTION_INDEX | OP_AMOUNT_4) +#define I8 (OP_ACTION_INDEX | OP_AMOUNT_8) +#define N0 (OP_ACTION_NOOP | OP_AMOUNT_0) + +/* the max of the regular templates - not including the special templates */ +#define OPS_MAX (0x1a) + +#endif diff --git a/lib/842/842_compress.c b/lib/842/842_compress.c new file mode 100644 index 0000000000..c02baa4168 --- /dev/null +++ b/lib/842/842_compress.c @@ -0,0 +1,630 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 842 Software Compression + * + * Copyright (C) 2015 Dan Streetman, IBM Corp + * + * See 842.h for details of the 842 compressed format. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#define MODULE_NAME "842_compress" + +#include <linux/hashtable.h> + +#include "842.h" +#include "842_debugfs.h" + +#define SW842_HASHTABLE8_BITS (10) +#define SW842_HASHTABLE4_BITS (11) +#define SW842_HASHTABLE2_BITS (10) + +/* By default, we allow compressing input buffers of any length, but we must + * use the non-standard "short data" template so the decompressor can correctly + * reproduce the uncompressed data buffer at the right length. However the + * hardware 842 compressor will not recognize the "short data" template, and + * will fail to decompress any compressed buffer containing it (I have no idea + * why anyone would want to use software to compress and hardware to decompress + * but that's beside the point). This parameter forces the compression + * function to simply reject any input buffer that isn't a multiple of 8 bytes + * long, instead of using the "short data" template, so that all compressed + * buffers produced by this function will be decompressable by the 842 hardware + * decompressor. Unless you have a specific need for that, leave this disabled + * so that any length buffer can be compressed. + */ +static bool sw842_strict; +module_param_named(strict, sw842_strict, bool, 0644); + +static u8 comp_ops[OPS_MAX][5] = { /* params size in bits */ + { I8, N0, N0, N0, 0x19 }, /* 8 */ + { I4, I4, N0, N0, 0x18 }, /* 18 */ + { I4, I2, I2, N0, 0x17 }, /* 25 */ + { I2, I2, I4, N0, 0x13 }, /* 25 */ + { I2, I2, I2, I2, 0x12 }, /* 32 */ + { I4, I2, D2, N0, 0x16 }, /* 33 */ + { I4, D2, I2, N0, 0x15 }, /* 33 */ + { I2, D2, I4, N0, 0x0e }, /* 33 */ + { D2, I2, I4, N0, 0x09 }, /* 33 */ + { I2, I2, I2, D2, 0x11 }, /* 40 */ + { I2, I2, D2, I2, 0x10 }, /* 40 */ + { I2, D2, I2, I2, 0x0d }, /* 40 */ + { D2, I2, I2, I2, 0x08 }, /* 40 */ + { I4, D4, N0, N0, 0x14 }, /* 41 */ + { D4, I4, N0, N0, 0x04 }, /* 41 */ + { I2, I2, D4, N0, 0x0f }, /* 48 */ + { I2, D2, I2, D2, 0x0c }, /* 48 */ + { I2, D4, I2, N0, 0x0b }, /* 48 */ + { D2, I2, I2, D2, 0x07 }, /* 48 */ + { D2, I2, D2, I2, 0x06 }, /* 48 */ + { D4, I2, I2, N0, 0x03 }, /* 48 */ + { I2, D2, D4, N0, 0x0a }, /* 56 */ + { D2, I2, D4, N0, 0x05 }, /* 56 */ + { D4, I2, D2, N0, 0x02 }, /* 56 */ + { D4, D2, I2, N0, 0x01 }, /* 56 */ + { D8, N0, N0, N0, 0x00 }, /* 64 */ +}; + +struct sw842_hlist_node8 { + struct hlist_node node; + u64 data; + u8 index; +}; + +struct sw842_hlist_node4 { + struct hlist_node node; + u32 data; + u16 index; +}; + +struct sw842_hlist_node2 { + struct hlist_node node; + u16 data; + u8 index; +}; + +#define INDEX_NOT_FOUND (-1) +#define INDEX_NOT_CHECKED (-2) + +struct sw842_param { + u8 *in; + u8 *instart; + u64 ilen; + u8 *out; + u64 olen; + u8 bit; + u64 data8[1]; + u32 data4[2]; + u16 data2[4]; + int index8[1]; + int index4[2]; + int index2[4]; + DECLARE_HASHTABLE(htable8, SW842_HASHTABLE8_BITS); + DECLARE_HASHTABLE(htable4, SW842_HASHTABLE4_BITS); + DECLARE_HASHTABLE(htable2, SW842_HASHTABLE2_BITS); + struct sw842_hlist_node8 node8[1 << I8_BITS]; + struct sw842_hlist_node4 node4[1 << I4_BITS]; + struct sw842_hlist_node2 node2[1 << I2_BITS]; +}; + +#define get_input_data(p, o, b) \ + be##b##_to_cpu(get_unaligned((__be##b *)((p)->in + (o)))) + +#define init_hashtable_nodes(p, b) do { \ + int _i; \ + hash_init((p)->htable##b); \ + for (_i = 0; _i < ARRAY_SIZE((p)->node##b); _i++) { \ + (p)->node##b[_i].index = _i; \ + (p)->node##b[_i].data = 0; \ + INIT_HLIST_NODE(&(p)->node##b[_i].node); \ + } \ +} while (0) + +#define find_index(p, b, n) ({ \ + struct sw842_hlist_node##b *_n; \ + p->index##b[n] = INDEX_NOT_FOUND; \ + hash_for_each_possible(p->htable##b, _n, node, p->data##b[n]) { \ + if (p->data##b[n] == _n->data) { \ + p->index##b[n] = _n->index; \ + break; \ + } \ + } \ + p->index##b[n] >= 0; \ +}) + +#define check_index(p, b, n) \ + ((p)->index##b[n] == INDEX_NOT_CHECKED \ + ? find_index(p, b, n) \ + : (p)->index##b[n] >= 0) + +#define replace_hash(p, b, i, d) do { \ + struct sw842_hlist_node##b *_n = &(p)->node##b[(i)+(d)]; \ + hash_del(&_n->node); \ + _n->data = (p)->data##b[d]; \ + pr_debug("add hash index%x %x pos %x data %lx\n", b, \ + (unsigned int)_n->index, \ + (unsigned int)((p)->in - (p)->instart), \ + (unsigned long)_n->data); \ + hash_add((p)->htable##b, &_n->node, _n->data); \ +} while (0) + +static u8 bmask[8] = { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe }; + +static int add_bits(struct sw842_param *p, u64 d, u8 n); + +static int __split_add_bits(struct sw842_param *p, u64 d, u8 n, u8 s) +{ + int ret; + + if (n <= s) + return -EINVAL; + + ret = add_bits(p, d >> s, n - s); + if (ret) + return ret; + return add_bits(p, d & GENMASK_ULL(s - 1, 0), s); +} + +static int add_bits(struct sw842_param *p, u64 d, u8 n) +{ + int b = p->bit, bits = b + n, s = round_up(bits, 8) - bits; + u64 o; + u8 *out = p->out; + + pr_debug("add %u bits %lx\n", (unsigned char)n, (unsigned long)d); + + if (n > 64) + return -EINVAL; + + /* split this up if writing to > 8 bytes (i.e. n == 64 && p->bit > 0), + * or if we're at the end of the output buffer and would write past end + */ + if (bits > 64) + return __split_add_bits(p, d, n, 32); + else if (p->olen < 8 && bits > 32 && bits <= 56) + return __split_add_bits(p, d, n, 16); + else if (p->olen < 4 && bits > 16 && bits <= 24) + return __split_add_bits(p, d, n, 8); + + if (DIV_ROUND_UP(bits, 8) > p->olen) + return -ENOSPC; + + o = *out & bmask[b]; + d <<= s; + + if (bits <= 8) + *out = o | d; + else if (bits <= 16) + put_unaligned(cpu_to_be16(o << 8 | d), (__be16 *)out); + else if (bits <= 24) + put_unaligned(cpu_to_be32(o << 24 | d << 8), (__be32 *)out); + else if (bits <= 32) + put_unaligned(cpu_to_be32(o << 24 | d), (__be32 *)out); + else if (bits <= 40) + put_unaligned(cpu_to_be64(o << 56 | d << 24), (__be64 *)out); + else if (bits <= 48) + put_unaligned(cpu_to_be64(o << 56 | d << 16), (__be64 *)out); + else if (bits <= 56) + put_unaligned(cpu_to_be64(o << 56 | d << 8), (__be64 *)out); + else + put_unaligned(cpu_to_be64(o << 56 | d), (__be64 *)out); + + p->bit += n; + + if (p->bit > 7) { + p->out += p->bit / 8; + p->olen -= p->bit / 8; + p->bit %= 8; + } + + return 0; +} + +static int add_template(struct sw842_param *p, u8 c) +{ + int ret, i, b = 0; + u8 *t = comp_ops[c]; + bool inv = false; + + if (c >= OPS_MAX) + return -EINVAL; + + pr_debug("template %x\n", t[4]); + + ret = add_bits(p, t[4], OP_BITS); + if (ret) + return ret; + + for (i = 0; i < 4; i++) { + pr_debug("op %x\n", t[i]); + + switch (t[i] & OP_AMOUNT) { + case OP_AMOUNT_8: + if (b) + inv = true; + else if (t[i] & OP_ACTION_INDEX) + ret = add_bits(p, p->index8[0], I8_BITS); + else if (t[i] & OP_ACTION_DATA) + ret = add_bits(p, p->data8[0], 64); + else + inv = true; + break; + case OP_AMOUNT_4: + if (b == 2 && t[i] & OP_ACTION_DATA) + ret = add_bits(p, get_input_data(p, 2, 32), 32); + else if (b != 0 && b != 4) + inv = true; + else if (t[i] & OP_ACTION_INDEX) + ret = add_bits(p, p->index4[b >> 2], I4_BITS); + else if (t[i] & OP_ACTION_DATA) + ret = add_bits(p, p->data4[b >> 2], 32); + else + inv = true; + break; + case OP_AMOUNT_2: + if (b != 0 && b != 2 && b != 4 && b != 6) + inv = true; + if (t[i] & OP_ACTION_INDEX) + ret = add_bits(p, p->index2[b >> 1], I2_BITS); + else if (t[i] & OP_ACTION_DATA) + ret = add_bits(p, p->data2[b >> 1], 16); + else + inv = true; + break; + case OP_AMOUNT_0: + inv = (b != 8) || !(t[i] & OP_ACTION_NOOP); + break; + default: + inv = true; + break; + } + + if (ret) + return ret; + + if (inv) { + pr_err("Invalid templ %x op %d : %x %x %x %x\n", + c, i, t[0], t[1], t[2], t[3]); + return -EINVAL; + } + + b += t[i] & OP_AMOUNT; + } + + if (b != 8) { + pr_err("Invalid template %x len %x : %x %x %x %x\n", + c, b, t[0], t[1], t[2], t[3]); + return -EINVAL; + } + + if (sw842_template_counts) + atomic_inc(&template_count[t[4]]); + + return 0; +} + +static int add_repeat_template(struct sw842_param *p, u8 r) +{ + int ret; + + /* repeat param is 0-based */ + if (!r || --r > REPEAT_BITS_MAX) + return -EINVAL; + + ret = add_bits(p, OP_REPEAT, OP_BITS); + if (ret) + return ret; + + ret = add_bits(p, r, REPEAT_BITS); + if (ret) + return ret; + + if (sw842_template_counts) + atomic_inc(&template_repeat_count); + + return 0; +} + +static int add_short_data_template(struct sw842_param *p, u8 b) +{ + int ret, i; + + if (!b || b > SHORT_DATA_BITS_MAX) + return -EINVAL; + + ret = add_bits(p, OP_SHORT_DATA, OP_BITS); + if (ret) + return ret; + + ret = add_bits(p, b, SHORT_DATA_BITS); + if (ret) + return ret; + + for (i = 0; i < b; i++) { + ret = add_bits(p, p->in[i], 8); + if (ret) + return ret; + } + + if (sw842_template_counts) + atomic_inc(&template_short_data_count); + + return 0; +} + +static int add_zeros_template(struct sw842_param *p) +{ + int ret = add_bits(p, OP_ZEROS, OP_BITS); + + if (ret) + return ret; + + if (sw842_template_counts) + atomic_inc(&template_zeros_count); + + return 0; +} + +static int add_end_template(struct sw842_param *p) +{ + int ret = add_bits(p, OP_END, OP_BITS); + + if (ret) + return ret; + + if (sw842_template_counts) + atomic_inc(&template_end_count); + + return 0; +} + +static bool check_template(struct sw842_param *p, u8 c) +{ + u8 *t = comp_ops[c]; + int i, match, b = 0; + + if (c >= OPS_MAX) + return false; + + for (i = 0; i < 4; i++) { + if (t[i] & OP_ACTION_INDEX) { + if (t[i] & OP_AMOUNT_2) + match = check_index(p, 2, b >> 1); + else if (t[i] & OP_AMOUNT_4) + match = check_index(p, 4, b >> 2); + else if (t[i] & OP_AMOUNT_8) + match = check_index(p, 8, 0); + else + return false; + if (!match) + return false; + } + + b += t[i] & OP_AMOUNT; + } + + return true; +} + +static void get_next_data(struct sw842_param *p) +{ + p->data8[0] = get_input_data(p, 0, 64); + p->data4[0] = get_input_data(p, 0, 32); + p->data4[1] = get_input_data(p, 4, 32); + p->data2[0] = get_input_data(p, 0, 16); + p->data2[1] = get_input_data(p, 2, 16); + p->data2[2] = get_input_data(p, 4, 16); + p->data2[3] = get_input_data(p, 6, 16); +} + +/* update the hashtable entries. + * only call this after finding/adding the current template + * the dataN fields for the current 8 byte block must be already updated + */ +static void update_hashtables(struct sw842_param *p) +{ + u64 pos = p->in - p->instart; + u64 n8 = (pos >> 3) % (1 << I8_BITS); + u64 n4 = (pos >> 2) % (1 << I4_BITS); + u64 n2 = (pos >> 1) % (1 << I2_BITS); + + replace_hash(p, 8, n8, 0); + replace_hash(p, 4, n4, 0); + replace_hash(p, 4, n4, 1); + replace_hash(p, 2, n2, 0); + replace_hash(p, 2, n2, 1); + replace_hash(p, 2, n2, 2); + replace_hash(p, 2, n2, 3); +} + +/* find the next template to use, and add it + * the p->dataN fields must already be set for the current 8 byte block + */ +static int process_next(struct sw842_param *p) +{ + int ret, i; + + p->index8[0] = INDEX_NOT_CHECKED; + p->index4[0] = INDEX_NOT_CHECKED; + p->index4[1] = INDEX_NOT_CHECKED; + p->index2[0] = INDEX_NOT_CHECKED; + p->index2[1] = INDEX_NOT_CHECKED; + p->index2[2] = INDEX_NOT_CHECKED; + p->index2[3] = INDEX_NOT_CHECKED; + + /* check up to OPS_MAX - 1; last op is our fallback */ + for (i = 0; i < OPS_MAX - 1; i++) { + if (check_template(p, i)) + break; + } + + ret = add_template(p, i); + if (ret) + return ret; + + return 0; +} + +/** + * sw842_compress + * + * Compress the uncompressed buffer of length @ilen at @in to the output buffer + * @out, using no more than @olen bytes, using the 842 compression format. + * + * Returns: 0 on success, error on failure. The @olen parameter + * will contain the number of output bytes written on success, or + * 0 on error. + */ +int sw842_compress(const u8 *in, unsigned int ilen, + u8 *out, unsigned int *olen, void *wmem) +{ + struct sw842_param *p = (struct sw842_param *)wmem; + int ret; + u64 last, next, pad, total; + u8 repeat_count = 0; + u32 crc; + + BUILD_BUG_ON(sizeof(*p) > SW842_MEM_COMPRESS); + + init_hashtable_nodes(p, 8); + init_hashtable_nodes(p, 4); + init_hashtable_nodes(p, 2); + + p->in = (u8 *)in; + p->instart = p->in; + p->ilen = ilen; + p->out = out; + p->olen = *olen; + p->bit = 0; + + total = p->olen; + + *olen = 0; + + /* if using strict mode, we can only compress a multiple of 8 */ + if (sw842_strict && (ilen % 8)) { + pr_err("Using strict mode, can't compress len %d\n", ilen); + return -EINVAL; + } + + /* let's compress at least 8 bytes, mkay? */ + if (unlikely(ilen < 8)) + goto skip_comp; + + /* make initial 'last' different so we don't match the first time */ + last = ~get_unaligned((u64 *)p->in); + + while (p->ilen > 7) { + next = get_unaligned((u64 *)p->in); + + /* must get the next data, as we need to update the hashtable + * entries with the new data every time + */ + get_next_data(p); + + /* we don't care about endianness in last or next; + * we're just comparing 8 bytes to another 8 bytes, + * they're both the same endianness + */ + if (next == last) { + /* repeat count bits are 0-based, so we stop at +1 */ + if (++repeat_count <= REPEAT_BITS_MAX) + goto repeat; + } + if (repeat_count) { + ret = add_repeat_template(p, repeat_count); + repeat_count = 0; + if (next == last) /* reached max repeat bits */ + goto repeat; + } + + if (next == 0) + ret = add_zeros_template(p); + else + ret = process_next(p); + + if (ret) + return ret; + +repeat: + last = next; + update_hashtables(p); + p->in += 8; + p->ilen -= 8; + } + + if (repeat_count) { + ret = add_repeat_template(p, repeat_count); + if (ret) + return ret; + } + +skip_comp: + if (p->ilen > 0) { + ret = add_short_data_template(p, p->ilen); + if (ret) + return ret; + + p->in += p->ilen; + p->ilen = 0; + } + + ret = add_end_template(p); + if (ret) + return ret; + + /* + * crc(0:31) is appended to target data starting with the next + * bit after End of stream template. + * nx842 calculates CRC for data in big-endian format. So doing + * same here so that sw842 decompression can be used for both + * compressed data. + */ + crc = crc32_be(0, in, ilen); + ret = add_bits(p, crc, CRC_BITS); + if (ret) + return ret; + + if (p->bit) { + p->out++; + p->olen--; + p->bit = 0; + } + + /* pad compressed length to multiple of 8 */ + pad = (8 - ((total - p->olen) % 8)) % 8; + if (pad) { + if (pad > p->olen) /* we were so close! */ + return -ENOSPC; + memset(p->out, 0, pad); + p->out += pad; + p->olen -= pad; + } + + if (unlikely((total - p->olen) > UINT_MAX)) + return -ENOSPC; + + *olen = total - p->olen; + + return 0; +} +EXPORT_SYMBOL_GPL(sw842_compress); + +static int __init sw842_init(void) +{ + if (sw842_template_counts) + sw842_debugfs_create(); + + return 0; +} +module_init(sw842_init); + +static void __exit sw842_exit(void) +{ + if (sw842_template_counts) + sw842_debugfs_remove(); +} +module_exit(sw842_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Software 842 Compressor"); +MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>"); diff --git a/lib/842/842_debugfs.h b/lib/842/842_debugfs.h new file mode 100644 index 0000000000..4469407c3e --- /dev/null +++ b/lib/842/842_debugfs.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __842_DEBUGFS_H__ +#define __842_DEBUGFS_H__ + +#include <linux/debugfs.h> + +static bool sw842_template_counts; +module_param_named(template_counts, sw842_template_counts, bool, 0444); + +static atomic_t template_count[OPS_MAX], template_repeat_count, + template_zeros_count, template_short_data_count, template_end_count; + +static struct dentry *sw842_debugfs_root; + +static int __init sw842_debugfs_create(void) +{ + umode_t m = S_IRUGO | S_IWUSR; + int i; + + if (!debugfs_initialized()) + return -ENODEV; + + sw842_debugfs_root = debugfs_create_dir(MODULE_NAME, NULL); + + for (i = 0; i < ARRAY_SIZE(template_count); i++) { + char name[32]; + + snprintf(name, 32, "template_%02x", i); + debugfs_create_atomic_t(name, m, sw842_debugfs_root, + &template_count[i]); + } + debugfs_create_atomic_t("template_repeat", m, sw842_debugfs_root, + &template_repeat_count); + debugfs_create_atomic_t("template_zeros", m, sw842_debugfs_root, + &template_zeros_count); + debugfs_create_atomic_t("template_short_data", m, sw842_debugfs_root, + &template_short_data_count); + debugfs_create_atomic_t("template_end", m, sw842_debugfs_root, + &template_end_count); + + return 0; +} + +static void __exit sw842_debugfs_remove(void) +{ + debugfs_remove_recursive(sw842_debugfs_root); +} + +#endif diff --git a/lib/842/842_decompress.c b/lib/842/842_decompress.c new file mode 100644 index 0000000000..582085ef8b --- /dev/null +++ b/lib/842/842_decompress.c @@ -0,0 +1,417 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 842 Software Decompression + * + * Copyright (C) 2015 Dan Streetman, IBM Corp + * + * See 842.h for details of the 842 compressed format. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#define MODULE_NAME "842_decompress" + +#include "842.h" +#include "842_debugfs.h" + +/* rolling fifo sizes */ +#define I2_FIFO_SIZE (2 * (1 << I2_BITS)) +#define I4_FIFO_SIZE (4 * (1 << I4_BITS)) +#define I8_FIFO_SIZE (8 * (1 << I8_BITS)) + +static u8 decomp_ops[OPS_MAX][4] = { + { D8, N0, N0, N0 }, + { D4, D2, I2, N0 }, + { D4, I2, D2, N0 }, + { D4, I2, I2, N0 }, + { D4, I4, N0, N0 }, + { D2, I2, D4, N0 }, + { D2, I2, D2, I2 }, + { D2, I2, I2, D2 }, + { D2, I2, I2, I2 }, + { D2, I2, I4, N0 }, + { I2, D2, D4, N0 }, + { I2, D4, I2, N0 }, + { I2, D2, I2, D2 }, + { I2, D2, I2, I2 }, + { I2, D2, I4, N0 }, + { I2, I2, D4, N0 }, + { I2, I2, D2, I2 }, + { I2, I2, I2, D2 }, + { I2, I2, I2, I2 }, + { I2, I2, I4, N0 }, + { I4, D4, N0, N0 }, + { I4, D2, I2, N0 }, + { I4, I2, D2, N0 }, + { I4, I2, I2, N0 }, + { I4, I4, N0, N0 }, + { I8, N0, N0, N0 } +}; + +struct sw842_param { + u8 *in; + u8 bit; + u64 ilen; + u8 *out; + u8 *ostart; + u64 olen; +}; + +#define beN_to_cpu(d, s) \ + ((s) == 2 ? be16_to_cpu(get_unaligned((__be16 *)d)) : \ + (s) == 4 ? be32_to_cpu(get_unaligned((__be32 *)d)) : \ + (s) == 8 ? be64_to_cpu(get_unaligned((__be64 *)d)) : \ + 0) + +static int next_bits(struct sw842_param *p, u64 *d, u8 n); + +static int __split_next_bits(struct sw842_param *p, u64 *d, u8 n, u8 s) +{ + u64 tmp = 0; + int ret; + + if (n <= s) { + pr_debug("split_next_bits invalid n %u s %u\n", n, s); + return -EINVAL; + } + + ret = next_bits(p, &tmp, n - s); + if (ret) + return ret; + ret = next_bits(p, d, s); + if (ret) + return ret; + *d |= tmp << s; + return 0; +} + +static int next_bits(struct sw842_param *p, u64 *d, u8 n) +{ + u8 *in = p->in, b = p->bit, bits = b + n; + + if (n > 64) { + pr_debug("next_bits invalid n %u\n", n); + return -EINVAL; + } + + /* split this up if reading > 8 bytes, or if we're at the end of + * the input buffer and would read past the end + */ + if (bits > 64) + return __split_next_bits(p, d, n, 32); + else if (p->ilen < 8 && bits > 32 && bits <= 56) + return __split_next_bits(p, d, n, 16); + else if (p->ilen < 4 && bits > 16 && bits <= 24) + return __split_next_bits(p, d, n, 8); + + if (DIV_ROUND_UP(bits, 8) > p->ilen) + return -EOVERFLOW; + + if (bits <= 8) + *d = *in >> (8 - bits); + else if (bits <= 16) + *d = be16_to_cpu(get_unaligned((__be16 *)in)) >> (16 - bits); + else if (bits <= 32) + *d = be32_to_cpu(get_unaligned((__be32 *)in)) >> (32 - bits); + else + *d = be64_to_cpu(get_unaligned((__be64 *)in)) >> (64 - bits); + + *d &= GENMASK_ULL(n - 1, 0); + + p->bit += n; + + if (p->bit > 7) { + p->in += p->bit / 8; + p->ilen -= p->bit / 8; + p->bit %= 8; + } + + return 0; +} + +static int do_data(struct sw842_param *p, u8 n) +{ + u64 v; + int ret; + + if (n > p->olen) + return -ENOSPC; + + ret = next_bits(p, &v, n * 8); + if (ret) + return ret; + + switch (n) { + case 2: + put_unaligned(cpu_to_be16((u16)v), (__be16 *)p->out); + break; + case 4: + put_unaligned(cpu_to_be32((u32)v), (__be32 *)p->out); + break; + case 8: + put_unaligned(cpu_to_be64((u64)v), (__be64 *)p->out); + break; + default: + return -EINVAL; + } + + p->out += n; + p->olen -= n; + + return 0; +} + +static int __do_index(struct sw842_param *p, u8 size, u8 bits, u64 fsize) +{ + u64 index, offset, total = round_down(p->out - p->ostart, 8); + int ret; + + ret = next_bits(p, &index, bits); + if (ret) + return ret; + + offset = index * size; + + /* a ring buffer of fsize is used; correct the offset */ + if (total > fsize) { + /* this is where the current fifo is */ + u64 section = round_down(total, fsize); + /* the current pos in the fifo */ + u64 pos = total - section; + + /* if the offset is past/at the pos, we need to + * go back to the last fifo section + */ + if (offset >= pos) + section -= fsize; + + offset += section; + } + + if (offset + size > total) { + pr_debug("index%x %lx points past end %lx\n", size, + (unsigned long)offset, (unsigned long)total); + return -EINVAL; + } + + if (size != 2 && size != 4 && size != 8) + WARN(1, "__do_index invalid size %x\n", size); + else + pr_debug("index%x to %lx off %lx adjoff %lx tot %lx data %lx\n", + size, (unsigned long)index, + (unsigned long)(index * size), (unsigned long)offset, + (unsigned long)total, + (unsigned long)beN_to_cpu(&p->ostart[offset], size)); + + memcpy(p->out, &p->ostart[offset], size); + p->out += size; + p->olen -= size; + + return 0; +} + +static int do_index(struct sw842_param *p, u8 n) +{ + switch (n) { + case 2: + return __do_index(p, 2, I2_BITS, I2_FIFO_SIZE); + case 4: + return __do_index(p, 4, I4_BITS, I4_FIFO_SIZE); + case 8: + return __do_index(p, 8, I8_BITS, I8_FIFO_SIZE); + default: + return -EINVAL; + } +} + +static int do_op(struct sw842_param *p, u8 o) +{ + int i, ret = 0; + + if (o >= OPS_MAX) + return -EINVAL; + + for (i = 0; i < 4; i++) { + u8 op = decomp_ops[o][i]; + + pr_debug("op is %x\n", op); + + switch (op & OP_ACTION) { + case OP_ACTION_DATA: + ret = do_data(p, op & OP_AMOUNT); + break; + case OP_ACTION_INDEX: + ret = do_index(p, op & OP_AMOUNT); + break; + case OP_ACTION_NOOP: + break; + default: + pr_err("Internal error, invalid op %x\n", op); + return -EINVAL; + } + + if (ret) + return ret; + } + + if (sw842_template_counts) + atomic_inc(&template_count[o]); + + return 0; +} + +/** + * sw842_decompress + * + * Decompress the 842-compressed buffer of length @ilen at @in + * to the output buffer @out, using no more than @olen bytes. + * + * The compressed buffer must be only a single 842-compressed buffer, + * with the standard format described in the comments in 842.h + * Processing will stop when the 842 "END" template is detected, + * not the end of the buffer. + * + * Returns: 0 on success, error on failure. The @olen parameter + * will contain the number of output bytes written on success, or + * 0 on error. + */ +int sw842_decompress(const u8 *in, unsigned int ilen, + u8 *out, unsigned int *olen) +{ + struct sw842_param p; + int ret; + u64 op, rep, tmp, bytes, total; + u64 crc; + + p.in = (u8 *)in; + p.bit = 0; + p.ilen = ilen; + p.out = out; + p.ostart = out; + p.olen = *olen; + + total = p.olen; + + *olen = 0; + + do { + ret = next_bits(&p, &op, OP_BITS); + if (ret) + return ret; + + pr_debug("template is %lx\n", (unsigned long)op); + + switch (op) { + case OP_REPEAT: + ret = next_bits(&p, &rep, REPEAT_BITS); + if (ret) + return ret; + + if (p.out == out) /* no previous bytes */ + return -EINVAL; + + /* copy rep + 1 */ + rep++; + + if (rep * 8 > p.olen) + return -ENOSPC; + + while (rep-- > 0) { + memcpy(p.out, p.out - 8, 8); + p.out += 8; + p.olen -= 8; + } + + if (sw842_template_counts) + atomic_inc(&template_repeat_count); + + break; + case OP_ZEROS: + if (8 > p.olen) + return -ENOSPC; + + memset(p.out, 0, 8); + p.out += 8; + p.olen -= 8; + + if (sw842_template_counts) + atomic_inc(&template_zeros_count); + + break; + case OP_SHORT_DATA: + ret = next_bits(&p, &bytes, SHORT_DATA_BITS); + if (ret) + return ret; + + if (!bytes || bytes > SHORT_DATA_BITS_MAX) + return -EINVAL; + + while (bytes-- > 0) { + ret = next_bits(&p, &tmp, 8); + if (ret) + return ret; + *p.out = (u8)tmp; + p.out++; + p.olen--; + } + + if (sw842_template_counts) + atomic_inc(&template_short_data_count); + + break; + case OP_END: + if (sw842_template_counts) + atomic_inc(&template_end_count); + + break; + default: /* use template */ + ret = do_op(&p, op); + if (ret) + return ret; + break; + } + } while (op != OP_END); + + /* + * crc(0:31) is saved in compressed data starting with the + * next bit after End of stream template. + */ + ret = next_bits(&p, &crc, CRC_BITS); + if (ret) + return ret; + + /* + * Validate CRC saved in compressed data. + */ + if (crc != (u64)crc32_be(0, out, total - p.olen)) { + pr_debug("CRC mismatch for decompression\n"); + return -EINVAL; + } + + if (unlikely((total - p.olen) > UINT_MAX)) + return -ENOSPC; + + *olen = total - p.olen; + + return 0; +} +EXPORT_SYMBOL_GPL(sw842_decompress); + +static int __init sw842_init(void) +{ + if (sw842_template_counts) + sw842_debugfs_create(); + + return 0; +} +module_init(sw842_init); + +static void __exit sw842_exit(void) +{ + if (sw842_template_counts) + sw842_debugfs_remove(); +} +module_exit(sw842_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Software 842 Decompressor"); +MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>"); diff --git a/lib/842/Makefile b/lib/842/Makefile new file mode 100644 index 0000000000..6f7aad2692 --- /dev/null +++ b/lib/842/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_842_COMPRESS) += 842_compress.o +obj-$(CONFIG_842_DECOMPRESS) += 842_decompress.o |