summaryrefslogtreecommitdiffstats
path: root/lib/842
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--lib/842/842.h130
-rw-r--r--lib/842/842_compress.c630
-rw-r--r--lib/842/842_debugfs.h50
-rw-r--r--lib/842/842_decompress.c417
-rw-r--r--lib/842/Makefile3
5 files changed, 1230 insertions, 0 deletions
diff --git a/lib/842/842.h b/lib/842/842.h
new file mode 100644
index 000000000..7b1f581a2
--- /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 000000000..c02baa416
--- /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 000000000..4469407c3
--- /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 000000000..582085ef8
--- /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 000000000..6f7aad269
--- /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
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-20 04:11:08 +0000