openwrt-xburst/target/linux/generic-2.6/patches-2.6.30/052-pcomp_lzma_support.patch

--- /dev/null
+++ b/crypto/unlzma.c
@@ -0,0 +1,748 @@
+/*
+ * LZMA uncompresion module for pcomp
+ * Copyright (C) 2009  Felix Fietkau <nbd@openwrt.org>
+ *
+ * Based on:
+ *  Initial Linux kernel adaptation
+ *  Copyright (C) 2006  Alain < alain@knaff.lu >
+ *
+ *  Based on small lzma deflate implementation/Small range coder
+ *  implementation for lzma.
+ *  Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
+ *
+ *  Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
+ *  Copyright (C) 1999-2005  Igor Pavlov
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * FIXME: the current implementation assumes that the caller will
+ * not free any output buffers until the whole decompression has been
+ * completed. This is necessary, because LZMA looks back at old output
+ * instead of doing a separate dictionary allocation, which saves RAM.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <linux/kthread.h>
+
+#include <crypto/internal/compress.h>
+#include <net/netlink.h>
+#include "unlzma.h"
+
+static int instance = 0;
+
+struct unlzma_buffer {
+	int offset;
+	int size;
+	u8 *ptr;
+};
+
+struct unlzma_ctx {
+	struct task_struct *thread;
+	wait_queue_head_t next_req;
+	struct mutex mutex;
+	bool active;
+	bool cancel;
+
+	const u8 *next_in;
+	int avail_in;
+
+	u8 *next_out;
+	int avail_out;
+
+	/* reader state */
+	u32 code;
+	u32 range;
+	u32 bound;
+
+	/* writer state */
+	u8 previous_byte;
+	ssize_t pos;
+	int buf_full;
+	int n_buffers;
+	int buffers_max;
+	struct unlzma_buffer *buffers;
+
+	/* cstate */
+	int state;
+	u32 rep0, rep1, rep2, rep3;
+
+	u32 dict_size;
+
+	void *workspace;
+	int workspace_size;
+};
+
+static inline bool
+unlzma_should_stop(struct unlzma_ctx *ctx)
+{
+	return unlikely(kthread_should_stop() || ctx->cancel);
+}
+
+static void
+get_buffer(struct unlzma_ctx *ctx)
+{
+	struct unlzma_buffer *bh;
+
+	BUG_ON(ctx->n_buffers >= ctx->buffers_max);
+	bh = &ctx->buffers[ctx->n_buffers++];
+	bh->ptr = ctx->next_out;
+	bh->offset = ctx->pos;
+	bh->size = ctx->avail_out;
+	ctx->buf_full = 0;
+}
+
+static void
+unlzma_request_buffer(struct unlzma_ctx *ctx, int *avail)
+{
+	do {
+		mutex_unlock(&ctx->mutex);
+		if (wait_event_interruptible(ctx->next_req,
+			unlzma_should_stop(ctx) || (*avail > 0)))
+			schedule();
+		mutex_lock(&ctx->mutex);
+	} while (*avail <= 0 && !unlzma_should_stop(ctx));
+
+	if (!unlzma_should_stop(ctx) && ctx->buf_full)
+		get_buffer(ctx);
+}
+
+static u8
+rc_read(struct unlzma_ctx *ctx)
+{
+	if (unlikely(ctx->avail_in <= 0))
+		unlzma_request_buffer(ctx, &ctx->avail_in);
+
+	if (unlzma_should_stop(ctx))
+		return 0;
+
+	ctx->avail_in--;
+	return *(ctx->next_in++);
+}
+
+
+static inline void
+rc_get_code(struct unlzma_ctx *ctx)
+{
+	ctx->code = (ctx->code << 8) | rc_read(ctx);
+}
+
+static void
+rc_normalize(struct unlzma_ctx *ctx)
+{
+	if (ctx->range < (1 << RC_TOP_BITS)) {
+		ctx->range <<= 8;
+		rc_get_code(ctx);
+	}
+}
+
+static int
+rc_is_bit_0(struct unlzma_ctx *ctx, u16 *p)
+{
+	rc_normalize(ctx);
+	ctx->bound = *p * (ctx->range >> RC_MODEL_TOTAL_BITS);
+	return ctx->code < ctx->bound;
+}
+
+static void
+rc_update_bit_0(struct unlzma_ctx *ctx, u16 *p)
+{
+	ctx->range = ctx->bound;
+	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
+}
+
+static void
+rc_update_bit_1(struct unlzma_ctx *ctx, u16 *p)
+{
+	ctx->range -= ctx->bound;
+	ctx->code -= ctx->bound;
+	*p -= *p >> RC_MOVE_BITS;
+}
+
+static bool
+rc_get_bit(struct unlzma_ctx *ctx, u16 *p, int *symbol)
+{
+	if (rc_is_bit_0(ctx, p)) {
+		rc_update_bit_0(ctx, p);
+		*symbol *= 2;
+		return 0;
+	} else {
+		rc_update_bit_1(ctx, p);
+		*symbol = *symbol * 2 + 1;
+		return 1;
+	}
+}
+
+static int
+rc_direct_bit(struct unlzma_ctx *ctx)
+{
+	rc_normalize(ctx);
+	ctx->range >>= 1;
+	if (ctx->code >= ctx->range) {
+		ctx->code -= ctx->range;
+		return 1;
+	}
+	return 0;
+}
+
+static void
+rc_bit_tree_decode(struct unlzma_ctx *ctx, u16 *p, int num_levels, int *symbol)
+{
+	int i = num_levels;
+
+	*symbol = 1;
+	while (i--)
+		rc_get_bit(ctx, p + *symbol, symbol);
+	*symbol -= 1 << num_levels;
+}
+
+static u8
+peek_old_byte(struct unlzma_ctx *ctx, u32 offs)
+{
+	struct unlzma_buffer *bh = &ctx->buffers[ctx->n_buffers - 1];
+	int i = ctx->n_buffers;
+	u32 pos;
+
+	BUG_ON(!ctx->n_buffers);
+	pos = ctx->pos - offs;
+	if (pos >= ctx->dict_size) {
+		pos = (~pos % ctx->dict_size);
+	}
+
+	while (bh->offset > pos) {
+		bh--;
+		i--;
+		BUG_ON(!i);
+	}
+
+	pos -= bh->offset;
+	BUG_ON(pos >= bh->size);
+
+	return bh->ptr[pos];
+}
+
+static void
+write_byte(struct unlzma_ctx *ctx, u8 byte)
+{
+	if (unlikely(ctx->avail_out <= 0)) {
+		unlzma_request_buffer(ctx, &ctx->avail_out);
+	}
+
+	if (!ctx->avail_out)
+		return;
+
+	ctx->previous_byte = byte;
+	*(ctx->next_out++) = byte;
+	ctx->avail_out--;
+	if (ctx->avail_out == 0)
+		ctx->buf_full = 1;
+	ctx->pos++;
+}
+
+
+static inline void
+copy_byte(struct unlzma_ctx *ctx, u32 offs)
+{
+	write_byte(ctx, peek_old_byte(ctx, offs));
+}
+
+static void
+copy_bytes(struct unlzma_ctx *ctx, u32 rep0, int len)
+{
+	do {
+		copy_byte(ctx, rep0);
+		len--;
+		if (unlzma_should_stop(ctx))
+			break;
+	} while (len != 0);
+}
+
+static void
+process_bit0(struct unlzma_ctx *ctx, u16 *p, int pos_state, u16 *prob,
+             int lc, u32 literal_pos_mask)
+{
+	int mi = 1;
+	rc_update_bit_0(ctx, prob);
+	prob = (p + LZMA_LITERAL +
+		(LZMA_LIT_SIZE
+		 * (((ctx->pos & literal_pos_mask) << lc)
+		    + (ctx->previous_byte >> (8 - lc))))
+		);
+
+	if (ctx->state >= LZMA_NUM_LIT_STATES) {
+		int match_byte = peek_old_byte(ctx, ctx->rep0);
+		do {
+			u16 bit;
+			u16 *prob_lit;
+
+			match_byte <<= 1;
+			bit = match_byte & 0x100;
+			prob_lit = prob + 0x100 + bit + mi;
+			if (rc_get_bit(ctx, prob_lit, &mi) != !!bit)
+				break;
+		} while (mi < 0x100);
+	}
+	while (mi < 0x100) {
+		u16 *prob_lit = prob + mi;
+		rc_get_bit(ctx, prob_lit, &mi);
+	}
+	write_byte(ctx, mi);
+	if (ctx->state < 4)
+		ctx->state = 0;
+	else if (ctx->state < 10)
+		ctx->state -= 3;
+	else
+		ctx->state -= 6;
+}
+
+static void
+process_bit1(struct unlzma_ctx *ctx, u16 *p, int pos_state, u16 *prob)
+{
+	int offset;
+	u16 *prob_len;
+	int num_bits;
+	int len;
+
+	rc_update_bit_1(ctx, prob);
+	prob = p + LZMA_IS_REP + ctx->state;
+	if (rc_is_bit_0(ctx, prob)) {
+		rc_update_bit_0(ctx, prob);
+		ctx->rep3 = ctx->rep2;
+		ctx->rep2 = ctx->rep1;
+		ctx->rep1 = ctx->rep0;
+		ctx->state = ctx->state < LZMA_NUM_LIT_STATES ? 0 : 3;
+		prob = p + LZMA_LEN_CODER;
+	} else {
+		rc_update_bit_1(ctx, prob);
+		prob = p + LZMA_IS_REP_G0 + ctx->state;
+		if (rc_is_bit_0(ctx, prob)) {
+			rc_update_bit_0(ctx, prob);
+			prob = (p + LZMA_IS_REP_0_LONG
+				+ (ctx->state <<
+				   LZMA_NUM_POS_BITS_MAX) +
+				pos_state);
+			if (rc_is_bit_0(ctx, prob)) {
+				rc_update_bit_0(ctx, prob);
+
+				ctx->state = ctx->state < LZMA_NUM_LIT_STATES ?
+					9 : 11;
+				copy_byte(ctx, ctx->rep0);
+				return;
+			} else {
+				rc_update_bit_1(ctx, prob);
+			}
+		} else {
+			u32 distance;
+
+			rc_update_bit_1(ctx, prob);
+			prob = p + LZMA_IS_REP_G1 + ctx->state;
+			if (rc_is_bit_0(ctx, prob)) {
+				rc_update_bit_0(ctx, prob);
+				distance = ctx->rep1;
+			} else {
+				rc_update_bit_1(ctx, prob);
+				prob = p + LZMA_IS_REP_G2 + ctx->state;
+				if (rc_is_bit_0(ctx, prob)) {
+					rc_update_bit_0(ctx, prob);
+					distance = ctx->rep2;
+				} else {
+					rc_update_bit_1(ctx, prob);
+					distance = ctx->rep3;
+					ctx->rep3 = ctx->rep2;
+				}
+				ctx->rep2 = ctx->rep1;
+			}
+			ctx->rep1 = ctx->rep0;
+			ctx->rep0 = distance;
+		}
+		ctx->state = ctx->state < LZMA_NUM_LIT_STATES ? 8 : 11;
+		prob = p + LZMA_REP_LEN_CODER;
+	}
+
+	prob_len = prob + LZMA_LEN_CHOICE;
+	if (rc_is_bit_0(ctx, prob_len)) {
+		rc_update_bit_0(ctx, prob_len);
+		prob_len = (prob + LZMA_LEN_LOW
+			    + (pos_state <<
+			       LZMA_LEN_NUM_LOW_BITS));
+		offset = 0;
+		num_bits = LZMA_LEN_NUM_LOW_BITS;
+	} else {
+		rc_update_bit_1(ctx, prob_len);
+		prob_len = prob + LZMA_LEN_CHOICE_2;
+		if (rc_is_bit_0(ctx, prob_len)) {
+			rc_update_bit_0(ctx, prob_len);
+			prob_len = (prob + LZMA_LEN_MID
+				    + (pos_state <<
+				       LZMA_LEN_NUM_MID_BITS));
+			offset = 1 << LZMA_LEN_NUM_LOW_BITS;
+			num_bits = LZMA_LEN_NUM_MID_BITS;
+		} else {
+			rc_update_bit_1(ctx, prob_len);
+			prob_len = prob + LZMA_LEN_HIGH;
+			offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
+				  + (1 << LZMA_LEN_NUM_MID_BITS));
+			num_bits = LZMA_LEN_NUM_HIGH_BITS;
+		}
+	}
+
+	rc_bit_tree_decode(ctx, prob_len, num_bits, &len);
+	len += offset;
+
+	if (ctx->state < 4) {
+		int pos_slot;
+
+		ctx->state += LZMA_NUM_LIT_STATES;
+		prob =
+			p + LZMA_POS_SLOT +
+			((len <
+			  LZMA_NUM_LEN_TO_POS_STATES ? len :
+			  LZMA_NUM_LEN_TO_POS_STATES - 1)
+			 << LZMA_NUM_POS_SLOT_BITS);
+		rc_bit_tree_decode(ctx, prob,
+				   LZMA_NUM_POS_SLOT_BITS,
+				   &pos_slot);
+		if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
+			int i, mi;
+			num_bits = (pos_slot >> 1) - 1;
+			ctx->rep0 = 2 | (pos_slot & 1);
+			if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
+				ctx->rep0 <<= num_bits;
+				prob = p + LZMA_SPEC_POS +
+					ctx->rep0 - pos_slot - 1;
+			} else {
+				num_bits -= LZMA_NUM_ALIGN_BITS;
+				while (num_bits--)
+					ctx->rep0 = (ctx->rep0 << 1) |
+						rc_direct_bit(ctx);
+				prob = p + LZMA_ALIGN;
+				ctx->rep0 <<= LZMA_NUM_ALIGN_BITS;
+				num_bits = LZMA_NUM_ALIGN_BITS;
+			}
+			i = 1;
+			mi = 1;
+			while (num_bits--) {
+				if (rc_get_bit(ctx, prob + mi, &mi))
+					ctx->rep0 |= i;
+				i <<= 1;
+			}
+		} else
+			ctx->rep0 = pos_slot;
+		if (++(ctx->rep0) == 0)
+			return;
+	}
+
+	len += LZMA_MATCH_MIN_LEN;
+
+	copy_bytes(ctx, ctx->rep0, len);
+}
+
+
+static int
+do_unlzma(struct unlzma_ctx *ctx)
+{
+	u8 hdr_buf[sizeof(struct lzma_header)];
+	struct lzma_header *header = (struct lzma_header *)hdr_buf;
+	u32 pos_state_mask;
+	u32 literal_pos_mask;
+	int lc, pb, lp;
+	int num_probs;
+	int i, mi;
+	u16 *p;
+
+	for (i = 0; i < sizeof(struct lzma_header); i++) {
+		hdr_buf[i] = rc_read(ctx);
+	}
+
+	ctx->n_buffers = 0;
+	ctx->pos = 0;
+	get_buffer(ctx);
+	ctx->active = true;
+	ctx->state = 0;
+	ctx->rep0 = ctx->rep1 = ctx->rep2 = ctx->rep3 = 1;
+
+	ctx->previous_byte = 0;
+	ctx->code = 0;
+	ctx->range = 0xFFFFFFFF;
+
+	ctx->dict_size = le32_to_cpu(header->dict_size);
+
+	if (header->pos >= (9 * 5 * 5))
+		return -1;
+
+	mi = 0;
+	lc = header->pos;
+	while (lc >= 9) {
+		mi++;
+		lc -= 9;
+	}
+	pb = 0;
+	lp = mi;
+	while (lp >= 5) {
+		pb++;
+		lp -= 5;
+	}
+	pos_state_mask = (1 << pb) - 1;
+	literal_pos_mask = (1 << lp) - 1;
+
+	if (ctx->dict_size == 0)
+		ctx->dict_size = 1;
+
+	num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
+	if (ctx->workspace_size < num_probs * sizeof(*p)) {
+		if (ctx->workspace)
+			vfree(ctx->workspace);
+		ctx->workspace_size = num_probs * sizeof(*p);
+		ctx->workspace = vmalloc(ctx->workspace_size);
+	}
+	p = (u16 *) ctx->workspace;
+	if (!p)
+		return -1;
+
+	num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
+	for (i = 0; i < num_probs; i++)
+		p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
+
+	for (i = 0; i < 5; i++)
+		rc_get_code(ctx);
+
+	while (1) {
+		int pos_state =	ctx->pos & pos_state_mask;
+		u16 *prob = p + LZMA_IS_MATCH +
+			(ctx->state << LZMA_NUM_POS_BITS_MAX) + pos_state;
+		if (rc_is_bit_0(ctx, prob))
+			process_bit0(ctx, p, pos_state, prob,
+				     lc, literal_pos_mask);
+		else {
+			process_bit1(ctx, p, pos_state, prob);
+			if (ctx->rep0 == 0)
+				break;
+		}
+		if (unlzma_should_stop(ctx))
+			break;
+	}
+	if (likely(!unlzma_should_stop(ctx)))
+		rc_normalize(ctx);
+
+	return ctx->pos;
+}
+
+
+static void
+unlzma_reset_buf(struct unlzma_ctx *ctx)
+{
+	ctx->avail_in = 0;
+	ctx->next_in = NULL;
+	ctx->avail_out = 0;
+	ctx->next_out = NULL;
+}
+
+static int
+unlzma_thread(void *data)
+{
+	struct unlzma_ctx *ctx = data;
+
+	mutex_lock(&ctx->mutex);
+	do {
+		if (do_unlzma(ctx) < 0)
+			ctx->pos = 0;
+		unlzma_reset_buf(ctx);
+		ctx->cancel = false;
+		ctx->active = false;
+	} while (!kthread_should_stop());
+	mutex_unlock(&ctx->mutex);
+	return 0;
+}
+
+
+static int
+unlzma_init(struct crypto_tfm *tfm)
+{
+	return 0;
+}
+
+static void
+unlzma_cancel(struct unlzma_ctx *ctx)
+{
+	unlzma_reset_buf(ctx);
+
+	if (!ctx->active)
+		return;
+
+	ctx->cancel = true;
+	do {
+		mutex_unlock(&ctx->mutex);
+		wake_up(&ctx->next_req);
+		schedule();
+		mutex_lock(&ctx->mutex);
+	} while (ctx->cancel);
+}
+
+
+static void
+unlzma_exit(struct crypto_tfm *tfm)
+{
+	struct unlzma_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (ctx->thread) {
+		unlzma_cancel(ctx);
+		kthread_stop(ctx->thread);
+		ctx->thread = NULL;
+		if (ctx->buffers)
+			kfree(ctx->buffers);
+		ctx->buffers_max = 0;
+		ctx->buffers = NULL;
+	}
+}
+
+static int
+unlzma_decompress_setup(struct crypto_pcomp *tfm, void *p, unsigned int len)
+{
+	struct unlzma_ctx *ctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
+	struct nlattr *tb[UNLZMA_DECOMP_MAX + 1];
+	int ret = 0;
+
+	if (ctx->thread)
+		return -EINVAL;
+
+	if (!p)
+		return -EINVAL;
+
+	ret = nla_parse(tb, UNLZMA_DECOMP_MAX, p, len, NULL);
+	if (!tb[UNLZMA_DECOMP_OUT_BUFFERS])
+		return -EINVAL;
+
+	if (ctx->buffers_max && (ctx->buffers_max <
+	    nla_get_u32(tb[UNLZMA_DECOMP_OUT_BUFFERS]))) {
+		kfree(ctx->buffers);
+		ctx->buffers_max = 0;
+		ctx->buffers = NULL;
+	}
+	if (!ctx->buffers) {
+		ctx->buffers_max = nla_get_u32(tb[UNLZMA_DECOMP_OUT_BUFFERS]);
+		ctx->buffers = kzalloc(sizeof(struct unlzma_buffer) * ctx->buffers_max, GFP_KERNEL);
+	}
+	if (!ctx->buffers)
+		return -ENOMEM;
+
+	mutex_init(&ctx->mutex);
+	init_waitqueue_head(&ctx->next_req);
+	ctx->thread = kthread_run(unlzma_thread, ctx, "unlzma/%d", instance++);
+	if (IS_ERR(ctx->thread)) {
+		ret = PTR_ERR(ctx->thread);
+		ctx->thread = NULL;
+	}
+
+	return ret;
+}
+
+static int
+unlzma_decompress_init(struct crypto_pcomp *tfm)
+{
+	struct unlzma_ctx *ctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
+
+	ctx->pos = 0;
+	return 0;
+}
+
+static void
+unlzma_wait_complete(struct unlzma_ctx *ctx, bool finish)
+{
+	do {
+		mutex_unlock(&ctx->mutex);
+		wake_up(&ctx->next_req);
+		schedule();
+		mutex_lock(&ctx->mutex);
+	} while (ctx->active &&	(ctx->avail_in > 0) && (ctx->avail_out > 0));
+}
+
+static int
+unlzma_decompress_update(struct crypto_pcomp *tfm, struct comp_request *req)
+{
+	struct unlzma_ctx *ctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
+	size_t pos = 0;
+
+	mutex_lock(&ctx->mutex);
+	if (!ctx->active && !req->avail_in)
+		goto out;
+
+	pos = ctx->pos;
+	ctx->next_in = req->next_in;
+	ctx->avail_in = req->avail_in;
+	ctx->next_out = req->next_out;
+	ctx->avail_out = req->avail_out;
+
+	unlzma_wait_complete(ctx, false);
+
+	req->next_in = ctx->next_in;
+	req->avail_in = ctx->avail_in;
+	req->next_out = ctx->next_out;
+	req->avail_out = ctx->avail_out;
+	ctx->next_in = 0;
+	ctx->avail_in = 0;
+	pos = ctx->pos - pos;
+
+out:
+	mutex_unlock(&ctx->mutex);
+	return pos;
+}
+
+static int
+unlzma_decompress_final(struct crypto_pcomp *tfm, struct comp_request *req)
+{
+	struct unlzma_ctx *ctx = crypto_tfm_ctx(crypto_pcomp_tfm(tfm));
+	int ret = 0;
+
+	/* cancel pending operation */
+	mutex_lock(&ctx->mutex);
+	if (ctx->active) {
+		// ret = -EINVAL;
+		unlzma_cancel(ctx);
+	}
+	ctx->pos = 0;
+	mutex_unlock(&ctx->mutex);
+	return ret;
+}
+
+
+static struct pcomp_alg unlzma_alg = {
+	.decompress_setup	= unlzma_decompress_setup,
+	.decompress_init	= unlzma_decompress_init,
+	.decompress_update	= unlzma_decompress_update,
+	.decompress_final	= unlzma_decompress_final,
+
+	.base			= {
+		.cra_name	= "lzma",
+		.cra_flags	= CRYPTO_ALG_TYPE_PCOMPRESS,
+		.cra_ctxsize	= sizeof(struct unlzma_ctx),
+		.cra_module	= THIS_MODULE,
+		.cra_init	= unlzma_init,
+		.cra_exit	= unlzma_exit,
+	}
+};
+
+static int __init
+unlzma_mod_init(void)
+{
+	return crypto_register_pcomp(&unlzma_alg);
+}
+
+static void __exit
+unlzma_mod_exit(void)
+{
+	crypto_unregister_pcomp(&unlzma_alg);
+}
+
+module_init(unlzma_mod_init);
+module_exit(unlzma_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZMA Decompression Algorithm");
+MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -758,6 +758,12 @@ config CRYPTO_ZLIB
 	help
 	  This is the zlib algorithm.
 
+config CRYPTO_UNLZMA
+	tristate "LZMA decompression"
+	select CRYPTO_PCOMP
+	help
+	  This is the lzma decompression module.
+
 config CRYPTO_LZO
 	tristate "LZO compression algorithm"
 	select CRYPTO_ALGAPI
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_CRYPTO_SEED) += seed.o
 obj-$(CONFIG_CRYPTO_SALSA20) += salsa20_generic.o
 obj-$(CONFIG_CRYPTO_DEFLATE) += deflate.o
 obj-$(CONFIG_CRYPTO_ZLIB) += zlib.o
+obj-$(CONFIG_CRYPTO_UNLZMA) += unlzma.o
 obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
 obj-$(CONFIG_CRYPTO_CRC32C) += crc32c.o
 obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o
--- /dev/null
+++ b/crypto/unlzma.h
@@ -0,0 +1,80 @@
+/* LZMA uncompresion module for pcomp
+ * Copyright (C) 2009  Felix Fietkau <nbd@openwrt.org>
+ *
+ * Based on:
+ *  Initial Linux kernel adaptation
+ *  Copyright (C) 2006  Alain < alain@knaff.lu >
+ *
+ *  Based on small lzma deflate implementation/Small range coder
+ *  implementation for lzma.
+ *  Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
+ *
+ *  Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
+ *  Copyright (C) 1999-2005  Igor Pavlov
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+#ifndef __UNLZMA_H
+#define __UNLZMA_H
+
+struct lzma_header {
+	__u8 pos;
+	__le32 dict_size;
+} __attribute__ ((packed)) ;
+
+
+#define RC_TOP_BITS 24
+#define RC_MOVE_BITS 5
+#define RC_MODEL_TOTAL_BITS 11
+
+#define LZMA_BASE_SIZE 1846
+#define LZMA_LIT_SIZE 768
+
+#define LZMA_NUM_POS_BITS_MAX 4
+
+#define LZMA_LEN_NUM_LOW_BITS 3
+#define LZMA_LEN_NUM_MID_BITS 3
+#define LZMA_LEN_NUM_HIGH_BITS 8
+
+#define LZMA_LEN_CHOICE 0
+#define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
+#define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
+#define LZMA_LEN_MID (LZMA_LEN_LOW \
+		      + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
+#define LZMA_LEN_HIGH (LZMA_LEN_MID \
+		       +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
+#define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
+
+#define LZMA_NUM_STATES 12
+#define LZMA_NUM_LIT_STATES 7
+
+#define LZMA_START_POS_MODEL_INDEX 4
+#define LZMA_END_POS_MODEL_INDEX 14
+#define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
+
+#define LZMA_NUM_POS_SLOT_BITS 6
+#define LZMA_NUM_LEN_TO_POS_STATES 4
+
+#define LZMA_NUM_ALIGN_BITS 4
+
+#define LZMA_MATCH_MIN_LEN 2
+
+#define LZMA_IS_MATCH 0
+#define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
+#define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
+#define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
+#define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
+#define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
+#define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
+		       + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
+#define LZMA_SPEC_POS (LZMA_POS_SLOT \
+		       +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
+#define LZMA_ALIGN (LZMA_SPEC_POS \
+		    + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
+#define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
+#define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
+#define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
+
+#endif
--- a/include/crypto/compress.h
+++ b/include/crypto/compress.h
@@ -49,6 +49,12 @@ enum zlib_decomp_params {
 
 #define ZLIB_DECOMP_MAX	(__ZLIB_DECOMP_MAX - 1)
 
+enum unlzma_decomp_params {
+	UNLZMA_DECOMP_OUT_BUFFERS = 1, /* naximum number of output buffers */
+	__UNLZMA_DECOMP_MAX,
+};
+#define UNLZMA_DECOMP_MAX	(__UNLZMA_DECOMP_MAX - 1)
+
 
 struct crypto_pcomp {
 	struct crypto_tfm base;