diff options
Diffstat (limited to 'drivers/crypto/nx/nx-842-crypto.c')
| -rw-r--r-- | drivers/crypto/nx/nx-842-crypto.c | 580 |
1 files changed, 580 insertions, 0 deletions
diff --git a/drivers/crypto/nx/nx-842-crypto.c b/drivers/crypto/nx/nx-842-crypto.c new file mode 100644 index 000000000..d53a1dcd7 --- /dev/null +++ b/drivers/crypto/nx/nx-842-crypto.c @@ -0,0 +1,580 @@ +/* + * Cryptographic API for the NX-842 hardware compression. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Copyright (C) IBM Corporation, 2011-2015 + * + * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com> + * Seth Jennings <sjenning@linux.vnet.ibm.com> + * + * Rewrite: Dan Streetman <ddstreet@ieee.org> + * + * This is an interface to the NX-842 compression hardware in PowerPC + * processors. Most of the complexity of this drvier is due to the fact that + * the NX-842 compression hardware requires the input and output data buffers + * to be specifically aligned, to be a specific multiple in length, and within + * specific minimum and maximum lengths. Those restrictions, provided by the + * nx-842 driver via nx842_constraints, mean this driver must use bounce + * buffers and headers to correct misaligned in or out buffers, and to split + * input buffers that are too large. + * + * This driver will fall back to software decompression if the hardware + * decompression fails, so this driver's decompression should never fail as + * long as the provided compressed buffer is valid. Any compressed buffer + * created by this driver will have a header (except ones where the input + * perfectly matches the constraints); so users of this driver cannot simply + * pass a compressed buffer created by this driver over to the 842 software + * decompression library. Instead, users must use this driver to decompress; + * if the hardware fails or is unavailable, the compressed buffer will be + * parsed and the header removed, and the raw 842 buffer(s) passed to the 842 + * software decompression library. + * + * This does not fall back to software compression, however, since the caller + * of this function is specifically requesting hardware compression; if the + * hardware compression fails, the caller can fall back to software + * compression, and the raw 842 compressed buffer that the software compressor + * creates can be passed to this driver for hardware decompression; any + * buffer without our specific header magic is assumed to be a raw 842 buffer + * and passed directly to the hardware. Note that the software compression + * library will produce a compressed buffer that is incompatible with the + * hardware decompressor if the original input buffer length is not a multiple + * of 8; if such a compressed buffer is passed to this driver for + * decompression, the hardware will reject it and this driver will then pass + * it over to the software library for decompression. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/crypto.h> +#include <linux/vmalloc.h> +#include <linux/sw842.h> +#include <linux/ratelimit.h> + +#include "nx-842.h" + +/* The first 5 bits of this magic are 0x1f, which is an invalid 842 5-bit + * template (see lib/842/842.h), so this magic number will never appear at + * the start of a raw 842 compressed buffer. That is important, as any buffer + * passed to us without this magic is assumed to be a raw 842 compressed + * buffer, and passed directly to the hardware to decompress. + */ +#define NX842_CRYPTO_MAGIC (0xf842) +#define NX842_CRYPTO_GROUP_MAX (0x20) +#define NX842_CRYPTO_HEADER_SIZE(g) \ + (sizeof(struct nx842_crypto_header) + \ + sizeof(struct nx842_crypto_header_group) * (g)) +#define NX842_CRYPTO_HEADER_MAX_SIZE \ + NX842_CRYPTO_HEADER_SIZE(NX842_CRYPTO_GROUP_MAX) + +/* bounce buffer size */ +#define BOUNCE_BUFFER_ORDER (2) +#define BOUNCE_BUFFER_SIZE \ + ((unsigned int)(PAGE_SIZE << BOUNCE_BUFFER_ORDER)) + +/* try longer on comp because we can fallback to sw decomp if hw is busy */ +#define COMP_BUSY_TIMEOUT (250) /* ms */ +#define DECOMP_BUSY_TIMEOUT (50) /* ms */ + +struct nx842_crypto_header_group { + __be16 padding; /* unused bytes at start of group */ + __be32 compressed_length; /* compressed bytes in group */ + __be32 uncompressed_length; /* bytes after decompression */ +} __packed; + +struct nx842_crypto_header { + __be16 magic; /* NX842_CRYPTO_MAGIC */ + __be16 ignore; /* decompressed end bytes to ignore */ + u8 groups; /* total groups in this header */ + struct nx842_crypto_header_group group[]; +} __packed; + +struct nx842_crypto_param { + u8 *in; + unsigned int iremain; + u8 *out; + unsigned int oremain; + unsigned int ototal; +}; + +static int update_param(struct nx842_crypto_param *p, + unsigned int slen, unsigned int dlen) +{ + if (p->iremain < slen) + return -EOVERFLOW; + if (p->oremain < dlen) + return -ENOSPC; + + p->in += slen; + p->iremain -= slen; + p->out += dlen; + p->oremain -= dlen; + p->ototal += dlen; + + return 0; +} + +struct nx842_crypto_ctx { + u8 *wmem; + u8 *sbounce, *dbounce; + + struct nx842_crypto_header header; + struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; +}; + +static int nx842_crypto_init(struct crypto_tfm *tfm) +{ + struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); + + ctx->wmem = kmalloc(nx842_workmem_size(), GFP_KERNEL); + ctx->sbounce = (u8 *)__get_free_pages(GFP_KERNEL, BOUNCE_BUFFER_ORDER); + ctx->dbounce = (u8 *)__get_free_pages(GFP_KERNEL, BOUNCE_BUFFER_ORDER); + if (!ctx->wmem || !ctx->sbounce || !ctx->dbounce) { + kfree(ctx->wmem); + free_page((unsigned long)ctx->sbounce); + free_page((unsigned long)ctx->dbounce); + return -ENOMEM; + } + + return 0; +} + +static void nx842_crypto_exit(struct crypto_tfm *tfm) +{ + struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); + + kfree(ctx->wmem); + free_page((unsigned long)ctx->sbounce); + free_page((unsigned long)ctx->dbounce); +} + +static int read_constraints(struct nx842_constraints *c) +{ + int ret; + + ret = nx842_constraints(c); + if (ret) { + pr_err_ratelimited("could not get nx842 constraints : %d\n", + ret); + return ret; + } + + /* limit maximum, to always have enough bounce buffer to decompress */ + if (c->maximum > BOUNCE_BUFFER_SIZE) { + c->maximum = BOUNCE_BUFFER_SIZE; + pr_info_once("limiting nx842 maximum to %x\n", c->maximum); + } + + return 0; +} + +static int nx842_crypto_add_header(struct nx842_crypto_header *hdr, u8 *buf) +{ + int s = NX842_CRYPTO_HEADER_SIZE(hdr->groups); + + /* compress should have added space for header */ + if (s > be16_to_cpu(hdr->group[0].padding)) { + pr_err("Internal error: no space for header\n"); + return -EINVAL; + } + + memcpy(buf, hdr, s); + + print_hex_dump_debug("header ", DUMP_PREFIX_OFFSET, 16, 1, buf, s, 0); + + return 0; +} + +static int compress(struct nx842_crypto_ctx *ctx, + struct nx842_crypto_param *p, + struct nx842_crypto_header_group *g, + struct nx842_constraints *c, + u16 *ignore, + unsigned int hdrsize) +{ + unsigned int slen = p->iremain, dlen = p->oremain, tmplen; + unsigned int adj_slen = slen; + u8 *src = p->in, *dst = p->out; + int ret, dskip = 0; + ktime_t timeout; + + if (p->iremain == 0) + return -EOVERFLOW; + + if (p->oremain == 0 || hdrsize + c->minimum > dlen) + return -ENOSPC; + + if (slen % c->multiple) + adj_slen = round_up(slen, c->multiple); + if (slen < c->minimum) + adj_slen = c->minimum; + if (slen > c->maximum) + adj_slen = slen = c->maximum; + if (adj_slen > slen || (u64)src % c->alignment) { + adj_slen = min(adj_slen, BOUNCE_BUFFER_SIZE); + slen = min(slen, BOUNCE_BUFFER_SIZE); + if (adj_slen > slen) + memset(ctx->sbounce + slen, 0, adj_slen - slen); + memcpy(ctx->sbounce, src, slen); + src = ctx->sbounce; + slen = adj_slen; + pr_debug("using comp sbounce buffer, len %x\n", slen); + } + + dst += hdrsize; + dlen -= hdrsize; + + if ((u64)dst % c->alignment) { + dskip = (int)(PTR_ALIGN(dst, c->alignment) - dst); + dst += dskip; + dlen -= dskip; + } + if (dlen % c->multiple) + dlen = round_down(dlen, c->multiple); + if (dlen < c->minimum) { +nospc: + dst = ctx->dbounce; + dlen = min(p->oremain, BOUNCE_BUFFER_SIZE); + dlen = round_down(dlen, c->multiple); + dskip = 0; + pr_debug("using comp dbounce buffer, len %x\n", dlen); + } + if (dlen > c->maximum) + dlen = c->maximum; + + tmplen = dlen; + timeout = ktime_add_ms(ktime_get(), COMP_BUSY_TIMEOUT); + do { + dlen = tmplen; /* reset dlen, if we're retrying */ + ret = nx842_compress(src, slen, dst, &dlen, ctx->wmem); + /* possibly we should reduce the slen here, instead of + * retrying with the dbounce buffer? + */ + if (ret == -ENOSPC && dst != ctx->dbounce) + goto nospc; + } while (ret == -EBUSY && ktime_before(ktime_get(), timeout)); + if (ret) + return ret; + + dskip += hdrsize; + + if (dst == ctx->dbounce) + memcpy(p->out + dskip, dst, dlen); + + g->padding = cpu_to_be16(dskip); + g->compressed_length = cpu_to_be32(dlen); + g->uncompressed_length = cpu_to_be32(slen); + + if (p->iremain < slen) { + *ignore = slen - p->iremain; + slen = p->iremain; + } + + pr_debug("compress slen %x ignore %x dlen %x padding %x\n", + slen, *ignore, dlen, dskip); + + return update_param(p, slen, dskip + dlen); +} + +static int nx842_crypto_compress(struct crypto_tfm *tfm, + const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen) +{ + struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); + struct nx842_crypto_header *hdr = &ctx->header; + struct nx842_crypto_param p; + struct nx842_constraints c; + unsigned int groups, hdrsize, h; + int ret, n; + bool add_header; + u16 ignore = 0; + + p.in = (u8 *)src; + p.iremain = slen; + p.out = dst; + p.oremain = *dlen; + p.ototal = 0; + + *dlen = 0; + + ret = read_constraints(&c); + if (ret) + return ret; + + groups = min_t(unsigned int, NX842_CRYPTO_GROUP_MAX, + DIV_ROUND_UP(p.iremain, c.maximum)); + hdrsize = NX842_CRYPTO_HEADER_SIZE(groups); + + /* skip adding header if the buffers meet all constraints */ + add_header = (p.iremain % c.multiple || + p.iremain < c.minimum || + p.iremain > c.maximum || + (u64)p.in % c.alignment || + p.oremain % c.multiple || + p.oremain < c.minimum || + p.oremain > c.maximum || + (u64)p.out % c.alignment); + + hdr->magic = cpu_to_be16(NX842_CRYPTO_MAGIC); + hdr->groups = 0; + hdr->ignore = 0; + + while (p.iremain > 0) { + n = hdr->groups++; + if (hdr->groups > NX842_CRYPTO_GROUP_MAX) + return -ENOSPC; + + /* header goes before first group */ + h = !n && add_header ? hdrsize : 0; + + if (ignore) + pr_warn("interal error, ignore is set %x\n", ignore); + + ret = compress(ctx, &p, &hdr->group[n], &c, &ignore, h); + if (ret) + return ret; + } + + if (!add_header && hdr->groups > 1) { + pr_err("Internal error: No header but multiple groups\n"); + return -EINVAL; + } + + /* ignore indicates the input stream needed to be padded */ + hdr->ignore = cpu_to_be16(ignore); + if (ignore) + pr_debug("marked %d bytes as ignore\n", ignore); + + if (add_header) + ret = nx842_crypto_add_header(hdr, dst); + if (ret) + return ret; + + *dlen = p.ototal; + + pr_debug("compress total slen %x dlen %x\n", slen, *dlen); + + return 0; +} + +static int decompress(struct nx842_crypto_ctx *ctx, + struct nx842_crypto_param *p, + struct nx842_crypto_header_group *g, + struct nx842_constraints *c, + u16 ignore, + bool usehw) +{ + unsigned int slen = be32_to_cpu(g->compressed_length); + unsigned int required_len = be32_to_cpu(g->uncompressed_length); + unsigned int dlen = p->oremain, tmplen; + unsigned int adj_slen = slen; + u8 *src = p->in, *dst = p->out; + u16 padding = be16_to_cpu(g->padding); + int ret, spadding = 0, dpadding = 0; + ktime_t timeout; + + if (!slen || !required_len) + return -EINVAL; + + if (p->iremain <= 0 || padding + slen > p->iremain) + return -EOVERFLOW; + + if (p->oremain <= 0 || required_len - ignore > p->oremain) + return -ENOSPC; + + src += padding; + + if (!usehw) + goto usesw; + + if (slen % c->multiple) + adj_slen = round_up(slen, c->multiple); + if (slen < c->minimum) + adj_slen = c->minimum; + if (slen > c->maximum) + goto usesw; + if (slen < adj_slen || (u64)src % c->alignment) { + /* we can append padding bytes because the 842 format defines + * an "end" template (see lib/842/842_decompress.c) and will + * ignore any bytes following it. + */ + if (slen < adj_slen) + memset(ctx->sbounce + slen, 0, adj_slen - slen); + memcpy(ctx->sbounce, src, slen); + src = ctx->sbounce; + spadding = adj_slen - slen; + slen = adj_slen; + pr_debug("using decomp sbounce buffer, len %x\n", slen); + } + + if (dlen % c->multiple) + dlen = round_down(dlen, c->multiple); + if (dlen < required_len || (u64)dst % c->alignment) { + dst = ctx->dbounce; + dlen = min(required_len, BOUNCE_BUFFER_SIZE); + pr_debug("using decomp dbounce buffer, len %x\n", dlen); + } + if (dlen < c->minimum) + goto usesw; + if (dlen > c->maximum) + dlen = c->maximum; + + tmplen = dlen; + timeout = ktime_add_ms(ktime_get(), DECOMP_BUSY_TIMEOUT); + do { + dlen = tmplen; /* reset dlen, if we're retrying */ + ret = nx842_decompress(src, slen, dst, &dlen, ctx->wmem); + } while (ret == -EBUSY && ktime_before(ktime_get(), timeout)); + if (ret) { +usesw: + /* reset everything, sw doesn't have constraints */ + src = p->in + padding; + slen = be32_to_cpu(g->compressed_length); + spadding = 0; + dst = p->out; + dlen = p->oremain; + dpadding = 0; + if (dlen < required_len) { /* have ignore bytes */ + dst = ctx->dbounce; + dlen = BOUNCE_BUFFER_SIZE; + } + pr_info_ratelimited("using software 842 decompression\n"); + ret = sw842_decompress(src, slen, dst, &dlen); + } + if (ret) + return ret; + + slen -= spadding; + + dlen -= ignore; + if (ignore) + pr_debug("ignoring last %x bytes\n", ignore); + + if (dst == ctx->dbounce) + memcpy(p->out, dst, dlen); + + pr_debug("decompress slen %x padding %x dlen %x ignore %x\n", + slen, padding, dlen, ignore); + + return update_param(p, slen + padding, dlen); +} + +static int nx842_crypto_decompress(struct crypto_tfm *tfm, + const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen) +{ + struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); + struct nx842_crypto_header *hdr; + struct nx842_crypto_param p; + struct nx842_constraints c; + int n, ret, hdr_len; + u16 ignore = 0; + bool usehw = true; + + p.in = (u8 *)src; + p.iremain = slen; + p.out = dst; + p.oremain = *dlen; + p.ototal = 0; + + *dlen = 0; + + if (read_constraints(&c)) + usehw = false; + + hdr = (struct nx842_crypto_header *)src; + + /* If it doesn't start with our header magic number, assume it's a raw + * 842 compressed buffer and pass it directly to the hardware driver + */ + if (be16_to_cpu(hdr->magic) != NX842_CRYPTO_MAGIC) { + struct nx842_crypto_header_group g = { + .padding = 0, + .compressed_length = cpu_to_be32(p.iremain), + .uncompressed_length = cpu_to_be32(p.oremain), + }; + + ret = decompress(ctx, &p, &g, &c, 0, usehw); + if (ret) + return ret; + + *dlen = p.ototal; + + return 0; + } + + if (!hdr->groups) { + pr_err("header has no groups\n"); + return -EINVAL; + } + if (hdr->groups > NX842_CRYPTO_GROUP_MAX) { + pr_err("header has too many groups %x, max %x\n", + hdr->groups, NX842_CRYPTO_GROUP_MAX); + return -EINVAL; + } + + hdr_len = NX842_CRYPTO_HEADER_SIZE(hdr->groups); + if (hdr_len > slen) + return -EOVERFLOW; + + memcpy(&ctx->header, src, hdr_len); + hdr = &ctx->header; + + for (n = 0; n < hdr->groups; n++) { + /* ignore applies to last group */ + if (n + 1 == hdr->groups) + ignore = be16_to_cpu(hdr->ignore); + + ret = decompress(ctx, &p, &hdr->group[n], &c, ignore, usehw); + if (ret) + return ret; + } + + *dlen = p.ototal; + + pr_debug("decompress total slen %x dlen %x\n", slen, *dlen); + + return 0; +} + +static struct crypto_alg alg = { + .cra_name = "842", + .cra_driver_name = "842-nx", + .cra_priority = 300, + .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, + .cra_ctxsize = sizeof(struct nx842_crypto_ctx), + .cra_module = THIS_MODULE, + .cra_init = nx842_crypto_init, + .cra_exit = nx842_crypto_exit, + .cra_u = { .compress = { + .coa_compress = nx842_crypto_compress, + .coa_decompress = nx842_crypto_decompress } } +}; + +static int __init nx842_crypto_mod_init(void) +{ + return crypto_register_alg(&alg); +} +module_init(nx842_crypto_mod_init); + +static void __exit nx842_crypto_mod_exit(void) +{ + crypto_unregister_alg(&alg); +} +module_exit(nx842_crypto_mod_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("IBM PowerPC Nest (NX) 842 Hardware Compression Interface"); +MODULE_ALIAS_CRYPTO("842"); +MODULE_ALIAS_CRYPTO("842-nx"); +MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>"); |