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Merge tag 'rslib-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Browse Source 
Pull reed-salomon library updates from Kees Cook:
 "Refactors rslib and callers to provide a per-instance allocation area
  instead of performing VLAs on the stack"

* tag 'rslib-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  rslib: Allocate decoder buffers to avoid VLAs
  mtd: rawnand: diskonchip: Allocate rs control per instance
  rslib: Split rs control struct
  rslib: Simplify error path
  rslib: Remove GPL boilerplate
  rslib: Add SPDX identifiers
  rslib: Cleanup top level comments
  rslib: Cleanup whitespace damage
  dm/verity_fec: Use GFP aware reed solomon init
  rslib: Add GFP aware init function
This commit is contained in:
Linus Torvalds
2018-06-05 10:48:05 -07:00
parent a74e0c4c9c 45888b40d2
commit 25d80be86c
7 changed files with 243 additions and 196 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
lib/reed_solomon/decode_rs.c
View File

@@ -1,22 +1,16 @@
// SPDX-License-Identifier: GPL-2.0
/*
* lib/reed_solomon/decode_rs.c
*
* Overview:
* Generic Reed Solomon encoder / decoder library
* Generic Reed Solomon encoder / decoder library
*
* Copyright 2002, Phil Karn, KA9Q
* May be used under the terms of the GNU General Public License (GPL)
*
* Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de)
*
* $Id: decode_rs.c,v 1.7 2005/11/07 11:14:59 gleixner Exp $
*
*/
/* Generic data width independent code which is included by the
* wrappers.
* Generic data width independent code which is included by the wrappers.
*/
{
struct rs_codec *rs = rsc->codec;
int deg_lambda, el, deg_omega;
int i, j, r, k, pad;
int nn = rs->nn;
@@ -27,16 +21,22 @@
uint16_t *alpha_to = rs->alpha_to;
uint16_t *index_of = rs->index_of;
uint16_t u, q, tmp, num1, num2, den, discr_r, syn_error;
/* Err+Eras Locator poly and syndrome poly The maximum value
* of nroots is 8. So the necessary stack size will be about
* 220 bytes max.
*/
uint16_t lambda[nroots + 1], syn[nroots];
uint16_t b[nroots + 1], t[nroots + 1], omega[nroots + 1];
uint16_t root[nroots], reg[nroots + 1], loc[nroots];
int count = 0;
uint16_t msk = (uint16_t) rs->nn;
/*
* The decoder buffers are in the rs control struct. They are
* arrays sized [nroots + 1]
*/
uint16_t *lambda = rsc->buffers + RS_DECODE_LAMBDA * (nroots + 1);
uint16_t *syn = rsc->buffers + RS_DECODE_SYN * (nroots + 1);
uint16_t *b = rsc->buffers + RS_DECODE_B * (nroots + 1);
uint16_t *t = rsc->buffers + RS_DECODE_T * (nroots + 1);
uint16_t *omega = rsc->buffers + RS_DECODE_OMEGA * (nroots + 1);
uint16_t *root = rsc->buffers + RS_DECODE_ROOT * (nroots + 1);
uint16_t *reg = rsc->buffers + RS_DECODE_REG * (nroots + 1);
uint16_t *loc = rsc->buffers + RS_DECODE_LOC * (nroots + 1);
/* Check length parameter for validity */
pad = nn - nroots - len;
BUG_ON(pad < 0 || pad >= nn);

15
lib/reed_solomon/encode_rs.c
View File

@@ -1,23 +1,16 @@
// SPDX-License-Identifier: GPL-2.0
/*
* lib/reed_solomon/encode_rs.c
*
* Overview:
* Generic Reed Solomon encoder / decoder library
* Generic Reed Solomon encoder / decoder library
*
* Copyright 2002, Phil Karn, KA9Q
* May be used under the terms of the GNU General Public License (GPL)
*
* Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de)
*
* $Id: encode_rs.c,v 1.5 2005/11/07 11:14:59 gleixner Exp $
*
*/
/* Generic data width independent code which is included by the
* wrappers.
* int encode_rsX (struct rs_control *rs, uintX_t *data, int len, uintY_t *par)
* Generic data width independent code which is included by the wrappers.
*/
{
struct rs_codec *rs = rsc->codec;
int i, j, pad;
int nn = rs->nn;
int nroots = rs->nroots;

240
lib/reed_solomon/reed_solomon.c
View File

@@ -1,43 +1,34 @@
// SPDX-License-Identifier: GPL-2.0
/*
* lib/reed_solomon/reed_solomon.c
*
* Overview:
* Generic Reed Solomon encoder / decoder library
* Generic Reed Solomon encoder / decoder library
*
* Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
*
* Reed Solomon code lifted from reed solomon library written by Phil Karn
* Copyright 2002 Phil Karn, KA9Q
*
* $Id: rslib.c,v 1.7 2005/11/07 11:14:59 gleixner Exp $
*
* 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.
*
* Description:
*
* The generic Reed Solomon library provides runtime configurable
* encoding / decoding of RS codes.
* Each user must call init_rs to get a pointer to a rs_control
* structure for the given rs parameters. This structure is either
* generated or a already available matching control structure is used.
* If a structure is generated then the polynomial arrays for
* fast encoding / decoding are built. This can take some time so
* make sure not to call this function from a time critical path.
* Usually a module / driver should initialize the necessary
* rs_control structure on module / driver init and release it
* on exit.
* The encoding puts the calculated syndrome into a given syndrome
* buffer.
* The decoding is a two step process. The first step calculates
* the syndrome over the received (data + syndrome) and calls the
* second stage, which does the decoding / error correction itself.
* Many hw encoders provide a syndrome calculation over the received
* data + syndrome and can call the second stage directly.
*
* Each user must call init_rs to get a pointer to a rs_control structure
* for the given rs parameters. The control struct is unique per instance.
* It points to a codec which can be shared by multiple control structures.
* If a codec is newly allocated then the polynomial arrays for fast
* encoding / decoding are built. This can take some time so make sure not
* to call this function from a time critical path. Usually a module /
* driver should initialize the necessary rs_control structure on module /
* driver init and release it on exit.
*
* The encoding puts the calculated syndrome into a given syndrome buffer.
*
* The decoding is a two step process. The first step calculates the
* syndrome over the received (data + syndrome) and calls the second stage,
* which does the decoding / error correction itself. Many hw encoders
* provide a syndrome calculation over the received data + syndrome and can
* call the second stage directly.
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -46,32 +37,44 @@
#include <linux/slab.h>
#include <linux/mutex.h>
/* This list holds all currently allocated rs control structures */
static LIST_HEAD (rslist);
enum {
RS_DECODE_LAMBDA,
RS_DECODE_SYN,
RS_DECODE_B,
RS_DECODE_T,
RS_DECODE_OMEGA,
RS_DECODE_ROOT,
RS_DECODE_REG,
RS_DECODE_LOC,
RS_DECODE_NUM_BUFFERS
};
/* This list holds all currently allocated rs codec structures */
static LIST_HEAD(codec_list);
/* Protection for the list */
static DEFINE_MUTEX(rslistlock);
/**
* rs_init - Initialize a Reed-Solomon codec
* codec_init - Initialize a Reed-Solomon codec
* @symsize: symbol size, bits (1-8)
* @gfpoly: Field generator polynomial coefficients
* @gffunc: Field generator function
* @fcr: first root of RS code generator polynomial, index form
* @prim: primitive element to generate polynomial roots
* @nroots: RS code generator polynomial degree (number of roots)
* @gfp: GFP_ flags for allocations
*
* Allocate a control structure and the polynom arrays for faster
* Allocate a codec structure and the polynom arrays for faster
* en/decoding. Fill the arrays according to the given parameters.
*/
static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
int fcr, int prim, int nroots)
static struct rs_codec *codec_init(int symsize, int gfpoly, int (*gffunc)(int),
int fcr, int prim, int nroots, gfp_t gfp)
{
struct rs_control *rs;
int i, j, sr, root, iprim;
struct rs_codec *rs;
/* Allocate the control structure */
rs = kmalloc(sizeof (struct rs_control), GFP_KERNEL);
if (rs == NULL)
rs = kzalloc(sizeof(*rs), gfp);
if (!rs)
return NULL;
INIT_LIST_HEAD(&rs->list);
@@ -85,17 +88,17 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
rs->gffunc = gffunc;
/* Allocate the arrays */
rs->alpha_to = kmalloc(sizeof(uint16_t) * (rs->nn + 1), GFP_KERNEL);
rs->alpha_to = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
if (rs->alpha_to == NULL)
goto errrs;
goto err;
rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), GFP_KERNEL);
rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
if (rs->index_of == NULL)
goto erralp;
goto err;
rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), GFP_KERNEL);
rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), gfp);
if(rs->genpoly == NULL)
goto erridx;
goto err;
/* Generate Galois field lookup tables */
rs->index_of[0] = rs->nn; /* log(zero) = -inf */
@@ -120,7 +123,7 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
}
/* If it's not primitive, exit */
if(sr != rs->alpha_to[0])
goto errpol;
goto err;
/* Find prim-th root of 1, used in decoding */
for(iprim = 1; (iprim % prim) != 0; iprim += rs->nn);
@@ -148,42 +151,52 @@ static struct rs_control *rs_init(int symsize, int gfpoly, int (*gffunc)(int),
/* convert rs->genpoly[] to index form for quicker encoding */
for (i = 0; i <= nroots; i++)
rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
rs->users = 1;
list_add(&rs->list, &codec_list);
return rs;
/* Error exit */
errpol:
err:
kfree(rs->genpoly);
erridx:
kfree(rs->index_of);
erralp:
kfree(rs->alpha_to);
errrs:
kfree(rs);
return NULL;
}
/**
* free_rs - Free the rs control structure, if it is no longer used
* @rs: the control structure which is not longer used by the
* free_rs - Free the rs control structure
* @rs: The control structure which is not longer used by the
* caller
*
* Free the control structure. If @rs is the last user of the associated
* codec, free the codec as well.
*/
void free_rs(struct rs_control *rs)
{
struct rs_codec *cd;
if (!rs)
return;
cd = rs->codec;
mutex_lock(&rslistlock);
rs->users--;
if(!rs->users) {
list_del(&rs->list);
kfree(rs->alpha_to);
kfree(rs->index_of);
kfree(rs->genpoly);
kfree(rs);
cd->users--;
if(!cd->users) {
list_del(&cd->list);
kfree(cd->alpha_to);
kfree(cd->index_of);
kfree(cd->genpoly);
kfree(cd);
}
mutex_unlock(&rslistlock);
kfree(rs);
}
EXPORT_SYMBOL_GPL(free_rs);
/**
* init_rs_internal - Find a matching or allocate a new rs control structure
* init_rs_internal - Allocate rs control, find a matching codec or allocate a new one
* @symsize: the symbol size (number of bits)
* @gfpoly: the extended Galois field generator polynomial coefficients,
* with the 0th coefficient in the low order bit. The polynomial
@@ -191,55 +204,69 @@ void free_rs(struct rs_control *rs)
* @gffunc: pointer to function to generate the next field element,
* or the multiplicative identity element if given 0. Used
* instead of gfpoly if gfpoly is 0
* @fcr: the first consecutive root of the rs code generator polynomial
* @fcr: the first consecutive root of the rs code generator polynomial
* in index form
* @prim: primitive element to generate polynomial roots
* @nroots: RS code generator polynomial degree (number of roots)
* @gfp: GFP_ flags for allocations
*/
static struct rs_control *init_rs_internal(int symsize, int gfpoly,
int (*gffunc)(int), int fcr,
int prim, int nroots)
int (*gffunc)(int), int fcr,
int prim, int nroots, gfp_t gfp)
{
struct list_head *tmp;
struct rs_control *rs;
struct list_head *tmp;
struct rs_control *rs;
unsigned int bsize;
/* Sanity checks */
if (symsize < 1)
return NULL;
if (fcr < 0 || fcr >= (1<<symsize))
return NULL;
return NULL;
if (prim <= 0 || prim >= (1<<symsize))
return NULL;
return NULL;
if (nroots < 0 || nroots >= (1<<symsize))
return NULL;
/*
* The decoder needs buffers in each control struct instance to
* avoid variable size or large fixed size allocations on
* stack. Size the buffers to arrays of [nroots + 1].
*/
bsize = sizeof(uint16_t) * RS_DECODE_NUM_BUFFERS * (nroots + 1);
rs = kzalloc(sizeof(*rs) + bsize, gfp);
if (!rs)
return NULL;
mutex_lock(&rslistlock);
/* Walk through the list and look for a matching entry */
list_for_each(tmp, &rslist) {
rs = list_entry(tmp, struct rs_control, list);
if (symsize != rs->mm)
list_for_each(tmp, &codec_list) {
struct rs_codec *cd = list_entry(tmp, struct rs_codec, list);
if (symsize != cd->mm)
continue;
if (gfpoly != rs->gfpoly)
if (gfpoly != cd->gfpoly)
continue;
if (gffunc != rs->gffunc)
if (gffunc != cd->gffunc)
continue;
if (fcr != rs->fcr)
if (fcr != cd->fcr)
continue;
if (prim != rs->prim)
if (prim != cd->prim)
continue;
if (nroots != rs->nroots)
if (nroots != cd->nroots)
continue;
/* We have a matching one already */
rs->users++;
cd->users++;
rs->codec = cd;
goto out;
}
/* Create a new one */
rs = rs_init(symsize, gfpoly, gffunc, fcr, prim, nroots);
if (rs) {
rs->users = 1;
list_add(&rs->list, &rslist);
rs->codec = codec_init(symsize, gfpoly, gffunc, fcr, prim, nroots, gfp);
if (!rs->codec) {
kfree(rs);
rs = NULL;
}
out:
mutex_unlock(&rslistlock);
@@ -247,45 +274,48 @@ out:
}
/**
* init_rs - Find a matching or allocate a new rs control structure
* init_rs_gfp - Create a RS control struct and initialize it
* @symsize: the symbol size (number of bits)
* @gfpoly: the extended Galois field generator polynomial coefficients,
* with the 0th coefficient in the low order bit. The polynomial
* must be primitive;
* @fcr: the first consecutive root of the rs code generator polynomial
* @fcr: the first consecutive root of the rs code generator polynomial
* in index form
* @prim: primitive element to generate polynomial roots
* @nroots: RS code generator polynomial degree (number of roots)
* @gfp: GFP_ flags for allocations
*/
struct rs_control *init_rs(int symsize, int gfpoly, int fcr, int prim,
int nroots)
struct rs_control *init_rs_gfp(int symsize, int gfpoly, int fcr, int prim,
int nroots, gfp_t gfp)
{
return init_rs_internal(symsize, gfpoly, NULL, fcr, prim, nroots);
return init_rs_internal(symsize, gfpoly, NULL, fcr, prim, nroots, gfp);
}
EXPORT_SYMBOL_GPL(init_rs_gfp);
/**
* init_rs_non_canonical - Find a matching or allocate a new rs control
* structure, for fields with non-canonical
* representation
* init_rs_non_canonical - Allocate rs control struct for fields with
* non-canonical representation
* @symsize: the symbol size (number of bits)
* @gffunc: pointer to function to generate the next field element,
* or the multiplicative identity element if given 0. Used
* instead of gfpoly if gfpoly is 0
* @fcr: the first consecutive root of the rs code generator polynomial
* @fcr: the first consecutive root of the rs code generator polynomial
* in index form
* @prim: primitive element to generate polynomial roots
* @nroots: RS code generator polynomial degree (number of roots)
*/
struct rs_control *init_rs_non_canonical(int symsize, int (*gffunc)(int),
int fcr, int prim, int nroots)
int fcr, int prim, int nroots)
{
return init_rs_internal(symsize, 0, gffunc, fcr, prim, nroots);
return init_rs_internal(symsize, 0, gffunc, fcr, prim, nroots,
GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(init_rs_non_canonical);
#ifdef CONFIG_REED_SOLOMON_ENC8
/**
* encode_rs8 - Calculate the parity for data values (8bit data width)
* @rs: the rs control structure
* @rsc: the rs control structure
* @data: data field of a given type
* @len: data length
* @par: parity data, must be initialized by caller (usually all 0)
@@ -295,7 +325,7 @@ struct rs_control *init_rs_non_canonical(int symsize, int (*gffunc)(int),
* symbol size > 8. The calling code must take care of encoding of the
* syndrome result for storage itself.
*/
int encode_rs8(struct rs_control *rs, uint8_t *data, int len, uint16_t *par,
int encode_rs8(struct rs_control *rsc, uint8_t *data, int len, uint16_t *par,
uint16_t invmsk)
{
#include "encode_rs.c"
@@ -306,7 +336,7 @@ EXPORT_SYMBOL_GPL(encode_rs8);
#ifdef CONFIG_REED_SOLOMON_DEC8
/**
* decode_rs8 - Decode codeword (8bit data width)
* @rs: the rs control structure
* @rsc: the rs control structure
* @data: data field of a given type
* @par: received parity data field
* @len: data length
@@ -319,9 +349,14 @@ EXPORT_SYMBOL_GPL(encode_rs8);
* The syndrome and parity uses a uint16_t data type to enable
* symbol size > 8. The calling code must take care of decoding of the
* syndrome result and the received parity before calling this code.
*
* Note: The rs_control struct @rsc contains buffers which are used for
* decoding, so the caller has to ensure that decoder invocations are
* serialized.
*
* Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
*/
int decode_rs8(struct rs_control *rs, uint8_t *data, uint16_t *par, int len,
int decode_rs8(struct rs_control *rsc, uint8_t *data, uint16_t *par, int len,
uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk,
uint16_t *corr)
{
@@ -333,7 +368,7 @@ EXPORT_SYMBOL_GPL(decode_rs8);
#ifdef CONFIG_REED_SOLOMON_ENC16
/**
* encode_rs16 - Calculate the parity for data values (16bit data width)
* @rs: the rs control structure
* @rsc: the rs control structure
* @data: data field of a given type
* @len: data length
* @par: parity data, must be initialized by caller (usually all 0)
@@ -341,7 +376,7 @@ EXPORT_SYMBOL_GPL(decode_rs8);
*
* Each field in the data array contains up to symbol size bits of valid data.
*/
int encode_rs16(struct rs_control *rs, uint16_t *data, int len, uint16_t *par,
int encode_rs16(struct rs_control *rsc, uint16_t *data, int len, uint16_t *par,
uint16_t invmsk)
{
#include "encode_rs.c"
@@ -352,7 +387,7 @@ EXPORT_SYMBOL_GPL(encode_rs16);
#ifdef CONFIG_REED_SOLOMON_DEC16
/**
* decode_rs16 - Decode codeword (16bit data width)
* @rs: the rs control structure
* @rsc: the rs control structure
* @data: data field of a given type
* @par: received parity data field
* @len: data length
@@ -363,9 +398,14 @@ EXPORT_SYMBOL_GPL(encode_rs16);
* @corr: buffer to store correction bitmask on eras_pos
*
* Each field in the data array contains up to symbol size bits of valid data.
*
* Note: The rc_control struct @rsc contains buffers which are used for
* decoding, so the caller has to ensure that decoder invocations are
* serialized.
*
* Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
*/
int decode_rs16(struct rs_control *rs, uint16_t *data, uint16_t *par, int len,
int decode_rs16(struct rs_control *rsc, uint16_t *data, uint16_t *par, int len,
uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk,
uint16_t *corr)
{
@@ -374,10 +414,6 @@ int decode_rs16(struct rs_control *rs, uint16_t *data, uint16_t *par, int len,
EXPORT_SYMBOL_GPL(decode_rs16);
#endif
EXPORT_SYMBOL_GPL(init_rs);
EXPORT_SYMBOL_GPL(init_rs_non_canonical);
EXPORT_SYMBOL_GPL(free_rs);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Reed Solomon encoder/decoder");
MODULE_AUTHOR("Phil Karn, Thomas Gleixner");