623 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2012 Google, Inc.4 */5 6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt7 8#include <linux/device.h>9#include <linux/err.h>10#include <linux/errno.h>11#include <linux/init.h>12#include <linux/io.h>13#include <linux/kernel.h>14#include <linux/list.h>15#include <linux/memblock.h>16#include <linux/rslib.h>17#include <linux/slab.h>18#include <linux/uaccess.h>19#include <linux/vmalloc.h>20#include <linux/mm.h>21#include <asm/page.h>22 23#include "ram_internal.h"24 25/**26 * struct persistent_ram_buffer - persistent circular RAM buffer27 *28 * @sig: Signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)29 * @start: First valid byte in the buffer.30 * @size: Number of valid bytes in the buffer.31 * @data: The contents of the buffer.32 */33struct persistent_ram_buffer {34 uint32_t sig;35 atomic_t start;36 atomic_t size;37 uint8_t data[];38};39 40#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */41 42static inline size_t buffer_size(struct persistent_ram_zone *prz)43{44 return atomic_read(&prz->buffer->size);45}46 47static inline size_t buffer_start(struct persistent_ram_zone *prz)48{49 return atomic_read(&prz->buffer->start);50}51 52/* increase and wrap the start pointer, returning the old value */53static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)54{55 int old;56 int new;57 unsigned long flags = 0;58 59 if (!(prz->flags & PRZ_FLAG_NO_LOCK))60 raw_spin_lock_irqsave(&prz->buffer_lock, flags);61 62 old = atomic_read(&prz->buffer->start);63 new = old + a;64 while (unlikely(new >= prz->buffer_size))65 new -= prz->buffer_size;66 atomic_set(&prz->buffer->start, new);67 68 if (!(prz->flags & PRZ_FLAG_NO_LOCK))69 raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);70 71 return old;72}73 74/* increase the size counter until it hits the max size */75static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)76{77 size_t old;78 size_t new;79 unsigned long flags = 0;80 81 if (!(prz->flags & PRZ_FLAG_NO_LOCK))82 raw_spin_lock_irqsave(&prz->buffer_lock, flags);83 84 old = atomic_read(&prz->buffer->size);85 if (old == prz->buffer_size)86 goto exit;87 88 new = old + a;89 if (new > prz->buffer_size)90 new = prz->buffer_size;91 atomic_set(&prz->buffer->size, new);92 93exit:94 if (!(prz->flags & PRZ_FLAG_NO_LOCK))95 raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);96}97 98static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,99 uint8_t *data, size_t len, uint8_t *ecc)100{101 int i;102 103 /* Initialize the parity buffer */104 memset(prz->ecc_info.par, 0,105 prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0]));106 encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0);107 for (i = 0; i < prz->ecc_info.ecc_size; i++)108 ecc[i] = prz->ecc_info.par[i];109}110 111static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,112 void *data, size_t len, uint8_t *ecc)113{114 int i;115 116 for (i = 0; i < prz->ecc_info.ecc_size; i++)117 prz->ecc_info.par[i] = ecc[i];118 return decode_rs8(prz->rs_decoder, data, prz->ecc_info.par, len,119 NULL, 0, NULL, 0, NULL);120}121 122static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,123 unsigned int start, unsigned int count)124{125 struct persistent_ram_buffer *buffer = prz->buffer;126 uint8_t *buffer_end = buffer->data + prz->buffer_size;127 uint8_t *block;128 uint8_t *par;129 int ecc_block_size = prz->ecc_info.block_size;130 int ecc_size = prz->ecc_info.ecc_size;131 int size = ecc_block_size;132 133 if (!ecc_size)134 return;135 136 block = buffer->data + (start & ~(ecc_block_size - 1));137 par = prz->par_buffer + (start / ecc_block_size) * ecc_size;138 139 do {140 if (block + ecc_block_size > buffer_end)141 size = buffer_end - block;142 persistent_ram_encode_rs8(prz, block, size, par);143 block += ecc_block_size;144 par += ecc_size;145 } while (block < buffer->data + start + count);146}147 148static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)149{150 struct persistent_ram_buffer *buffer = prz->buffer;151 152 if (!prz->ecc_info.ecc_size)153 return;154 155 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),156 prz->par_header);157}158 159static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)160{161 struct persistent_ram_buffer *buffer = prz->buffer;162 uint8_t *block;163 uint8_t *par;164 165 if (!prz->ecc_info.ecc_size)166 return;167 168 block = buffer->data;169 par = prz->par_buffer;170 while (block < buffer->data + buffer_size(prz)) {171 int numerr;172 int size = prz->ecc_info.block_size;173 if (block + size > buffer->data + prz->buffer_size)174 size = buffer->data + prz->buffer_size - block;175 numerr = persistent_ram_decode_rs8(prz, block, size, par);176 if (numerr > 0) {177 pr_devel("error in block %p, %d\n", block, numerr);178 prz->corrected_bytes += numerr;179 } else if (numerr < 0) {180 pr_devel("uncorrectable error in block %p\n", block);181 prz->bad_blocks++;182 }183 block += prz->ecc_info.block_size;184 par += prz->ecc_info.ecc_size;185 }186}187 188static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,189 struct persistent_ram_ecc_info *ecc_info)190{191 int numerr;192 struct persistent_ram_buffer *buffer = prz->buffer;193 size_t ecc_blocks;194 size_t ecc_total;195 196 if (!ecc_info || !ecc_info->ecc_size)197 return 0;198 199 prz->ecc_info.block_size = ecc_info->block_size ?: 128;200 prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;201 prz->ecc_info.symsize = ecc_info->symsize ?: 8;202 prz->ecc_info.poly = ecc_info->poly ?: 0x11d;203 204 ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,205 prz->ecc_info.block_size +206 prz->ecc_info.ecc_size);207 ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;208 if (ecc_total >= prz->buffer_size) {209 pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",210 __func__, prz->ecc_info.ecc_size,211 ecc_total, prz->buffer_size);212 return -EINVAL;213 }214 215 prz->buffer_size -= ecc_total;216 prz->par_buffer = buffer->data + prz->buffer_size;217 prz->par_header = prz->par_buffer +218 ecc_blocks * prz->ecc_info.ecc_size;219 220 /*221 * first consecutive root is 0222 * primitive element to generate roots = 1223 */224 prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,225 0, 1, prz->ecc_info.ecc_size);226 if (prz->rs_decoder == NULL) {227 pr_info("init_rs failed\n");228 return -EINVAL;229 }230 231 /* allocate workspace instead of using stack VLA */232 prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size,233 sizeof(*prz->ecc_info.par),234 GFP_KERNEL);235 if (!prz->ecc_info.par) {236 pr_err("cannot allocate ECC parity workspace\n");237 return -ENOMEM;238 }239 240 prz->corrected_bytes = 0;241 prz->bad_blocks = 0;242 243 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),244 prz->par_header);245 if (numerr > 0) {246 pr_info("error in header, %d\n", numerr);247 prz->corrected_bytes += numerr;248 } else if (numerr < 0) {249 pr_info_ratelimited("uncorrectable error in header\n");250 prz->bad_blocks++;251 }252 253 return 0;254}255 256ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,257 char *str, size_t len)258{259 ssize_t ret;260 261 if (!prz->ecc_info.ecc_size)262 return 0;263 264 if (prz->corrected_bytes || prz->bad_blocks)265 ret = snprintf(str, len, ""266 "\nECC: %d Corrected bytes, %d unrecoverable blocks\n",267 prz->corrected_bytes, prz->bad_blocks);268 else269 ret = snprintf(str, len, "\nECC: No errors detected\n");270 271 return ret;272}273 274static void notrace persistent_ram_update(struct persistent_ram_zone *prz,275 const void *s, unsigned int start, unsigned int count)276{277 struct persistent_ram_buffer *buffer = prz->buffer;278 memcpy_toio(buffer->data + start, s, count);279 persistent_ram_update_ecc(prz, start, count);280}281 282static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,283 const void __user *s, unsigned int start, unsigned int count)284{285 struct persistent_ram_buffer *buffer = prz->buffer;286 int ret = unlikely(copy_from_user(buffer->data + start, s, count)) ?287 -EFAULT : 0;288 persistent_ram_update_ecc(prz, start, count);289 return ret;290}291 292void persistent_ram_save_old(struct persistent_ram_zone *prz)293{294 struct persistent_ram_buffer *buffer = prz->buffer;295 size_t size = buffer_size(prz);296 size_t start = buffer_start(prz);297 298 if (!size)299 return;300 301 if (!prz->old_log) {302 persistent_ram_ecc_old(prz);303 prz->old_log = kvzalloc(size, GFP_KERNEL);304 }305 if (!prz->old_log) {306 pr_err("failed to allocate buffer\n");307 return;308 }309 310 prz->old_log_size = size;311 memcpy_fromio(prz->old_log, &buffer->data[start], size - start);312 memcpy_fromio(prz->old_log + size - start, &buffer->data[0], start);313}314 315int notrace persistent_ram_write(struct persistent_ram_zone *prz,316 const void *s, unsigned int count)317{318 int rem;319 int c = count;320 size_t start;321 322 if (unlikely(c > prz->buffer_size)) {323 s += c - prz->buffer_size;324 c = prz->buffer_size;325 }326 327 buffer_size_add(prz, c);328 329 start = buffer_start_add(prz, c);330 331 rem = prz->buffer_size - start;332 if (unlikely(rem < c)) {333 persistent_ram_update(prz, s, start, rem);334 s += rem;335 c -= rem;336 start = 0;337 }338 persistent_ram_update(prz, s, start, c);339 340 persistent_ram_update_header_ecc(prz);341 342 return count;343}344 345int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,346 const void __user *s, unsigned int count)347{348 int rem, ret = 0, c = count;349 size_t start;350 351 if (unlikely(c > prz->buffer_size)) {352 s += c - prz->buffer_size;353 c = prz->buffer_size;354 }355 356 buffer_size_add(prz, c);357 358 start = buffer_start_add(prz, c);359 360 rem = prz->buffer_size - start;361 if (unlikely(rem < c)) {362 ret = persistent_ram_update_user(prz, s, start, rem);363 s += rem;364 c -= rem;365 start = 0;366 }367 if (likely(!ret))368 ret = persistent_ram_update_user(prz, s, start, c);369 370 persistent_ram_update_header_ecc(prz);371 372 return unlikely(ret) ? ret : count;373}374 375size_t persistent_ram_old_size(struct persistent_ram_zone *prz)376{377 return prz->old_log_size;378}379 380void *persistent_ram_old(struct persistent_ram_zone *prz)381{382 return prz->old_log;383}384 385void persistent_ram_free_old(struct persistent_ram_zone *prz)386{387 kvfree(prz->old_log);388 prz->old_log = NULL;389 prz->old_log_size = 0;390}391 392void persistent_ram_zap(struct persistent_ram_zone *prz)393{394 atomic_set(&prz->buffer->start, 0);395 atomic_set(&prz->buffer->size, 0);396 persistent_ram_update_header_ecc(prz);397}398 399#define MEM_TYPE_WCOMBINE 0400#define MEM_TYPE_NONCACHED 1401#define MEM_TYPE_NORMAL 2402 403static void *persistent_ram_vmap(phys_addr_t start, size_t size,404 unsigned int memtype)405{406 struct page **pages;407 phys_addr_t page_start;408 unsigned int page_count;409 pgprot_t prot;410 unsigned int i;411 void *vaddr;412 413 page_start = start - offset_in_page(start);414 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);415 416 switch (memtype) {417 case MEM_TYPE_NORMAL:418 prot = PAGE_KERNEL;419 break;420 case MEM_TYPE_NONCACHED:421 prot = pgprot_noncached(PAGE_KERNEL);422 break;423 case MEM_TYPE_WCOMBINE:424 prot = pgprot_writecombine(PAGE_KERNEL);425 break;426 default:427 pr_err("invalid mem_type=%d\n", memtype);428 return NULL;429 }430 431 pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);432 if (!pages) {433 pr_err("%s: Failed to allocate array for %u pages\n",434 __func__, page_count);435 return NULL;436 }437 438 for (i = 0; i < page_count; i++) {439 phys_addr_t addr = page_start + i * PAGE_SIZE;440 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);441 }442 /*443 * VM_IOREMAP used here to bypass this region during vread()444 * and kmap_atomic() (i.e. kcore) to avoid __va() failures.445 */446 vaddr = vmap(pages, page_count, VM_MAP | VM_IOREMAP, prot);447 kfree(pages);448 449 /*450 * Since vmap() uses page granularity, we must add the offset451 * into the page here, to get the byte granularity address452 * into the mapping to represent the actual "start" location.453 */454 return vaddr + offset_in_page(start);455}456 457static void *persistent_ram_iomap(phys_addr_t start, size_t size,458 unsigned int memtype, char *label)459{460 void *va;461 462 if (!request_mem_region(start, size, label ?: "ramoops")) {463 pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",464 label ?: "ramoops",465 (unsigned long long)size, (unsigned long long)start);466 return NULL;467 }468 469 if (memtype)470 va = ioremap(start, size);471 else472 va = ioremap_wc(start, size);473 474 /*475 * Since request_mem_region() and ioremap() are byte-granularity476 * there is no need handle anything special like we do when the477 * vmap() case in persistent_ram_vmap() above.478 */479 return va;480}481 482static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,483 struct persistent_ram_zone *prz, int memtype)484{485 prz->paddr = start;486 prz->size = size;487 488 if (pfn_valid(start >> PAGE_SHIFT))489 prz->vaddr = persistent_ram_vmap(start, size, memtype);490 else491 prz->vaddr = persistent_ram_iomap(start, size, memtype,492 prz->label);493 494 if (!prz->vaddr) {495 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,496 (unsigned long long)size, (unsigned long long)start);497 return -ENOMEM;498 }499 500 prz->buffer = prz->vaddr;501 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);502 503 return 0;504}505 506static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,507 struct persistent_ram_ecc_info *ecc_info)508{509 int ret;510 bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);511 512 ret = persistent_ram_init_ecc(prz, ecc_info);513 if (ret) {514 pr_warn("ECC failed %s\n", prz->label);515 return ret;516 }517 518 sig ^= PERSISTENT_RAM_SIG;519 520 if (prz->buffer->sig == sig) {521 if (buffer_size(prz) == 0 && buffer_start(prz) == 0) {522 pr_debug("found existing empty buffer\n");523 return 0;524 }525 526 if (buffer_size(prz) > prz->buffer_size ||527 buffer_start(prz) > buffer_size(prz)) {528 pr_info("found existing invalid buffer, size %zu, start %zu\n",529 buffer_size(prz), buffer_start(prz));530 zap = true;531 } else {532 pr_debug("found existing buffer, size %zu, start %zu\n",533 buffer_size(prz), buffer_start(prz));534 persistent_ram_save_old(prz);535 }536 } else {537 pr_debug("no valid data in buffer (sig = 0x%08x)\n",538 prz->buffer->sig);539 prz->buffer->sig = sig;540 zap = true;541 }542 543 /* Reset missing, invalid, or single-use memory area. */544 if (zap)545 persistent_ram_zap(prz);546 547 return 0;548}549 550void persistent_ram_free(struct persistent_ram_zone **_prz)551{552 struct persistent_ram_zone *prz;553 554 if (!_prz)555 return;556 557 prz = *_prz;558 if (!prz)559 return;560 561 if (prz->vaddr) {562 if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {563 /* We must vunmap() at page-granularity. */564 vunmap(prz->vaddr - offset_in_page(prz->paddr));565 } else {566 iounmap(prz->vaddr);567 release_mem_region(prz->paddr, prz->size);568 }569 prz->vaddr = NULL;570 }571 if (prz->rs_decoder) {572 free_rs(prz->rs_decoder);573 prz->rs_decoder = NULL;574 }575 kfree(prz->ecc_info.par);576 prz->ecc_info.par = NULL;577 578 persistent_ram_free_old(prz);579 kfree(prz->label);580 kfree(prz);581 *_prz = NULL;582}583 584struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,585 u32 sig, struct persistent_ram_ecc_info *ecc_info,586 unsigned int memtype, u32 flags, char *label)587{588 struct persistent_ram_zone *prz;589 int ret = -ENOMEM;590 591 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);592 if (!prz) {593 pr_err("failed to allocate persistent ram zone\n");594 goto err;595 }596 597 /* Initialize general buffer state. */598 raw_spin_lock_init(&prz->buffer_lock);599 prz->flags = flags;600 prz->label = kstrdup(label, GFP_KERNEL);601 if (!prz->label)602 goto err;603 604 ret = persistent_ram_buffer_map(start, size, prz, memtype);605 if (ret)606 goto err;607 608 ret = persistent_ram_post_init(prz, sig, ecc_info);609 if (ret)610 goto err;611 612 pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",613 prz->label, prz->size, (unsigned long long)prz->paddr,614 sizeof(*prz->buffer), prz->buffer_size,615 prz->size - sizeof(*prz->buffer) - prz->buffer_size,616 prz->ecc_info.ecc_size, prz->ecc_info.block_size);617 618 return prz;619err:620 persistent_ram_free(&prz);621 return ERR_PTR(ret);622}623