text: /*
   * RAM Oops/Panic logger
   *
   * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
   *
   * 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.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   *
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/kernel.h>
  #include <linux/err.h>
  #include <linux/module.h>
  #include <linux/version.h>
  #include <linux/pstore.h>
  #include <linux/time.h>
  #include <linux/io.h>
  #include <linux/ioport.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/compiler.h>
  #include <linux/pstore_ram.h>
  
  #define RAMOOPS_KERNMSG_HDR "===="
  #define MIN_MEM_SIZE 4096UL
  
  static ulong record_size = MIN_MEM_SIZE;
  module_param(record_size, ulong, 0400);
  MODULE_PARM_DESC(record_size,
  		"size of each dump done on oops/panic");
  
  static ulong ramoops_console_size = MIN_MEM_SIZE;
  module_param_named(console_size, ramoops_console_size, ulong, 0400);
  MODULE_PARM_DESC(console_size, "size of kernel console log");
  
  static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  
  static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
  module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
  MODULE_PARM_DESC(pmsg_size, "size of user space message log");
  
  static ulong mem_address;
  module_param(mem_address, ulong, 0400);
  MODULE_PARM_DESC(mem_address,
  		"start of reserved RAM used to store oops/panic logs");
  
  static ulong mem_size;
  module_param(mem_size, ulong, 0400);
  MODULE_PARM_DESC(mem_size,
  		"size of reserved RAM used to store oops/panic logs");
  
  static unsigned int mem_type;
  module_param(mem_type, uint, 0600);
  MODULE_PARM_DESC(mem_type,
  		"set to 1 to try to use unbuffered memory (default 0)");
  
  static int dump_oops = 1;
  module_param(dump_oops, int, 0600);
  MODULE_PARM_DESC(dump_oops,
  		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
  
  static int ramoops_ecc;
  module_param_named(ecc, ramoops_ecc, int, 0600);
  MODULE_PARM_DESC(ramoops_ecc,
  		"if non-zero, the option enables ECC support and specifies "
  		"ECC buffer size in bytes (1 is a special value, means 16 "
  		"bytes ECC)");
  
  struct ramoops_context {
  	struct persistent_ram_zone **przs;
  	struct persistent_ram_zone *cprz;
  	struct persistent_ram_zone *fprz;
  	struct persistent_ram_zone *mprz;
  	phys_addr_t phys_addr;
  	unsigned long size;
  	unsigned int memtype;
  	size_t record_size;
  	size_t console_size;
  	size_t ftrace_size;
  	size_t pmsg_size;
  	int dump_oops;
  	struct persistent_ram_ecc_info ecc_info;
  	unsigned int max_dump_cnt;
  	unsigned int dump_write_cnt;
  	/* _read_cnt need clear on ramoops_pstore_open */
  	unsigned int dump_read_cnt;
  	unsigned int console_read_cnt;
  	unsigned int ftrace_read_cnt;
  	unsigned int pmsg_read_cnt;
  	struct pstore_info pstore;
  };
  
  static struct platform_device *dummy;
  static struct ramoops_platform_data *dummy_data;
  
  static int ramoops_pstore_open(struct pstore_info *psi)
  {
  	struct ramoops_context *cxt = psi->data;
  
  	cxt->dump_read_cnt = 0;
  	cxt->console_read_cnt = 0;
  	cxt->ftrace_read_cnt = 0;
  	cxt->pmsg_read_cnt = 0;
  	return 0;
  }
  
  static struct persistent_ram_zone *
  ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
  		     u64 *id,
  		     enum pstore_type_id *typep, enum pstore_type_id type,
  		     bool update)
  {
  	struct persistent_ram_zone *prz;
  	int i = (*c)++;
  
  	if (i >= max)
  		return NULL;
  
  	prz = przs[i];
  	if (!prz)
  		return NULL;
  
  	/* Update old/shadowed buffer. */
  	if (update)
  		persistent_ram_save_old(prz);
  
  	if (!persistent_ram_old_size(prz))
  		return NULL;
  
  	*typep = type;
  	*id = i;
  
  	return prz;
  }
  
  static int ramoops_read_kmsg_hdr(char *buffer, struct timespec *time,
  				  bool *compressed)
  {
  	char data_type;
  	int header_length = 0;
  
  	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n%n", &time->tv_sec,
  			&time->tv_nsec, &data_type, &header_length) == 3) {
  		if (data_type == 'C')
  			*compressed = true;
  		else
  			*compressed = false;
  	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu\n%n",
  			&time->tv_sec, &time->tv_nsec, &header_length) == 2) {
  			*compressed = false;
  	} else {
  		time->tv_sec = 0;
  		time->tv_nsec = 0;
  		*compressed = false;
  	}
  	return header_length;
  }
  
  static bool prz_ok(struct persistent_ram_zone *prz)
  {
  	return !!prz && !!(persistent_ram_old_size(prz) +
  			   persistent_ram_ecc_string(prz, NULL, 0));
  }
  
  static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
  				   int *count, struct timespec *time,
  				   char **buf, bool *compressed,
  				   struct pstore_info *psi)
  {
  	ssize_t size;
  	ssize_t ecc_notice_size;
  	struct ramoops_context *cxt = psi->data;
  	struct persistent_ram_zone *prz;
  	int header_length;
  
  	prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
  				   cxt->max_dump_cnt, id, type,
  				   PSTORE_TYPE_DMESG, 1);
  	if (!prz_ok(prz))
  		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
  					   1, id, type, PSTORE_TYPE_CONSOLE, 0);
  	if (!prz_ok(prz))
  		prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
  					   1, id, type, PSTORE_TYPE_FTRACE, 0);
  	if (!prz_ok(prz))
  		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
  					   1, id, type, PSTORE_TYPE_PMSG, 0);
  	if (!prz_ok(prz))
  		return 0;
  
  	if (!persistent_ram_old(prz))
  		return 0;
  
  	size = persistent_ram_old_size(prz);
  	header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz), time,
  			compressed);
  	size -= header_length;
  
  	/* ECC correction notice */
  	ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
  
  	*buf = kmalloc(size + ecc_notice_size + 1, GFP_KERNEL);
  	if (*buf == NULL)
  		return -ENOMEM;
  
  	memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
  	persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
  
  	return size + ecc_notice_size;
  }
  
  static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
  				     bool compressed)
  {
  	char *hdr;
  	struct timespec timestamp;
  	size_t len;
  
  	/* Report zeroed timestamp if called before timekeeping has resumed. */
  	if (__getnstimeofday(&timestamp)) {
  		timestamp.tv_sec = 0;
  		timestamp.tv_nsec = 0;
  	}
  	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
  		(long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
  		compressed ? 'C' : 'D');
  	WARN_ON_ONCE(!hdr);
  	len = hdr ? strlen(hdr) : 0;
  	persistent_ram_write(prz, hdr, len);
  	kfree(hdr);
  
  	return len;
  }
  
  static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
  					    enum kmsg_dump_reason reason,
  					    u64 *id, unsigned int part,
  					    const char *buf,
  					    bool compressed, size_t size,
  					    struct pstore_info *psi)
  {
  	struct ramoops_context *cxt = psi->data;
  	struct persistent_ram_zone *prz;
  	size_t hlen;
  
  	if (type == PSTORE_TYPE_CONSOLE) {
  		if (!cxt->cprz)
  			return -ENOMEM;
  		persistent_ram_write(cxt->cprz, buf, size);
  		return 0;
  	} else if (type == PSTORE_TYPE_FTRACE) {
  		if (!cxt->fprz)
  			return -ENOMEM;
  		persistent_ram_write(cxt->fprz, buf, size);
  		return 0;
  	} else if (type == PSTORE_TYPE_PMSG) {
  		if (!cxt->mprz)
  			return -ENOMEM;
  		persistent_ram_write(cxt->mprz, buf, size);
  		return 0;
  	}
  
  	if (type != PSTORE_TYPE_DMESG)
  		return -EINVAL;
  
  	/* Out of the various dmesg dump types, ramoops is currently designed
  	 * to only store crash logs, rather than storing general kernel logs.
  	 */
  	if (reason != KMSG_DUMP_OOPS &&
  	    reason != KMSG_DUMP_PANIC)
  		return -EINVAL;
  
  	/* Skip Oopes when configured to do so. */
  	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
  		return -EINVAL;
  
  	/* Explicitly only take the first part of any new crash.
  	 * If our buffer is larger than kmsg_bytes, this can never happen,
  	 * and if our buffer is smaller than kmsg_bytes, we don't want the
  	 * report split across multiple records.
  	 */
  	if (part != 1)
  		return -ENOSPC;
  
  	if (!cxt->przs)
  		return -ENOSPC;
  
  	prz = cxt->przs[cxt->dump_write_cnt];
  
  	hlen = ramoops_write_kmsg_hdr(prz, compressed);
  	if (size + hlen > prz->buffer_size)
  		size = prz->buffer_size - hlen;
  	persistent_ram_write(prz, buf, size);
  
  	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
  
  	return 0;
  }
  
  static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
  				struct timespec time, struct pstore_info *psi)
  {
  	struct ramoops_context *cxt = psi->data;
  	struct persistent_ram_zone *prz;
  
  	switch (type) {
  	case PSTORE_TYPE_DMESG:
  		if (id >= cxt->max_dump_cnt)
  			return -EINVAL;
  		prz = cxt->przs[id];
  		break;
  	case PSTORE_TYPE_CONSOLE:
  		prz = cxt->cprz;
  		break;
  	case PSTORE_TYPE_FTRACE:
  		prz = cxt->fprz;
  		break;
  	case PSTORE_TYPE_PMSG:
  		prz = cxt->mprz;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	persistent_ram_free_old(prz);
  	persistent_ram_zap(prz);
  
  	return 0;
  }
  
  static struct ramoops_context oops_cxt = {
  	.pstore = {
  		.owner	= THIS_MODULE,
  		.name	= "ramoops",
  		.open	= ramoops_pstore_open,
  		.read	= ramoops_pstore_read,
  		.write_buf	= ramoops_pstore_write_buf,
  		.erase	= ramoops_pstore_erase,
  	},
  };
  
  static void ramoops_free_przs(struct ramoops_context *cxt)
  {
  	int i;
  
  	cxt->max_dump_cnt = 0;
  	if (!cxt->przs)
  		return;
  
  	for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
  		persistent_ram_free(cxt->przs[i]);
  	kfree(cxt->przs);
  }
  
  static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
  			     phys_addr_t *paddr, size_t dump_mem_sz)
  {
  	int err = -ENOMEM;
  	int i;
  
  	if (!cxt->record_size)
  		return 0;
  
  	if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
  		dev_err(dev, "no room for dumps\n");
  		return -ENOMEM;
  	}
  
  	cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
  	if (!cxt->max_dump_cnt)
  		return -ENOMEM;
  
  	cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
  			     GFP_KERNEL);
  	if (!cxt->przs) {
  		dev_err(dev, "failed to initialize a prz array for dumps\n");
  		goto fail_prz;
  	}
  
  	for (i = 0; i < cxt->max_dump_cnt; i++) {
  		size_t sz = cxt->record_size;
  
  		cxt->przs[i] = persistent_ram_new(*paddr, sz, 0,
  						  &cxt->ecc_info,
  						  cxt->memtype);
  		if (IS_ERR(cxt->przs[i])) {
  			err = PTR_ERR(cxt->przs[i]);
  			dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
  				sz, (unsigned long long)*paddr, err);
  			goto fail_prz;
  		}
  		*paddr += sz;
  	}
  
  	return 0;
  fail_prz:
  	ramoops_free_przs(cxt);
  	return err;
  }
  
  static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
  			    struct persistent_ram_zone **prz,
  			    phys_addr_t *paddr, size_t sz, u32 sig)
  {
  	if (!sz)
  		return 0;
  
  	if (*paddr + sz - cxt->phys_addr > cxt->size) {
  		dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
  			sz, (unsigned long long)*paddr,
  			cxt->size, (unsigned long long)cxt->phys_addr);
  		return -ENOMEM;
  	}
  
  	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype);
  	if (IS_ERR(*prz)) {
  		int err = PTR_ERR(*prz);
  
  		dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
  			sz, (unsigned long long)*paddr, err);
  		return err;
  	}
  
  	persistent_ram_zap(*prz);
  
  	*paddr += sz;
  
  	return 0;
  }
  
  static int ramoops_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct ramoops_platform_data *pdata = pdev->dev.platform_data;
  	struct ramoops_context *cxt = &oops_cxt;
  	size_t dump_mem_sz;
  	phys_addr_t paddr;
  	int err = -EINVAL;
  
  	/* Only a single ramoops area allowed at a time, so fail extra
  	 * probes.
  	 */
  	if (cxt->max_dump_cnt)
  		goto fail_out;
  
  	if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
  			!pdata->ftrace_size && !pdata->pmsg_size)) {
  		pr_err("The memory size and the record/console size must be "
  			"non-zero\n");
  		goto fail_out;
  	}
  
  	if (pdata->record_size && !is_power_of_2(pdata->record_size))
  		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
  	if (pdata->console_size && !is_power_of_2(pdata->console_size))
  		pdata->console_size = rounddown_pow_of_two(pdata->console_size);
  	if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
  		pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
  	if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
  		pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
  
  	cxt->size = pdata->mem_size;
  	cxt->phys_addr = pdata->mem_address;
  	cxt->memtype = pdata->mem_type;
  	cxt->record_size = pdata->record_size;
  	cxt->console_size = pdata->console_size;
  	cxt->ftrace_size = pdata->ftrace_size;
  	cxt->pmsg_size = pdata->pmsg_size;
  	cxt->dump_oops = pdata->dump_oops;
  	cxt->ecc_info = pdata->ecc_info;
  
  	paddr = cxt->phys_addr;
  
  	dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
  			- cxt->pmsg_size;
  	err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
  	if (err)
  		goto fail_out;
  
  	err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
  			       cxt->console_size, 0);
  	if (err)
  		goto fail_init_cprz;
  
  	err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
  			       LINUX_VERSION_CODE);
  	if (err)
  		goto fail_init_fprz;
  
  	err = ramoops_init_prz(dev, cxt, &cxt->mprz, &paddr, cxt->pmsg_size, 0);
  	if (err)
  		goto fail_init_mprz;
  
  	cxt->pstore.data = cxt;
  	/*
  	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
  	 * have to handle dumps, we must have at least record_size buffer. And
  	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
  	 * ZERO_SIZE_PTR).
  	 */
  	if (cxt->console_size)
  		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
  	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
  	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
  	spin_lock_init(&cxt->pstore.buf_lock);
  	if (!cxt->pstore.buf) {
  		pr_err("cannot allocate pstore buffer\n");
  		err = -ENOMEM;
  		goto fail_clear;
  	}
  
  	err = pstore_register(&cxt->pstore);
  	if (err) {
  		pr_err("registering with pstore failed\n");
  		goto fail_buf;
  	}
  
  	/*
  	 * Update the module parameter variables as well so they are visible
  	 * through /sys/module/ramoops/parameters/
  	 */
  	mem_size = pdata->mem_size;
  	mem_address = pdata->mem_address;
  	record_size = pdata->record_size;
  	dump_oops = pdata->dump_oops;
  	ramoops_console_size = pdata->console_size;
  	ramoops_pmsg_size = pdata->pmsg_size;
  	ramoops_ftrace_size = pdata->ftrace_size;
  
  	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
  		cxt->size, (unsigned long long)cxt->phys_addr,
  		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
  
  	return 0;
  
  fail_buf:
  	kfree(cxt->pstore.buf);
  fail_clear:
  	cxt->pstore.bufsize = 0;
  	kfree(cxt->mprz);
  fail_init_mprz:
  	kfree(cxt->fprz);
  fail_init_fprz:
  	kfree(cxt->cprz);
  fail_init_cprz:
  	ramoops_free_przs(cxt);
  fail_out:
  	return err;
  }
  
  static int __exit ramoops_remove(struct platform_device *pdev)
  {
  #if 0
  	/* TODO(kees): We cannot unload ramoops since pstore doesn't support
  	 * unregistering yet.
  	 */
  	struct ramoops_context *cxt = &oops_cxt;
  
  	iounmap(cxt->virt_addr);
  	release_mem_region(cxt->phys_addr, cxt->size);
  	cxt->max_dump_cnt = 0;
  
  	/* TODO(kees): When pstore supports unregistering, call it here. */
  	kfree(cxt->pstore.buf);
  	cxt->pstore.bufsize = 0;
  
  	return 0;
  #endif
  	return -EBUSY;
  }
  
  static struct platform_driver ramoops_driver = {
  	.probe		= ramoops_probe,
  	.remove		= __exit_p(ramoops_remove),
  	.driver		= {
  		.name	= "ramoops",
  	},
  };
  
  static void ramoops_register_dummy(void)
  {
  	if (!mem_size)
  		return;
  
  	pr_info("using module parameters\n");
  
  	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
  	if (!dummy_data) {
  		pr_info("could not allocate pdata\n");
  		return;
  	}
  
  	dummy_data->mem_size = mem_size;
  	dummy_data->mem_address = mem_address;
  	dummy_data->mem_type = 0;
  	dummy_data->record_size = record_size;
  	dummy_data->console_size = ramoops_console_size;
  	dummy_data->ftrace_size = ramoops_ftrace_size;
  	dummy_data->pmsg_size = ramoops_pmsg_size;
  	dummy_data->dump_oops = dump_oops;
  	/*
  	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
  	 * (using 1 byte for ECC isn't much of use anyway).
  	 */
  	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
  
  	dummy = platform_device_register_data(NULL, "ramoops", -1,
  			dummy_data, sizeof(struct ramoops_platform_data));
  	if (IS_ERR(dummy)) {
  		pr_info("could not create platform device: %ld\n",
  			PTR_ERR(dummy));
  	}
  }
  
  static int __init ramoops_init(void)
  {
  	ramoops_register_dummy();
  	return platform_driver_register(&ramoops_driver);
  }
  postcore_initcall(ramoops_init);
  
  static void __exit ramoops_exit(void)
  {
  	platform_driver_unregister(&ramoops_driver);
  	platform_device_unregister(dummy);
  	kfree(dummy_data);
  }
  module_exit(ramoops_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
  MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
  