fs: Add pstore filesystem

pstore is a persistent storage filesystem used for RAMOOPS. It is used
to store console logs, panics, ftrace and other information in case of a
crash/panic/oops/reboot.

pstore is implemented for barebox as a read-only filesystem at the
moment. It may be extended later on. The idea is to provide a way to
extract essential data from the last running kernel.

Most of the code is copied from the kernel. However this is only a
lightweight implementation without real write support yet.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 507 insertions, 0 deletions

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
new file mode 100644
index 0000000000..dc31ed16f9
--- /dev/null
+++ b/fs/pstore/ram.c
@@ -0,0 +1,507 @@
+/*
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/pstore.h>
+#include <linux/time.h>
+#include <linux/ioport.h>
+#include <linux/compiler.h>
+#include <linux/pstore_ram.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/log2.h>
+#include <malloc.h>
+#include <printk.h>
+#include <stdio.h>
+#include <globalvar.h>
+#include <init.h>
+#include <common.h>
+
+#define RAMOOPS_KERNMSG_HDR "===="
+#define MIN_MEM_SIZE 4096UL
+
+static const ulong record_size = CONFIG_FS_PSTORE_RAMOOPS_RECORD_SIZE;
+
+static const ulong ramoops_console_size = CONFIG_FS_PSTORE_RAMOOPS_CONSOLE_SIZE;
+
+static const ulong ramoops_ftrace_size = CONFIG_FS_PSTORE_RAMOOPS_FTRACE_SIZE;
+
+static const ulong ramoops_pmsg_size = CONFIG_FS_PSTORE_RAMOOPS_PMSG_SIZE;
+
+static const ulong mem_size = CONFIG_FS_PSTORE_RAMOOPS_SIZE;
+
+static const int dump_oops = 1;
+
+static const int ramoops_ecc = CONFIG_FS_PSTORE_ECC_SIZE;
+
+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 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 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, 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;
+
+	prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
+				   cxt->max_dump_cnt, id, type,
+				   PSTORE_TYPE_DMESG, 0);
+	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);
+
+	/* 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), size);
+	persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
+
+	return size + ecc_notice_size;
+}
+
+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;
+
+	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;
+
+	/* 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];
+
+	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 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 = {
+		.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 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) {
+		pr_err("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) {
+		pr_err("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]);
+			pr_err("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 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) {
+		pr_err("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);
+
+		pr_err("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 ramoops_platform_data *pdata)
+{
+	struct ramoops_context *cxt = &oops_cxt;
+	size_t dump_mem_sz;
+	phys_addr_t paddr;
+	int err = -EINVAL;
+	char kernelargs[512];
+
+	/* 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(cxt, &paddr, dump_mem_sz);
+	if (err)
+		goto fail_out;
+
+	err = ramoops_init_prz(cxt, &cxt->cprz, &paddr,
+			       cxt->console_size, 0);
+	if (err)
+		goto fail_init_cprz;
+
+	err = ramoops_init_prz(cxt, &cxt->fprz, &paddr, cxt->ftrace_size, 0);
+	if (err)
+		goto fail_init_fprz;
+
+	err = ramoops_init_prz(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;
+	}
+
+	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);
+
+	scnprintf(kernelargs, sizeof(kernelargs),
+		  "ramoops.record_size=0x%x "
+		  "ramoops.console_size=0x%x "
+		  "ramoops.ftrace_size=0x%x "
+		  "ramoops.pmsg_size=0x%x "
+		  "ramoops.mem_address=0x%llx "
+		  "ramoops.mem_size=0x%lx "
+		  "ramoops.ecc=%d",
+		  cxt->record_size,
+		  cxt->console_size,
+		  cxt->ftrace_size,
+		  cxt->pmsg_size,
+		  (unsigned long long)cxt->phys_addr,
+		  mem_size,
+		  ramoops_ecc);
+	globalvar_add_simple("linux.bootargs.ramoops", kernelargs);
+
+	of_add_reserve_entry(cxt->phys_addr, cxt->phys_addr + mem_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;
+}
+unsigned long arm_mem_ramoops_get(void);
+
+static void ramoops_register_dummy(void)
+{
+	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 = arm_mem_ramoops_get();
+	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;
+
+	ramoops_probe(dummy_data);
+}
+
+static int __init ramoops_init(void)
+{
+	ramoops_register_dummy();
+	return 0;
+}
+postcore_initcall(ramoops_init);