Add efi variables as a pstore backend

Add efi variables as a pstore backend

[Matthew Garrett]

The same as the last attempt, but with Tony's comments on patch 4 addressed.

[PATCH V2 1/9] pstore: Extend API

[Matthew Garrett]

Some pstore implementations may not have a static context, so extend the
API to pass the pstore_info struct to all calls and allow for a context
pointer.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/acpi/apei/erst.c |   18 +++++++++++++-----
 fs/pstore/inode.c        |   10 +++++-----
 fs/pstore/internal.h     |    2 +-
 fs/pstore/platform.c     |   13 +++++++------
 include/linux/pstore.h   |    8 +++++---
 5 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index c8ba9da..8aac55e 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -932,8 +932,10 @@ static int erst_check_table(struct acpi_table_erst *erst_tab)
 static int erst_open_pstore(struct pstore_info *psi);
 static int erst_close_pstore(struct pstore_info *psi);
 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
-		       struct timespec *time);
-static u64 erst_writer(enum pstore_type_id type, size_t size);
+			   struct timespec *time, struct pstore_info *psi);
+static u64 erst_writer(enum pstore_type_id type, size_t size,
+		       struct pstore_info *psi);
+static int erst_clearer(u64 id, struct pstore_info *psi);
 
 static struct pstore_info erst_info = {
 	.owner		= THIS_MODULE,
@@ -942,7 +944,7 @@ static struct pstore_info erst_info = {
 	.close		= erst_close_pstore,
 	.read		= erst_reader,
 	.write		= erst_writer,
-	.erase		= erst_clear
+	.erase		= erst_clearer
 };
 
 #define CPER_CREATOR_PSTORE						\
@@ -983,7 +985,7 @@ static int erst_close_pstore(struct pstore_info *psi)
 }
 
 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
-		       struct timespec *time)
+			   struct timespec *time, struct pstore_info *psi)
 {
 	int rc;
 	ssize_t len = 0;
@@ -1037,7 +1039,8 @@ out:
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static u64 erst_writer(enum pstore_type_id type, size_t size)
+static u64 erst_writer(enum pstore_type_id type, size_t size,
+		       struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
 					(erst_info.buf - sizeof(*rcd));
@@ -1080,6 +1083,11 @@ static u64 erst_writer(enum pstore_type_id type, size_t size)
 	return rcd->hdr.record_id;
 }
 
+static int erst_clearer(u64 id, struct pstore_info *psi)
+{
+	return erst_clear(id);
+}
+
 static int __init erst_init(void)
 {
 	int rc = 0;
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 977ed27..b19884a 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -40,7 +40,7 @@
 
 struct pstore_private {
 	u64	id;
-	int	(*erase)(u64);
+	struct pstore_info *psi;
 	ssize_t	size;
 	char	data[];
 };
@@ -73,7 +73,7 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct pstore_private *p = dentry->d_inode->i_private;
 
-	p->erase(p->id);
+	p->psi->erase(p->id, p->psi);
 
 	return simple_unlink(dir, dentry);
 }
@@ -175,8 +175,8 @@ int pstore_is_mounted(void)
  * Set the mtime & ctime to the date that this record was originally stored.
  */
 int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
-			      char *data, size_t size,
-			      struct timespec time, int (*erase)(u64))
+		  char *data, size_t size, struct timespec time,
+		  struct pstore_info *psi)
 {
 	struct dentry		*root = pstore_sb->s_root;
 	struct dentry		*dentry;
@@ -193,7 +193,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 	if (!private)
 		goto fail_alloc;
 	private->id = id;
-	private->erase = erase;
+	private->psi = psi;
 
 	switch (type) {
 	case PSTORE_TYPE_DMESG:
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 8c9f23e..611c1b3 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -2,5 +2,5 @@ extern void	pstore_set_kmsg_bytes(int);
 extern void	pstore_get_records(void);
 extern int	pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
 			      char *data, size_t size,
-			      struct timespec time, int (*erase)(u64));
+			      struct timespec time, struct pstore_info *psi);
 extern int	pstore_is_mounted(void);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index f2c3ff2..221c04e 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -94,11 +94,12 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		memcpy(dst, s1 + s1_start, l1_cpy);
 		memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
 
-		id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy);
+		id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy,
+				   psinfo);
 		if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
 			pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
 				      psinfo->buf, hsize + l1_cpy + l2_cpy,
-				      CURRENT_TIME, psinfo->erase);
+				      CURRENT_TIME, psinfo);
 		l1 -= l1_cpy;
 		l2 -= l2_cpy;
 		total += l1_cpy + l2_cpy;
@@ -166,9 +167,9 @@ void pstore_get_records(void)
 	if (rc)
 		goto out;
 
-	while ((size = psi->read(&id, &type, &time)) > 0) {
+	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
 		if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
-				  time, psi->erase))
+				  time, psi))
 			failed++;
 	}
 	psi->close(psi);
@@ -196,10 +197,10 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 
 	mutex_lock(&psinfo->buf_mutex);
 	memcpy(psinfo->buf, buf, size);
-	id = psinfo->write(type, size);
+	id = psinfo->write(type, size, psinfo);
 	if (pstore_is_mounted())
 		pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
-			      size, CURRENT_TIME, psinfo->erase);
+			      size, CURRENT_TIME, psinfo);
 	mutex_unlock(&psinfo->buf_mutex);
 
 	return 0;
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 2455ef2..b2f1d97 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -38,9 +38,11 @@ struct pstore_info {
 	int		(*open)(struct pstore_info *psi);
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
-			struct timespec *time);
-	u64		(*write)(enum pstore_type_id type, size_t size);
-	int		(*erase)(u64 id);
+			struct timespec *time, struct pstore_info *psi);
+	u64		(*write)(enum pstore_type_id type, size_t size,
+			struct pstore_info *psi);
+	int		(*erase)(u64 id, struct pstore_info *psi);
+	void		*data;
 };
 
 #ifdef CONFIG_PSTORE
-- 
1.7.6

[PATCH V2 2/9] pstore: Add extra context for writes and erases

[Matthew Garrett]

EFI only provides small amounts of individual storage, and conventionally
puts metadata in the storage variable name. Rather than add a metadata
header to the (already limited) variable storage, it's easier for us to
modify pstore to pass all the information we need to construct a unique
variable name to the appropriate functions.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/acpi/apei/erst.c |   10 ++++++----
 fs/pstore/inode.c        |    6 ++++--
 fs/pstore/platform.c     |    9 +++++----
 include/linux/pstore.h   |    5 +++--
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index 8aac55e..51cf7ba 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -933,9 +933,10 @@ static int erst_open_pstore(struct pstore_info *psi);
 static int erst_close_pstore(struct pstore_info *psi);
 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
 			   struct timespec *time, struct pstore_info *psi);
-static u64 erst_writer(enum pstore_type_id type, size_t size,
+static u64 erst_writer(enum pstore_type_id type, int part, size_t size,
 		       struct pstore_info *psi);
-static int erst_clearer(u64 id, struct pstore_info *psi);
+static int erst_clearer(enum pstore_type_id type, u64 id,
+			struct pstore_info *psi);
 
 static struct pstore_info erst_info = {
 	.owner		= THIS_MODULE,
@@ -1039,7 +1040,7 @@ out:
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static u64 erst_writer(enum pstore_type_id type, size_t size,
+static u64 erst_writer(enum pstore_type_id type, int part, size_t size,
 		       struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
@@ -1083,7 +1084,8 @@ static u64 erst_writer(enum pstore_type_id type, size_t size,
 	return rcd->hdr.record_id;
 }
 
-static int erst_clearer(u64 id, struct pstore_info *psi)
+static int erst_clearer(enum pstore_type_id type, u64 id,
+			struct pstore_info *psi)
 {
 	return erst_clear(id);
 }
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index b19884a..893b961 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -39,8 +39,9 @@
 #define	PSTORE_NAMELEN	64
 
 struct pstore_private {
-	u64	id;
 	struct pstore_info *psi;
+	enum pstore_type_id type;
+	u64	id;
 	ssize_t	size;
 	char	data[];
 };
@@ -73,7 +74,7 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct pstore_private *p = dentry->d_inode->i_private;
 
-	p->psi->erase(p->id, p->psi);
+	p->psi->erase(p->type, p->id, p->psi);
 
 	return simple_unlink(dir, dentry);
 }
@@ -192,6 +193,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 	private = kmalloc(sizeof *private + size, GFP_KERNEL);
 	if (!private)
 		goto fail_alloc;
+	private->type = type;
 	private->id = id;
 	private->psi = psi;
 
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 221c04e..163bb40 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -78,7 +78,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 	oopscount++;
 	while (total < kmsg_bytes) {
 		dst = psinfo->buf;
-		hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part++);
+		hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
 		size = psinfo->bufsize - hsize;
 		dst += hsize;
 
@@ -94,8 +94,8 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		memcpy(dst, s1 + s1_start, l1_cpy);
 		memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
 
-		id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy,
-				   psinfo);
+		id = psinfo->write(PSTORE_TYPE_DMESG, part,
+				   hsize + l1_cpy + l2_cpy, psinfo);
 		if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
 			pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
 				      psinfo->buf, hsize + l1_cpy + l2_cpy,
@@ -103,6 +103,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		l1 -= l1_cpy;
 		l2 -= l2_cpy;
 		total += l1_cpy + l2_cpy;
+		part++;
 	}
 	mutex_unlock(&psinfo->buf_mutex);
 }
@@ -197,7 +198,7 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 
 	mutex_lock(&psinfo->buf_mutex);
 	memcpy(psinfo->buf, buf, size);
-	id = psinfo->write(type, size, psinfo);
+	id = psinfo->write(type, 0, size, psinfo);
 	if (pstore_is_mounted())
 		pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
 			      size, CURRENT_TIME, psinfo);
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index b2f1d97..12be8f1 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -39,9 +39,10 @@ struct pstore_info {
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
 			struct timespec *time, struct pstore_info *psi);
-	u64		(*write)(enum pstore_type_id type, size_t size,
+	u64		(*write)(enum pstore_type_id type, int part,
+			size_t size, struct pstore_info *psi);
+	int		(*erase)(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);
-	int		(*erase)(u64 id, struct pstore_info *psi);
 	void		*data;
 };
 
-- 
1.7.6

[PATCH V2 3/9] pstore: Make "part" unsigned

[Matthew Garrett]

We'll never have a negative part, so just make this an unsigned int.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/acpi/apei/erst.c |    8 ++++----
 fs/pstore/platform.c     |    3 ++-
 include/linux/pstore.h   |    2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index 51cf7ba..2ca59dc 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -933,8 +933,8 @@ static int erst_open_pstore(struct pstore_info *psi);
 static int erst_close_pstore(struct pstore_info *psi);
 static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
 			   struct timespec *time, struct pstore_info *psi);
-static u64 erst_writer(enum pstore_type_id type, int part, size_t size,
-		       struct pstore_info *psi);
+static u64 erst_writer(enum pstore_type_id type, unsigned int part,
+		       size_t size, struct pstore_info *psi);
 static int erst_clearer(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);
 
@@ -1040,8 +1040,8 @@ out:
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static u64 erst_writer(enum pstore_type_id type, int part, size_t size,
-		       struct pstore_info *psi)
+static u64 erst_writer(enum pstore_type_id type, unsigned int part,
+		       size_t size, struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
 					(erst_info.buf - sizeof(*rcd));
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 163bb40..49ff1de 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -67,7 +67,8 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 	unsigned long	size, total = 0;
 	char		*dst, *why;
 	u64		id;
-	int		hsize, part = 1;
+	int		hsize;
+	unsigned int	part = 1;
 
 	if (reason < ARRAY_SIZE(reason_str))
 		why = reason_str[reason];
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 12be8f1..cc03bbf 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -39,7 +39,7 @@ struct pstore_info {
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
 			struct timespec *time, struct pstore_info *psi);
-	u64		(*write)(enum pstore_type_id type, int part,
+	u64		(*write)(enum pstore_type_id type, unsigned int part,
 			size_t size, struct pstore_info *psi);
 	int		(*erase)(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);
-- 
1.7.6

[PATCH V2 4/9] pstore: Allow the user to explicitly choose a backend

[Matthew Garrett]

pstore only allows one backend to be registered at present, but the
system may provide several. Add a parameter to allow the user to choose
which backend will be used rather than just relying on load order.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 Documentation/ABI/testing/pstore    |    6 ++++++
 Documentation/kernel-parameters.txt |    2 ++
 fs/pstore/platform.c                |   11 +++++++++++
 3 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/pstore b/Documentation/ABI/testing/pstore
index ddf451e..ff1df4e 100644
--- a/Documentation/ABI/testing/pstore
+++ b/Documentation/ABI/testing/pstore
@@ -39,3 +39,9 @@ Description:	Generic interface to platform dependent persistent storage.
 		multiple) files based on the record size of the underlying
 		persistent storage until at least this amount is reached.
 		Default is 10 Kbytes.
+
+		Pstore only supports one backend at a time. If multiple
+		backends are available, the preferred backend may be
+		set by passing the pstore.backend= argument to the kernel at
+		boot time.
+
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ede3209..abafa88 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2156,6 +2156,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			[HW,MOUSE] Controls Logitech smartscroll autorepeat.
 			0 = disabled, 1 = enabled (default).
 
+	pstore.backend=	Specify the name of the pstore backend to use
+
 	pt.		[PARIDE]
 			See Documentation/blockdev/paride.txt.
 
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 49ff1de..c5300ec 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -37,6 +37,8 @@
 static DEFINE_SPINLOCK(pstore_lock);
 static struct pstore_info *psinfo;
 
+static char *backend;
+
 /* How much of the console log to snapshot */
 static unsigned long kmsg_bytes = 10240;
 
@@ -131,6 +133,12 @@ int pstore_register(struct pstore_info *psi)
 		spin_unlock(&pstore_lock);
 		return -EBUSY;
 	}
+
+	if (backend && strcmp(backend, psi->name)) {
+		spin_unlock(&pstore_lock);
+		return -EINVAL;
+	}
+
 	psinfo = psi;
 	spin_unlock(&pstore_lock);
 
@@ -208,3 +216,6 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_write);
+
+module_param(backend, charp, 0444);
+MODULE_PARM_DESC(backend, "Pstore backend to use");
-- 
1.7.6

[PATCH V2 5/9] efi: Add support for using efivars as a pstore backend

[Matthew Garrett]

EFI provides an area of nonvolatile storage managed by the firmware. We
can use this as a pstore backend to maintain copies of oopses, aiding
diagnosis.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/firmware/efivars.c |  191 +++++++++++++++++++++++++++++++++++++++++++-
 include/linux/efi.h        |    6 ++
 2 files changed, 195 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 5f29aaf..2bbb226 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -78,6 +78,7 @@
 #include <linux/kobject.h>
 #include <linux/device.h>
 #include <linux/slab.h>
+#include <linux/pstore.h>
 
 #include <asm/uaccess.h>
 
@@ -89,6 +90,8 @@ MODULE_DESCRIPTION("sysfs interface to EFI Variables");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(EFIVARS_VERSION);
 
+#define DUMP_NAME_LEN 52
+
 /*
  * The maximum size of VariableName + Data = 1024
  * Therefore, it's reasonable to save that much
@@ -161,18 +164,28 @@ utf8_strsize(efi_char16_t *data, unsigned long maxlength)
 }
 
 static efi_status_t
-get_var_data(struct efivars *efivars, struct efi_variable *var)
+get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 {
 	efi_status_t status;
 
-	spin_lock(&efivars->lock);
 	var->DataSize = 1024;
 	status = efivars->ops->get_variable(var->VariableName,
 					    &var->VendorGuid,
 					    &var->Attributes,
 					    &var->DataSize,
 					    var->Data);
+	return status;
+}
+
+static efi_status_t
+get_var_data(struct efivars *efivars, struct efi_variable *var)
+{
+	efi_status_t status;
+
+	spin_lock(&efivars->lock);
+	status = get_var_data_locked(efivars, var);
 	spin_unlock(&efivars->lock);
+
 	if (status != EFI_SUCCESS) {
 		printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
 			status);
@@ -387,12 +400,176 @@ static struct kobj_type efivar_ktype = {
 	.default_attrs = def_attrs,
 };
 
+static struct pstore_info efi_pstore_info;
+
 static inline void
 efivar_unregister(struct efivar_entry *var)
 {
 	kobject_put(&var->kobj);
 }
 
+#ifdef CONFIG_PSTORE
+
+static int efi_pstore_open(struct pstore_info *psi)
+{
+	struct efivars *efivars = psi->data;
+
+	spin_lock(&efivars->lock);
+	efivars->walk_entry = list_first_entry(&efivars->list,
+					       struct efivar_entry, list);
+	return 0;
+}
+
+static int efi_pstore_close(struct pstore_info *psi)
+{
+	struct efivars *efivars = psi->data;
+
+	spin_unlock(&efivars->lock);
+	return 0;
+}
+
+static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
+			       struct timespec *timespec, struct pstore_info *psi)
+{
+	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+	struct efivars *efivars = psi->data;
+	char name[DUMP_NAME_LEN];
+	int i;
+	unsigned int part, size;
+	unsigned long time;
+
+	while (&efivars->walk_entry->list != &efivars->list) {
+		if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
+				 vendor)) {
+			for (i = 0; i < DUMP_NAME_LEN; i++) {
+				name[i] = efivars->walk_entry->var.VariableName[i];
+			}
+			if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
+				*id = part;
+				timespec->tv_sec = time;
+				timespec->tv_nsec = 0;
+				get_var_data_locked(efivars, &efivars->walk_entry->var);
+				size = efivars->walk_entry->var.DataSize;
+				memcpy(psi->buf, efivars->walk_entry->var.Data, size);
+				efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
+					           struct efivar_entry, list);
+				return size;
+			}
+		}
+		efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
+						 struct efivar_entry, list);
+	}
+	return 0;
+}
+
+static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
+			    size_t size, struct pstore_info *psi)
+{
+	char name[DUMP_NAME_LEN];
+	char stub_name[DUMP_NAME_LEN];
+	efi_char16_t efi_name[DUMP_NAME_LEN];
+	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+	struct efivars *efivars = psi->data;
+	struct efivar_entry *entry, *found = NULL;
+	int i;
+
+	sprintf(stub_name, "dump-type%u-%u-", type, part);
+	sprintf(name, "%s%lu", stub_name, get_seconds());
+
+	spin_lock(&efivars->lock);
+
+	for (i = 0; i < DUMP_NAME_LEN; i++)
+		efi_name[i] = stub_name[i];
+
+	/*
+	 * Clean up any entries with the same name
+	 */
+
+	list_for_each_entry(entry, &efivars->list, list) {
+		get_var_data_locked(efivars, &entry->var);
+
+		for (i = 0; i < DUMP_NAME_LEN; i++) {
+			if (efi_name[i] == 0) {
+				found = entry;
+				efivars->ops->set_variable(entry->var.VariableName,
+							   &entry->var.VendorGuid,
+							   EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
+							   0, NULL);
+				break;
+			} else if (efi_name[i] != entry->var.VariableName[i]) {
+				break;
+			}
+		}
+	}
+
+	if (found)
+		list_del(&found->list);
+
+	for (i = 0; i < DUMP_NAME_LEN; i++)
+		efi_name[i] = name[i];
+
+	efivars->ops->set_variable(efi_name, &vendor,
+				   EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
+				   size, psi->buf);
+
+	spin_unlock(&efivars->lock);
+
+	if (found)
+		efivar_unregister(found);
+
+	if (size)
+		efivar_create_sysfs_entry(efivars, utf8_strsize(efi_name, DUMP_NAME_LEN * 2),
+					  efi_name, &vendor);
+
+	return part;
+};
+
+static int efi_pstore_erase(enum pstore_type_id type, u64 id,
+			    struct pstore_info *psi)
+{
+	efi_pstore_write(type, id, 0, psi);
+
+	return 0;
+}
+#else
+static int efi_pstore_open(struct pstore_info *psi)
+{
+	return 0;
+}
+
+static int efi_pstore_close(struct pstore_info *psi)
+{
+	return 0;
+}
+
+static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
+			       struct timespec *time, struct pstore_info *psi)
+{
+	return -1;
+}
+
+static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size,
+			    struct pstore_info *psi)
+{
+	return 0;
+}
+
+static int efi_pstore_erase(enum pstore_type_id type, u64 id,
+			    struct pstore_info *psi)
+{
+	return 0;
+}
+#endif
+
+static struct pstore_info efi_pstore_info = {
+	.owner		= THIS_MODULE,
+	.name		= "efi",
+	.open		= efi_pstore_open,
+	.close		= efi_pstore_close,
+	.read		= efi_pstore_read,
+	.write		= efi_pstore_write,
+	.erase		= efi_pstore_erase,
+};
 
 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 			     struct bin_attribute *bin_attr,
@@ -763,6 +940,16 @@ int register_efivars(struct efivars *efivars,
 	if (error)
 		unregister_efivars(efivars);
 
+	efivars->efi_pstore_info = efi_pstore_info;
+
+	efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+	if (efivars->efi_pstore_info.buf) {
+		efivars->efi_pstore_info.bufsize = 1024;
+		efivars->efi_pstore_info.data = efivars;
+		mutex_init(&efivars->efi_pstore_info.buf_mutex);
+		pstore_register(&efivars->efi_pstore_info);
+	}
+
 out:
 	kfree(variable_name);
 
diff --git a/include/linux/efi.h b/include/linux/efi.h
index ec25726..2362a0b 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -19,6 +19,7 @@
 #include <linux/rtc.h>
 #include <linux/ioport.h>
 #include <linux/pfn.h>
+#include <linux/pstore.h>
 
 #include <asm/page.h>
 #include <asm/system.h>
@@ -232,6 +233,9 @@ typedef efi_status_t efi_query_capsule_caps_t(efi_capsule_header_t **capsules,
 #define UV_SYSTEM_TABLE_GUID \
     EFI_GUID(  0x3b13a7d4, 0x633e, 0x11dd, 0x93, 0xec, 0xda, 0x25, 0x56, 0xd8, 0x95, 0x93 )
 
+#define LINUX_EFI_CRASH_GUID \
+    EFI_GUID(  0xcfc8fc79, 0xbe2e, 0x4ddc, 0x97, 0xf0, 0x9f, 0x98, 0xbf, 0xe2, 0x98, 0xa0 )
+
 typedef struct {
 	efi_guid_t guid;
 	unsigned long table;
@@ -458,6 +462,8 @@ struct efivars {
 	struct kset *kset;
 	struct bin_attribute *new_var, *del_var;
 	const struct efivar_operations *ops;
+	struct efivar_entry *walk_entry;
+	struct pstore_info efi_pstore_info;
 };
 
 int register_efivars(struct efivars *efivars,
-- 
1.7.6

[PATCH V2 6/9] efivars: String functions

[Matthew Garrett]

From: Mike Waychison <mikew@google.com>

Fix the string functions in the efivars driver to be called utf16_*
instead of utf8_* as the encoding is utf16, not utf8.

As well, rename utf16_strlen to utf16_strnlen as it takes a maxlength
argument and the name should be consistent with the standard C function
names.  utf16_strlen is still provided for convenience in a subsequent
patch.

Signed-off-by: Mike Waychison <mikew@google.com>
---
 drivers/firmware/efivars.c |   30 +++++++++++++++++++-----------
 1 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 2bbb226..4202a31 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -144,23 +144,29 @@ efivar_create_sysfs_entry(struct efivars *efivars,
 
 /* Return the number of unicode characters in data */
 static unsigned long
-utf8_strlen(efi_char16_t *data, unsigned long maxlength)
+utf16_strnlen(efi_char16_t *s, size_t maxlength)
 {
 	unsigned long length = 0;
 
-	while (*data++ != 0 && length < maxlength)
+	while (*s++ != 0 && length < maxlength)
 		length++;
 	return length;
 }
 
+static unsigned long
+utf16_strlen(efi_char16_t *s)
+{
+	return utf16_strnlen(s, ~0UL);
+}
+
 /*
  * Return the number of bytes is the length of this string
  * Note: this is NOT the same as the number of unicode characters
  */
 static inline unsigned long
-utf8_strsize(efi_char16_t *data, unsigned long maxlength)
+utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 {
-	return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
+	return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 }
 
 static efi_status_t
@@ -518,7 +524,9 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 		efivar_unregister(found);
 
 	if (size)
-		efivar_create_sysfs_entry(efivars, utf8_strsize(efi_name, DUMP_NAME_LEN * 2),
+		efivar_create_sysfs_entry(efivars,
+					  utf16_strsize(efi_name,
+							DUMP_NAME_LEN * 2),
 					  efi_name, &vendor);
 
 	return part;
@@ -591,8 +599,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 	 * Does this variable already exist?
 	 */
 	list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
-		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
-		strsize2 = utf8_strsize(new_var->VariableName, 1024);
+		strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
+		strsize2 = utf16_strsize(new_var->VariableName, 1024);
 		if (strsize1 == strsize2 &&
 			!memcmp(&(search_efivar->var.VariableName),
 				new_var->VariableName, strsize1) &&
@@ -624,8 +632,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 
 	/* Create the entry in sysfs.  Locking is not required here */
 	status = efivar_create_sysfs_entry(efivars,
-					   utf8_strsize(new_var->VariableName,
-							1024),
+					   utf16_strsize(new_var->VariableName,
+							 1024),
 					   new_var->VariableName,
 					   &new_var->VendorGuid);
 	if (status) {
@@ -654,8 +662,8 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 	 * Does this variable already exist?
 	 */
 	list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
-		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
-		strsize2 = utf8_strsize(del_var->VariableName, 1024);
+		strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
+		strsize2 = utf16_strsize(del_var->VariableName, 1024);
 		if (strsize1 == strsize2 &&
 			!memcmp(&(search_efivar->var.VariableName),
 				del_var->VariableName, strsize1) &&
-- 
1.7.6

[PATCH V2 7/9] efivars: introduce utf16_strncmp

[Matthew Garrett]

From: Mike Waychison <mikew@google.com>

Introduce utf16_strncmp which is used in the next patch.  Semantics
should be the same as the strncmp C function.

Signed-off-by: Mike Waychison <mikew@google.com>
---
 drivers/firmware/efivars.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 4202a31..15b9a01 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -169,6 +169,24 @@ utf16_strsize(efi_char16_t *data, unsigned long maxlength)
 	return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
 }
 
+static inline int
+utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
+{
+	while (1) {
+		if (len == 0)
+			return 0;
+		if (*a < *b)
+			return -1;
+		if (*a > *b)
+			return 1;
+		if (*a == 0) /* implies *b == 0 */
+			return 0;
+		a++;
+		b++;
+		len--;
+	}
+}
+
 static efi_status_t
 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
 {
-- 
1.7.6

[PATCH V2 8/9] efivars: Use string functions in pstore_write

[Matthew Garrett]

From: Mike Waychison <mikew@google.com>

Instead of open-coding the string operations for comparing the prefix of
the variable names, use the provided utf16_* string functions.

This patch also changes the calls to efi.set_variable to
efivars->ops->set_variable so that the right function gets called in the
case of gsmi (which doesn't have a valid efi structure).

As well, make sure that we only consider variables with the right vendor
string.

Signed-off-by: Mike Waychison <mikew@google.com>
---
 drivers/firmware/efivars.c |   26 ++++++++++++++------------
 1 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 15b9a01..563492e 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -512,18 +512,20 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 	list_for_each_entry(entry, &efivars->list, list) {
 		get_var_data_locked(efivars, &entry->var);
 
-		for (i = 0; i < DUMP_NAME_LEN; i++) {
-			if (efi_name[i] == 0) {
-				found = entry;
-				efivars->ops->set_variable(entry->var.VariableName,
-							   &entry->var.VendorGuid,
-							   EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
-							   0, NULL);
-				break;
-			} else if (efi_name[i] != entry->var.VariableName[i]) {
-				break;
-			}
-		}
+		if (efi_guidcmp(entry->var.VendorGuid, vendor))
+			continue;
+		if (utf16_strncmp(entry->var.VariableName, efi_name,
+				  utf16_strlen(efi_name)))
+			continue;
+		/* Needs to be a prefix */
+		if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
+			continue;
+
+		/* found */
+		found = entry;
+		efivars->ops->set_variable(entry->var.VariableName, &entry->var.VendorGuid,
+					   EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
+					   0, NULL);
 	}
 
 	if (found)
-- 
1.7.6

[PATCH V2 9/9] efivars: Introduce PSTORE_EFI_ATTRIBUTES

[Matthew Garrett]

From: Mike Waychison <mikew@google.com>

Consolidate the attributes listed for pstore operations in one place,
PSTORE_EFI_ATTRIBUTES.

Signed-off-by: Mike Waychison <mikew@google.com>
---
 drivers/firmware/efivars.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 563492e..eacb05e 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -122,6 +122,10 @@ struct efivar_attribute {
 	ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
 };
 
+#define PSTORE_EFI_ATTRIBUTES \
+	(EFI_VARIABLE_NON_VOLATILE | \
+	 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
+	 EFI_VARIABLE_RUNTIME_ACCESS)
 
 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
 struct efivar_attribute efivar_attr_##_name = { \
@@ -523,8 +527,9 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 
 		/* found */
 		found = entry;
-		efivars->ops->set_variable(entry->var.VariableName, &entry->var.VendorGuid,
-					   EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
+		efivars->ops->set_variable(entry->var.VariableName,
+					   &entry->var.VendorGuid,
+					   PSTORE_EFI_ATTRIBUTES,
 					   0, NULL);
 	}
 
@@ -534,8 +539,7 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 	for (i = 0; i < DUMP_NAME_LEN; i++)
 		efi_name[i] = name[i];
 
-	efivars->ops->set_variable(efi_name, &vendor,
-				   EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
+	efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
 				   size, psi->buf);
 
 	spin_unlock(&efivars->lock);
-- 
1.7.6

Re: Add efi variables as a pstore backend

[Mike Waychison]

On Thu, Jul 21, 2011 at 1:57 PM, Matthew Garrett <mjg@redhat.com> wrote:
> The same as the last attempt, but with Tony's comments on patch 4 addressed.
>
>

I just read through these and it looks good to me.

We can deal with the unload side of things when needed.

Re: [PATCH V2 6/9] efivars: String functions

[Tony Luck]

On Thu, Jul 21, 2011 at 1:57 PM, Matthew Garrett <mjg@redhat.com> wrote:
> +static unsigned long
> +utf16_strlen(efi_char16_t *s)
> +{
> +       return utf16_strnlen(s, ~0UL);
> +}
> +

When building with CONFIG_PSTORE=n, I see a warning:

drivers/firmware/efivars.c:161: warning: ‘utf16_strlen’ defined but not used

I can just slap:

#ifdef CONFIG_PSTORE
...
#endif

around this function definition - but I wondered if there was a better way
to fix it?

-Tony

Also with CONFIG_PSTORE=n I see:
drivers/firmware/efivars.c:602: warning: initialization from
incompatible pointer type
but that one just needs the stub definition of "efi_pstore_write" to
match the real
definition with "part" being unsigned.