Merge tag 'pstore-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:

 - Fix bug in module unloading

 - Switch to always using spinlock over cmpxchg

 - Explicitly define pstore backend's supported modes

 - Remove bounce buffer from pmsg

 - Switch to using memcpy_to/fromio()

 - Error checking improvements

* tag 'pstore-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  ramoops: move spin_lock_init after kmalloc error checking
  pstore/ram: Use memcpy_fromio() to save old buffer
  pstore/ram: Use memcpy_toio instead of memcpy
  pstore/pmsg: drop bounce buffer
  pstore/ram: Set pstore flags dynamically
  pstore: Split pstore fragile flags
  pstore/core: drop cmpxchg based updates
  pstore/ramoops: fixup driver removal

4 files changed, 142 insertions, 88 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 16ecca5b72d8..14984d902a99 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -623,6 +623,40 @@ static int pstore_write_compat(enum pstore_type_id type,
 			     size, psi);
 }
 
+static int pstore_write_buf_user_compat(enum pstore_type_id type,
+			       enum kmsg_dump_reason reason,
+			       u64 *id, unsigned int part,
+			       const char __user *buf,
+			       bool compressed, size_t size,
+			       struct pstore_info *psi)
+{
+	unsigned long flags = 0;
+	size_t i, bufsize = size;
+	long ret = 0;
+
+	if (unlikely(!access_ok(VERIFY_READ, buf, size)))
+		return -EFAULT;
+	if (bufsize > psinfo->bufsize)
+		bufsize = psinfo->bufsize;
+	spin_lock_irqsave(&psinfo->buf_lock, flags);
+	for (i = 0; i < size; ) {
+		size_t c = min(size - i, bufsize);
+
+		ret = __copy_from_user(psinfo->buf, buf + i, c);
+		if (unlikely(ret != 0)) {
+			ret = -EFAULT;
+			break;
+		}
+		ret = psi->write_buf(type, reason, id, part, psinfo->buf,
+				     compressed, c, psi);
+		if (unlikely(ret < 0))
+			break;
+		i += c;
+	}
+	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+	return unlikely(ret < 0) ? ret : size;
+}
+
 /*
  * platform specific persistent storage driver registers with
  * us here. If pstore is already mounted, call the platform
@@ -645,6 +679,8 @@ int pstore_register(struct pstore_info *psi)
 
 	if (!psi->write)
 		psi->write = pstore_write_compat;
+	if (!psi->write_buf_user)
+		psi->write_buf_user = pstore_write_buf_user_compat;
 	psinfo = psi;
 	mutex_init(&psinfo->read_mutex);
 	spin_unlock(&pstore_lock);
@@ -659,13 +695,14 @@ int pstore_register(struct pstore_info *psi)
 	if (pstore_is_mounted())
 		pstore_get_records(0);
 
-	pstore_register_kmsg();
-
-	if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
+	if (psi->flags & PSTORE_FLAGS_DMESG)
+		pstore_register_kmsg();
+	if (psi->flags & PSTORE_FLAGS_CONSOLE)
 		pstore_register_console();
+	if (psi->flags & PSTORE_FLAGS_FTRACE)
 		pstore_register_ftrace();
+	if (psi->flags & PSTORE_FLAGS_PMSG)
 		pstore_register_pmsg();
-	}
 
 	if (pstore_update_ms >= 0) {
 		pstore_timer.expires = jiffies +
@@ -689,12 +726,14 @@ EXPORT_SYMBOL_GPL(pstore_register);
 
 void pstore_unregister(struct pstore_info *psi)
 {
-	if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
+	if (psi->flags & PSTORE_FLAGS_PMSG)
 		pstore_unregister_pmsg();
+	if (psi->flags & PSTORE_FLAGS_FTRACE)
 		pstore_unregister_ftrace();
+	if (psi->flags & PSTORE_FLAGS_CONSOLE)
 		pstore_unregister_console();
-	}
-	pstore_unregister_kmsg();
+	if (psi->flags & PSTORE_FLAGS_DMESG)
+		pstore_unregister_kmsg();
 
 	free_buf_for_compression();
 
diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c
index 7de20cd3797f..78f6176c020f 100644
--- a/fs/pstore/pmsg.c
+++ b/fs/pstore/pmsg.c
@@ -19,48 +19,25 @@
 #include "internal.h"
 
 static DEFINE_MUTEX(pmsg_lock);
-#define PMSG_MAX_BOUNCE_BUFFER_SIZE (2*PAGE_SIZE)
 
 static ssize_t write_pmsg(struct file *file, const char __user *buf,
 			  size_t count, loff_t *ppos)
 {
-	size_t i, buffer_size;
-	char *buffer;
+	u64 id;
+	int ret;
 
 	if (!count)
 		return 0;
 
+	/* check outside lock, page in any data. write_buf_user also checks */
 	if (!access_ok(VERIFY_READ, buf, count))
 		return -EFAULT;
 
-	buffer_size = count;
-	if (buffer_size > PMSG_MAX_BOUNCE_BUFFER_SIZE)
-		buffer_size = PMSG_MAX_BOUNCE_BUFFER_SIZE;
-	buffer = vmalloc(buffer_size);
-	if (!buffer)
-		return -ENOMEM;
-
 	mutex_lock(&pmsg_lock);
-	for (i = 0; i < count; ) {
-		size_t c = min(count - i, buffer_size);
-		u64 id;
-		long ret;
-
-		ret = __copy_from_user(buffer, buf + i, c);
-		if (unlikely(ret != 0)) {
-			mutex_unlock(&pmsg_lock);
-			vfree(buffer);
-			return -EFAULT;
-		}
-		psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c,
-				  psinfo);
-
-		i += c;
-	}
-
+	ret = psinfo->write_buf_user(PSTORE_TYPE_PMSG, 0, &id, 0, buf, 0, count,
+				     psinfo);
 	mutex_unlock(&pmsg_lock);
-	vfree(buffer);
-	return count;
+	return ret ? ret : count;
 }
 
 static const struct file_operations pmsg_fops = {
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 7a034d62cf8c..6ad831b9d1b8 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -331,6 +331,24 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 	return 0;
 }
 
+static int notrace ramoops_pstore_write_buf_user(enum pstore_type_id type,
+						 enum kmsg_dump_reason reason,
+						 u64 *id, unsigned int part,
+						 const char __user *buf,
+						 bool compressed, size_t size,
+						 struct pstore_info *psi)
+{
+	if (type == PSTORE_TYPE_PMSG) {
+		struct ramoops_context *cxt = psi->data;
+
+		if (!cxt->mprz)
+			return -ENOMEM;
+		return persistent_ram_write_user(cxt->mprz, buf, size);
+	}
+
+	return -EINVAL;
+}
+
 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
 				struct timespec time, struct pstore_info *psi)
 {
@@ -369,6 +387,7 @@ static struct ramoops_context oops_cxt = {
 		.open	= ramoops_pstore_open,
 		.read	= ramoops_pstore_read,
 		.write_buf	= ramoops_pstore_write_buf,
+		.write_buf_user	= ramoops_pstore_write_buf_user,
 		.erase	= ramoops_pstore_erase,
 	},
 };
@@ -377,13 +396,14 @@ 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++)
+	for (i = 0; i < cxt->max_dump_cnt; i++)
 		persistent_ram_free(cxt->przs[i]);
+
 	kfree(cxt->przs);
+	cxt->max_dump_cnt = 0;
 }
 
 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
@@ -408,7 +428,7 @@ static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 			     GFP_KERNEL);
 	if (!cxt->przs) {
 		dev_err(dev, "failed to initialize a prz array for dumps\n");
-		goto fail_prz;
+		goto fail_mem;
 	}
 
 	for (i = 0; i < cxt->max_dump_cnt; i++) {
@@ -419,6 +439,11 @@ static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 			err = PTR_ERR(cxt->przs[i]);
 			dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 				cxt->record_size, (unsigned long long)*paddr, err);
+
+			while (i > 0) {
+				i--;
+				persistent_ram_free(cxt->przs[i]);
+			}
 			goto fail_prz;
 		}
 		*paddr += cxt->record_size;
@@ -426,7 +451,9 @@ static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 
 	return 0;
 fail_prz:
-	ramoops_free_przs(cxt);
+	kfree(cxt->przs);
+fail_mem:
+	cxt->max_dump_cnt = 0;
 	return err;
 }
 
@@ -608,12 +635,20 @@ static int ramoops_probe(struct platform_device *pdev)
 		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;
 	}
+	spin_lock_init(&cxt->pstore.buf_lock);
+
+	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
+	if (cxt->console_size)
+		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
+	if (cxt->ftrace_size)
+		cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
+	if (cxt->pmsg_size)
+		cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
 
 	err = pstore_register(&cxt->pstore);
 	if (err) {
@@ -659,7 +694,6 @@ static int ramoops_remove(struct platform_device *pdev)
 	struct ramoops_context *cxt = &oops_cxt;
 
 	pstore_unregister(&cxt->pstore);
-	cxt->max_dump_cnt = 0;
 
 	kfree(cxt->pstore.buf);
 	cxt->pstore.bufsize = 0;
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 76c3f80efdfa..3975deec02f8 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -17,15 +17,16 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/errno.h>
-#include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/memblock.h>
+#include <linux/pstore_ram.h>
 #include <linux/rslib.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 #include <linux/vmalloc.h>
-#include <linux/pstore_ram.h>
 #include <asm/page.h>
 
 struct persistent_ram_buffer {
@@ -47,43 +48,10 @@ static inline size_t buffer_start(struct persistent_ram_zone *prz)
 	return atomic_read(&prz->buffer->start);
 }
 
-/* increase and wrap the start pointer, returning the old value */
-static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
-{
-	int old;
-	int new;
-
-	do {
-		old = atomic_read(&prz->buffer->start);
-		new = old + a;
-		while (unlikely(new >= prz->buffer_size))
-			new -= prz->buffer_size;
-	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
-
-	return old;
-}
-
-/* increase the size counter until it hits the max size */
-static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
-{
-	size_t old;
-	size_t new;
-
-	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
-		return;
-
-	do {
-		old = atomic_read(&prz->buffer->size);
-		new = old + a;
-		if (new > prz->buffer_size)
-			new = prz->buffer_size;
-	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
-}
-
 static DEFINE_RAW_SPINLOCK(buffer_lock);
 
 /* increase and wrap the start pointer, returning the old value */
-static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
+static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
 {
 	int old;
 	int new;
@@ -103,7 +71,7 @@ static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
 }
 
 /* increase the size counter until it hits the max size */
-static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
+static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
 {
 	size_t old;
 	size_t new;
@@ -124,9 +92,6 @@ exit:
 	raw_spin_unlock_irqrestore(&buffer_lock, flags);
 }
 
-static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic;
-static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic;
-
 static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
 	uint8_t *data, size_t len, uint8_t *ecc)
 {
@@ -299,10 +264,20 @@ static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
 	const void *s, unsigned int start, unsigned int count)
 {
 	struct persistent_ram_buffer *buffer = prz->buffer;
-	memcpy(buffer->data + start, s, count);
+	memcpy_toio(buffer->data + start, s, count);
 	persistent_ram_update_ecc(prz, start, count);
 }
 
+static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
+	const void __user *s, unsigned int start, unsigned int count)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
+		-EFAULT : 0;
+	persistent_ram_update_ecc(prz, start, count);
+	return ret;
+}
+
 void persistent_ram_save_old(struct persistent_ram_zone *prz)
 {
 	struct persistent_ram_buffer *buffer = prz->buffer;
@@ -322,8 +297,8 @@ void persistent_ram_save_old(struct persistent_ram_zone *prz)
 	}
 
 	prz->old_log_size = size;
-	memcpy(prz->old_log, &buffer->data[start], size - start);
-	memcpy(prz->old_log + size - start, &buffer->data[0], start);
+	memcpy_fromio(prz->old_log, &buffer->data[start], size - start);
+	memcpy_fromio(prz->old_log + size - start, &buffer->data[0], start);
 }
 
 int notrace persistent_ram_write(struct persistent_ram_zone *prz,
@@ -356,6 +331,38 @@ int notrace persistent_ram_write(struct persistent_ram_zone *prz,
 	return count;
 }
 
+int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
+	const void __user *s, unsigned int count)
+{
+	int rem, ret = 0, c = count;
+	size_t start;
+
+	if (unlikely(!access_ok(VERIFY_READ, s, count)))
+		return -EFAULT;
+	if (unlikely(c > prz->buffer_size)) {
+		s += c - prz->buffer_size;
+		c = prz->buffer_size;
+	}
+
+	buffer_size_add(prz, c);
+
+	start = buffer_start_add(prz, c);
+
+	rem = prz->buffer_size - start;
+	if (unlikely(rem < c)) {
+		ret = persistent_ram_update_user(prz, s, start, rem);
+		s += rem;
+		c -= rem;
+		start = 0;
+	}
+	if (likely(!ret))
+		ret = persistent_ram_update_user(prz, s, start, c);
+
+	persistent_ram_update_header_ecc(prz);
+
+	return unlikely(ret) ? ret : count;
+}
+
 size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
 {
 	return prz->old_log_size;
@@ -426,9 +433,6 @@ static void *persistent_ram_iomap(phys_addr_t start, size_t size,
 		return NULL;
 	}
 
-	buffer_start_add = buffer_start_add_locked;
-	buffer_size_add = buffer_size_add_locked;
-
 	if (memtype)
 		va = ioremap(start, size);
 	else