[PATCH v8 08/11] pstore/blk: Provide way to query pstore configuration

From: Kees Cook
Date: Mon May 11 2020 - 19:33:26 EST


From: WeiXiong Liao <liaoweixiong@xxxxxxxxxxxxxxxxx>

In order to configure itself, the MTD backend needs to be able to query
the current pstore configuration. Introduce pstore_blk_get_config() for
this purpose.

Signed-off-by: WeiXiong Liao <liaoweixiong@xxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1585126506-18635-10-git-send-email-liaoweixiong@xxxxxxxxxxxxxxxxx
Co-developed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/pstore/blk.c | 37 ++++++++++++++++++++++++++++++-------
include/linux/pstore_blk.h | 28 ++++++++++++++++++++++++++++
2 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 8c78eb9906fb..95436cff8976 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -94,6 +94,17 @@ struct bdev_info {
sector_t start_sect;
};

+#define check_size(name, alignsize) ({ \
+ long _##name_ = (name); \
+ _##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \
+ if (_##name_ & ((alignsize) - 1)) { \
+ pr_info(#name " must align to %d\n", \
+ (alignsize)); \
+ _##name_ = ALIGN(name, (alignsize)); \
+ } \
+ _##name_; \
+})
+
/**
* struct pstore_device_info - back-end pstore/blk driver structure.
*
@@ -149,13 +160,11 @@ static int psblk_register_do(struct pstore_device_info *dev)
dev->flags = UINT_MAX;

#define verify_size(name, alignsize, enabled) { \
- long _##name_ = (enabled) ? (name) : 0; \
- _##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \
- if (_##name_ & ((alignsize) - 1)) { \
- pr_info(#name " must align to %d\n", \
- (alignsize)); \
- _##name_ = ALIGN(name, (alignsize)); \
- } \
+ long _##name_; \
+ if (enabled) \
+ _##name_ = check_size(name, alignsize); \
+ else \
+ _##name_ = 0; \
name = _##name_ / 1024; \
pstore_zone_info->name = _##name_; \
}
@@ -456,6 +465,20 @@ void unregister_pstore_blk(unsigned int major)
}
EXPORT_SYMBOL_GPL(unregister_pstore_blk);

+/* get information of pstore/blk */
+int pstore_blk_get_config(struct pstore_blk_config *info)
+{
+ strncpy(info->device, blkdev, 80);
+ info->max_reason = max_reason;
+ info->kmsg_size = check_size(kmsg_size, 4096);
+ info->pmsg_size = check_size(pmsg_size, 4096);
+ info->ftrace_size = check_size(ftrace_size, 4096);
+ info->console_size = check_size(console_size, 4096);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pstore_blk_get_config);
+
static void __exit pstore_blk_exit(void)
{
mutex_lock(&pstore_blk_lock);
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index ccba8c068752..0c40774e71e0 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -49,4 +49,32 @@ struct pstore_blk_info {
int register_pstore_blk(struct pstore_blk_info *info);
void unregister_pstore_blk(unsigned int major);

+/**
+ * struct pstore_blk_config - the pstore_blk backend configuration
+ *
+ * @device: Name of the desired block device
+ * @max_reason: Maximum kmsg dump reason to store to block device
+ * @kmsg_size: Total size of for kmsg dumps
+ * @pmsg_size: Total size of the pmsg storage area
+ * @console_size: Total size of the console storage area
+ * @ftrace_size: Total size for ftrace logging data (for all CPUs)
+ */
+struct pstore_blk_config {
+ char device[80];
+ enum kmsg_dump_reason max_reason;
+ unsigned long kmsg_size;
+ unsigned long pmsg_size;
+ unsigned long console_size;
+ unsigned long ftrace_size;
+};
+
+/**
+ * pstore_blk_get_config - get a copy of the pstore_blk backend configuration
+ *
+ * @info: The sturct pstore_blk_config to be filled in
+ *
+ * Failure returns negative error code, and success returns 0.
+ */
+int pstore_blk_get_config(struct pstore_blk_config *info);
+
#endif
--
2.20.1