[PATCH v2 1/2] printk: Add function to return log buffer address and size

From: Vasant Hegde
Date: Thu Jul 31 2014 - 11:36:07 EST

Platforms like IBM Power Systems supports service processor
assisted dump. It provides interface to add memory region to
be captured when system is crashed.

During initialization/running we can add kernel memory region
to be collected.

Presently we don't have a way to get the log buffer base address
and size. This patch adds support to return log buffer address
and size.

Signed-off-by: Vasant Hegde <hegdevasant@xxxxxxxxxxxxxxxxxx>

Next patch extends arch specific code to add log buffer to platform


include/linux/printk.h | 3 +++
kernel/printk/printk.c | 12 ++++++++++++
2 files changed, 15 insertions(+)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 319ff7e..aae82c4 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -10,6 +10,9 @@
extern const char linux_banner[];
extern const char linux_proc_banner[];

+extern void *get_log_buf_addr(void);
+extern u32 get_log_buf_len(void);
static inline int printk_get_level(const char *buffer)
if (buffer[0] == KERN_SOH_ASCII && buffer[1]) {
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 13e839d..4049f7b 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -270,6 +270,18 @@ static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
static char *log_buf = __log_buf;
static u32 log_buf_len = __LOG_BUF_LEN;

+/* Return log buffer address */
+void *get_log_buf_addr(void)
+ return log_buf;
+/* Return log buffer size */
+u32 get_log_buf_len(void)
+ return log_buf_len;
/* human readable text of the record */
static char *log_text(const struct printk_log *msg)

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