printk: Add function to return log buffer address and size (14c4000a) · Commits · 戴 / test

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@linux.vnet.ibm.com> Signed-off-by:

Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by:

Andrew Morton <akpm@linux-foundation.org>

include/linux/printk.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -10,6 +10,9 @@
		extern const char linux_banner[];
		extern const char linux_proc_banner[];

		extern char *log_buf_addr_get(void);
		extern u32 log_buf_len_get(void);

		static inline int printk_get_level(const char *buffer)
		{
		if (buffer[0] == KERN_SOH_ASCII && buffer[1]) {

kernel/printk/printk.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -272,6 +272,18 @@ 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 */
		char *log_buf_addr_get(void)
		{
		return log_buf;
		}

		/* Return log buffer size */
		u32 log_buf_len_get(void)
		{
		return log_buf_len;
		}

		/* human readable text of the record */
		static char log_text(const struct printk_log msg)
		{

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