Commit 816b5fea authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Alexander Gordeev
Browse files

s390/boot: Introduce ring buffer for boot messages 



Collect all boot messages into a ring buffer independent of the current
log level. This allows to retain all boot-time messages, which is
particularly useful for analyzing early crashes.

Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent bbbaf061

arch/s390/boot/printk.c

+19 −1
Original line number Diff line number Diff line
@@ -13,6 +13,20 @@ 


int boot_console_loglevel = CONFIG_CONSOLE_LOGLEVEL_DEFAULT;

bool boot_ignore_loglevel;

char boot_rb[PAGE_SIZE * 2];

size_t boot_rb_off;



static void boot_rb_add(const char *str, size_t len)

{

	/* leave double '\0' in the end */

	size_t avail = sizeof(boot_rb) - boot_rb_off - 1;



	/* store strings separated by '\0' */

	if (len + 1 > avail)

		boot_rb_off = 0;

	strcpy(boot_rb + boot_rb_off, str);

	boot_rb_off += len + 1;

}



const char hex_asc[] = "0123456789abcdef";
@@ -229,5 +243,9 @@ void boot_printk(const char *fmt, ...) 
	}

out:

	va_end(args);

	len = strlen(buf);

	if (len) {

		boot_rb_add(buf, len);

		boot_console_earlyprintk(buf);

	}

}

arch/s390/include/asm/boot_data.h

+13 −0
Original line number Diff line number Diff line
@@ -15,4 +15,17 @@ extern unsigned long ipl_cert_list_size; 
extern unsigned long early_ipl_comp_list_addr;

extern unsigned long early_ipl_comp_list_size;



extern char boot_rb[PAGE_SIZE * 2];

extern size_t boot_rb_off;



#define boot_rb_foreach(cb)							\

	do {									\

		size_t off = boot_rb_off + strlen(boot_rb + boot_rb_off) + 1;	\

		size_t len;							\

		for (; off < sizeof(boot_rb) && (len = strlen(boot_rb + off)); off += len + 1) \

			cb(boot_rb + off);					\

		for (off = 0; off < boot_rb_off && (len = strlen(boot_rb + off)); off += len + 1) \

			cb(boot_rb + off);					\

	} while (0)



#endif /* _ASM_S390_BOOT_DATA_H */