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s390/boot: Introduce ring buffer for boot messages

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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: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Vasily Gorbik 2024-11-20 20:10:50 +01:00 committed by Alexander Gordeev
parent bbbaf06123
commit 816b5feaed
2 changed files with 32 additions and 1 deletions
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20
arch/s390/boot/printk.c
View File

@ -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);
boot_console_earlyprintk(buf);
len = strlen(buf);
if (len) {
boot_rb_add(buf, len);
boot_console_earlyprintk(buf);
}
}

13
arch/s390/include/asm/boot_data.h
View File

@ -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 */