From b64d7254ffe8b11010150fa97a4b235ec36e7a90 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 28 Nov 2022 14:16:06 +0100 Subject: [PATCH] s390/sclp: introduce sclp_emergency_printk() Introduce sclp_emergency_printk() which can be used to emit a message in emergency cases. sclp_emergency_printk() is only supposed to be used in cases where it can be assumed that regular console device drivers may not work anymore. For example this may be the case for unrecoverable machine checks. Reviewed-by: Peter Oberparleiter Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev --- arch/s390/include/asm/sclp.h | 1 + drivers/s390/char/sclp_early_core.c | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h index 67a24dda17b6b..dac7da88f61fa 100644 --- a/arch/s390/include/asm/sclp.h +++ b/arch/s390/include/asm/sclp.h @@ -132,6 +132,7 @@ void sclp_early_get_ipl_info(struct sclp_ipl_info *info); void sclp_early_detect(void); void sclp_early_printk(const char *s); void __sclp_early_printk(const char *s, unsigned int len); +void sclp_emergency_printk(const char *s); int sclp_early_get_memsize(unsigned long *mem); int sclp_early_get_hsa_size(unsigned long *hsa_size); diff --git a/drivers/s390/char/sclp_early_core.c b/drivers/s390/char/sclp_early_core.c index baf1cd2b0854d..ac1d00980fa66 100644 --- a/drivers/s390/char/sclp_early_core.c +++ b/drivers/s390/char/sclp_early_core.c @@ -240,6 +240,30 @@ void sclp_early_printk(const char *str) __sclp_early_printk(str, strlen(str)); } +/* + * Use sclp_emergency_printk() to print a string when the system is in a + * state where regular console drivers cannot be assumed to work anymore. + * + * Callers must make sure that no concurrent SCLP requests are outstanding + * and all other CPUs are stopped, or at least disabled for external + * interrupts. + */ +void sclp_emergency_printk(const char *str) +{ + int have_linemode, have_vt220; + unsigned int len; + + len = strlen(str); + /* + * Don't care about return values; if requests fail, just ignore and + * continue to have a rather high chance that anything is printed. + */ + sclp_early_setup(0, &have_linemode, &have_vt220); + sclp_early_print_lm(str, len); + sclp_early_print_vt220(str, len); + sclp_early_setup(1, &have_linemode, &have_vt220); +} + /* * We can't pass sclp_info_sccb to sclp_early_cmd() here directly, * because it might not fulfil the requiremets for a SCLP communication buffer: -- 2.30.2