From: Michael Holzheu Date: Fri, 8 Aug 2014 15:57:31 +0000 (+0200) Subject: s390/kdump: Clear subchannel ID to signal non-CCW/SCSI IPL X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=852ffd0f4e23248b47531058e531066a988434b5;p=linux-beck.git s390/kdump: Clear subchannel ID to signal non-CCW/SCSI IPL For CCW and SCSI IPL the hardware sets the subchannel ID and number correctly at 0xb8. For kdump at 0xb8 normally there is the data of the previously IPLed system. In order to be clean now for kdump and kexec always set the subchannel ID and number to zero. This tells the next OS that no CCW/SCSI IPL has been done. Reviewed-by: Sebastian Ott Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c index 633ca7504536..22aac5885ba2 100644 --- a/arch/s390/kernel/ipl.c +++ b/arch/s390/kernel/ipl.c @@ -2060,6 +2060,13 @@ void s390_reset_system(void (*func)(void *), void *data) S390_lowcore.program_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_pgm_handler; + /* + * Clear subchannel ID and number to signal new kernel that no CCW or + * SCSI IPL has been done (for kexec and kdump) + */ + S390_lowcore.subchannel_id = 0; + S390_lowcore.subchannel_nr = 0; + /* Store status at absolute zero */ store_status();