From f2879a5c9e45e8432d15deea84fdf53586e9949c Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 1 Jul 2014 12:17:41 +0200 Subject: [PATCH] pc-bios/s390-ccw: store proper subsystem information word POP chapter 17 requires to store a subsystem information word at 184 during IPL. Furthermore bytes 188-191 should be zero. The bootmap might contain data blocks that are written to the first page. We have to write these values after we processed the bootmap and before the final IPL. Signed-off-by: Christian Borntraeger Reviewed-by: Cornelia Huck Signed-off-by: Cornelia Huck --- pc-bios/s390-ccw/bootmap.c | 2 ++ pc-bios/s390-ccw/main.c | 17 ++++++++++++++++- pc-bios/s390-ccw/s390-ccw.h | 1 + 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c index fa54abb4d3..f1756796df 100644 --- a/pc-bios/s390-ccw/bootmap.c +++ b/pc-bios/s390-ccw/bootmap.c @@ -51,6 +51,8 @@ static void jump_to_IPL_2(void) static void jump_to_IPL_code(uint64_t address) { + /* store the subsystem information _after_ the bootmap was loaded */ + write_subsystem_identification(); /* * The IPL PSW is at address 0. We also must not overwrite the * content of non-BIOS memory after we loaded the guest, so we diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c index dbfb40e685..f9ec2157ad 100644 --- a/pc-bios/s390-ccw/main.c +++ b/pc-bios/s390-ccw/main.c @@ -13,6 +13,22 @@ char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE))); uint64_t boot_value; +struct subchannel_id blk_schid = { .one = 1 }; + +/* + * Priniciples of Operations (SA22-7832-09) chapter 17 requires that + * a subsystem-identification is at 184-187 and bytes 188-191 are zero + * after list-directed-IPL and ccw-IPL. + */ +void write_subsystem_identification(void) +{ + struct subchannel_id *schid = (struct subchannel_id *) 184; + uint32_t *zeroes = (uint32_t *) 188; + + *schid = blk_schid; + *zeroes = 0; +} + void virtio_panic(const char *string) { @@ -23,7 +39,6 @@ void virtio_panic(const char *string) static void virtio_setup(uint64_t dev_info) { - struct subchannel_id blk_schid = { .one = 1 }; struct schib schib; int i; int r; diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h index 959aed0d0b..2b773deafa 100644 --- a/pc-bios/s390-ccw/s390-ccw.h +++ b/pc-bios/s390-ccw/s390-ccw.h @@ -50,6 +50,7 @@ void disabled_wait(void); /* main.c */ void virtio_panic(const char *string); +void write_subsystem_identification(void); /* sclp-ascii.c */ void sclp_print(const char *string);