diff options
| author | Sumanth Korikkar <sumanthk@linux.ibm.com> | 2020-11-11 01:03:02 -0600 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2020-11-18 12:16:02 +0100 |
| commit | b971cbd03ee0a24f7af47b681e8f911794c69780 (patch) | |
| tree | e5eaec17dc4235384324ad7302f1031da587f66f /drivers/s390/char/sclp_early_core.c | |
| parent | d25d23e134a43457759fa602a15c1e9fce741727 (diff) | |
s390/sclp: provide extended sccb support
As the number of cpus increases, the sccb response can exceed 4k for
read cpu and read scp info sclp commands. Hence, all cpu info entries
cant be embedded within a sccb response
Solution:
To overcome this limitation, extended sccb facility is provided by sclp.
1. Check if the extended sccb facility is installed.
2. If extended sccb is installed, perform the read scp and read cpu
command considering a max sccb length of three page size. This max
length is based on factors like max cpus, sccb header.
3. If extended sccb is not installed, perform the read scp and read cpu
sclp command considering a max sccb length of one page size.
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'drivers/s390/char/sclp_early_core.c')
| -rw-r--r-- | drivers/s390/char/sclp_early_core.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/s390/char/sclp_early_core.c b/drivers/s390/char/sclp_early_core.c index d4fb61c10d7c..ec9f8ad5341c 100644 --- a/drivers/s390/char/sclp_early_core.c +++ b/drivers/s390/char/sclp_early_core.c @@ -11,6 +11,7 @@ #include <asm/irq.h> #include <asm/sections.h> #include <asm/mem_detect.h> +#include <asm/facility.h> #include "sclp.h" #include "sclp_rw.h" @@ -237,13 +238,14 @@ void sclp_early_printk(const char *str) int __init sclp_early_read_info(void) { int i; + int length = test_facility(140) ? EXT_SCCB_READ_SCP : PAGE_SIZE; struct read_info_sccb *sccb = &sclp_info_sccb; sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED, SCLP_CMDW_READ_SCP_INFO}; for (i = 0; i < ARRAY_SIZE(commands); i++) { - memset(sccb, 0, sizeof(*sccb)); - sccb->header.length = sizeof(*sccb); + memset(sccb, 0, length); + sccb->header.length = length; sccb->header.function_code = 0x80; sccb->header.control_mask[2] = 0x80; if (sclp_early_cmd(commands[i], sccb)) |