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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>
This commit is contained in:
Sumanth Korikkar 2020-11-11 01:03:02 -06:00 committed by Heiko Carstens
parent d25d23e134
commit b971cbd03e
6 changed files with 25 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/s390/include/asm/sclp.h
View File

@ -12,7 +12,12 @@
#include <asm/cpu.h>
#define SCLP_CHP_INFO_MASK_SIZE 32
#define SCLP_MAX_CORES 256
#define EARLY_SCCB_SIZE PAGE_SIZE
#define SCLP_MAX_CORES 512
/* 144 + 16 * SCLP_MAX_CORES + 2 * (SCLP_MAX_CORES - 1) */
#define EXT_SCCB_READ_SCP (3 * PAGE_SIZE)
/* 24 + 16 * SCLP_MAX_CORES */
#define EXT_SCCB_READ_CPU (3 * PAGE_SIZE)
struct sclp_chp_info {
u8 recognized[SCLP_CHP_INFO_MASK_SIZE];

2
arch/s390/include/asm/setup.h
View File

@ -16,8 +16,6 @@
#define EARLY_SCCB_OFFSET 0x11000
#define HEAD_END 0x12000
#define EARLY_SCCB_SIZE PAGE_SIZE
/*
* Machine features detected in early.c
*/

8
drivers/s390/char/sclp.h
View File

@ -156,7 +156,11 @@ struct read_cpu_info_sccb {
u16 offset_configured;
u16 nr_standby;
u16 offset_standby;
u8 reserved[4096 - 16];
/*
* Without ext sccb, struct size is PAGE_SIZE.
* With ext sccb, struct size is EXT_SCCB_READ_CPU.
*/
u8 reserved[];
} __attribute__((packed, aligned(PAGE_SIZE)));
struct read_info_sccb {
@ -199,7 +203,7 @@ struct read_info_sccb {
u8 byte_134; /* 134 */
u8 cpudirq; /* 135 */
u16 cbl; /* 136-137 */
u8 _pad_138[4096 - 138]; /* 138-4095 */
u8 _pad_138[EXT_SCCB_READ_SCP - 138];
} __packed __aligned(PAGE_SIZE);
struct read_storage_sccb {

10
drivers/s390/char/sclp_cmd.c
View File

@ -27,6 +27,7 @@
#include <asm/page.h>
#include <asm/sclp.h>
#include <asm/numa.h>
#include <asm/facility.h>
#include "sclp.h"
@ -87,14 +88,17 @@ out:
int _sclp_get_core_info(struct sclp_core_info *info)
{
int rc;
int length = test_facility(140) ? EXT_SCCB_READ_CPU : PAGE_SIZE;
struct read_cpu_info_sccb *sccb;
if (!SCLP_HAS_CPU_INFO)
return -EOPNOTSUPP;
sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
sccb = (void *)__get_free_pages(GFP_KERNEL | GFP_DMA | __GFP_ZERO, get_order(length));
if (!sccb)
return -ENOMEM;
sccb->header.length = sizeof(*sccb);
sccb->header.length = length;
sccb->header.control_mask[2] = 0x80;
rc = sclp_sync_request_timeout(SCLP_CMDW_READ_CPU_INFO, sccb,
SCLP_QUEUE_INTERVAL);
if (rc)
@ -107,7 +111,7 @@ int _sclp_get_core_info(struct sclp_core_info *info)
}
sclp_fill_core_info(info, sccb);
out:
free_page((unsigned long) sccb);
free_pages((unsigned long) sccb, get_order(length));
return rc;
}

3
drivers/s390/char/sclp_early.c
View File

@ -14,6 +14,7 @@
#include <asm/sclp.h>
#include <asm/ipl.h>
#include <asm/setup.h>
#include <asm/facility.h>
#include "sclp_sdias.h"
#include "sclp.h"
@ -114,7 +115,7 @@ void __init sclp_early_get_ipl_info(struct sclp_ipl_info *info)
int __init sclp_early_get_core_info(struct sclp_core_info *info)
{
struct read_cpu_info_sccb *sccb;
int length = PAGE_SIZE;
int length = test_facility(140) ? EXT_SCCB_READ_CPU : PAGE_SIZE;
int rc = 0;
if (!SCLP_HAS_CPU_INFO)

6
drivers/s390/char/sclp_early_core.c
View File

@ -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))