[S390] sclp: introduce some new interfaces.

Introduce some new interfaces so that random subsystems don't have to
mess around with sclp internal structures.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 121 insertions, 101 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 50538e545618..9fcf3f1f47b6 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -171,37 +171,6 @@ static inline int memory_fast_detect(void)
 }
 #endif
 
-#define ADDR2G  (1UL << 31)
-
-static noinline __init unsigned long sclp_memory_detect(void)
-{
-        struct sclp_readinfo_sccb *sccb;
-        unsigned long long memsize;
-
-        sccb = &s390_readinfo_sccb;
-
-        if (sccb->header.response_code != 0x10)
-                return 0;
-
-        if (sccb->rnsize)
-                memsize = sccb->rnsize << 20;
-        else
-                memsize = sccb->rnsize2 << 20;
-        if (sccb->rnmax)
-                memsize *= sccb->rnmax;
-        else
-                memsize *= sccb->rnmax2;
-#ifndef CONFIG_64BIT
-        /*
-         * Can't deal with more than 2G in 31 bit addressing mode, so
-         * limit the value in order to avoid strange side effects.
-         */
-        if (memsize > ADDR2G)
-                memsize = ADDR2G;
-#endif
-        return (unsigned long) memsize;
-}
-
 static inline __init unsigned long __tprot(unsigned long addr)
 {
         int cc = -1;
@@ -218,6 +187,7 @@ static inline __init unsigned long __tprot(unsigned long addr)
 
 /* Checking memory in 128KB increments. */
 #define CHUNK_INCR      (1UL << 17)
+#define ADDR2G          (1UL << 31)
 
 static noinline __init void find_memory_chunks(unsigned long memsize)
 {
@@ -293,7 +263,7 @@ static noinline __init void setup_lowcore_early(void)
  */
 void __init startup_init(void)
 {
-        unsigned long memsize;
+        unsigned long long memsize;
 
         ipl_save_parameters();
         clear_bss_section();
@@ -306,7 +276,15 @@ void __init startup_init(void)
         setup_lowcore_early();
         sclp_readinfo_early();
         memsize = sclp_memory_detect();
+#ifndef CONFIG_64BIT
+        /*
+         * Can't deal with more than 2G in 31 bit addressing mode, so
+         * limit the value in order to avoid strange side effects.
+         */
+        if (memsize > ADDR2G)
+                memsize = ADDR2G;
+#endif
         if (memory_fast_detect() < 0)
-                find_memory_chunks(memsize);
+                find_memory_chunks((unsigned long) memsize);
         lockdep_on();
 }
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 367caf92ea78..82b131ddd7ff 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -25,10 +25,6 @@
 
 #define IPL_PARM_BLOCK_VERSION 0
 
-#define SCCB_VALID (s390_readinfo_sccb.header.response_code == 0x10)
-#define SCCB_LOADPARM (&s390_readinfo_sccb.loadparm)
-#define SCCB_FLAG (s390_readinfo_sccb.flags)
-
 #define IPL_UNKNOWN_STR         "unknown"
 #define IPL_CCW_STR             "ccw"
 #define IPL_FCP_STR             "fcp"
@@ -146,6 +142,8 @@ static struct ipl_parameter_block *dump_block_ccw;
 
 static enum shutdown_action on_panic_action = SHUTDOWN_STOP;
 
+static struct sclp_ipl_info sclp_ipl_info;
+
 int diag308(unsigned long subcode, void *addr)
 {
         register unsigned long _addr asm("0") = (unsigned long) addr;
@@ -375,9 +373,9 @@ static ssize_t ipl_ccw_loadparm_show(struct kset *kset, char *page)
 {
         char loadparm[LOADPARM_LEN + 1] = {};
 
-        if (!SCCB_VALID)
+        if (!sclp_ipl_info.is_valid)
                 return sprintf(page, "#unknown#\n");
-        memcpy(loadparm, SCCB_LOADPARM, LOADPARM_LEN);
+        memcpy(loadparm, &sclp_ipl_info.loadparm, LOADPARM_LEN);
         EBCASC(loadparm, LOADPARM_LEN);
         strstrip(loadparm);
         return sprintf(page, "%s\n", loadparm);
@@ -910,9 +908,9 @@ static int __init reipl_ccw_init(void)
         reipl_block_ccw->hdr.blk0_len = IPL_PARM_BLK0_CCW_LEN;
         reipl_block_ccw->hdr.pbt = DIAG308_IPL_TYPE_CCW;
         /* check if read scp info worked and set loadparm */
-        if (SCCB_VALID)
+        if (sclp_ipl_info.is_valid)
                 memcpy(reipl_block_ccw->ipl_info.ccw.load_param,
-                       SCCB_LOADPARM, LOADPARM_LEN);
+                       &sclp_ipl_info.loadparm, LOADPARM_LEN);
         else
                 /* read scp info failed: set empty loadparm (EBCDIC blanks) */
                 memset(reipl_block_ccw->ipl_info.ccw.load_param, 0x40,
@@ -1007,7 +1005,7 @@ static int __init dump_fcp_init(void)
 {
         int rc;
 
-        if(!(SCCB_FLAG & 0x2) || !SCCB_VALID)
+        if (!sclp_ipl_info.has_dump)
                 return 0; /* LDIPL DUMP is not installed */
         if (!diag308_set_works)
                 return 0;
@@ -1088,6 +1086,7 @@ static int __init s390_ipl_init(void)
 {
         int rc;
 
+        sclp_get_ipl_info(&sclp_ipl_info);
         reipl_probe();
         rc = ipl_init();
         if (rc)
diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index dbb99d1b6f57..cb5888f79007 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -72,6 +72,13 @@ typedef unsigned int sclp_cmdw_t;
 
 typedef u32 sccb_mask_t;        /* ATTENTION: assumes 32bit mask !!! */
 
+struct sccb_header {
+        u16     length;
+        u8      function_code;
+        u8      control_mask[3];
+        u16     response_code;
+} __attribute__((packed));
+
 struct gds_subvector {
         u8      length;
         u8      key;
diff --git a/drivers/s390/char/sclp_info.c b/drivers/s390/char/sclp_info.c
index 7bcbe643b087..7d21dbb12fcd 100644
--- a/drivers/s390/char/sclp_info.c
+++ b/drivers/s390/char/sclp_info.c
@@ -11,47 +11,97 @@
 #include <asm/sclp.h>
 #include "sclp.h"
 
-struct sclp_readinfo_sccb s390_readinfo_sccb;
+struct sclp_readinfo_sccb {
+        struct  sccb_header header;     /* 0-7 */
+        u16     rnmax;                  /* 8-9 */
+        u8      rnsize;                 /* 10 */
+        u8      _reserved0[24 - 11];    /* 11-23 */
+        u8      loadparm[8];            /* 24-31 */
+        u8      _reserved1[48 - 32];    /* 32-47 */
+        u64     facilities;             /* 48-55 */
+        u8      _reserved2[91 - 56];    /* 56-90 */
+        u8      flags;                  /* 91 */
+        u8      _reserved3[100 - 92];   /* 92-99 */
+        u32     rnsize2;                /* 100-103 */
+        u64     rnmax2;                 /* 104-111 */
+        u8      _reserved4[4096 - 112]; /* 112-4095 */
+} __attribute__((packed, aligned(4096)));
+
+static struct sclp_readinfo_sccb __initdata early_readinfo_sccb;
+static int __initdata early_readinfo_sccb_valid;
 
 void __init sclp_readinfo_early(void)
 {
-        sclp_cmdw_t command;
-        struct sccb_header *sccb;
         int ret;
+        int i;
+        struct sclp_readinfo_sccb *sccb;
+        sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
+                                  SCLP_CMDW_READ_SCP_INFO};
 
-        __ctl_set_bit(0, 9); /* enable service signal subclass mask */
-
-        sccb = &s390_readinfo_sccb.header;
-        command = SCLP_CMDW_READ_SCP_INFO_FORCED;
-        while (1) {
-                u16 response;
-
-                memset(&s390_readinfo_sccb, 0, sizeof(s390_readinfo_sccb));
-                sccb->length = sizeof(s390_readinfo_sccb);
-                sccb->control_mask[2] = 0x80;
-
-                ret = sclp_service_call(command, &s390_readinfo_sccb);
-
-                if (ret == -EIO)
-                        goto out;
-                if (ret == -EBUSY)
-                        continue;
+        /* Enable service signal subclass mask. */
+        __ctl_set_bit(0, 9);
+        sccb = &early_readinfo_sccb;
+        for (i = 0; i < ARRAY_SIZE(commands); i++) {
+                do {
+                        memset(sccb, 0, sizeof(*sccb));
+                        sccb->header.length = sizeof(*sccb);
+                        sccb->header.control_mask[2] = 0x80;
+                        ret = sclp_service_call(commands[i], sccb);
+                } while (ret == -EBUSY);
 
+                if (ret)
+                        break;
                 __load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
                                 PSW_MASK_WAIT | PSW_DEFAULT_KEY);
                 local_irq_disable();
+                /*
+                 * Contents of the sccb might have changed
+                 * therefore a barrier is needed.
+                 */
                 barrier();
+                if (sccb->header.response_code == 0x10) {
+                        early_readinfo_sccb_valid = 1;
+                        break;
+                }
+                if (sccb->header.response_code != 0x1f0)
+                        break;
+        }
+        /* Disable service signal subclass mask again. */
+        __ctl_clear_bit(0, 9);
+}
 
-                response = sccb->response_code;
+unsigned long long __init sclp_memory_detect(void)
+{
+        unsigned long long memsize;
+        struct sclp_readinfo_sccb *sccb;
 
-                if (response == 0x10)
-                        break;
+        if (!early_readinfo_sccb_valid)
+                return 0;
+        sccb = &early_readinfo_sccb;
+        if (sccb->rnsize)
+                memsize = sccb->rnsize << 20;
+        else
+                memsize = sccb->rnsize2 << 20;
+        if (sccb->rnmax)
+                memsize *= sccb->rnmax;
+        else
+                memsize *= sccb->rnmax2;
+        return memsize;
+}
 
-                if (response != 0x1f0 || command == SCLP_CMDW_READ_SCP_INFO)
-                        break;
+/*
+ * This function will be called after sclp_memory_detect(), which gets called
+ * early from early.c code. Therefore the sccb should have valid contents.
+ */
+void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
+{
+        struct sclp_readinfo_sccb *sccb;
 
-                command = SCLP_CMDW_READ_SCP_INFO;
-        }
-out:
-        __ctl_clear_bit(0, 9); /* disable service signal subclass mask */
+        if (!early_readinfo_sccb_valid)
+                return;
+        sccb = &early_readinfo_sccb;
+        info->is_valid = 1;
+        if (sccb->flags & 0x2)
+                info->has_dump = 1;
+        memcpy(&info->loadparm, &sccb->loadparm, LOADPARM_LEN);
 }
diff --git a/include/asm-s390/sclp.h b/include/asm-s390/sclp.h
index 21ed64773210..ddfaa8db47be 100644
--- a/include/asm-s390/sclp.h
+++ b/include/asm-s390/sclp.h
@@ -11,29 +11,6 @@
 #include <linux/types.h>
 #include <asm/chpid.h>
 
-struct sccb_header {
-        u16     length;
-        u8      function_code;
-        u8      control_mask[3];
-        u16     response_code;
-} __attribute__((packed));
-
-#define LOADPARM_LEN 8
-
-struct sclp_readinfo_sccb {
-        struct  sccb_header header;     /* 0-7 */
-        u16     rnmax;                  /* 8-9 */
-        u8      rnsize;                 /* 10 */
-        u8      _reserved0[24 - 11];    /* 11-23 */
-        u8      loadparm[LOADPARM_LEN]; /* 24-31 */
-        u8      _reserved1[91 - 32];    /* 32-90 */
-        u8      flags;                  /* 91 */
-        u8      _reserved2[100 - 92];   /* 92-99 */
-        u32     rnsize2;                /* 100-103 */
-        u64     rnmax2;                 /* 104-111 */
-        u8      _reserved3[4096 - 112]; /* 112-4095 */
-} __attribute__((packed, aligned(4096)));
-
 #define SCLP_CHP_INFO_MASK_SIZE         32
 
 struct sclp_chp_info {
@@ -42,12 +19,21 @@ struct sclp_chp_info {
         u8 configured[SCLP_CHP_INFO_MASK_SIZE];
 };
 
-extern struct sclp_readinfo_sccb s390_readinfo_sccb;
-extern void sclp_readinfo_early(void);
-extern int sclp_sdias_blk_count(void);
-extern int sclp_sdias_copy(void *dest, int blk_num, int nr_blks);
-extern int sclp_chp_configure(struct chp_id chpid);
-extern int sclp_chp_deconfigure(struct chp_id chpid);
-extern int sclp_chp_read_info(struct sclp_chp_info *info);
+#define LOADPARM_LEN 8
+
+struct sclp_ipl_info {
+        int is_valid;
+        int has_dump;
+        char loadparm[LOADPARM_LEN];
+};
+
+void sclp_readinfo_early(void);
+unsigned long long sclp_memory_detect(void);
+int sclp_sdias_blk_count(void);
+int sclp_sdias_copy(void *dest, int blk_num, int nr_blks);
+int sclp_chp_configure(struct chp_id chpid);
+int sclp_chp_deconfigure(struct chp_id chpid);
+int sclp_chp_read_info(struct sclp_chp_info *info);
+void sclp_get_ipl_info(struct sclp_ipl_info *info);
 
 #endif /* _ASM_S390_SCLP_H */