s390/sclp: make early sclp code readable

This patch

 - unifies the old sclp early code and the sclp early printk code, so
   they can use common functions

 - makes sure all sclp early functions and variables have the same
   "sclp_early" prefix

 - converts the sclp early printk code into readable code by using
   existing data structures instead of hard coded magic arrays

 - splits the early sclp code into two files: sclp_early.c and
   sclp_early_core.c. The core file contains everything that is
   required by the kernel decompressor and may not call functions not
   contained within the core file. Otherwise the result would be a
   link error.

 - changes interrupt handling to be completely synchronous. The old
   early sclp code had a small window which allowed to receive several
   interrupts instead of exactly the single expected interrupt. This
   did hide a subtle potential bug, which is fixed with this large
   rework.

 - contains a couple of small cleanups.

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/compressed/misc.c

@@ -66,7 +66,7 @@ static unsigned long free_mem_end_ptr;
 
 static int puts(const char *s)
 {
-	_sclp_print_early(s);
+	sclp_early_printk(s);
 	return 0;
 }
 

arch/s390/include/asm/sclp.h

@@ -101,7 +101,12 @@ struct zpci_report_error_header {
 	u8 data[0];	/* Subsequent Data passed verbatim to SCLP ET 24 */
 } __packed;
 
-int _sclp_get_core_info_early(struct sclp_core_info *info);
+int sclp_early_get_core_info(struct sclp_core_info *info);
+void sclp_early_get_ipl_info(struct sclp_ipl_info *info);
+void sclp_early_detect(void);
+void sclp_early_printk(const char *s);
+void __sclp_early_printk(const char *s, unsigned int len);
+
 int _sclp_get_core_info(struct sclp_core_info *info);
 int sclp_core_configure(u8 core);
 int sclp_core_deconfigure(u8 core);
@@ -110,21 +115,17 @@ 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);
 int sclp_pci_configure(u32 fid);
 int sclp_pci_deconfigure(u32 fid);
 int sclp_pci_report(struct zpci_report_error_header *report, u32 fh, u32 fid);
 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count);
 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count);
-void sclp_early_detect(void);
-void _sclp_print_early(const char *);
-void __sclp_print_early(const char *s, unsigned int len);
 void sclp_ocf_cpc_name_copy(char *dst);
 
 static inline int sclp_get_core_info(struct sclp_core_info *info, int early)
 {
 	if (early)
-		return _sclp_get_core_info_early(info);
+		return sclp_early_get_core_info(info);
 	return _sclp_get_core_info(info);
 }
 

arch/s390/kernel/als.c

@@ -41,7 +41,7 @@ static void __init print_machine_type(void)
 	get_cpu_id(&id);
 	u16_to_hex(type_str, id.machine);
 	strcat(mach_str, type_str);
-	_sclp_print_early(mach_str);
+	sclp_early_printk(mach_str);
 }
 
 static void __init u16_to_decimal(char *str, u16 val)
@@ -79,7 +79,7 @@ static void __init print_missing_facilities(void)
 			 * z/VM adds a four character prefix.
 			 */
 			if (strlen(als_str) > 70) {
-				_sclp_print_early(als_str);
+				sclp_early_printk(als_str);
 				*als_str = '\0';
 			}
 			u16_to_decimal(val_str, i * BITS_PER_LONG + j);
@@ -87,13 +87,13 @@ static void __init print_missing_facilities(void)
 			first = 0;
 		}
 	}
-	_sclp_print_early(als_str);
-	_sclp_print_early("See Principles of Operations for facility bits");
+	sclp_early_printk(als_str);
+	sclp_early_printk("See Principles of Operations for facility bits");
 }
 
 static void __init facility_mismatch(void)
 {
-	_sclp_print_early("The Linux kernel requires more recent processor hardware");
+	sclp_early_printk("The Linux kernel requires more recent processor hardware");
 	print_machine_type();
 	print_missing_facilities();
 	disabled_wait(0x8badcccc);

arch/s390/kernel/early_printk.c

@@ -9,7 +9,7 @@
 
 static void sclp_early_write(struct console *con, const char *s, unsigned int len)
 {
-	__sclp_print_early(s, len);
+	__sclp_early_printk(s, len);
 }
 
 static struct console sclp_early_console = {

arch/s390/kernel/ipl.c

@@ -1864,7 +1864,7 @@ static int __init s390_ipl_init(void)
 {
 	char str[8] = {0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40};
 
-	sclp_get_ipl_info(&sclp_ipl_info);
+	sclp_early_get_ipl_info(&sclp_ipl_info);
 	/*
 	 * Fix loadparm: There are systems where the (SCSI) LOADPARM
 	 * returned by read SCP info is invalid (contains EBCDIC blanks)

arch/s390/kernel/swsusp.S

@@ -196,7 +196,7 @@ pgm_check_entry:
 	larl	%r15,init_thread_union
 	ahi	%r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER)
 	larl	%r2,.Lpanic_string
-	larl	%r3,_sclp_print_early
+	larl	%r3,sclp_early_printk
 	lghi	%r1,0
 	sam31
 	sigp	%r1,%r0,SIGP_SET_ARCHITECTURE

drivers/s390/char/sclp.c

@@ -140,31 +140,6 @@ static void __sclp_make_read_req(void);
 static int sclp_init_mask(int calculate);
 static int sclp_init(void);
 
-/* Perform service call. Return 0 on success, non-zero otherwise. */
-int
-sclp_service_call(sclp_cmdw_t command, void *sccb)
-{
-	int cc = 4; /* Initialize for program check handling */
-
-	asm volatile(
-		"0:	.insn	rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
-		"1:	ipm	%0\n"
-		"	srl	%0,28\n"
-		"2:\n"
-		EX_TABLE(0b, 2b)
-		EX_TABLE(1b, 2b)
-		: "+&d" (cc) : "d" (command), "a" (__pa(sccb))
-		: "cc", "memory");
-	if (cc == 4)
-		return -EINVAL;
-	if (cc == 3)
-		return -EIO;
-	if (cc == 2)
-		return -EBUSY;
-	return 0;
-}
-
-
 static void
 __sclp_queue_read_req(void)
 {

drivers/s390/char/sclp.h

@@ -204,7 +204,6 @@ void sclp_unregister(struct sclp_register *reg);
 int sclp_remove_processed(struct sccb_header *sccb);
 int sclp_deactivate(void);
 int sclp_reactivate(void);
-int sclp_service_call(sclp_cmdw_t command, void *sccb);
 int sclp_sync_request(sclp_cmdw_t command, void *sccb);
 int sclp_sync_request_timeout(sclp_cmdw_t command, void *sccb, int timeout);
 
@@ -222,8 +221,41 @@ extern int sclp_console_pages;
 extern int sclp_console_drop;
 extern unsigned long sclp_console_full;
 
+extern char sclp_early_sccb[PAGE_SIZE];
+
+void sclp_early_wait_irq(void);
+int sclp_early_cmd_sync(sclp_cmdw_t cmd, void *sccb);
+int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb);
+unsigned int sclp_early_con_check_linemode(struct init_sccb *sccb);
+int sclp_early_set_event_mask(struct init_sccb *sccb,
+			      unsigned long receive_mask,
+			      unsigned long send_mask);
+
 /* useful inlines */
 
+/* Perform service call. Return 0 on success, non-zero otherwise. */
+static inline int sclp_service_call(sclp_cmdw_t command, void *sccb)
+{
+	int cc = 4; /* Initialize for program check handling */
+
+	asm volatile(
+		"0:	.insn	rre,0xb2200000,%1,%2\n"	 /* servc %1,%2 */
+		"1:	ipm	%0\n"
+		"	srl	%0,28\n"
+		"2:\n"
+		EX_TABLE(0b, 2b)
+		EX_TABLE(1b, 2b)
+		: "+&d" (cc) : "d" (command), "a" ((unsigned long)sccb)
+		: "cc", "memory");
+	if (cc == 4)
+		return -EINVAL;
+	if (cc == 3)
+		return -EIO;
+	if (cc == 2)
+		return -EBUSY;
+	return 0;
+}
+
 /* VM uses EBCDIC 037, LPAR+native(SE+HMC) use EBCDIC 500 */
 /* translate single character from ASCII to EBCDIC */
 static inline unsigned char

drivers/s390/char/sclp_early.c

@@ -55,31 +55,12 @@ struct read_info_sccb {
 	u8	_pad_128[4096 - 128];	/* 128-4095 */
 } __packed __aligned(PAGE_SIZE);
 
-static char sccb_early[PAGE_SIZE] __aligned(PAGE_SIZE) __initdata;
 static struct sclp_ipl_info sclp_ipl_info;
 
 struct sclp_info sclp;
 EXPORT_SYMBOL(sclp);
 
-static int __init sclp_cmd_sync_early(sclp_cmdw_t cmd, void *sccb)
-{
-	int rc;
-
-	__ctl_set_bit(0, 9);
-	rc = sclp_service_call(cmd, sccb);
-	if (rc)
-		goto out;
-	__load_psw_mask(PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_EA |
-			PSW_MASK_BA | PSW_MASK_EXT | PSW_MASK_WAIT);
-	local_irq_disable();
-out:
-	/* Contents of the sccb might have changed. */
-	barrier();
-	__ctl_clear_bit(0, 9);
-	return rc;
-}
-
-static int __init sclp_read_info_early(struct read_info_sccb *sccb)
+static int __init sclp_early_read_info(struct read_info_sccb *sccb)
 {
 	int rc, i;
 	sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
@@ -91,7 +72,7 @@ static int __init sclp_read_info_early(struct read_info_sccb *sccb)
 			sccb->header.length = sizeof(*sccb);
 			sccb->header.function_code = 0x80;
 			sccb->header.control_mask[2] = 0x80;
-			rc = sclp_cmd_sync_early(commands[i], sccb);
+			rc = sclp_early_cmd_sync(commands[i], sccb);
 		} while (rc == -EBUSY);
 
 		if (rc)
@@ -104,12 +85,12 @@ static int __init sclp_read_info_early(struct read_info_sccb *sccb)
 	return -EIO;
 }
 
-static void __init sclp_facilities_detect(struct read_info_sccb *sccb)
+static void __init sclp_early_facilities_detect(struct read_info_sccb *sccb)
 {
 	struct sclp_core_entry *cpue;
 	u16 boot_cpu_address, cpu;
 
-	if (sclp_read_info_early(sccb))
+	if (sclp_early_read_info(sccb))
 		return;
 
 	sclp.facilities = sccb->facilities;
@@ -172,59 +153,19 @@ static void __init sclp_facilities_detect(struct read_info_sccb *sccb)
 }
 
 /*
- * This function will be called after sclp_facilities_detect(), which gets
- * called from early.c code. The sclp_facilities_detect() function retrieves
+ * This function will be called after sclp_early_facilities_detect(), which gets
+ * called from early.c code. The sclp_early_facilities_detect() function retrieves
  * and saves the IPL information.
  */
-void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
+void __init sclp_early_get_ipl_info(struct sclp_ipl_info *info)
 {
 	*info = sclp_ipl_info;
 }
 
-static int __init sclp_cmd_early(sclp_cmdw_t cmd, void *sccb)
-{
-	int rc;
+static struct sclp_core_info sclp_early_core_info __initdata;
+static int sclp_early_core_info_valid __initdata;
 
-	do {
-		rc = sclp_cmd_sync_early(cmd, sccb);
-	} while (rc == -EBUSY);
-
-	if (rc)
-		return -EIO;
-	if (((struct sccb_header *) sccb)->response_code != 0x0020)
-		return -EIO;
-	return 0;
-}
-
-static void __init sccb_init_eq_size(struct sdias_sccb *sccb)
-{
-	memset(sccb, 0, sizeof(*sccb));
-
-	sccb->hdr.length = sizeof(*sccb);
-	sccb->evbuf.hdr.length = sizeof(struct sdias_evbuf);
-	sccb->evbuf.hdr.type = EVTYP_SDIAS;
-	sccb->evbuf.event_qual = SDIAS_EQ_SIZE;
-	sccb->evbuf.data_id = SDIAS_DI_FCP_DUMP;
-	sccb->evbuf.event_id = 4712;
-	sccb->evbuf.dbs = 1;
-}
-
-static int __init sclp_set_event_mask(struct init_sccb *sccb,
-				      unsigned long receive_mask,
-				      unsigned long send_mask)
-{
-	memset(sccb, 0, sizeof(*sccb));
-	sccb->header.length = sizeof(*sccb);
-	sccb->mask_length = sizeof(sccb_mask_t);
-	sccb->receive_mask = receive_mask;
-	sccb->send_mask = send_mask;
-	return sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_MASK, sccb);
-}
-
-static struct sclp_core_info sclp_core_info_early __initdata;
-static int sclp_core_info_early_valid __initdata;
-
-static void __init sclp_init_core_info_early(struct read_cpu_info_sccb *sccb)
+static void __init sclp_early_init_core_info(struct read_cpu_info_sccb *sccb)
 {
 	int rc;
 
@@ -233,80 +174,76 @@ static void __init sclp_init_core_info_early(struct read_cpu_info_sccb *sccb)
 	memset(sccb, 0, sizeof(*sccb));
 	sccb->header.length = sizeof(*sccb);
 	do {
-		rc = sclp_cmd_sync_early(SCLP_CMDW_READ_CPU_INFO, sccb);
+		rc = sclp_early_cmd_sync(SCLP_CMDW_READ_CPU_INFO, sccb);
 	} while (rc == -EBUSY);
 	if (rc)
 		return;
 	if (sccb->header.response_code != 0x0010)
 		return;
-	sclp_fill_core_info(&sclp_core_info_early, sccb);
-	sclp_core_info_early_valid = 1;
+	sclp_fill_core_info(&sclp_early_core_info, sccb);
+	sclp_early_core_info_valid = 1;
 }
 
-int __init _sclp_get_core_info_early(struct sclp_core_info *info)
+int __init sclp_early_get_core_info(struct sclp_core_info *info)
 {
-	if (!sclp_core_info_early_valid)
+	if (!sclp_early_core_info_valid)
 		return -EIO;
-	*info = sclp_core_info_early;
+	*info = sclp_early_core_info;
 	return 0;
 }
 
-static long __init sclp_hsa_size_init(struct sdias_sccb *sccb)
+static long __init sclp_early_hsa_size_init(struct sdias_sccb *sccb)
 {
-	sccb_init_eq_size(sccb);
-	if (sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_DATA, sccb))
+	memset(sccb, 0, sizeof(*sccb));
+	sccb->hdr.length = sizeof(*sccb);
+	sccb->evbuf.hdr.length = sizeof(struct sdias_evbuf);
+	sccb->evbuf.hdr.type = EVTYP_SDIAS;
+	sccb->evbuf.event_qual = SDIAS_EQ_SIZE;
+	sccb->evbuf.data_id = SDIAS_DI_FCP_DUMP;
+	sccb->evbuf.event_id = 4712;
+	sccb->evbuf.dbs = 1;
+	if (sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb))
 		return -EIO;
 	if (sccb->evbuf.blk_cnt == 0)
 		return 0;
 	return (sccb->evbuf.blk_cnt - 1) * PAGE_SIZE;
 }
 
-static long __init sclp_hsa_copy_wait(struct sccb_header *sccb)
+static long __init sclp_early_hsa_copy_wait(struct sdias_sccb *sccb)
 {
 	memset(sccb, 0, PAGE_SIZE);
-	sccb->length = PAGE_SIZE;
-	if (sclp_cmd_early(SCLP_CMDW_READ_EVENT_DATA, sccb))
+	sccb->hdr.length = PAGE_SIZE;
+	if (sclp_early_cmd(SCLP_CMDW_READ_EVENT_DATA, sccb))
 		return -EIO;
-	if (((struct sdias_sccb *) sccb)->evbuf.blk_cnt == 0)
+	if (sccb->evbuf.blk_cnt == 0)
 		return 0;
-	return (((struct sdias_sccb *) sccb)->evbuf.blk_cnt - 1) * PAGE_SIZE;
+	return (sccb->evbuf.blk_cnt - 1) * PAGE_SIZE;
 }
 
-static void __init sclp_hsa_size_detect(void *sccb)
+static void __init sclp_early_hsa_size_detect(void *sccb)
 {
-	long size;
+	unsigned long flags;
+	long size = -EIO;
 
-	/* First try synchronous interface (LPAR) */
-	if (sclp_set_event_mask(sccb, 0, 0x40000010))
-		return;
-	size = sclp_hsa_size_init(sccb);
-	if (size < 0)
-		return;
-	if (size != 0)
+	raw_local_irq_save(flags);
+	if (sclp_early_set_event_mask(sccb, EVTYP_SDIAS_MASK, EVTYP_SDIAS_MASK))
 		goto out;
-	/* Then try asynchronous interface (z/VM) */
-	if (sclp_set_event_mask(sccb, 0x00000010, 0x40000010))
-		return;
-	size = sclp_hsa_size_init(sccb);
-	if (size < 0)
-		return;
-	size = sclp_hsa_copy_wait(sccb);
-	if (size < 0)
-		return;
+	size = sclp_early_hsa_size_init(sccb);
+	/* First check for synchronous response (LPAR) */
+	if (size)
+		goto out_mask;
+	if (!(S390_lowcore.ext_params & 1))
+		sclp_early_wait_irq();
+	size = sclp_early_hsa_copy_wait(sccb);
+out_mask:
+	sclp_early_set_event_mask(sccb, 0, 0);
 out:
-	sclp.hsa_size = size;
-}
-
-static unsigned int __init sclp_con_check_linemode(struct init_sccb *sccb)
-{
-	if (!(sccb->sclp_send_mask & EVTYP_OPCMD_MASK))
-		return 0;
-	if (!(sccb->sclp_receive_mask & (EVTYP_MSG_MASK | EVTYP_PMSGCMD_MASK)))
-		return 0;
-	return 1;
+	raw_local_irq_restore(flags);
+	if (size > 0)
+		sclp.hsa_size = size;
 }
 
-static void __init sclp_console_detect(struct init_sccb *sccb)
+static void __init sclp_early_console_detect(struct init_sccb *sccb)
 {
 	if (sccb->header.response_code != 0x20)
 		return;
@@ -314,21 +251,22 @@ static void __init sclp_console_detect(struct init_sccb *sccb)
 	if (sccb->sclp_send_mask & EVTYP_VT220MSG_MASK)
 		sclp.has_vt220 = 1;
 
-	if (sclp_con_check_linemode(sccb))
+	if (sclp_early_con_check_linemode(sccb))
 		sclp.has_linemode = 1;
 }
 
 void __init sclp_early_detect(void)
 {
-	void *sccb = &sccb_early;
+	void *sccb = &sclp_early_sccb;
 
-	sclp_facilities_detect(sccb);
-	sclp_init_core_info_early(sccb);
-	sclp_hsa_size_detect(sccb);
+	sclp_early_facilities_detect(sccb);
+	sclp_early_init_core_info(sccb);
+	sclp_early_hsa_size_detect(sccb);
 
-	/* Turn off SCLP event notifications.  Also save remote masks in the
+	/*
+	 * Turn off SCLP event notifications.  Also save remote masks in the
 	 * sccb.  These are sufficient to detect sclp console capabilities.
 	 */
-	sclp_set_event_mask(sccb, 0, 0);
-	sclp_console_detect(sccb);
+	sclp_early_set_event_mask(sccb, 0, 0);
+	sclp_early_console_detect(sccb);
 }

drivers/s390/char/sclp_early_core.c

@@ -2,29 +2,24 @@
  *    Copyright IBM Corp. 2015
  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
  */
+
 #include <linux/kernel.h>
+#include <asm/processor.h>
+#include <asm/lowcore.h>
 #include <asm/ebcdic.h>
 #include <asm/irq.h>
-#include <asm/lowcore.h>
-#include <asm/processor.h>
-#include <asm/sclp.h>
-
-#define EVTYP_VT220MSG_MASK	0x00000040
-#define EVTYP_MSG_MASK		0x40000000
-
-static char _sclp_work_area[4096] __aligned(PAGE_SIZE) __section(data);
-static bool have_vt220 __section(data);
-static bool have_linemode __section(data);
+#include "sclp.h"
+#include "sclp_rw.h"
 
+char sclp_early_sccb[PAGE_SIZE] __aligned(PAGE_SIZE) __section(data);
 int sclp_init_state __section(data) = sclp_init_state_uninitialized;
 
-static void _sclp_wait_int(void)
+void sclp_early_wait_irq(void)
 {
-	unsigned long psw_mask, addr, flags;
+	unsigned long psw_mask, addr;
 	psw_t psw_ext_save, psw_wait;
 	union ctlreg0 cr0, cr0_new;
 
-	raw_local_irq_save(flags);
 	__ctl_store(cr0.val, 0, 0);
 	cr0_new.val = cr0.val & ~CR0_IRQ_SUBCLASS_MASK;
 	cr0_new.lap = 0;
@@ -53,165 +48,173 @@ static void _sclp_wait_int(void)
 
 	S390_lowcore.external_new_psw = psw_ext_save;
 	__ctl_load(cr0.val, 0, 0);
-	raw_local_irq_restore(flags);
 }
 
-static int _sclp_servc(unsigned int cmd, char *sccb)
+int sclp_early_cmd_sync(sclp_cmdw_t cmd, void *sccb)
 {
-	unsigned int cc;
+	unsigned long flags;
+	int rc;
 
-	do {
-		asm volatile(
-			"	.insn	rre,0xb2200000,%1,%2\n"
-			"	ipm	%0\n"
-			: "=d" (cc) : "d" (cmd), "a" (sccb)
-			: "cc", "memory");
-		cc >>= 28;
-		if (cc == 3)
-			return -EINVAL;
-		_sclp_wait_int();
-	} while (cc != 0);
-	return (*(unsigned short *)(sccb + 6) == 0x20) ? 0 : -EIO;
+	raw_local_irq_save(flags);
+	rc = sclp_service_call(cmd, sccb);
+	if (rc)
+		goto out;
+	sclp_early_wait_irq();
+out:
+	raw_local_irq_restore(flags);
+	return rc;
 }
 
-static int _sclp_setup(int disable)
+int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb)
 {
-	static unsigned char init_sccb[] = {
-		0x00, 0x1c,
-		0x00, 0x00, 0x00, 0x00,	0x00, 0x00, 0x00, 0x00,
-		0x00, 0x04,
-		0x80, 0x00, 0x00, 0x00,	0x40, 0x00, 0x00, 0x40,
-		0x00, 0x00, 0x00, 0x00,	0x00, 0x00, 0x00, 0x00
-	};
-	unsigned int *masks;
 	int rc;
 
-	memcpy(_sclp_work_area, init_sccb, 28);
-	masks = (unsigned int *)(_sclp_work_area + 12);
-	if (disable)
-		memset(masks, 0, 16);
-	/* SCLP write mask */
-	rc = _sclp_servc(0x00780005, _sclp_work_area);
+	do {
+		rc = sclp_early_cmd_sync(cmd, sccb);
+	} while (rc == -EBUSY);
 	if (rc)
-		return rc;
-	have_vt220 = masks[2] & EVTYP_VT220MSG_MASK;
-	have_linemode = masks[2] & EVTYP_MSG_MASK;
+		return -EIO;
+	if (((struct sccb_header *) sccb)->response_code != 0x0020)
+		return -EIO;
 	return 0;
 }
 
+struct write_sccb {
+	struct sccb_header header;
+	struct msg_buf msg;
+} __packed;
+
 /* Output multi-line text using SCLP Message interface. */
-static void _sclp_print_lm(const char *str, unsigned int len)
+static void sclp_early_print_lm(const char *str, unsigned int len)
 {
-	static unsigned char write_head[] = {
-		/* sccb header */
-		0x00, 0x52,					/* 0 */
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00,		/* 2 */
-		/* evbuf */
-		0x00, 0x4a,					/* 8 */
-		0x02, 0x00, 0x00, 0x00,				/* 10 */
-		/* mdb */
-		0x00, 0x44,					/* 14 */
-		0x00, 0x01,					/* 16 */
-		0xd4, 0xc4, 0xc2, 0x40,				/* 18 */
-		0x00, 0x00, 0x00, 0x01,				/* 22 */
-		/* go */
-		0x00, 0x38,					/* 26 */
-		0x00, 0x01,					/* 28 */
-		0x00, 0x00, 0x00, 0x00,				/* 30 */
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 34 */
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 42 */
-		0x00, 0x00, 0x00, 0x00,				/* 50 */
-		0x00, 0x00,					/* 54 */
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 56 */
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 64 */
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 72 */
-		0x00, 0x00,					/* 80 */
-	};
-	static unsigned char write_mto[] = {
-		/* mto	*/
-		0x00, 0x0a,					/* 0 */
-		0x00, 0x04,					/* 2 */
-		0x10, 0x00,					/* 4 */
-		0x00, 0x00, 0x00, 0x00				/* 6 */
-	};
-	unsigned char *ptr, *end_ptr, ch;
-	unsigned int count, num;
-
-	num = 0;
-	memcpy(_sclp_work_area, write_head, sizeof(write_head));
-	ptr = _sclp_work_area + sizeof(write_head);
-	end_ptr = _sclp_work_area + sizeof(_sclp_work_area) - 1;
+	unsigned char *ptr, *end, ch;
+	unsigned int count, offset;
+	struct write_sccb *sccb;
+	struct msg_buf *msg;
+	struct mdb *mdb;
+	struct mto *mto;
+	struct go *go;
+
+	sccb = (struct write_sccb *) &sclp_early_sccb;
+	end = (unsigned char *) sccb + sizeof(sclp_early_sccb) - 1;
+	memset(sccb, 0, sizeof(*sccb));
+	ptr = (unsigned char *) &sccb->msg.mdb.mto;
+	offset = 0;
 	do {
-		if (ptr + sizeof(write_mto) > end_ptr)
-			break;
-		memcpy(ptr, write_mto, sizeof(write_mto));
-		for (count = sizeof(write_mto); num < len; count++) {
-			num++;
-			ch = *str++;
-			if (ch == 0x0a)
-				break;
-			if (ptr > end_ptr)
+		for (count = sizeof(*mto); offset < len; count++) {
+			ch = str[offset++];
+			if ((ch == 0x0a) || (ptr + count > end))
 				break;
 			ptr[count] = _ascebc[ch];
 		}
-		/* Update length fields in mto, mdb, evbuf and sccb */
-		*(unsigned short *) ptr = count;
-		*(unsigned short *)(_sclp_work_area + 14) += count;
-		*(unsigned short *)(_sclp_work_area + 8) += count;
-		*(unsigned short *)(_sclp_work_area + 0) += count;
+		mto = (struct mto *) ptr;
+		memset(mto, 0, sizeof(*mto));
+		mto->length = count;
+		mto->type = 4;
+		mto->line_type_flags = LNTPFLGS_ENDTEXT;
 		ptr += count;
-	} while (num < len);
-
-	/* SCLP write data */
-	_sclp_servc(0x00760005, _sclp_work_area);
+	} while ((offset < len) && (ptr + sizeof(*mto) <= end));
+	len = ptr - (unsigned char *) sccb;
+	sccb->header.length = len - offsetof(struct write_sccb, header);
+	msg = &sccb->msg;
+	msg->header.type = EVTYP_MSG;
+	msg->header.length = len - offsetof(struct write_sccb, msg.header);
+	mdb = &msg->mdb;
+	mdb->header.type = 1;
+	mdb->header.tag = 0xD4C4C240;
+	mdb->header.revision_code = 1;
+	mdb->header.length = len - offsetof(struct write_sccb, msg.mdb.header);
+	go = &mdb->go;
+	go->length = sizeof(*go);
+	go->type = 1;
+	sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
 }
 
+struct vt220_sccb {
+	struct sccb_header header;
+	struct {
+		struct evbuf_header header;
+		char data[];
+	} msg;
+} __packed;
+
 /* Output multi-line text (plus a newline) using SCLP VT220
  * interface.
  */
-static void _sclp_print_vt220(const char *str, unsigned int len)
+static void sclp_early_print_vt220(const char *str, unsigned int len)
+{
+	struct vt220_sccb *sccb;
+
+	sccb = (struct vt220_sccb *) &sclp_early_sccb;
+	if (sizeof(*sccb) + len >= sizeof(sclp_early_sccb))
+		len = sizeof(sclp_early_sccb) - sizeof(*sccb) - 1;
+	memset(sccb, 0, sizeof(*sccb));
+	memcpy(&sccb->msg.data, str, len);
+	sccb->msg.data[len] = '\n';
+	sccb->header.length = sizeof(*sccb) + len + 1;
+	sccb->msg.header.length = sizeof(sccb->msg) + len + 1;
+	sccb->msg.header.type = EVTYP_VT220MSG;
+	sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
+}
+
+int sclp_early_set_event_mask(struct init_sccb *sccb,
+			      unsigned long receive_mask,
+			      unsigned long send_mask)
+{
+	memset(sccb, 0, sizeof(*sccb));
+	sccb->header.length = sizeof(*sccb);
+	sccb->mask_length = sizeof(sccb_mask_t);
+	sccb->receive_mask = receive_mask;
+	sccb->send_mask = send_mask;
+	return sclp_early_cmd(SCLP_CMDW_WRITE_EVENT_MASK, sccb);
+}
+
+unsigned int sclp_early_con_check_linemode(struct init_sccb *sccb)
 {
-	static unsigned char const write_head[] = {
-		/* sccb header */
-		0x00, 0x0e,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		/* evbuf header */
-		0x00, 0x06,
-		0x1a, 0x00, 0x00, 0x00,
-	};
-
-	if (sizeof(write_head) + len >= sizeof(_sclp_work_area))
-		len = sizeof(_sclp_work_area) - sizeof(write_head) - 1;
-
-	memcpy(_sclp_work_area, write_head, sizeof(write_head));
-	memcpy(_sclp_work_area + sizeof(write_head), str, len);
-	_sclp_work_area[sizeof(write_head) + len] = '\n';
-
-	/* Update length fields in evbuf and sccb headers */
-	*(unsigned short *)(_sclp_work_area + 8) += len + 1;
-	*(unsigned short *)(_sclp_work_area + 0) += len + 1;
-
-	/* SCLP write data */
-	(void)_sclp_servc(0x00760005, _sclp_work_area);
+	if (!(sccb->sclp_send_mask & EVTYP_OPCMD_MASK))
+		return 0;
+	if (!(sccb->sclp_receive_mask & (EVTYP_MSG_MASK | EVTYP_PMSGCMD_MASK)))
+		return 0;
+	return 1;
+}
+
+static int sclp_early_setup(int disable, int *have_linemode, int *have_vt220)
+{
+	unsigned long receive_mask, send_mask;
+	struct init_sccb *sccb;
+	int rc;
+
+	*have_linemode = *have_vt220 = 0;
+	sccb = (struct init_sccb *) &sclp_early_sccb;
+	receive_mask = disable ? 0 : EVTYP_OPCMD_MASK;
+	send_mask = disable ? 0 : EVTYP_VT220MSG_MASK | EVTYP_MSG_MASK;
+	rc = sclp_early_set_event_mask(sccb, receive_mask, send_mask);
+	if (rc)
+		return rc;
+	*have_linemode = sclp_early_con_check_linemode(sccb);
+	*have_vt220 = sccb->send_mask & EVTYP_VT220MSG_MASK;
+	return rc;
 }
 
 /* Output one or more lines of text on the SCLP console (VT220 and /
  * or line-mode). All lines get terminated; no need for a trailing LF.
  */
-void __sclp_print_early(const char *str, unsigned int len)
+void __sclp_early_printk(const char *str, unsigned int len)
 {
+	int have_linemode, have_vt220;
+
 	if (sclp_init_state != sclp_init_state_uninitialized)
 		return;
-	if (_sclp_setup(0) != 0)
+	if (sclp_early_setup(0, &have_linemode, &have_vt220) != 0)
 		return;
 	if (have_linemode)
-		_sclp_print_lm(str, len);
+		sclp_early_print_lm(str, len);
 	if (have_vt220)
-		_sclp_print_vt220(str, len);
-	_sclp_setup(1);
+		sclp_early_print_vt220(str, len);
+	sclp_early_setup(1, &have_linemode, &have_vt220);
 }
 
-void _sclp_print_early(const char *str)
+void sclp_early_printk(const char *str)
 {
-	__sclp_print_early(str, strlen(str));
+	__sclp_early_printk(str, strlen(str));
 }