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Commit 740b5706 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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[S390] cpcmd <-> __cpcmd calling issues 



In case of reipl cpcmd gets called when all other cpus are not running
anymore. To prevent deadlocks change __cpcmd so that it doesn't take
any locks and call cpcmd or __cpcmd, whatever is correct in the current
context.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a1a392f0

arch/s390/kernel/cpcmd.c

+11 −7
Original line number Diff line number Diff line
@@ -21,14 +21,15 @@ static DEFINE_SPINLOCK(cpcmd_lock); 
static char cpcmd_buf[241];



/*

 * the caller of __cpcmd has to ensure that the response buffer is below 2 GB

 * __cpcmd has some restrictions over cpcmd

 *  - the response buffer must reside below 2GB (if any)

 *  - __cpcmd is unlocked and therefore not SMP-safe

 */

int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)

{

	unsigned long flags, cmdlen;

	unsigned cmdlen;

	int return_code, return_len;



	spin_lock_irqsave(&cpcmd_lock, flags);

	cmdlen = strlen(cmd);

	BUG_ON(cmdlen > 240);

	memcpy(cpcmd_buf, cmd, cmdlen);
@@ -74,7 +75,6 @@ int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 
			: "+d" (reg3) : "d" (reg2) : "cc");

		return_code = (int) reg3;

        }

	spin_unlock_irqrestore(&cpcmd_lock, flags);

	if (response_code != NULL)

		*response_code = return_code;

	return return_len;
@@ -82,15 +82,18 @@ int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 


EXPORT_SYMBOL(__cpcmd);



#ifdef CONFIG_64BIT

int cpcmd(const char *cmd, char *response, int rlen, int *response_code)

{

	char *lowbuf;

	int len;

	unsigned long flags;



	if ((rlen == 0) || (response == NULL)

	    || !((unsigned long)response >> 31))

	    || !((unsigned long)response >> 31)) {

		spin_lock_irqsave(&cpcmd_lock, flags);

		len = __cpcmd(cmd, response, rlen, response_code);

		spin_unlock_irqrestore(&cpcmd_lock, flags);

	}

	else {

		lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);

		if (!lowbuf) {
@@ -98,7 +101,9 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 
				"cpcmd: could not allocate response buffer\n");

			return -ENOMEM;

		}

		spin_lock_irqsave(&cpcmd_lock, flags);

		len = __cpcmd(cmd, lowbuf, rlen, response_code);

		spin_unlock_irqrestore(&cpcmd_lock, flags);

		memcpy(response, lowbuf, rlen);

		kfree(lowbuf);

	}
@@ -106,4 +111,3 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 
}



EXPORT_SYMBOL(cpcmd);
 
#endif		/* CONFIG_64BIT */

arch/s390/kernel/ipl.c

+5 −5
Original line number Diff line number Diff line
@@ -677,7 +677,7 @@ void do_reipl(void) 
		else

			sprintf(buf, "IPL %X LOADPARM '%s'",

				reipl_block_ccw->ipl_info.ccw.devno, loadparm);

		cpcmd(buf, NULL, 0, NULL);

		__cpcmd(buf, NULL, 0, NULL);

		break;

	case IPL_METHOD_CCW_DIAG:

		diag308(DIAG308_SET, reipl_block_ccw);
@@ -691,12 +691,12 @@ void do_reipl(void) 
		diag308(DIAG308_IPL, NULL);

		break;

	case IPL_METHOD_FCP_RO_VM:

		cpcmd("IPL", NULL, 0, NULL);

		__cpcmd("IPL", NULL, 0, NULL);

		break;

	case IPL_METHOD_NONE:

	default:

		if (MACHINE_IS_VM)

			cpcmd("IPL", NULL, 0, NULL);

			__cpcmd("IPL", NULL, 0, NULL);

		diag308(DIAG308_IPL, NULL);

		break;

	}
@@ -732,9 +732,9 @@ static void do_dump(void) 
	case IPL_METHOD_CCW_VM:

		dump_smp_stop_all();

		sprintf(buf, "STORE STATUS");

		cpcmd(buf, NULL, 0, NULL);

		__cpcmd(buf, NULL, 0, NULL);

		sprintf(buf, "IPL %X", dump_block_ccw->ipl_info.ccw.devno);

		cpcmd(buf, NULL, 0, NULL);

		__cpcmd(buf, NULL, 0, NULL);

		break;

	case IPL_METHOD_CCW_DIAG:

		diag308(DIAG308_SET, dump_block_ccw);

arch/s390/kernel/setup.c

+5 −5
Original line number Diff line number Diff line
@@ -229,11 +229,11 @@ static void __init conmode_default(void) 
	char *ptr;



        if (MACHINE_IS_VM) {

		__cpcmd("QUERY CONSOLE", query_buffer, 1024, NULL);

		cpcmd("QUERY CONSOLE", query_buffer, 1024, NULL);

		console_devno = simple_strtoul(query_buffer + 5, NULL, 16);

		ptr = strstr(query_buffer, "SUBCHANNEL =");

		console_irq = simple_strtoul(ptr + 13, NULL, 16);

		__cpcmd("QUERY TERM", query_buffer, 1024, NULL);

		cpcmd("QUERY TERM", query_buffer, 1024, NULL);

		ptr = strstr(query_buffer, "CONMODE");

		/*

		 * Set the conmode to 3215 so that the device recognition
@@ -242,7 +242,7 @@ static void __init conmode_default(void) 
		 * 3215 and the 3270 driver will try to access the console

		 * device (3215 as console and 3270 as normal tty).

		 */

		__cpcmd("TERM CONMODE 3215", NULL, 0, NULL);

		cpcmd("TERM CONMODE 3215", NULL, 0, NULL);

		if (ptr == NULL) {

#if defined(CONFIG_SCLP_CONSOLE)

			SET_CONSOLE_SCLP;
@@ -299,14 +299,14 @@ static void do_machine_restart_nonsmp(char * __unused) 
static void do_machine_halt_nonsmp(void)

{

        if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)

                cpcmd(vmhalt_cmd, NULL, 0, NULL);

		__cpcmd(vmhalt_cmd, NULL, 0, NULL);

        signal_processor(smp_processor_id(), sigp_stop_and_store_status);

}



static void do_machine_power_off_nonsmp(void)

{

        if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)

                cpcmd(vmpoff_cmd, NULL, 0, NULL);

		__cpcmd(vmpoff_cmd, NULL, 0, NULL);

        signal_processor(smp_processor_id(), sigp_stop_and_store_status);

}

include/asm-s390/cpcmd.h

+3 −7
Original line number Diff line number Diff line
@@ -7,8 +7,8 @@ 
 *               Christian Borntraeger (cborntra@de.ibm.com),

 */



#ifndef __CPCMD__

#define __CPCMD__

#ifndef _ASM_S390_CPCMD_H

#define _ASM_S390_CPCMD_H



/*

 * the lowlevel function for cpcmd
@@ -16,9 +16,6 @@ 
 */

extern int __cpcmd(const char *cmd, char *response, int rlen, int *response_code);



#ifndef __s390x__

#define cpcmd __cpcmd

#else

/*

 * cpcmd is the in-kernel interface for issuing CP commands

 *
@@ -33,6 +30,5 @@ extern int __cpcmd(const char *cmd, char *response, int rlen, int *response_code 
 * NOTE: If the response buffer is not below 2 GB, cpcmd can sleep

 */

extern int cpcmd(const char *cmd, char *response, int rlen, int *response_code);

#endif /*__s390x__*/



#endif
 
#endif /* _ASM_S390_CPCMD_H */