Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936930AbWLDOyb (ORCPT ); Mon, 4 Dec 2006 09:54:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936921AbWLDOyW (ORCPT ); Mon, 4 Dec 2006 09:54:22 -0500 Received: from mtagate4.de.ibm.com ([195.212.29.153]:16535 "EHLO mtagate4.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936945AbWLDOyO (ORCPT ); Mon, 4 Dec 2006 09:54:14 -0500 Date: Mon, 4 Dec 2006 15:54:10 +0100 From: Martin Schwidefsky To: linux-kernel@vger.kernel.org, heiko.carstens@de.ibm.com Subject: [S390] cpcmd <-> __cpcmd calling issues Message-ID: <20061204145410.GR32059@skybase> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7142 Lines: 204 From: Heiko Carstens [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: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/cpcmd.c | 18 +++++++++++------- arch/s390/kernel/ipl.c | 10 +++++----- arch/s390/kernel/setup.c | 10 +++++----- include/asm-s390/cpcmd.h | 10 +++------- 4 files changed, 24 insertions(+), 24 deletions(-) diff -urpN linux-2.6/arch/s390/kernel/cpcmd.c linux-2.6-patched/arch/s390/kernel/cpcmd.c --- linux-2.6/arch/s390/kernel/cpcmd.c 2006-11-29 22:57:37.000000000 +0100 +++ linux-2.6-patched/arch/s390/kernel/cpcmd.c 2006-12-04 14:50:49.000000000 +0100 @@ -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 *resp : "+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 *resp 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 *respons "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 *respons } EXPORT_SYMBOL(cpcmd); -#endif /* CONFIG_64BIT */ diff -urpN linux-2.6/arch/s390/kernel/ipl.c linux-2.6-patched/arch/s390/kernel/ipl.c --- linux-2.6/arch/s390/kernel/ipl.c 2006-12-04 14:50:48.000000000 +0100 +++ linux-2.6-patched/arch/s390/kernel/ipl.c 2006-12-04 14:50:49.000000000 +0100 @@ -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); diff -urpN linux-2.6/arch/s390/kernel/setup.c linux-2.6-patched/arch/s390/kernel/setup.c --- linux-2.6/arch/s390/kernel/setup.c 2006-11-29 22:57:37.000000000 +0100 +++ linux-2.6-patched/arch/s390/kernel/setup.c 2006-12-04 14:50:49.000000000 +0100 @@ -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(ch 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); } diff -urpN linux-2.6/include/asm-s390/cpcmd.h linux-2.6-patched/include/asm-s390/cpcmd.h --- linux-2.6/include/asm-s390/cpcmd.h 2006-11-29 22:57:37.000000000 +0100 +++ linux-2.6-patched/include/asm-s390/cpcmd.h 2006-12-04 14:50:49.000000000 +0100 @@ -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 * 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 */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/