I found what my error was.
In the declaration of the system call in the "user_prs_sysclkutils.h" file (in the target file system)
I had to replace :
_syscall2(long,prs_sysClkUtils,char *,todo,int,arg);
by:
static inline _syscall2(long,prs_sysClkUtils,char *,todo,int,arg)
That's it !
-------- Message d'origine--------
De: Garcia Jérémie
Date: ven. 26/08/2005 16:15
À: kernelnewbies@xxxxxxxxxxxx
Objet : Error in using a new system call
Hi everybody, as you can guess, I need your help!
First of all, I'm using a linux montavista pro 3.1 (kernel 2.4.20) for a cross compilation.
For my project, I had to develop some new system calls. This done, I wrote a C/C++ proj
that uses this new features.
Everything is ok during compile time but when linking, I get the following error messages.
Below you'll find only one link error cause the message is the same for each new system call used.
I don't understand what goes wrong... So I give you what I modified in the linux montavista sources and
the changes in the target file system.
Do I need to add a library for the compile time?
/**************/
/* LINK ERROR
/**************/
ppc_405-g++ -static -L/myWorks/en-cours/target/usr/lib -o ssc.exe libSsc.a -lpthread -lposixtime
libSsc.a(ppcbsos2.o)(.text+0x0): In function `prs_sysClkUtils':
/myWorks/en-cours/target/usr/include/sys/user_prs_sysclkutils.h:6: définitions multiples de « prs_sysClkUtils »
libSsc.a(ppcbsos1.o)(.text+0x6c):/myWorks/en-cours/target/usr/include/sys/user_prs_sysclkutils.h:6: défini pour la première fois ici
/*******************************************/
/* "montavista/arch/ppc/prs/prs_sysClkUtils.c":
/* this is the system call source file added in
/* montavista src
/*******************************************/
#include <linux/prs_sysclkutils.h>
static int sysClkRunning = FALSE;
static unsigned int pitCountVal = -1; /* PIT counter value */
static int sysClkTicksPerSecond = 100; /* default 100 ticks/second */
static int sysTimerClkFreq = 200000000; /* Timer clock frequency */
static short isInited = -1;
static long previousJiffiesVal;
static long virtualTickCounter;
asmlinkage long sys_prs_sysClkUtils(char * todo , int arg)
{
long rc = -1;
/* Test if the counters have been inited or not. These ones must be inited with jiffies value
* but we can't do that at compile time cause jiffies is not a constant. Furthermore, we do not
* protect these values with a semaphore cause only the sscManager uses it once. So there is
* no concurrent access to them.
*/
if(isInited == -1)
{
previousJiffiesVal = jiffies;
virtualTickCounter = jiffies;
isInited = 0;
}
/* We want to make a sysClkDisable */
if(my_strcmp(todo,"sysClkDisable")==0)
{
if(sysClkRunning)
{
/* disable the PIT interrupt and auto-reload capability */
mtspr(SPRN_TCR ,mfspr(SPRN_TCR ) & ~ (TCR_PIE | TCR_ARE));
/* clear the PIT counter */
mtspr(SPRN_PIT,0);
/* clear the pending PIT interrupt */
mtspr(SPRN_TSR,SPRN_TSR | TSR_PIS);
/* reset the running flag */
sysClkRunning =FALSE;
rc = 0;
}
else
rc = -1;
}
if(my_strcmp(todo,"sysClkRateSet")==0)
{
if( (arg < SYS_CLK_RATE_MIN) || (arg > SYS_CLK_RATE_MAX) )
rc = -1;
else
{
/* save the new value for the system clock rate */
sysClkTicksPerSecond = arg;
pitCountVal = sysTimerClkFreq / sysClkTicksPerSecond ;
mtspr(SPRN_PIT,pitCountVal);
rc = 0;
}
}
/* Bad use of this system call */
return rc;
}
/********************************************/
/* "montavista/include/linux/prs_sysClkUtils.h"
/* this is the header file for our system call
/* source file
/********************************************/
#ifndef __LINUX_PRS_SYSCLKUTILS_H
#define __LINUX_PRS_SYSCLKUTILS_H
/* We need the compiler to recognize the word "asmlinkage" */
#include <linux/linkage.h>
/* We need to access to powerPC registers */
#include <asm/processor.h>
#include <linux/sched.h>
#endif /* __LINUX_PRS_SYSCLKUTILS_H */
/*********************************************/
/* montavista/arch/ppc/kernel/misc.S
/********************************************/
[...]
.long sys_clock_gettime
.long sys_clock_getres
.long sys_clock_nanosleep /* 240 */
.long sys_prs_sysClkUtils
/*********************************************/
/* montavista/include/linux/unistd.h
/********************************************/
[...]
#define __NR_io_cancel 231
#define __NR_timer_create 232
#define __NR_timer_settime (__NR_timer_create+1)
#define __NR_timer_gettime (__NR_timer_create+2)
#define __NR_timer_getoverrun (__NR_timer_create+3)
#define __NR_timer_delete (__NR_timer_create+4)
#define __NR_clock_settime (__NR_timer_create+5)
#define __NR_clock_gettime (__NR_timer_create+6)
#define __NR_clock_getres (__NR_timer_create+7)
#define __NR_clock_nanosleep (__NR_timer_create+8)
#define __NR_prs_sysClkUtils 241
/***********************************************************/
/* "targetFileSystem/usr/include/sys/user_prs_sysclkutils.h"
/* this is the file added in the target file system to allow
/* user space progs to use the nex sys call
/***********************************************************/
#ifndef __USER_PRS_SYSCLKUTILS_H
#define __USER_PRS_SYSCLKUTILS_H
#include <linux/unistd.h>
_syscall2(long,prs_sysClkUtils,char *,todo,int,arg);
#endif
/*********************************/
/* User space program
/********************************/
#include <sys/user_prs_sysclkutils.h>
int sysTickGet(void)
{
return(prs_sysClkUtils("sysClkRateSet",0));
}
Tks a lot
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