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    SubjectRe: [PATCH] compatibility syscall layer (lets try again)
    Linus Torvalds wrote:
    >
    > On Wed, 4 Dec 2002, george anzinger wrote:
    > >
    > > Once it changes the system call (eax, right), could the new
    > > call code then just get the parms from the restart_block.
    >
    > Agreed.
    >
    > > I think it would be best to keep this as generic as
    > > possible, i.e. let the new call code fetch its own
    > > paramerers from the restart_block.
    >
    > We could even have one _single_ a generic "restart" system call, and have
    > the function pointer for that be in the restart block.
    >
    > > My question is who sets up these values? I think you are
    > > saying it should be the system call. Is this right?
    >
    > Whatever system call that return -ERESTART_RESTARTBLOCK, yes.
    >
    > So it would never get set up at all in the fast path. Only in the error
    > case path of a system call that wants to have restarting capabilities.
    >
    > Linus

    Ok, here is a patch to do all this. This is against
    2.5.50-bk4. (Bk5 did not get posted this evening.)

    I think this covers all the bases. It builds boots and
    runs. I haven't tested nano_sleep to see if it does the
    right thing yet...

    --
    George Anzinger george@mvista.com
    High-res-timers:
    http://sourceforge.net/projects/high-res-timers/
    Preemption patch:
    http://www.kernel.org/pub/linux/kernel/people/rmldiff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/arch/i386/kernel/entry.S linux/arch/i386/kernel/entry.S
    --- linux-2.5.50-bk4-kb/arch/i386/kernel/entry.S Wed Dec 4 23:28:20 2002
    +++ linux/arch/i386/kernel/entry.S Wed Dec 4 23:48:49 2002
    @@ -769,6 +769,7 @@
    .long sys_epoll_wait
    .long sys_remap_file_pages
    .long sys_set_tid_address
    + .long sys_restart_syscall


    .rept NR_syscalls-(.-sys_call_table)/4
    diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/arch/i386/kernel/signal.c linux/arch/i386/kernel/signal.c
    --- linux-2.5.50-bk4-kb/arch/i386/kernel/signal.c Thu Oct 3 10:41:57 2002
    +++ linux/arch/i386/kernel/signal.c Thu Dec 5 00:27:21 2002
    @@ -507,6 +507,7 @@
    /* If so, check system call restarting.. */
    switch (regs->eax) {
    case -ERESTARTNOHAND:
    + case -ERESTART_RESTARTBLOCK:
    regs->eax = -EINTR;
    break;

    @@ -589,6 +590,10 @@
    regs->eax == -ERESTARTSYS ||
    regs->eax == -ERESTARTNOINTR) {
    regs->eax = regs->orig_eax;
    + regs->eip -= 2;
    + }
    + if (regs->eax == -ERESTART_RESTARTBLOCK){
    + regs->eax = __NR_restart_syscall;
    regs->eip -= 2;
    }
    }
    diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/include/asm-i386/thread_info.h linux/include/asm-i386/thread_info.h
    --- linux-2.5.50-bk4-kb/include/asm-i386/thread_info.h Mon Sep 9 10:35:03 2002
    +++ linux/include/asm-i386/thread_info.h Thu Dec 5 01:07:23 2002
    @@ -20,6 +20,12 @@
    * - if the contents of this structure are changed, the assembly constants must also be changed
    */
    #ifndef __ASSEMBLY__
    +struct restart_block {
    + int (*fun)(void *);
    + long arg0;
    + long arg1;
    +};
    +
    struct thread_info {
    struct task_struct *task; /* main task structure */
    struct exec_domain *exec_domain; /* execution domain */
    @@ -31,6 +37,7 @@
    0-0xBFFFFFFF for user-thead
    0-0xFFFFFFFF for kernel-thread
    */
    + struct restart_block restart_block;

    __u8 supervisor_stack[0];
    };
    @@ -44,6 +51,7 @@
    #define TI_CPU 0x0000000C
    #define TI_PRE_COUNT 0x00000010
    #define TI_ADDR_LIMIT 0x00000014
    +#define TI_RESTART_BLOCK 0x0000018

    #endif

    @@ -63,6 +71,9 @@
    .cpu = 0, \
    .preempt_count = 1, \
    .addr_limit = KERNEL_DS, \
    + .restart_block = { \
    + .fun = 0, \
    + }, \
    }

    #define init_thread_info (init_thread_union.thread_info)
    diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/include/asm-i386/unistd.h linux/include/asm-i386/unistd.h
    --- linux-2.5.50-bk4-kb/include/asm-i386/unistd.h Wed Nov 27 15:49:22 2002
    +++ linux/include/asm-i386/unistd.h Wed Dec 4 23:48:46 2002
    @@ -263,7 +263,7 @@
    #define __NR_sys_epoll_wait 256
    #define __NR_remap_file_pages 257
    #define __NR_set_tid_address 258
    -
    +#define __NR_restart_syscall 259

    /* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */

    diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/include/linux/errno.h linux/include/linux/errno.h
    --- linux-2.5.50-bk4-kb/include/linux/errno.h Mon Sep 9 10:35:15 2002
    +++ linux/include/linux/errno.h Wed Dec 4 23:53:21 2002
    @@ -10,6 +10,7 @@
    #define ERESTARTNOINTR 513
    #define ERESTARTNOHAND 514 /* restart if no handler.. */
    #define ENOIOCTLCMD 515 /* No ioctl command */
    +#define ERESTART_RESTARTBLOCK 516 /* restart by calling sys_restart_syscall */

    /* Defined for the NFSv3 protocol */
    #define EBADHANDLE 521 /* Illegal NFS file handle */
    diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/kernel/signal.c linux/kernel/signal.c
    --- linux-2.5.50-bk4-kb/kernel/signal.c Wed Dec 4 23:27:02 2002
    +++ linux/kernel/signal.c Thu Dec 5 01:18:20 2002
    @@ -1351,6 +1351,15 @@
    * System call entry points.
    */

    +asmlinkage long
    +sys_restart_syscall( void *parm)
    +{
    + if ( ! current_thread_info()->restart_block.fun){
    + return current_thread_info()->restart_block.fun(&parm);
    + }
    + return -ENOSYS;
    +}
    +
    /*
    * We don't need to get the kernel lock - this is all local to this
    * particular thread.. (and that's good, because this is _heavily_
    diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.50-bk4-kb/kernel/timer.c linux/kernel/timer.c
    --- linux-2.5.50-bk4-kb/kernel/timer.c Wed Dec 4 23:27:02 2002
    +++ linux/kernel/timer.c Thu Dec 5 01:16:03 2002
    @@ -1020,19 +1020,39 @@
    return current->pid;
    }

    +struct nano_sleep_call {
    + struct timespec *rqtp;
    + struct timespec *rmtp;
    +};
    +
    +asmlinkage long sys_nanosleep_restart( struct nano_sleep_call * parms);
    +
    asmlinkage long sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp)
    {
    struct timespec t;
    unsigned long expire;
    + struct restart_block *restart_block;

    - if(copy_from_user(&t, rqtp, sizeof(struct timespec)))
    - return -EFAULT;
    -
    - if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0 || t.tv_sec < 0)
    - return -EINVAL;
    + if (rqtp) {
    + if(copy_from_user(&t, rqtp, sizeof(struct timespec)))
    + return -EFAULT;

    - expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
    + if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0 || t.tv_sec < 0)
    + return -EINVAL;
    + expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);

    + }else{
    + restart_block = &current_thread_info()->restart_block;
    + if( restart_block->fun !=
    + (int (*)(void *))sys_nanosleep_restart ||
    + ! restart_block->arg0){
    + return -EFAULT;
    + }
    + restart_block->fun = NULL;
    + expire = restart_block->arg0 - jiffies;
    + if (expire < 0)
    + return 0;
    + }
    current->state = TASK_INTERRUPTIBLE;
    expire = schedule_timeout(expire);

    @@ -1042,10 +1062,19 @@
    if (copy_to_user(rmtp, &t, sizeof(struct timespec)))
    return -EFAULT;
    }
    - return -EINTR;
    + restart_block = &current_thread_info()->restart_block;
    + restart_block->fun = (int (*)(void *))sys_nanosleep_restart;
    + restart_block->arg0 = jiffies + expire;
    + return -ERESTART_RESTARTBLOCK;
    }
    return 0;
    }
    +
    +asmlinkage long sys_nanosleep_restart( struct nano_sleep_call * parms)
    +{
    + return sys_nanosleep(NULL, parms->rmtp);
    +}
    +

    /*
    * sys_sysinfo - fill in sysinfo struct
    \
     
     \ /
      Last update: 2005-03-22 13:31    [W:0.032 / U:0.228 seconds]
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