Re: [PATCH] compatibility syscall layer (lets try again)

From: george anzinger (george@mvista.com)
Date: Thu Dec 05 2002 - 04:48:18 EST

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/rml

diff -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

- 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/

This archive was generated by hypermail 2b29 : Sat Dec 07 2002 - 22:00:22 EST