Re: Fwd: [PATCH] s390 (1/7): s390 arch fixes.

Re: Fwd: [PATCH] s390 (1/7): s390 arch fixes.

[Pete Zaitcev]

> --- linux-2.5.64/include/asm-s390/system.h	Wed Mar  5 04:29:54 2003
> +++ linux-2.5.64-s390/include/asm-s390/system.h	Fri Mar  7 11:40:12 2003
> @@ -82,7 +82,7 @@
>  		break;							     \
>  	save_fp_regs(&prev->thread.fp_regs);				     \
>  	restore_fp_regs(&next->thread.fp_regs);				     \
> -	resume(prev,next);						     \
> +	prev = resume(prev,next);					     \
>  } while (0)
>  
>  #define nop() __asm__ __volatile__ ("nop")

Are you sure it's not "last = resume(prev, next);"?

-- Pete

Re: Fwd: [PATCH] s390 (1/7): s390 arch fixes.

[Pete Zaitcev]

> --- linux-2.5.64/arch/s390/kernel/time.c	Wed Mar  5 04:28:53 2003
> +++ linux-2.5.64-s390/arch/s390/kernel/time.c	Fri Mar  7 11:40:12 2003
> @@ -202,14 +203,14 @@
>  	unsigned long cr0;
>  	__u64 timer;
>  
> +	timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
> +	S390_lowcore.jiffy_timer = timer;
> +	timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION;
> +	asm volatile ("SCKC %0" : : "m" (timer));
>          /* allow clock comparator timer interrupt */
>          asm volatile ("STCTL 0,0,%0" : "=m" (cr0) : : "memory");
>          cr0 |= 0x800;
>          asm volatile ("LCTL 0,0,%0" : : "m" (cr0) : "memory");
> -	timer = init_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
> -	S390_lowcore.jiffy_timer = timer;
> -	timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION;
> -	asm volatile ("SCKC %0" : : "m" (timer));
>  }
>  
>  /*

This is a good fix, I confirm it fixing my booting problem ...
on 2.4! Seriously, I can't believe it worked before.
Please send it to Marcelo, too.

-- Pete

Re: Fwd: [PATCH] s390 (1/7): s390 arch fixes.

[Martin Schwidefsky]

> This is a good fix, I confirm it fixing my booting problem ...
> on 2.4! Seriously, I can't believe it worked before.
> Please send it to Marcelo, too.

Well, the POP states under "Initial CPU Reset":
2. The contents of the current PSW, prefix, CPU
   timer, clock comparator, and TOD programmable
   register are set to zero.

The fix should be necessary but it fixed some boot
problems for me as well ...

This fix is already in patch-2.4.21-pre5.

blue skies,
   Martin

Re: Fwd: [PATCH] s390 (1/7): s390 arch fixes.

[Martin Schwidefsky]

> Are you sure it's not "last = resume(prev, next);"?
>
> -- Pete

switch_to is called in context_switch as follows:

      switch_to(prev, next, prev);

At the moment it doesn't matter but thinking about the
meaning of the parameter names your are probably right.
This should better be last = resume(prev, next).

blue skies,
   Martin