Ed Tomlinson <[EMAIL PROTECTED]> wrote:
>
> > Don't think so - it works OK here.  Checked the .config?  Does the serial
>  > port work if you do `echo foo > /dev/ttyS0'?  ACPI?
> 
>  Turned out it was some old ups software that got reactivated on the box 
> displaying the
>  console - was a pain to disable it....

OK.

>  In any case, when the box reboots there are not any messages.  Any ideas on 
> what debug
>  options to enable or suggestions on how we can figure out the cause of the 
> reboots.

There were a few problems in the task switching area - maybe that.




From: Ingo Molnar <[EMAIL PROTECTED]>

delay the reloading of segment registers into switch_mm(), so that if
the LDT size changes we dont get a (silent) fault and a zeroed selector
register upon reloading.

Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---

 25-akpm/arch/i386/kernel/process.c     |   10 +++++-----
 25-akpm/include/asm-i386/mmu_context.h |    7 +++++++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff -puN arch/i386/kernel/process.c~sched-unlocked-context-switches-fix 
arch/i386/kernel/process.c
--- 25/arch/i386/kernel/process.c~sched-unlocked-context-switches-fix   
2005-04-12 03:43:07.254363568 -0700
+++ 25-akpm/arch/i386/kernel/process.c  2005-04-12 03:43:07.259362808 -0700
@@ -653,12 +653,12 @@ struct task_struct fastcall * __switch_t
        asm volatile("mov %%gs,%0":"=m" (prev->gs));
 
        /*
-        * Restore %fs and %gs if needed.
+        * Clear selectors if needed:
         */
-       if (unlikely(prev->fs | prev->gs | next->fs | next->gs)) {
-               loadsegment(fs, next->fs);
-               loadsegment(gs, next->gs);
-       }
+        if (unlikely((prev->fs | prev->gs) && !(next->fs | next->gs))) {
+                loadsegment(fs, next->fs);
+                loadsegment(gs, next->gs);
+        }
 
        /*
         * Now maybe reload the debug registers
diff -puN include/asm-i386/mmu_context.h~sched-unlocked-context-switches-fix 
include/asm-i386/mmu_context.h
--- 25/include/asm-i386/mmu_context.h~sched-unlocked-context-switches-fix       
2005-04-12 03:43:07.256363264 -0700
+++ 25-akpm/include/asm-i386/mmu_context.h      2005-04-12 03:43:07.260362656 
-0700
@@ -61,6 +61,13 @@ static inline void switch_mm(struct mm_s
                }
        }
 #endif
+       /*
+        * Now that we've switched the LDT, load segments:
+        */
+       if (unlikely(current->thread.fs | current->thread.gs)) {
+               loadsegment(fs, current->thread.fs);
+               loadsegment(gs, current->thread.gs);
+       }
 }
 
 #define deactivate_mm(tsk, mm) \
_

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to