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Re: problems execve("/sbin/init",...)

To: glonnon@ridgerun.com
Subject: Re: problems execve("/sbin/init",...)
From: Jun Sun <jsun@mvista.com>
Date: Fri, 29 Sep 2000 16:05:46 -0700
Cc: linux-mips@oss.sgi.com, linux-mips@fnet.fr
References: <39D3FFE4.35E83599@ridgerun.com>
Sender: owner-linux-mips@oss.sgi.com
Greg Lonnon wrote:
> 
> So, my questions are:
> 1) Does anyone have a good way to debug in this small window going
> between kernel mode and user mode for the first time?

Not really.  One time I had similar problem.  I was able to figure out
the problem by setting breakpoints in fault handlers.

> 2) Is there anything else I could try to prove out that the kernel is
> going into user mode?

Try to set breakpoint in fault handlers.

> 3) Has anyone else had these issues?
>

I found one bug in arch/mm/r4xx0.c, where cache invalidation causes
recursive page faults.  See the page below.  Not sure if it is fixed in
the tree yet.

diff -Nru linux/arch/mips/mm/r4xx0.c.orig linux/arch/mips/mm/r4xx0.c
--- linux/arch/mips/mm/r4xx0.c.orig     Sun Jul 30 20:39:50 2000
+++ linux/arch/mips/mm/r4xx0.c  Thu Aug 10 16:08:20 2000
@@ -1972,7 +1972,8 @@
        if (!(vma->vm_flags & VM_EXEC))
                return;

-       blast_icache32_page(address);
+        address = KSEG0 + (address & PAGE_MASK & (dcache_size - 1));
+        blast_icache32_page_indexed(address);
 }

 /*
 
Jun

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