On Wed, Feb 21, 2007 at 09:57:50PM -0800, H. Peter Anvin wrote: > Russell King wrote: > > > > >Plainly, %ebx changed across the call to serial_in() at c01c0f7b. > >First thing to notice is this violates the C code - "up" can not > >change. > > > >Now let's look at serial_in: > > > >c01bfa70: 55 push %ebp > >c01bfa71: 89 e5 mov %esp,%ebp > >c01bfa73: 53 push %ebx > >... > >c01bfab7: 5b pop %ebx > >c01bfab8: 5d pop %ebp > >c01bfab9: c3 ret > > > >This code tells the CPU to preserves %ebx and %ebp. But we know %ebx > >_wasn't_ preserved. Ergo, your CPU is plainly not doing what the code > >told it to do. > > > > ... assuming nothing else clobbered the stack slot (which would be a > compiler error, or a wild pointer.) > > Got a disassembly of the whole function?
See Jose's subsequent message to the one I replied to. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - 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/
