On 4/3/21 10:46 PM, Madhavan T. Venkataraman wrote: >> I'm somewhat arm-ignorant, so take the following comments with a grain >> of salt. >> >> >> I don't think changing these to 'bl' is necessary, unless you wanted >> __primary_switched() and __secondary_switched() to show up in the >> stacktrace for some reason? If so, that seems like a separate patch. >> > The problem is with __secondary_switched. If you trace the code back to where > a secondary CPU is started, I don't see any calls anywhere. There are only > branches if I am not mistaken. So, the return address register never gets > set up with a proper address. The stack trace shows some hexadecimal value > instead of a symbol name. > Actually, I take that back. There are calls in that code path. But I did only see some hexadecimal value instead of a proper address in the stack trace. Sorry about that confusion. My reason to convert the branches to calls is this - the value of the return address register at that point is the return PC of the previous branch and link instruction wherever that happens to be. I think that is a little arbitrary. Instead, if I call start_kernel() and secondary_start_kernel(), the return address gets set up to the next instruction which, IMHO, is better. But I am open to other suggestions. Madhavan
