On 05/09/14 19:04, Nicolas Pitre wrote: > On Fri, 5 Sep 2014, Daniel Thompson wrote: > >> On 04/09/14 19:57, Nicolas Pitre wrote: >>> On Thu, 4 Sep 2014, Daniel Thompson wrote: >>> >>>> +@ svc_exit_via_fiq - similar to svc_exit but switches to FIQ mode before >>>> exit >>>> +@ >>>> +@ This macro acts in a similar manner to svc_exit but switches to FIQ >>>> +@ mode to restore the final part of the register state. >>>> +@ >>>> +@ We cannot use the normal svc_exit procedure because that would >>>> +@ clobber spsr_svc (FIQ could be delivered during the first few >>>> instructions >>>> +@ of vector_swi meaning its contents have not been saved anywhere). >>>> +@ >>> >>> Wouldn't it be better for this macro to live in entry-header.S alongside >>> the others? >> >> I'm not sure either way. >> >> svc_exit_from_fiq isn't needed by entry-common.S and cannot be used by >> entry-v7m.S because v7m has no FIQ. For that reason I decided to place >> it alongside svc_entry in entry-armv.S rather than alongside svc_exit in >> entry-header.S . > > Here's a list of macros from entry-headers.S that I don't see being used > in entry-v7m.S: zero_fp, alignment_trap, store_user_sp_lr, > load_user_sp_lr, svc_exit, ct_user_exit, ct_user_enter.
All except one of of these are consumed either by entry-common.S or by entry-header.S itself. svc_exit is the only exception, it is exclusively consumed by entry-armv.S. > Yet, entry-header.S contains macros such as v7m_exception_entry and > v7m_exception_slow_exit which are unlikely to ever be used in > entry-armv.S. Although these macros are v7m specific they are used in conditionally compiled code within entry-common.S in order to implement system call handlers. >> I am happy to move it if you have a strong preference here. Please let >> me know. > > I don't have a strong preference, but a preference nevertheless. > > It just looks odd that a file is already dedicated to gather all those > macros for similar purposes and this one is not there. That makes > future code review/maintenance a bit annoying if similar things are not > kept in one place. I will move the macro to entry-common.S in order to keep it alongside its workalike function svc_exit. That said, I do retain a (pretty weakly held) view that both these macros might be better off moved to entry-armv.S . -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
