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.
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.
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.
Nicolas