Hello Sascha, On Fri, Mar 04, 2016 at 08:04:48AM +0100, Sascha Hauer wrote: > Hi Alexander, > > On Wed, Mar 02, 2016 at 11:51:28PM +0100, Alexander Kurz wrote: > > This is a re-application of fix 17644b55. > > arm_cpu_lowlevel_init() will set the processor mode to 0x13 (supervisor). > > When this function is entered via a different processor mode, register > > banking will happen to lr (r14), resulting in an invalid return address. > > This fix will preserve the return address manually. > > > > Signed-off-by: Alexander Kurz <akurz@xxxxxxxx> > > --- > > arch/arm/cpu/lowlevel.S | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm/cpu/lowlevel.S b/arch/arm/cpu/lowlevel.S > > index b76222d..e5baa12 100644 > > --- a/arch/arm/cpu/lowlevel.S > > +++ b/arch/arm/cpu/lowlevel.S > > @@ -4,6 +4,8 @@ > > > > .section ".text_bare_init_","ax" > > ENTRY(arm_cpu_lowlevel_init) > > + /* save lr, since it may be banked away with a processor mode change */ > > + mov r2, lr Acked-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > Thanks for fixing this and for adding a comment why this is done. This > hopefully prevents us from breaking it again. > > Out of interest, what system are you using where this fix is necesssary? > > Uwe, now we know why that was done and why e190bcf (arm/cpu/lowlevel: > Don't save the return address in another register) was a bad idea. Right. :-) But even if I had seen 17644b55cae9c234b26213d644e9fd939b0ec815 back then I would have wondered because the commit log isn't that verbose :-( Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
