Hi Julien, On 28.02.2022 11:11, Julien Grall wrote: > From: Julien Grall <[email protected]> > > Since commit 54c4ae18d158 ("xen/arm32: head: Rework and document > launch()"), the boot code is not using the register r12. > > So update the documentation to show r12 has no specific purpose. > > Signed-off-by: Julien Grall <[email protected]> > --- > xen/arch/arm/arm32/head.S | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S > index 13cfc837d39c..78274a1c034f 100644 > --- a/xen/arch/arm/arm32/head.S > +++ b/xen/arch/arm/arm32/head.S > @@ -79,7 +79,7 @@ > * r9 - paddr(start) > * r10 - phys offset > * r11 - UART address > - * r12 - is_secondary_cpu > + * r12 - > * r13 - SP > * r14 - LR > * r15 - PC >
FWICS, there are still 2 instructions in this file assigning #0 or #1 to r12 and each of them has a comment "/* r12 := is_secondary_cpu */". So I have 2 questions: 1. Do we even need these instructions? (I do not think so) 2. If we need these instructions, do we need these comments? Cheers, Michal
