On Monday 01 September 2014 18:00:58 long.wanglong wrote:
> On 2014/9/1 13:49, Wang Long wrote:
> >
> > Hi,all
> >
> > In kernel 3.17-rc2, when i set CONFIG_HAVE_SMP = y and CONFIG_SMP_ON_UP = y
> > in .config file. the secondary core can not boot.
> >
> > when i set CONFIG_HAVE_SMP = y and CONFIG_SMP_ON_UP = n in .config file,
> > the secondary core can boot.
> >
> > But this does not happen in kernel 3.10 lts kernel, Whether the
> > CONFIG_SMP_ON_UP is set yes or no ,the secondary core can boot.
> >
> > Does the meaning of CONFIG_SMP_ON_UP changed or this is a bug in kernel
> > 3.17-rc2 ?
> >
> >
>
> hi Arnd
>
> In above two cases, i also set CONFIG_SMP = y. in addtion,
> the CONFIG_SMP_ON_UP depends on CONFIG_SMP. when set
> CONFIG_SMP_ON_UP = y, the value of CONFIG_SMP must be y.
I see.
I'm looking at the code more closely now:
> > config: set CONFIG_HAVE_SMP = y and CONFIG_SMP_ON_UP = y
> > command: # qemu-system-arm -M vexpress-a9 -smp 2 -m 128M -kernel
> > arch/arm/boot/zImage -nographic
> > The output:
> >
> > ..........
> > is_smp() return false;
This test basically checks whether the __fixup_smp_on_up code was
run or not. This has changed in bc41b8724f24 "ARM: 7846/1: Update
SMP_ON_UP code to detect A9MPCore with 1 CPU devices", in order
to support a quirk in the Aegis platform. Can you try reverting
that commit?
Arnd
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