Messages in this thread | | | Date | Thu, 19 Mar 2015 10:18:43 +0100 | From | "maxime.ripard" <> | Subject | Re: [linux-sunxi] Re: [PATCH 2/3] ARM: sun8i: Add SMP support for the Allwinner A23 |
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Hi Kevin,
On Thu, Mar 19, 2015 at 12:05:06PM +0800, kevin.z.m.zh@gmail.com wrote: > >> One question I couldn't find any answer to is that does the SMP bit is > >> set in secondary_startup? > >> > >> I couldn't find where it was set, but it still looks like the right > >> thing to do, so I would expect the code to do that. > > > > I don't see it either. The sun8i code is just the sun6i code with the > > power clamps removed. And sun6i secondary_startup was removed some time > > ago in commit 1146b600044d ("ARM: sunxi: fix build for THUMB2_KERNEL"). > > > > ChenYu > > The SMP bit should be set in the function of "__v7_ca7mp_setup", which is located > in the file: > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/mm/proc-v7.S?id=refs/tags/v4.0-rc4 > I'm not sure if this is your discussion.
It is, but I wasn't seeing it called anywhere in the secondary_startup code path.
I was expecting a direct call, but it looks like it's a dynamic call, with a function-pointer like call, that is indeed run both in the kernel entry point and the secondary_startup.
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/kernel/head.S?id=refs/tags/v4.0-rc4#n389
Thanks! Maxime
-- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com [unhandled content-type:application/pgp-signature] | |