Messages in this thread | | | Date | Wed, 21 Jul 2010 20:29:56 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [PATCH 00/10] x86, xsave: some code cleanups and reworks |
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On Wed, Jul 21, 2010 at 06:16:54PM +0200, Robert Richter wrote: > On 20.07.10 16:17:40, Cyrill Gorcunov wrote: > > > note the snippet > > > > if (cpu == boot_cpu_id) > > switch_to_new_gdt(cpu); > > > > but cycle of assignment is done over all possible cpus so > > smp_processor_id will be = 0 for BP but definitely it's > > confusing and better to check for BP via explicit cpu == boot_cpu_id > > I think. Though I might be missing something. > > This in smpboot.c makes it clear: > > void __cpuinit smp_store_cpu_info(int id) > { > struct cpuinfo_x86 *c = &cpu_data(id); > > copy_cpuinfo_x86(c, &boot_cpu_data); > c->cpu_index = id; > if (id != 0) > identify_secondary_cpu(c); > } > > So boot cpu id is always 0.
yeah, thanks!
> > Also note, as Hans Peter already pointed out, this for CONFIG_SMP: > > &cpu_data(0) != &boot_cpu_data > > The data in boot_cpu_data is (partly) already available after > early_cpu_init(). It is later copied to the &cpu_data() structures. So > boot_cpu_data should be used for init code. > > Also, to make the test obviously, instead of testing (cpu == > boot_cpu_id) I rather tend to use an is_boot_cpu() macro as you > suggested in your earlier mail. > > -Robert > > -- > Advanced Micro Devices, Inc. > Operating System Research Center >
ok, thanks Robert!
-- Cyrill
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