[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] x86/xen/apic: Work with UP, non-SMP 32-bit kernels.
On Tue, Mar 03, 2015 at 03:20:41PM -0500, Konrad Rzeszutek Wilk wrote: > Most of the APIC code that use APIC_LDR is not used on > 64-bit. On 32-bit it is bit of an hack - and the mechanism > it is uses is to "setup" the APIC_LDR via apci->init_apic_ldr > (which we set to NULL) and then use apic->x86_32_early_logical_apicid > to get an CPU to APIC ID mapping and also apic->read to match > the APIC_LDR. > > The 'x86_32_early_logical_apicid' is called from 'setup_local_APIC' > which is called from the following functions: > - start_secondary ->smp_callin -> apic_ap_setup [not called on PV] > - native_smp_prepare_cpus -> apci_bsp_setup [not called on PV] > - up_late_init -> APIC_init_uniprocessor -> apic_bsp_setup ->setup_local_APIC > [called on PV with CONFIG_SMP not defined, CONFIG_X86_32 and UP kernel] > > This patch fixes the build issue and also allows the bootup > to continue without warnings. > > Reported-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > --- > arch/x86/xen/apic.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c > index 86bea3e..de1c74d 100644 > --- a/arch/x86/xen/apic.c > +++ b/arch/x86/xen/apic.c > @@ -56,7 +56,10 @@ static u32 xen_apic_read(u32 reg) > > if (reg == APIC_LVR) > return 0x10; > - > +#ifdef CONFIG_X86_32 > + if (reg == APIC_LDR) > + return SET_APIC_LOGICAL_ID(1UL << smp_processor_id()); > +#endif > if (reg != APIC_ID) > return 0; > > @@ -117,6 +120,12 @@ static int xen_phys_pkg_id(int initial_apic_id, int > index_msb) > return initial_apic_id >> index_msb; > } > > +static int xen_x86_32_early_logical_apicid(int cpu) > +{ > + /* Match with APIC_LDR read. Otherwise setup_local_APIC complains. */ > + return 1 << cpu; > +} > + Argh. That should have been wrapped with CONFIG_X86_32 otherwise it will complain on 64-bit (not used.. etc). David, I can commit it in and fix it up. > static void xen_noop(void) > { > } > @@ -176,8 +185,8 @@ static struct apic xen_pv_apic = { > .safe_wait_icr_idle = xen_safe_apic_wait_icr_idle, > > #ifdef CONFIG_X86_32 > - /* generic_processor_info */ > - .x86_32_early_logical_apicid = default_x86_32_early_logical_apicid, > + /* generic_processor_info and setup_local_APIC. */ > + .x86_32_early_logical_apicid = xen_x86_32_early_logical_apicid, > #endif > }; > > -- > 1.8.4.2 > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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