Alexander Gordeev ff16432412 x86/apic: Make cpu_mask_to_apicid() operations return error code ... Current cpu_mask_to_apicid() and cpu_mask_to_apicid_and() implementations have few shortcomings: 1. A value returned by cpu_mask_to_apicid() is written to hardware registers unconditionally. Should BAD_APICID get ever returned it will be written to a hardware too. But the value of BAD_APICID is not universal across all hardware in all modes and might cause unexpected results, i.e. interrupts might get routed to CPUs that are not configured to receive it. 2. Because the value of BAD_APICID is not universal it is counter- intuitive to return it for a hardware where it does not make sense (i.e. x2apic). 3. cpu_mask_to_apicid_and() operation is thought as an complement to cpu_mask_to_apicid() that only applies a AND mask on top of a cpumask being passed. Yet, as consequence of 18374d8 commit the two operations are inconsistent in that of: cpu_mask_to_apicid() should not get a offline CPU with the cpumask cpu_mask_to_apicid_and() should not fail and return BAD_APICID These limitations are impossible to realize just from looking at the operations prototypes. Most of these shortcomings are resolved by returning a error code instead of BAD_APICID. As the result, faults are reported back early rather than possibilities to cause a unexpected behaviour exist (in case of [1]). The only exception is setup_timer_IRQ0_pin() routine. Although obviously controversial to this fix, its existing behaviour is preserved to not break the fragile check_timer() and would better addressed in a separate fix. Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/20120607131559.GF4759@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2012-06-08 11:44:29 +02:00
..
bios_uv.c	x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE	2011-10-31 19:30:35 -04:00
Makefile	x86: Move uv to platform	2010-10-27 14:30:02 +02:00
tlb_uv.c	x86/uv: Fix uninitialized spinlocks	2012-01-26 10:58:34 +01:00
uv_irq.c	x86/apic: Make cpu_mask_to_apicid() operations return error code	2012-06-08 11:44:29 +02:00
uv_sysfs.c	driver-core: remove sysdev.h usage.	2011-12-21 16:26:03 -08:00
uv_time.c	x86/UV: Lower UV rtc clocksource rating	2012-02-20 09:07:56 +01:00