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x86/smpboot: Sanitize uniprocessor init 

The UP related setups for local apic are mangled into smp_sanity_check().

That results in duplicate calls to disable_smp() and makes the code
hard to follow. Let smp_sanity_check() return dedicated values for the
various exit reasons and handle them at the call site.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.987833932@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2015-01-15 21:22:42 +00:00
parent 05f7e46d2a
commit 613c25efbd
1 changed files with 26 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
arch/x86/kernel/smpboot.c
View File

@ -990,6 +990,8 @@ void arch_disable_smp_support(void)
*/ */
static __init void disable_smp(void) static __init void disable_smp(void)
{ {
pr_info("SMP disabled\n");
disable_ioapic_support(); disable_ioapic_support();
init_cpu_present(cpumask_of(0)); init_cpu_present(cpumask_of(0));
@ -1003,6 +1005,13 @@ static __init void disable_smp(void)
cpumask_set_cpu(0, cpu_core_mask(0)); cpumask_set_cpu(0, cpu_core_mask(0));
} }
enum {
SMP_OK,
SMP_NO_CONFIG,
SMP_NO_APIC,
SMP_FORCE_UP,
};
/* /*
* Various sanity checks. * Various sanity checks.
*/ */
@ -1050,10 +1059,7 @@ static int __init smp_sanity_check(unsigned max_cpus)
if (!smp_found_config && !acpi_lapic) { if (!smp_found_config && !acpi_lapic) {
preempt_enable(); preempt_enable();
pr_notice("SMP motherboard not detected\n"); pr_notice("SMP motherboard not detected\n");
disable_smp(); return SMP_NO_CONFIG;
if (APIC_init_uniprocessor())
pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");
return -1;
} }
/* /*
@ -1077,7 +1083,7 @@ static int __init smp_sanity_check(unsigned max_cpus)
boot_cpu_physical_apicid); boot_cpu_physical_apicid);
pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n"); pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");
} }
return -1; return SMP_NO_APIC;
} }
verify_local_APIC(); verify_local_APIC();
@ -1087,12 +1093,10 @@ static int __init smp_sanity_check(unsigned max_cpus)
*/ */
if (!max_cpus) { if (!max_cpus) {
pr_info("SMP mode deactivated\n"); pr_info("SMP mode deactivated\n");
disable_ioapic_support(); return SMP_FORCE_UP;
apic_bsp_setup();
return -1;
} }
return 0; return SMP_OK;
} }
static void __init smp_cpu_index_default(void) static void __init smp_cpu_index_default(void)
@ -1132,10 +1136,21 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
} }
set_cpu_sibling_map(0); set_cpu_sibling_map(0);
if (smp_sanity_check(max_cpus) < 0) { switch (smp_sanity_check(max_cpus)) {
pr_info("SMP disabled\n"); case SMP_NO_CONFIG:
disable_smp();
if (APIC_init_uniprocessor())
pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");
return;
case SMP_NO_APIC:
disable_smp(); disable_smp();
return; return;
case SMP_FORCE_UP:
disable_smp();
apic_bsp_setup();
return;
case SMP_OK:
break;
} }
default_setup_apic_routing(); default_setup_apic_routing();