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Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull x86/apic changes from Ingo Molnar:
 "Two main changes:

   - improve local APIC Error Status Register reporting robustness

   - add the 'disable_cpu_apicid=x' boot parameter for kexec booting"

* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, apic: Make disabled_cpu_apicid static read_mostly, fix typos
  x86, apic, kexec: Add disable_cpu_apicid kernel parameter
  x86/apic: Read Error Status Register correctly
This commit is contained in:
Linus Torvalds
2014-01-20 11:50:01 -08:00
parent 6c64614356 5b4d1dbc24
commit 1a7dbbcc8c
2 changed files with 66 additions and 9 deletions
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66
arch/x86/kernel/apic/apic.c
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@@ -74,6 +74,13 @@ unsigned int max_physical_apicid;
*/
physid_mask_t phys_cpu_present_map;
/*
* Processor to be disabled specified by kernel parameter
* disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to
* avoid undefined behaviour caused by sending INIT from AP to BSP.
*/
static unsigned int disabled_cpu_apicid __read_mostly = BAD_APICID;
/*
* Map cpu index to physical APIC ID
*/
@@ -1968,7 +1975,7 @@ __visible void smp_trace_spurious_interrupt(struct pt_regs *regs)
*/
static inline void __smp_error_interrupt(struct pt_regs *regs)
{
u32 v0, v1;
u32 v;
u32 i = 0;
static const char * const error_interrupt_reason[] = {
"Send CS error", /* APIC Error Bit 0 */
@@ -1982,21 +1989,20 @@ static inline void __smp_error_interrupt(struct pt_regs *regs)
};
/* First tickle the hardware, only then report what went on. -- REW */
v0 = apic_read(APIC_ESR);
apic_write(APIC_ESR, 0);
v1 = apic_read(APIC_ESR);
v = apic_read(APIC_ESR);
ack_APIC_irq();
atomic_inc(&irq_err_count);
apic_printk(APIC_DEBUG, KERN_DEBUG "APIC error on CPU%d: %02x(%02x)",
smp_processor_id(), v0 , v1);
apic_printk(APIC_DEBUG, KERN_DEBUG "APIC error on CPU%d: %02x",
smp_processor_id(), v);
v1 = v1 & 0xff;
while (v1) {
if (v1 & 0x1)
v &= 0xff;
while (v) {
if (v & 0x1)
apic_printk(APIC_DEBUG, KERN_CONT " : %s", error_interrupt_reason[i]);
i++;
v1 >>= 1;
v >>= 1;
}
apic_printk(APIC_DEBUG, KERN_CONT "\n");
@@ -2114,6 +2120,39 @@ int generic_processor_info(int apicid, int version)
bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
phys_cpu_present_map);
/*
* boot_cpu_physical_apicid is designed to have the apicid
* returned by read_apic_id(), i.e, the apicid of the
* currently booting-up processor. However, on some platforms,
* it is temporarily modified by the apicid reported as BSP
* through MP table. Concretely:
*
* - arch/x86/kernel/mpparse.c: MP_processor_info()
* - arch/x86/mm/amdtopology.c: amd_numa_init()
* - arch/x86/platform/visws/visws_quirks.c: MP_processor_info()
*
* This function is executed with the modified
* boot_cpu_physical_apicid. So, disabled_cpu_apicid kernel
* parameter doesn't work to disable APs on kdump 2nd kernel.
*
* Since fixing handling of boot_cpu_physical_apicid requires
* another discussion and tests on each platform, we leave it
* for now and here we use read_apic_id() directly in this
* function, generic_processor_info().
*/
if (disabled_cpu_apicid != BAD_APICID &&
disabled_cpu_apicid != read_apic_id() &&
disabled_cpu_apicid == apicid) {
int thiscpu = num_processors + disabled_cpus;
pr_warning("APIC: Disabling requested cpu."
" Processor %d/0x%x ignored.\n",
thiscpu, apicid);
disabled_cpus++;
return -ENODEV;
}
/*
* If boot cpu has not been detected yet, then only allow upto
* nr_cpu_ids - 1 processors and keep one slot free for boot cpu
@@ -2592,3 +2631,12 @@ static int __init lapic_insert_resource(void)
* that is using request_resource
*/
late_initcall(lapic_insert_resource);
static int __init apic_set_disabled_cpu_apicid(char *arg)
{
if (!arg || !get_option(&arg, &disabled_cpu_apicid))
return -EINVAL;
return 0;
}
early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);