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liaocj committed Nov 23, 2024
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171 changes: 170 additions & 1 deletion linux/内核-驱动/中断/硬中断--apic.md
Original file line number Diff line number Diff line change
Expand Up @@ -28,4 +28,173 @@ APIC的信息在SDM vol3中有比较详细的介绍
ISR: In-Service Register
IRR: Interrupt Request Register
TMR: Trigger Mode Register
```
```
# 初始化
```c
/**
* setup_local_APIC - setup the local APIC
*
* Used to setup local APIC while initializing BSP or bringing up APs.
* Always called with preemption disabled.
*/
static void setup_local_APIC(void)
{
int cpu = smp_processor_id();
unsigned int value;
if (disable_apic) {
disable_ioapic_support();
return;
}
/*
* If this comes from kexec/kcrash the APIC might be enabled in
* SPIV. Soft disable it before doing further initialization.
*/
value = apic_read(APIC_SPIV);
value &= ~APIC_SPIV_APIC_ENABLED;
apic_write(APIC_SPIV, value);
#ifdef CONFIG_X86_32
/* Pound the ESR really hard over the head with a big hammer - mbligh */
if (lapic_is_integrated() && apic->disable_esr) {
apic_write(APIC_ESR, 0);
apic_write(APIC_ESR, 0);
apic_write(APIC_ESR, 0);
apic_write(APIC_ESR, 0);
}
#endif
/*
* Double-check whether this APIC is really registered.
* This is meaningless in clustered apic mode, so we skip it.
*/
BUG_ON(!apic->apic_id_registered());
/*
* Intel recommends to set DFR, LDR and TPR before enabling
* an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
* document number 292116). So here it goes...
*/
apic->init_apic_ldr();
#ifdef CONFIG_X86_32
if (apic->dest_mode_logical) {
int logical_apicid, ldr_apicid;
/*
* APIC LDR is initialized. If logical_apicid mapping was
* initialized during get_smp_config(), make sure it matches
* the actual value.
*/
logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu);
ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
if (logical_apicid != BAD_APICID)
WARN_ON(logical_apicid != ldr_apicid);
/* Always use the value from LDR. */
early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid;
}
#endif
/*
* Set Task Priority to 'accept all except vectors 0-31'. An APIC
* vector in the 16-31 range could be delivered if TPR == 0, but we
* would think it's an exception and terrible things will happen. We
* never change this later on.
*/
value = apic_read(APIC_TASKPRI);
value &= ~APIC_TPRI_MASK;
value |= 0x10;
apic_write(APIC_TASKPRI, value);
/* Clear eventually stale ISR/IRR bits */
apic_pending_intr_clear();
/*
* Now that we are all set up, enable the APIC
*/
value = apic_read(APIC_SPIV);
value &= ~APIC_VECTOR_MASK;
/*
* Enable APIC
*/
value |= APIC_SPIV_APIC_ENABLED;
#ifdef CONFIG_X86_32
/*
* Some unknown Intel IO/APIC (or APIC) errata is biting us with
* certain networking cards. If high frequency interrupts are
* happening on a particular IOAPIC pin, plus the IOAPIC routing
* entry is masked/unmasked at a high rate as well then sooner or
* later IOAPIC line gets 'stuck', no more interrupts are received
* from the device. If focus CPU is disabled then the hang goes
* away, oh well :-(
*
* [ This bug can be reproduced easily with a level-triggered
* PCI Ne2000 networking cards and PII/PIII processors, dual
* BX chipset. ]
*/
/*
* Actually disabling the focus CPU check just makes the hang less
* frequent as it makes the interrupt distribution model be more
* like LRU than MRU (the short-term load is more even across CPUs).
*/
/*
* - enable focus processor (bit==0)
* - 64bit mode always use processor focus
* so no need to set it
*/
value &= ~APIC_SPIV_FOCUS_DISABLED;
#endif
/*
* Set spurious IRQ vector
*/
value |= SPURIOUS_APIC_VECTOR;
apic_write(APIC_SPIV, value);
perf_events_lapic_init();
/*
* Set up LVT0, LVT1:
*
* set up through-local-APIC on the boot CPU's LINT0. This is not
* strictly necessary in pure symmetric-IO mode, but sometimes
* we delegate interrupts to the 8259A.
*/
/*
* TODO: set up through-local-APIC from through-I/O-APIC? --macro
*/
value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
if (!cpu && (pic_mode || !value || skip_ioapic_setup)) {
value = APIC_DM_EXTINT;
apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", cpu);
} else {
value = APIC_DM_EXTINT | APIC_LVT_MASKED;
apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n", cpu);
}
apic_write(APIC_LVT0, value);
/*
* Only the BSP sees the LINT1 NMI signal by default. This can be
* modified by apic_extnmi= boot option.
*/
if ((!cpu && apic_extnmi != APIC_EXTNMI_NONE) ||
apic_extnmi == APIC_EXTNMI_ALL)
value = APIC_DM_NMI;
else
value = APIC_DM_NMI | APIC_LVT_MASKED;
/* Is 82489DX ? */
if (!lapic_is_integrated())
value |= APIC_LVT_LEVEL_TRIGGER;
apic_write(APIC_LVT1, value);
#ifdef CONFIG_X86_MCE_INTEL
/* Recheck CMCI information after local APIC is up on CPU #0 */
if (!cpu)
cmci_recheck();
#endif
}
```

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