Now, there are many switches in kernel which are used to determine the
final interrupt delivery mode, as shown below:
1) kconfig:
CONFIG_X86_64; CONFIG_X86_LOCAL_APIC; CONFIG_x86_IO_APIC
2) kernel option: disable_apic; skip_ioapic_setup
3) CPU Capability: boot_cpu_has(X86_FEATURE_APIC)
4) MP table: smp_found_config
5) ACPI: acpi_lapic; acpi_ioapic; nr_ioapic
These switches are disordered and scattered. Hard to wrap them.
Unify them into a single function, select an interrupt delivery
mode for BSP through these switches.
Signed-off-by: Dou Liyang <douly.f...@cn.fujitsu.com>
---
arch/x86/kernel/apic/apic.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 221056a..c754e48 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1153,6 +1153,63 @@ void __init sync_Arb_IDs(void)
APIC_INT_LEVELTRIG | APIC_DM_INIT);
}
+enum apic_interrupt_mode {
+ APIC_PIC = 0,
+ APIC_VIRTUAL_WIRE,
+ APIC_SYMMETRIC_IO,
+ APIC_MODE_COUNT
+};
+
+static int __init apic_bsp_mode_check(void)
+{
+
+ /* Check kernel option */
+ if (disable_apic) {
+ pr_info("APIC disabled via kernel command line\n");
+ return APIC_PIC;
+ }
+ /* Check BIOS */
+#ifdef CONFIG_X86_64
+ /* On 64-bit, The APIC is integrated, So, must have APIC feature */
+ if (!boot_cpu_has(X86_FEATURE_APIC)) {
+ disable_apic = 1;
+ pr_info("APIC disabled by BIOS\n");
+ return APIC_PIC;
+ }
+#else
+ if (!boot_cpu_has(X86_FEATURE_APIC) &&
+ APIC_INTEGRATED(boot_cpu_apic_version)) {
+ disable_apic = 1;
+ pr_err(FW_BUG "Local APIC %d not detected, force emulation\n",
+ boot_cpu_physical_apicid);
+ return APIC_PIC;
+ }
+#endif
+ /*
+ * Check MP table, if neither an integrated nor a separate chip
+ * doesn't exist.
+ */
+ if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) {
+ pr_info("BIOS don't support APIC, and no SMP configuration\n");
+ return APIC_PIC;
+ }
+
+ /* Check MP table, if it is the virtual wire */
+ if (!smp_found_config) {
+ disable_ioapic_support();
+
+ /* Check local APIC, if there is no SMP motherboard */
+ if (!acpi_lapic)
+ pr_info("SMP motherboard not detected\n");
+
+ return APIC_VIRTUAL_WIRE;
+ }
+
+ /* Other checks of ACPI options will be done in each setup function */
+
+ return APIC_SYMMETRIC_IO;
+}
+
/*
* Setup the through-local-APIC virtual wire mode.
*/
--
2.5.5
