Hi Thomas,
At 04/05/2017 07:46 PM, Thomas Gleixner wrote:
On Wed, 29 Mar 2017, Dou Liyang wrote:
Now, there are two ways to setup local apic and io-apic in X86 arch:
1. In an SMP-capable system, it will be done when preparing the
cpus in native_smp_prepare_boot_cpu().
2. If UP_LATE_INIT is y, it will be done in smp_init()
And, there are many switches in kernel which can determine the way of
APIC mode setup, 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. BIOS : boot_cpu_has(X86_FEATURE_APIC)
4. MP table: smp_found_config
5. ACPI: acpi_lapic; acpi_ioapic; nr_ioapic
The setup is late which cause the dump-capture kernel hangs with 'notsc'
option in 1st kernel option. and the use of these switches is messily.
Before make the APIC mode setup earlier, construct a framework first to
prepare for the work and make the logic clear.
Calling that a framework is slightly exaggerated. It's a selector function
for the interrupt delivery mode.
Yes, Selector is what I want.
To tell the truth, I've been looking for a word that can summarize this
patch for a long time. :)
#ifdef CONFIG_X86_X2APIC
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f4fc949..bf4ccd0 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_bsp_mode {
+ APIC_BSP_MODEL_PIC = 0,
+ APIC_BSP_MODEL_VIRTUAL_WIRE,
+ APIC_BSP_MODEL_SYMMETRIC_IO,
+ APIC_BSP_MODEL_COUNT
+};
+
+static int __init apic_bsp_mode_check(void)
+{
+
+ /* Check kernel option */
+ if (disable_apic) {
+ pr_info("APIC disabled by kernel option\n");
kernel option is ambiguous. "APIC disabled via kernel command line" is telling
clearly where this comes from.
Thanks, will modify in my next version.
+ return APIC_BSP_MODEL_PIC;
+ }
+ /* Check BOIS */
+#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");
Please use APIC consistently.
Oops, Yes.
+ return APIC_BSP_MODEL_PIC;
+ }
+#else
+ if (!boot_cpu_has(X86_FEATURE_APIC) &&
+ APIC_INTEGRATED(boot_cpu_apic_version)) {
+ pr_err("BIOS bug, local APIC #%d not detected!...\n",
+ boot_cpu_physical_apicid);
Please make that
pr_err(FW_BUG, "Local APIC %d not detected, force emulation",
boot_cpu_physical_apicid);
and for consistency reasosns this should also set disable_apic to 1.
+ return APIC_BSP_MODEL_PIC;
Yes. I will.
+ }
+#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("BOIS don't support APIC, and no SMP configuration.\n");
s/BOIS/BIOS/
and for consistency reasosns this should also set disable_apic to 1.
OK.
+ return APIC_BSP_MODEL_PIC;
+ }
+
+ /* Check MP table, ps: if the virtual wire has been setup */
+ if (!smp_found_config) {
+ disable_ioapic_support();
+
+ /* Check local APIC, if SMP_NO_CONFIG */
+ if (!acpi_lapic)
+ pr_info("SMP motherboard not detected\n");
+
+ return APIC_BSP_MODEL_VIRTUAL_WIRE;
+ }
+
+ /* Other checks of ACPI options will be done in each setup function */
+
+ return APIC_BSP_MODEL_SYMMETRIC_IO;
+}
+
/*
* Setup the through-local-APIC virtual wire mode.
*/
@@ -1202,6 +1259,22 @@ void apic_virture_wire_mode_setup(void)
apic_write(APIC_LVT1, value);
}
+/* init the interrupt routing model for the BSP */
+void __init init_bsp_APIC(void)
+{
+ switch (apic_bsp_mode_check()) {
+ case APIC_BSP_MODEL_PIC:
+ pr_info("Keep in PIC mode(8259)\n");
+ return;
+ case APIC_BSP_MODEL_VIRTUAL_WIRE:
+ pr_info("switch to virtual wire model.\n");
Please consistently start sentences with upper case letters.
Yes, I will check all the sentences and comments again carefully.
Thanks,
Liyang
Thanks,
tglx
