Commit-ID: 0114a8e87772c4172bf7fefa4c7a9a6bbc52d2ab
Gitweb: http://git.kernel.org/tip/0114a8e87772c4172bf7fefa4c7a9a6bbc52d2ab
Author: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
AuthorDate: Wed, 13 Sep 2017 17:12:44 +0800
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 25 Sep 2017 15:03:14 +0200
x86/apic: Construct a selector for the interrupt delivery mode
There are quite some switches 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) Command line options: 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 and there are also some
dependencies between them. These make the code difficult to maintain and
read.
Construct a selector to unify them into a single function, then, Use this
selector to get an interrupt delivery mode directly.
Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: yinghai@xxxxxxxxxx
Cc: bhe@xxxxxxxxxx
Link: https://lkml.kernel.org/r/1505293975-26005-2-git-send-email-douly.fnst@xxxxxxxxxxxxxx
---
arch/x86/kernel/apic/apic.c | 52 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index d705c76..39cb8c1 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1218,6 +1218,58 @@ void __init sync_Arb_IDs(void)
APIC_INT_LEVELTRIG | APIC_DM_INIT);
}
+enum apic_intr_mode {
+ APIC_PIC,
+ APIC_VIRTUAL_WIRE,
+ APIC_SYMMETRIC_IO,
+};
+
+static int __init apic_intr_mode_select(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 must be integrated, Check local APIC only */
+ if (!boot_cpu_has(X86_FEATURE_APIC)) {
+ disable_apic = 1;
+ pr_info("APIC disabled by BIOS\n");
+ return APIC_PIC;
+ }
+#else
+ /* On 32-bit, the APIC may be integrated APIC or 82489DX */
+
+ /* Neither 82489DX nor integrated APIC ? */
+ if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) {
+ disable_apic = 1;
+ return APIC_PIC;
+ }
+
+ /* If the BIOS pretends there is an integrated APIC ? */
+ 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 or ACPI MADT configuration */
+ if (!smp_found_config) {
+ disable_ioapic_support();
+ if (!acpi_lapic)
+ pr_info("APIC: ACPI MADT or MP tables are not detected\n");
+ return APIC_VIRTUAL_WIRE;
+ }
+
+ return APIC_SYMMETRIC_IO;
+}
+
/*
* An initial setup of the virtual wire mode.
*/
--
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