lkml.org 
[lkml]   [2017]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v9 01/12] x86/apic: Construct a selector for the interrupt delivery mode
Date
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 and there are also some
dependencies with each other. 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@cn.fujitsu.com>
---
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.
*/
--
2.5.5


\
 
 \ /
  Last update: 2017-09-13 11:15    [W:0.114 / U:33.324 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site