Commit-ID: 07806c50bddd2f0493f97584198733946952409c
Gitweb: http://git.kernel.org/tip/07806c50bddd2f0493f97584198733946952409c
Author: Jiang Liu <jiang....@linux.intel.com>
AuthorDate: Wed, 7 Jan 2015 15:31:34 +0800
Committer: Thomas Gleixner <t...@linutronix.de>
CommitDate: Thu, 15 Jan 2015 11:24:23 +0100
x86/apic: Refine enable_IR_x2apic() and related functions
Refine enable_IR_x2apic() and related functions for better readability.
[ tglx: Removed the XAPIC mode change and split it out into a seperate
patch. Added comments. ]
Signed-off-by: Jiang Liu <jiang....@linux.intel.com>
Cc: Tony Luck <tony.l...@intel.com>
Cc: io...@lists.linux-foundation.org
Cc: H. Peter Anvin <h...@linux.intel.com>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Yinghai Lu <ying...@kernel.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: David Rientjes <rient...@google.com>
Cc: HATAYAMA Daisuke <d.hatay...@jp.fujitsu.com>
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Richard Weinberger <rich...@nod.at>
Cc: Oren Twaig <o...@scalemp.com>
Link:
http://lkml.kernel.org/r/1420615903-28253-8-git-send-email-jiang....@linux.intel.com
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
arch/x86/kernel/apic/apic.c | 92 +++++++++++++++++++++++----------------------
1 file changed, 47 insertions(+), 45 deletions(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 11358df..fa77be8 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1573,7 +1573,7 @@ void enable_x2apic(void)
}
#endif /* CONFIG_X86_X2APIC */
-int __init enable_IR(void)
+static int __init try_to_enable_IR(void)
{
#ifdef CONFIG_IRQ_REMAP
if (!irq_remapping_supported()) {
@@ -1586,17 +1586,51 @@ int __init enable_IR(void)
"io-apic setup\n");
return -1;
}
-
+#endif
return irq_remapping_enable();
+}
+
+static __init void try_to_enable_x2apic(int ir_stat)
+{
+#ifdef CONFIG_X86_X2APIC
+ if (!x2apic_supported())
+ return;
+
+ if (ir_stat < 0) {
+ /* IR is required if there is APIC ID > 255 even when running
+ * under KVM
+ */
+ if (max_physical_apicid > 255 ||
+ !hypervisor_x2apic_available()) {
+ pr_info("IRQ remapping doesn't support X2APIC mode,
disable x2apic.\n");
+ if (x2apic_preenabled)
+ disable_x2apic();
+ return;
+ }
+
+ /*
+ * without IR all CPUs can be addressed by IOAPIC/MSI
+ * only in physical mode
+ */
+ x2apic_force_phys();
+
+ } else if (ir_stat == IRQ_REMAP_XAPIC_MODE) {
+ pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n");
+ return;
+ }
+
+ if (!x2apic_mode) {
+ x2apic_mode = 1;
+ enable_x2apic();
+ pr_info("Enabled x2apic\n");
+ }
#endif
- return -1;
}
void __init enable_IR_x2apic(void)
{
unsigned long flags;
- int ret;
- int hardware_init_ret;
+ int ret, ir_stat;
if (!IS_ENABLED(CONFIG_X86_X2APIC)) {
u64 msr;
@@ -1606,8 +1640,8 @@ void __init enable_IR_x2apic(void)
panic("BIOS has enabled x2apic but kernel doesn't
support x2apic, please disable x2apic in BIOS.\n");
}
- hardware_init_ret = irq_remapping_prepare();
- if (hardware_init_ret && !x2apic_supported())
+ ir_stat = irq_remapping_prepare();
+ if (ir_stat < 0 && !x2apic_supported())
return;
ret = save_ioapic_entries();
@@ -1622,45 +1656,13 @@ void __init enable_IR_x2apic(void)
if (x2apic_preenabled && nox2apic)
disable_x2apic();
+ /* If irq_remapping_prepare() succeded, try to enable it */
+ if (ir_stat >= 0)
+ ir_stat = try_to_enable_IR();
+ /* ir_stat contains the remap mode or an error code */
+ try_to_enable_x2apic(ir_stat);
- if (hardware_init_ret)
- ret = -1;
- else
- ret = enable_IR();
-
- if (!x2apic_supported())
- goto skip_x2apic;
-
- if (ret < 0) {
- /* IR is required if there is APIC ID > 255 even when running
- * under KVM
- */
- if (max_physical_apicid > 255 ||
- !hypervisor_x2apic_available()) {
- if (x2apic_preenabled)
- disable_x2apic();
- goto skip_x2apic;
- }
- /*
- * without IR all CPUs can be addressed by IOAPIC/MSI
- * only in physical mode
- */
- x2apic_force_phys();
- }
-
- if (ret == IRQ_REMAP_XAPIC_MODE) {
- pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n");
- goto skip_x2apic;
- }
-
- if (x2apic_supported() && !x2apic_mode) {
- x2apic_mode = 1;
- enable_x2apic();
- pr_info("Enabled x2apic\n");
- }
-
-skip_x2apic:
- if (ret < 0) /* IR enabling failed */
+ if (ir_stat < 0)
restore_ioapic_entries();
legacy_pic->restore_mask();
local_irq_restore(flags);
--
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