x86, apic: Introduce .apicdrivers section to find the list of apic drivers

This will pave the way for each apic driver to be self-contained
and eliminate the need for apic_probe[].

Order in which apic drivers are listed in the .apicdrivers
section is important, as this determines the apic probe order.
And this is enforced by the ordering of apic driver files in the
Makefile and the macros apic_driver()/apic_drivers().

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: steiner@sgi.com
Cc: gorcunov@openvz.org
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20110521005526.068775085@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

12 files changed, 63 insertions, 6 deletions

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index a0c46f061210..80b243c7f0f0 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -381,6 +381,26 @@ struct apic {
 extern struct apic *apic;
 
 /*
+ * APIC drivers are probed based on how they are listed in the .apicdrivers
+ * section. So the order is important and enforced by the ordering
+ * of different apic driver files in the Makefile.
+ *
+ * For the files having two apic drivers, we use apic_drivers()
+ * to enforce the order with in them.
+ */
+#define apic_driver(sym)					\
+	static struct apic *__apicdrivers_##sym __used		\
+	__aligned(sizeof(struct apic *))			\
+	__section(.apicdrivers) = { &sym }
+
+#define apic_drivers(sym1, sym2)					\
+	static struct apic *__apicdrivers_##sym1##sym2[2] __used	\
+	__aligned(sizeof(struct apic *))				\
+	__section(.apicdrivers) = { &sym1, &sym2 }
+
+extern struct apic *__apicdrivers[], *__apicdrivers_end[];
+
+/*
  * APIC functionality to boot other CPUs - only used on SMP:
  */
 #ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/apic/Makefile b/arch/x86/kernel/apic/Makefile
index 3966b564ea47..767fd04f2843 100644
--- a/arch/x86/kernel/apic/Makefile
+++ b/arch/x86/kernel/apic/Makefile
@@ -2,20 +2,25 @@
 # Makefile for local APIC drivers and for the IO-APIC code
 #
 
-obj-$(CONFIG_X86_LOCAL_APIC)	+= apic.o apic_noop.o probe_$(BITS).o ipi.o
+obj-$(CONFIG_X86_LOCAL_APIC)	+= apic.o apic_noop.o ipi.o
 obj-y				+= hw_nmi.o
 
 obj-$(CONFIG_X86_IO_APIC)	+= io_apic.o
 obj-$(CONFIG_SMP)		+= ipi.o
 
 ifeq ($(CONFIG_X86_64),y)
-obj-y				+= apic_flat_64.o
-obj-$(CONFIG_X86_X2APIC)	+= x2apic_cluster.o
-obj-$(CONFIG_X86_X2APIC)	+= x2apic_phys.o
+# APIC probe will depend on the listing order here
 obj-$(CONFIG_X86_UV)		+= x2apic_uv_x.o
+obj-$(CONFIG_X86_X2APIC)	+= x2apic_phys.o
+obj-$(CONFIG_X86_X2APIC)	+= x2apic_cluster.o
+obj-y				+= apic_flat_64.o
 endif
 
-obj-$(CONFIG_X86_BIGSMP)	+= bigsmp_32.o
+# APIC probe will depend on the listing order here
 obj-$(CONFIG_X86_NUMAQ)		+= numaq_32.o
-obj-$(CONFIG_X86_ES7000)	+= es7000_32.o
 obj-$(CONFIG_X86_SUMMIT)	+= summit_32.o
+obj-$(CONFIG_X86_BIGSMP)	+= bigsmp_32.o
+obj-$(CONFIG_X86_ES7000)	+= es7000_32.o
+
+# For 32bit, probe_32 need to be listed last
+obj-$(CONFIG_X86_LOCAL_APIC)	+= probe_$(BITS).o
diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
index 025921f03eb3..6ce0f7f08c57 100644
--- a/arch/x86/kernel/apic/apic_flat_64.c
+++ b/arch/x86/kernel/apic/apic_flat_64.c
@@ -377,3 +377,8 @@ struct apic apic_physflat =  {
 	.wait_icr_idle			= native_apic_wait_icr_idle,
 	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
 };
+
+/*
+ * We need to check for physflat first, so this order is important.
+ */
+apic_drivers(apic_physflat, apic_flat);
diff --git a/arch/x86/kernel/apic/bigsmp_32.c b/arch/x86/kernel/apic/bigsmp_32.c
index d84ac5a584b5..cfb13c3e5451 100644
--- a/arch/x86/kernel/apic/bigsmp_32.c
+++ b/arch/x86/kernel/apic/bigsmp_32.c
@@ -254,3 +254,5 @@ struct apic apic_bigsmp = {
 
 	.x86_32_early_logical_apicid	= bigsmp_early_logical_apicid,
 };
+
+apic_driver(apic_bigsmp);
diff --git a/arch/x86/kernel/apic/es7000_32.c b/arch/x86/kernel/apic/es7000_32.c
index 70533de5bd29..80de0d78cbca 100644
--- a/arch/x86/kernel/apic/es7000_32.c
+++ b/arch/x86/kernel/apic/es7000_32.c
@@ -747,3 +747,9 @@ struct apic __refdata apic_es7000 = {
 
 	.x86_32_early_logical_apicid	= es7000_early_logical_apicid,
 };
+
+/*
+ * Need to check for es7000 followed by es7000_cluster, so this order
+ * in apic_drivers is important.
+ */
+apic_drivers(apic_es7000, apic_es7000_cluster);
diff --git a/arch/x86/kernel/apic/numaq_32.c b/arch/x86/kernel/apic/numaq_32.c
index 30f13319e24b..4caab0d13d99 100644
--- a/arch/x86/kernel/apic/numaq_32.c
+++ b/arch/x86/kernel/apic/numaq_32.c
@@ -537,3 +537,5 @@ struct apic __refdata apic_numaq = {
 	.x86_32_early_logical_apicid	= noop_x86_32_early_logical_apicid,
 	.x86_32_numa_cpu_node		= numaq_numa_cpu_node,
 };
+
+apic_driver(apic_numaq);
diff --git a/arch/x86/kernel/apic/probe_32.c b/arch/x86/kernel/apic/probe_32.c
index 6541e471fd91..a319b33cfc14 100644
--- a/arch/x86/kernel/apic/probe_32.c
+++ b/arch/x86/kernel/apic/probe_32.c
@@ -174,6 +174,8 @@ struct apic apic_default = {
 	.x86_32_early_logical_apicid	= default_x86_32_early_logical_apicid,
 };
 
+apic_driver(apic_default);
+
 extern struct apic apic_numaq;
 extern struct apic apic_summit;
 extern struct apic apic_bigsmp;
diff --git a/arch/x86/kernel/apic/summit_32.c b/arch/x86/kernel/apic/summit_32.c
index 35bcd7d995a1..447ec0fa9aa1 100644
--- a/arch/x86/kernel/apic/summit_32.c
+++ b/arch/x86/kernel/apic/summit_32.c
@@ -552,3 +552,5 @@ struct apic apic_summit = {
 
 	.x86_32_early_logical_apicid	= summit_early_logical_apicid,
 };
+
+apic_driver(apic_summit);
diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
index f7875d9a18c2..7595c5775a54 100644
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -264,3 +264,5 @@ struct apic apic_x2apic_cluster = {
 	.wait_icr_idle			= native_x2apic_wait_icr_idle,
 	.safe_wait_icr_idle		= native_safe_x2apic_wait_icr_idle,
 };
+
+apic_driver(apic_x2apic_cluster);
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 78c8f33a09fa..f7ba21cb3e25 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -168,3 +168,5 @@ struct apic apic_x2apic_phys = {
 	.wait_icr_idle			= native_x2apic_wait_icr_idle,
 	.safe_wait_icr_idle		= native_safe_x2apic_wait_icr_idle,
 };
+
+apic_driver(apic_x2apic_phys);
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 6bb80b1c8a7a..b6c629838f00 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -864,3 +864,5 @@ void __init uv_system_init(void)
 	if (is_kdump_kernel())
 		reboot_type = BOOT_ACPI;
 }
+
+apic_driver(apic_x2apic_uv_x);
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 624a2016198e..49927a863cc1 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -306,6 +306,13 @@ SECTIONS
 	}
 
 	. = ALIGN(8);
+	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
+		__apicdrivers = .;
+		*(.apicdrivers);
+		__apicdrivers_end = .;
+	}
+
+	. = ALIGN(8);
 	/*
 	 * .exit.text is discard at runtime, not link time, to deal with
 	 *  references from .altinstructions and .eh_frame