9 files changed, 171 insertions, 4 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 795c487af8e4..56689ef1a159 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1377,6 +1377,8 @@ and is between 256 and 4096 characters. It is defined in the file
 
         nolapic_timer   [X86-32,APIC] Do not use the local APIC timer.
 
+        nox2apic        [X86-64,APIC] Do not enable x2APIC mode.
+
         noltlbs         [PPC] Do not use large page/tlb entries for kernel
                         lowmem mapping on PPC40x.
 
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 785700a08e9d..8705262ddcda 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1337,7 +1337,9 @@ static void __init acpi_process_madt(void)
                                 acpi_ioapic = 1;
 
                                 smp_found_config = 1;
+#ifdef CONFIG_X86_32
                                 setup_apic_routing();
+#endif
                         }
                 }
                 if (error == -EINVAL) {
diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
index d5c06917b5b1..dd0501039f09 100644
--- a/arch/x86/kernel/apic_64.c
+++ b/arch/x86/kernel/apic_64.c
@@ -27,6 +27,7 @@
 #include <linux/clockchips.h>
 #include <linux/acpi_pmtmr.h>
 #include <linux/module.h>
+#include <linux/dmar.h>
 
 #include <asm/atomic.h>
 #include <asm/smp.h>
@@ -39,6 +40,7 @@
 #include <asm/proto.h>
 #include <asm/timex.h>
 #include <asm/apic.h>
+#include <asm/i8259.h>
 
 #include <mach_ipi.h>
 #include <mach_apic.h>
@@ -46,8 +48,12 @@
 static int disable_apic_timer __cpuinitdata;
 static int apic_calibrate_pmtmr __initdata;
 int disable_apic;
+int disable_x2apic;
 int x2apic;
 
+/* x2apic enabled before OS handover */
+int x2apic_preenabled;
+
 /* Local APIC timer works in C2 */
 int local_apic_timer_c2_ok;
 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
@@ -896,6 +902,125 @@ void __cpuinit end_local_APIC_setup(void)
         apic_pm_activate();
 }
 
+void check_x2apic(void)
+{
+        int msr, msr2;
+
+        rdmsr(MSR_IA32_APICBASE, msr, msr2);
+
+        if (msr & X2APIC_ENABLE) {
+                printk("x2apic enabled by BIOS, switching to x2apic ops\n");
+                x2apic_preenabled = x2apic = 1;
+                apic_ops = &x2apic_ops;
+        }
+}
+
+void enable_x2apic(void)
+{
+        int msr, msr2;
+
+        rdmsr(MSR_IA32_APICBASE, msr, msr2);
+        if (!(msr & X2APIC_ENABLE)) {
+                printk("Enabling x2apic\n");
+                wrmsr(MSR_IA32_APICBASE, msr | X2APIC_ENABLE, 0);
+        }
+}
+
+void enable_IR_x2apic(void)
+{
+#ifdef CONFIG_INTR_REMAP
+        int ret;
+        unsigned long flags;
+
+        if (!cpu_has_x2apic)
+                return;
+
+        if (!x2apic_preenabled && disable_x2apic) {
+                printk(KERN_INFO
+                       "Skipped enabling x2apic and Interrupt-remapping "
+                       "because of nox2apic\n");
+                return;
+        }
+
+        if (x2apic_preenabled && disable_x2apic)
+                panic("Bios already enabled x2apic, can't enforce nox2apic");
+
+        if (!x2apic_preenabled && skip_ioapic_setup) {
+                printk(KERN_INFO
+                       "Skipped enabling x2apic and Interrupt-remapping "
+                       "because of skipping io-apic setup\n");
+                return;
+        }
+
+        ret = dmar_table_init();
+        if (ret) {
+                printk(KERN_INFO
+                       "dmar_table_init() failed with %d:\n", ret);
+
+                if (x2apic_preenabled)
+                        panic("x2apic enabled by bios. But IR enabling failed");
+                else
+                        printk(KERN_INFO
+                               "Not enabling x2apic,Intr-remapping\n");
+                return;
+        }
+
+        local_irq_save(flags);
+        mask_8259A();
+        save_mask_IO_APIC_setup();
+
+        ret = enable_intr_remapping(1);
+
+        if (ret && x2apic_preenabled) {
+                local_irq_restore(flags);
+                panic("x2apic enabled by bios. But IR enabling failed");
+        }
+
+        if (ret)
+                goto end;
+
+        if (!x2apic) {
+                x2apic = 1;
+                apic_ops = &x2apic_ops;
+                enable_x2apic();
+        }
+end:
+        if (ret)
+                /*
+                 * IR enabling failed
+                 */
+                restore_IO_APIC_setup();
+        else
+                reinit_intr_remapped_IO_APIC(x2apic_preenabled);
+
+        unmask_8259A();
+        local_irq_restore(flags);
+
+        if (!ret) {
+                if (!x2apic_preenabled)
+                        printk(KERN_INFO
+                               "Enabled x2apic and interrupt-remapping\n");
+                else
+                        printk(KERN_INFO
+                               "Enabled Interrupt-remapping\n");
+        } else
+                printk(KERN_ERR
+                       "Failed to enable Interrupt-remapping and x2apic\n");
+#else
+        if (!cpu_has_x2apic)
+                return;
+
+        if (x2apic_preenabled)
+                panic("x2apic enabled prior OS handover,"
+                      " enable CONFIG_INTR_REMAP");
+
+        printk(KERN_INFO "Enable CONFIG_INTR_REMAP for enabling intr-remapping "
+               " and x2apic\n");
+#endif
+
+        return;
+}
+
 /*
  * Detect and enable local APICs on non-SMP boards.
  * Original code written by Keir Fraser.
@@ -943,6 +1068,11 @@ void __init early_init_lapic_mapping(void)
  */
 void __init init_apic_mappings(void)
 {
+        if (x2apic) {
+                boot_cpu_physical_apicid = GET_APIC_ID(read_apic_id());
+                return;
+        }
+
         /*
          * If no local APIC can be found then set up a fake all
          * zeroes page to simulate the local APIC and another
@@ -981,6 +1111,9 @@ int __init APIC_init_uniprocessor(void)
                 return -1;
         }
 
+        enable_IR_x2apic();
+        setup_apic_routing();
+
         verify_local_APIC();
 
         connect_bsp_APIC();
@@ -1238,10 +1371,14 @@ static int lapic_resume(struct sys_device *dev)
         maxlvt = lapic_get_maxlvt();
 
         local_irq_save(flags);
-        rdmsr(MSR_IA32_APICBASE, l, h);
-        l &= ~MSR_IA32_APICBASE_BASE;
-        l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
-        wrmsr(MSR_IA32_APICBASE, l, h);
+        if (!x2apic) {
+                rdmsr(MSR_IA32_APICBASE, l, h);
+                l &= ~MSR_IA32_APICBASE_BASE;
+                l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
+                wrmsr(MSR_IA32_APICBASE, l, h);
+        } else
+                enable_x2apic();
+
         apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
         apic_write(APIC_ID, apic_pm_state.apic_id);
         apic_write(APIC_DFR, apic_pm_state.apic_dfr);
@@ -1381,6 +1518,15 @@ __cpuinit int apic_is_clustered_box(void)
         return (clusters > 2);
 }
 
+static __init int setup_nox2apic(char *str)
+{
+        disable_x2apic = 1;
+        clear_cpu_cap(&boot_cpu_data, X86_FEATURE_X2APIC);
+        return 0;
+}
+early_param("nox2apic", setup_nox2apic);
+
+
 /*
  * APIC command line parameters
  */
diff --git a/arch/x86/kernel/cpu/common_64.c b/arch/x86/kernel/cpu/common_64.c
index 36537ab9e56a..e7bf3c2dc5fe 100644
--- a/arch/x86/kernel/cpu/common_64.c
+++ b/arch/x86/kernel/cpu/common_64.c
@@ -606,6 +606,8 @@ void __cpuinit cpu_init(void)
         barrier();
 
         check_efer();
+        if (cpu != 0 && x2apic)
+                enable_x2apic();
 
         /*
          * set up and load the per-CPU TSS
diff --git a/arch/x86/kernel/genapic_64.c b/arch/x86/kernel/genapic_64.c
index 1029e178cdf7..792e21ba1a81 100644
--- a/arch/x86/kernel/genapic_64.c
+++ b/arch/x86/kernel/genapic_64.c
@@ -16,6 +16,7 @@
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/hardirq.h>
+#include <linux/dmar.h>
 
 #include <asm/smp.h>
 #include <asm/ipi.h>
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 3b25e49380c6..70e1f3e287fb 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -545,7 +545,9 @@ static int __init smp_read_mpc(struct mp_config_table *mpc, unsigned early)
        generic_bigsmp_probe();
 #endif
 
+#ifdef CONFIG_X86_32
         setup_apic_routing();
+#endif
         if (!num_processors)
                 printk(KERN_ERR "MPTABLE: no processors registered!\n");
         return num_processors;
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 987b6fde3a99..2e78a143dec3 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -730,6 +730,8 @@ void __init setup_arch(char **cmdline_p)
         num_physpages = max_pfn;
 
         check_efer();
+        if (cpu_has_x2apic)
+                check_x2apic();
 
         /* How many end-of-memory variables you have, grandma! */
         /* need this before calling reserve_initrd */
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index c55263b3df02..0c43e1f2e7d3 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1145,6 +1145,11 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
         current_thread_info()->cpu = 0;  /* needed? */
         set_cpu_sibling_map(0);
 
+#ifdef CONFIG_X86_64
+        enable_IR_x2apic();
+        setup_apic_routing();
+#endif
+
         if (smp_sanity_check(max_cpus) < 0) {
                 printk(KERN_INFO "SMP disabled\n");
                 disable_smp();
diff --git a/include/asm-x86/apic.h b/include/asm-x86/apic.h
index aa746704a5c9..129752dd2525 100644
--- a/include/asm-x86/apic.h
+++ b/include/asm-x86/apic.h
@@ -100,6 +100,11 @@ extern void apic_wait_icr_idle(void);
 extern u32 safe_apic_wait_icr_idle(void);
 extern void apic_icr_write(u32 low, u32 id);
 #else
+extern int x2apic, x2apic_preenabled;
+extern void check_x2apic(void);
+extern void enable_x2apic(void);
+extern void enable_IR_x2apic(void);
+extern void x2apic_icr_write(u32 low, u32 id);
 
 struct apic_ops {
         u32 (*read)(u32 reg);