7 files changed, 29 insertions, 17 deletions

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index 1e60acbed3c1..6c8e483ce9e4 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -2317,6 +2317,8 @@ static int __init apm_init(void)
 
         for (i = 0; i < NR_CPUS; i++) {
                 struct desc_struct *gdt = get_cpu_gdt_table(i);
+                if (!gdt)
+                        continue;
                 set_base(gdt[APM_CS >> 3],
                          __va((unsigned long)apm_info.bios.cseg << 4));
                 set_base(gdt[APM_CS_16 >> 3],
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index 31e344b26bae..cbc32069683f 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -18,9 +18,6 @@
 
 #include "cpu.h"
 
-DEFINE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]);
-EXPORT_PER_CPU_SYMBOL(cpu_gdt_table);
-
 DEFINE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
 EXPORT_PER_CPU_SYMBOL(cpu_16bit_stack);
 
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index e437fb367498..870f20bf33c8 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -525,3 +525,5 @@ ENTRY(cpu_gdt_table)
         .quad 0x0000000000000000        /* 0xf0 - unused */
         .quad 0x0000000000000000        /* 0xf8 - GDT entry 31: double-fault TSS */
 
+        /* Be sure this is zeroed to avoid false validations in Xen */
+        .fill PAGE_SIZE_asm / 8 - GDT_ENTRIES,8,0
diff --git a/arch/i386/kernel/i386_ksyms.c b/arch/i386/kernel/i386_ksyms.c
index 180f070d03cb..3999bec50c33 100644
--- a/arch/i386/kernel/i386_ksyms.c
+++ b/arch/i386/kernel/i386_ksyms.c
@@ -3,8 +3,7 @@
 #include <asm/checksum.h>
 #include <asm/desc.h>
 
-/* This is definitely a GPL-only symbol */
-EXPORT_SYMBOL_GPL(cpu_gdt_table);
+EXPORT_SYMBOL_GPL(cpu_gdt_descr);
 
 EXPORT_SYMBOL(__down_failed);
 EXPORT_SYMBOL(__down_failed_interruptible);
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 9ed449af8e9f..b3c2e2c26743 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -903,6 +903,12 @@ static int __devinit do_boot_cpu(int apicid, int cpu)
         unsigned long start_eip;
         unsigned short nmi_high = 0, nmi_low = 0;
 
+        if (!cpu_gdt_descr[cpu].address &&
+            !(cpu_gdt_descr[cpu].address = get_zeroed_page(GFP_KERNEL))) {
+                printk("Failed to allocate GDT for CPU %d\n", cpu);
+                return 1;
+        }
+
         ++cpucount;
 
         /*
diff --git a/drivers/pnp/pnpbios/bioscalls.c b/drivers/pnp/pnpbios/bioscalls.c
index 6b7583f497d0..7cb476ed7f91 100644
--- a/drivers/pnp/pnpbios/bioscalls.c
+++ b/drivers/pnp/pnpbios/bioscalls.c
@@ -69,14 +69,16 @@ __asm__(
 
 #define Q_SET_SEL(cpu, selname, address, size) \
 do { \
-set_base(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], __va((u32)(address))); \
-set_limit(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], size); \
+struct desc_struct *gdt = get_cpu_gdt_table((cpu)); \
+set_base(gdt[(selname) >> 3], __va((u32)(address))); \
+set_limit(gdt[(selname) >> 3], size); \
 } while(0)
 
 #define Q2_SET_SEL(cpu, selname, address, size) \
 do { \
-set_base(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], (u32)(address)); \
-set_limit(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], size); \
+struct desc_struct *gdt = get_cpu_gdt_table((cpu)); \
+set_base(gdt[(selname) >> 3], (u32)(address)); \
+set_limit(gdt[(selname) >> 3], size); \
 } while(0)
 
 static struct desc_struct bad_bios_desc = { 0, 0x00409200 };
@@ -115,8 +117,8 @@ static inline u16 call_pnp_bios(u16 func, u16 arg1, u16 arg2, u16 arg3,
                 return PNP_FUNCTION_NOT_SUPPORTED;
 
         cpu = get_cpu();
-        save_desc_40 = per_cpu(cpu_gdt_table,cpu)[0x40 / 8];
-        per_cpu(cpu_gdt_table,cpu)[0x40 / 8] = bad_bios_desc;
+        save_desc_40 = get_cpu_gdt_table(cpu)[0x40 / 8];
+        get_cpu_gdt_table(cpu)[0x40 / 8] = bad_bios_desc;
 
         /* On some boxes IRQ's during PnP BIOS calls are deadly.  */
         spin_lock_irqsave(&pnp_bios_lock, flags);
@@ -158,7 +160,7 @@ static inline u16 call_pnp_bios(u16 func, u16 arg1, u16 arg2, u16 arg3,
         );
         spin_unlock_irqrestore(&pnp_bios_lock, flags);
 
-        per_cpu(cpu_gdt_table,cpu)[0x40 / 8] = save_desc_40;
+        get_cpu_gdt_table(cpu)[0x40 / 8] = save_desc_40;
         put_cpu();
 
         /* If we get here and this is set then the PnP BIOS faulted on us. */
@@ -535,8 +537,10 @@ void pnpbios_calls_init(union pnp_bios_install_struct *header)
 
         set_base(bad_bios_desc, __va((unsigned long)0x40 << 4));
         _set_limit((char *)&bad_bios_desc, 4095 - (0x40 << 4));
-        for(i=0; i < NR_CPUS; i++)
-        {
+        for (i = 0; i < NR_CPUS; i++) {
+                struct desc_struct *gdt = get_cpu_gdt_table(i);
+                if (!gdt)
+                        continue;
                 Q2_SET_SEL(i, PNP_CS32, &pnp_bios_callfunc, 64 * 1024);
                 Q_SET_SEL(i, PNP_CS16, header->fields.pm16cseg, 64 * 1024);
                 Q_SET_SEL(i, PNP_DS, header->fields.pm16dseg, 64 * 1024);
diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index 29b851a18c6e..494e73bca095 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -15,9 +15,6 @@
 #include <asm/mmu.h>
 
 extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
-DECLARE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]);
-
-#define get_cpu_gdt_table(_cpu) (per_cpu(cpu_gdt_table,_cpu))
 
 DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
 
@@ -29,6 +26,11 @@ struct Xgt_desc_struct {
 
 extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS];
 
+static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
+{
+        return ((struct desc_struct *)cpu_gdt_descr[cpu].address);
+}
+
 #define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8))
 #define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8))