x86: change write_gdt_entry signature.

This patch changes the write_gdt_entry function signature.
Instead of the old "a" and "b" parameters, it now receives
a pointer to a desc_struct, and the size of the entry being
handled. This is because x86_64 can have some 16-byte entries
as well as 8-byte ones.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
CC: Zachary Amsden <zach@vmware.com>
CC: Jeremy Fitzhardinge <Jeremy.Fitzhardinge.citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 28 insertions, 19 deletions

diff --git a/arch/x86/kernel/paravirt_32.c b/arch/x86/kernel/paravirt_32.c
index 13bbc99b639b..77602c1252d7 100644
--- a/arch/x86/kernel/paravirt_32.c
+++ b/arch/x86/kernel/paravirt_32.c
@@ -380,7 +380,7 @@ struct pv_cpu_ops pv_cpu_ops = {
 	.store_tr = native_store_tr,
 	.load_tls = native_load_tls,
 	.write_ldt_entry = write_dt_entry,
-	.write_gdt_entry = write_dt_entry,
+	.write_gdt_entry = native_write_gdt_entry,
 	.write_idt_entry = native_write_idt_entry,
 	.load_sp0 = native_load_sp0,
 
diff --git a/arch/x86/kernel/smpcommon_32.c b/arch/x86/kernel/smpcommon_32.c
index bbfe85a0f699..8bc38af29aef 100644
--- a/arch/x86/kernel/smpcommon_32.c
+++ b/arch/x86/kernel/smpcommon_32.c
@@ -14,10 +14,11 @@ __cpuinit void init_gdt(int cpu)
 {
 	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 
-	pack_descriptor((u32 *)&gdt[GDT_ENTRY_PERCPU].a,
-			(u32 *)&gdt[GDT_ENTRY_PERCPU].b,
+	pack_descriptor(&gdt[GDT_ENTRY_PERCPU],
 			__per_cpu_offset[cpu], 0xFFFFF,
-			0x80 | DESCTYPE_S | 0x2, 0x8);
+			0x2 | DESCTYPE_S, 0x8);
+
+	gdt[GDT_ENTRY_PERCPU].s = 1;
 
 	per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
 	per_cpu(cpu_number, cpu) = cpu;
diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index a635b22de25f..21edd0d6eae5 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -63,6 +63,7 @@ static struct {
 	void (*_set_ldt)(u32 selector);
 	void (*set_tr)(u32 selector);
 	void (*write_idt_entry)(struct desc_struct *, int, u32, u32);
+	void (*write_gdt_entry)(struct desc_struct *, int, u32, u32);
 	void (*set_kernel_stack)(u32 selector, u32 sp0);
 	void (*allocate_page)(u32, u32, u32, u32, u32);
 	void (*release_page)(u32, u32);
@@ -187,7 +188,7 @@ static void vmi_cpuid(unsigned int *ax, unsigned int *bx,
 static inline void vmi_maybe_load_tls(struct desc_struct *gdt, int nr, struct desc_struct *new)
 {
 	if (gdt[nr].a != new->a || gdt[nr].b != new->b)
-		write_gdt_entry(gdt, nr, new->a, new->b);
+		write_gdt_entry(gdt, nr, new, 0);
 }
 
 static void vmi_load_tls(struct thread_struct *t, unsigned int cpu)
@@ -201,12 +202,12 @@ static void vmi_load_tls(struct thread_struct *t, unsigned int cpu)
 static void vmi_set_ldt(const void *addr, unsigned entries)
 {
 	unsigned cpu = smp_processor_id();
-	u32 low, high;
+	struct desc_struct desc;
 
-	pack_descriptor(&low, &high, (unsigned long)addr,
+	pack_descriptor(&desc, (unsigned long)addr,
 			entries * sizeof(struct desc_struct) - 1,
-			DESCTYPE_LDT, 0);
-	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, low, high);
+			DESC_LDT, 0);
+	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, &desc, DESC_LDT);
 	vmi_ops._set_ldt(entries ? GDT_ENTRY_LDT*sizeof(struct desc_struct) : 0);
 }
 
@@ -221,6 +222,13 @@ static void vmi_write_idt_entry(gate_desc *dt, int entry, const gate_desc *g)
 	vmi_ops.write_idt_entry(dt, entry, idt_entry[0], idt_entry[2]);
 }
 
+static void vmi_write_gdt_entry(struct desc_struct *dt, int entry,
+				const void *desc, int type)
+{
+	u32 *gdt_entry = (u32 *)desc;
+	vmi_ops.write_gdt_entry(dt, entry, gdt_entry[0], gdt_entry[2]);
+}
+
 static void vmi_load_sp0(struct tss_struct *tss,
 				   struct thread_struct *thread)
 {
@@ -798,7 +806,8 @@ static inline int __init activate_vmi(void)
 	para_fill(pv_cpu_ops.store_tr, GetTR);
 	pv_cpu_ops.load_tls = vmi_load_tls;
 	para_fill(pv_cpu_ops.write_ldt_entry, WriteLDTEntry);
-	para_fill(pv_cpu_ops.write_gdt_entry, WriteGDTEntry);
+	para_wrap(pv_cpu_ops.write_gdt_entry, vmi_write_gdt_entry,
+		  write_gdt_entry, WriteGDTEntry);
 	para_wrap(pv_cpu_ops.write_idt_entry, vmi_write_idt_entry,
 		  write_idt_entry, WriteIDTEntry);
 	para_wrap(pv_cpu_ops.load_sp0, vmi_load_sp0, set_kernel_stack, UpdateKernelStack);
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index b50c8ad25ab4..a63373759f08 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -262,10 +262,10 @@ static void lguest_load_gdt(const struct desc_ptr *desc)
 /* For a single GDT entry which changes, we do the lazy thing: alter our GDT,
  * then tell the Host to reload the entire thing.  This operation is so rare
  * that this naive implementation is reasonable. */
-static void lguest_write_gdt_entry(struct desc_struct *dt,
-				   int entrynum, u32 low, u32 high)
+static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
+				   const void *desc, int type)
 {
-	write_dt_entry(dt, entrynum, low, high);
+	native_write_gdt_entry(dt, entrynum, desc, type);
 	hcall(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES, 0);
 }
 
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b7b7346d8cdc..7f98c63f6381 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -475,22 +475,21 @@ static void xen_load_idt(const struct desc_ptr *desc)
 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
    they're handled differently. */
 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
-				u32 low, u32 high)
+				const void *desc, int type)
 {
 	preempt_disable();
 
-	switch ((high >> 8) & 0xff) {
-	case DESCTYPE_LDT:
-	case DESCTYPE_TSS:
+	switch (type) {
+	case DESC_LDT:
+	case DESC_TSS:
 		/* ignore */
 		break;
 
 	default: {
 		xmaddr_t maddr = virt_to_machine(&dt[entry]);
-		u64 desc = (u64)high << 32 | low;
 
 		xen_mc_flush();
-		if (HYPERVISOR_update_descriptor(maddr.maddr, desc))
+		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
 			BUG();
 	}