x86: merge arch/x86/kernel/ldt_32/64.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/Makefile_32

@@ -6,7 +6,7 @@ extra-y := head_32.o init_task.o vmlinux.lds
 CPPFLAGS_vmlinux.lds += -Ui386
 
 obj-y	:= process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \
-		ptrace_32.o time_32.o ioport_32.o ldt_32.o setup_32.o i8259_32.o sys_i386_32.o \
+		ptrace_32.o time_32.o ioport_32.o ldt.o setup_32.o i8259_32.o sys_i386_32.o \
 		pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\
 		quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o io_delay.o
 

arch/x86/kernel/Makefile_64

@@ -7,7 +7,7 @@ CPPFLAGS_vmlinux.lds += -Ux86_64
 EXTRA_AFLAGS	:= -traditional
 
 obj-y	:= process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \
-		ptrace_64.o time_64.o ioport_64.o ldt_64.o setup_64.o i8259_64.o sys_x86_64.o \
+		ptrace_64.o time_64.o ioport_64.o ldt.o setup_64.o i8259_64.o sys_x86_64.o \
 		x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \
 		setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \
 		pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \

arch/x86/kernel/ldt_64.c → arch/x86/kernel/ldt.c

@@ -50,7 +50,11 @@ static int alloc_ldt(mm_context_t *pc, int mincount, int reload)
 	oldldt = pc->ldt;
 	memset(newldt + oldsize * LDT_ENTRY_SIZE, 0,
 	       (mincount - oldsize) * LDT_ENTRY_SIZE);
+
+#ifdef CONFIG_X86_64
+	/* CHECKME: Do we really need this ? */
 	wmb();
+#endif
 	pc->ldt = newldt;
 	wmb();
 	pc->size = mincount;
@@ -110,11 +114,18 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 }
 
 /*
- * Don't touch the LDT register - we're already in the next thread.
+ * No need to lock the MM as we are the last user
+ *
+ * 64bit: Don't touch the LDT register - we're already in the next thread.
  */
 void destroy_context(struct mm_struct *mm)
 {
 	if (mm->context.size) {
+#ifdef CONFIG_X86_32
+		/* CHECKME: Can this ever happen ? */
+		if (mm == current->active_mm)
+			clear_LDT();
+#endif
 		if (mm->context.size * LDT_ENTRY_SIZE > PAGE_SIZE)
 			vfree(mm->context.ldt);
 		else
@@ -159,10 +170,14 @@ error_return:
 
 static int read_default_ldt(void __user *ptr, unsigned long bytecount)
 {
-	/* Arbitrary number */
-	/* x86-64 default LDT is all zeros */
-	if (bytecount > 128)
-		bytecount = 128;
+	/* CHECKME: Can we use _one_ random number ? */
+#ifdef CONFIG_X86_32
+	unsigned long size = 5 * sizeof(struct desc_struct);
+#else
+	unsigned long size = 128;
+#endif
+	if (bytecount > size)
+		bytecount = size;
 	if (clear_user(ptr, bytecount))
 		return -EFAULT;
 	return bytecount;

arch/x86/kernel/ldt_32.c

-/*
- * Copyright (C) 1992 Krishna Balasubramanian and Linus Torvalds
- * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
- */
-
-#include <linux/errno.h>
-#include <linux/sched.h>
-#include <linux/string.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/vmalloc.h>
-#include <linux/slab.h>
-
-#include <asm/uaccess.h>
-#include <asm/system.h>
-#include <asm/ldt.h>
-#include <asm/desc.h>
-#include <asm/mmu_context.h>
-
-#ifdef CONFIG_SMP
-static void flush_ldt(void *null)
-{
-	if (current->active_mm)
-		load_LDT(&current->active_mm->context);
-}
-#endif
-
-static int alloc_ldt(mm_context_t *pc, int mincount, int reload)
-{
-	void *oldldt, *newldt;
-	int oldsize;
-
-	if (mincount <= pc->size)
-		return 0;
-	oldsize = pc->size;
-	mincount = (mincount + 511) & (~511);
-	if (mincount * LDT_ENTRY_SIZE > PAGE_SIZE)
-		newldt = vmalloc(mincount * LDT_ENTRY_SIZE);
-	else
-		newldt = kmalloc(mincount * LDT_ENTRY_SIZE, GFP_KERNEL);
-
-	if (!newldt)
-		return -ENOMEM;
-
-	if (oldsize)
-		memcpy(newldt, pc->ldt, oldsize * LDT_ENTRY_SIZE);
-	oldldt = pc->ldt;
-	memset(newldt + oldsize * LDT_ENTRY_SIZE, 0,
-	       (mincount - oldsize) * LDT_ENTRY_SIZE);
-	pc->ldt = newldt;
-	wmb();
-	pc->size = mincount;
-	wmb();
-
-	if (reload) {
-#ifdef CONFIG_SMP
-		cpumask_t mask;
-
-		preempt_disable();
-		load_LDT(pc);
-		mask = cpumask_of_cpu(smp_processor_id());
-		if (!cpus_equal(current->mm->cpu_vm_mask, mask))
-			smp_call_function(flush_ldt, NULL, 1, 1);
-		preempt_enable();
-#else
-		load_LDT(pc);
-#endif
-	}
-	if (oldsize) {
-		if (oldsize * LDT_ENTRY_SIZE > PAGE_SIZE)
-			vfree(oldldt);
-		else
-			kfree(oldldt);
-	}
-	return 0;
-}
-
-static inline int copy_ldt(mm_context_t *new, mm_context_t *old)
-{
-	int err = alloc_ldt(new, old->size, 0);
-
-	if (err < 0)
-		return err;
-	memcpy(new->ldt, old->ldt, old->size * LDT_ENTRY_SIZE);
-	return 0;
-}
-
-/*
- * we do not have to muck with descriptors here, that is
- * done in switch_mm() as needed.
- */
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
-{
-	struct mm_struct *old_mm;
-	int retval = 0;
-
-	mutex_init(&mm->context.lock);
-	mm->context.size = 0;
-	old_mm = current->mm;
-	if (old_mm && old_mm->context.size > 0) {
-		mutex_lock(&old_mm->context.lock);
-		retval = copy_ldt(&mm->context, &old_mm->context);
-		mutex_unlock(&old_mm->context.lock);
-	}
-	return retval;
-}
-
-/*
- * No need to lock the MM as we are the last user
- */
-void destroy_context(struct mm_struct *mm)
-{
-	if (mm->context.size) {
-		if (mm == current->active_mm)
-			clear_LDT();
-		if (mm->context.size * LDT_ENTRY_SIZE > PAGE_SIZE)
-			vfree(mm->context.ldt);
-		else
-			kfree(mm->context.ldt);
-		mm->context.size = 0;
-	}
-}
-
-static int read_ldt(void __user *ptr, unsigned long bytecount)
-{
-	int err;
-	unsigned long size;
-	struct mm_struct *mm = current->mm;
-
-	if (!mm->context.size)
-		return 0;
-	if (bytecount > LDT_ENTRY_SIZE * LDT_ENTRIES)
-		bytecount = LDT_ENTRY_SIZE * LDT_ENTRIES;
-
-	mutex_lock(&mm->context.lock);
-	size = mm->context.size * LDT_ENTRY_SIZE;
-	if (size > bytecount)
-		size = bytecount;
-
-	err = 0;
-	if (copy_to_user(ptr, mm->context.ldt, size))
-		err = -EFAULT;
-	mutex_unlock(&mm->context.lock);
-	if (err < 0)
-		goto error_return;
-	if (size != bytecount) {
-		/* zero-fill the rest */
-		if (clear_user(ptr + size, bytecount - size) != 0) {
-			err = -EFAULT;
-			goto error_return;
-		}
-	}
-	return bytecount;
-error_return:
-	return err;
-}
-
-static int read_default_ldt(void __user *ptr, unsigned long bytecount)
-{
-	int err;
-	unsigned long size;
-
-	err = 0;
-	size = 5 * sizeof(struct desc_struct);
-	if (size > bytecount)
-		size = bytecount;
-
-	err = size;
-	if (clear_user(ptr, size))
-		err = -EFAULT;
-
-	return err;
-}
-
-static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
-{
-	struct mm_struct *mm = current->mm;
-	__u32 entry_1, entry_2;
-	int error;
-	struct user_desc ldt_info;
-
-	error = -EINVAL;
-	if (bytecount != sizeof(ldt_info))
-		goto out;
-	error = -EFAULT;
-	if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info)))
-		goto out;
-
-	error = -EINVAL;
-	if (ldt_info.entry_number >= LDT_ENTRIES)
-		goto out;
-	if (ldt_info.contents == 3) {
-		if (oldmode)
-			goto out;
-		if (ldt_info.seg_not_present == 0)
-			goto out;
-	}
-
-	mutex_lock(&mm->context.lock);
-	if (ldt_info.entry_number >= mm->context.size) {
-		error = alloc_ldt(&current->mm->context,
-				  ldt_info.entry_number + 1, 1);
-		if (error < 0)
-			goto out_unlock;
-	}
-
-	/* Allow LDTs to be cleared by the user. */
-	if (ldt_info.base_addr == 0 && ldt_info.limit == 0) {
-		if (oldmode || LDT_empty(&ldt_info)) {
-			entry_1 = 0;
-			entry_2 = 0;
-			goto install;
-		}
-	}
-
-	entry_1 = LDT_entry_a(&ldt_info);
-	entry_2 = LDT_entry_b(&ldt_info);
-	if (oldmode)
-		entry_2 &= ~(1 << 20);
-
-	/* Install the new entry ...  */
-install:
-	write_ldt_entry(mm->context.ldt, ldt_info.entry_number, entry_1,
-			entry_2);
-	error = 0;
-
-out_unlock:
-	mutex_unlock(&mm->context.lock);
-out:
-	return error;
-}
-
-asmlinkage int sys_modify_ldt(int func, void __user *ptr,
-			      unsigned long bytecount)
-{
-	int ret = -ENOSYS;
-
-	switch (func) {
-	case 0:
-		ret = read_ldt(ptr, bytecount);
-		break;
-	case 1:
-		ret = write_ldt(ptr, bytecount, 1);
-		break;
-	case 2:
-		ret = read_default_ldt(ptr, bytecount);
-		break;
-	case 0x11:
-		ret = write_ldt(ptr, bytecount, 0);
-		break;
-	}
-	return ret;
-}