1 files changed, 147 insertions, 0 deletions

diff --git a/arch/ia64/ia32/ia32_ldt.c b/arch/ia64/ia32/ia32_ldt.c
new file mode 100644
index 000000000000..a152738c7d0d
--- /dev/null
+++ b/arch/ia64/ia32/ia32_ldt.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2001, 2004 Hewlett-Packard Co
+ *      David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * Adapted from arch/i386/kernel/ldt.c
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/vmalloc.h>
+
+#include <asm/uaccess.h>
+
+#include "ia32priv.h"
+
+/*
+ * read_ldt() is not really atomic - this is not a problem since synchronization of reads
+ * and writes done to the LDT has to be assured by user-space anyway. Writes are atomic,
+ * to protect the security checks done on new descriptors.
+ */
+static int
+read_ldt (void __user *ptr, unsigned long bytecount)
+{
+        unsigned long bytes_left, n;
+        char __user *src, *dst;
+        char buf[256];  /* temporary buffer (don't overflow kernel stack!) */
+
+        if (bytecount > IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE)
+                bytecount = IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE;
+
+        bytes_left = bytecount;
+
+        src = (void __user *) IA32_LDT_OFFSET;
+        dst = ptr;
+
+        while (bytes_left) {
+                n = sizeof(buf);
+                if (n > bytes_left)
+                        n = bytes_left;
+
+                /*
+                 * We know we're reading valid memory, but we still must guard against
+                 * running out of memory.
+                 */
+                if (__copy_from_user(buf, src, n))
+                        return -EFAULT;
+
+                if (copy_to_user(dst, buf, n))
+                        return -EFAULT;
+
+                src += n;
+                dst += n;
+                bytes_left -= n;
+        }
+        return bytecount;
+}
+
+static int
+read_default_ldt (void __user * ptr, unsigned long bytecount)
+{
+        unsigned long size;
+        int err;
+
+        /* XXX fix me: should return equivalent of default_ldt[0] */
+        err = 0;
+        size = 8;
+        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 ia32_user_desc ldt_info;
+        __u64 entry;
+        int ret;
+
+        if (bytecount != sizeof(ldt_info))
+                return -EINVAL;
+        if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info)))
+                return -EFAULT;
+
+        if (ldt_info.entry_number >= IA32_LDT_ENTRIES)
+                return -EINVAL;
+        if (ldt_info.contents == 3) {
+                if (oldmode)
+                        return -EINVAL;
+                if (ldt_info.seg_not_present == 0)
+                        return -EINVAL;
+        }
+
+        if (ldt_info.base_addr == 0 && ldt_info.limit == 0
+            && (oldmode || (ldt_info.contents == 0 && ldt_info.read_exec_only == 1
+                            && ldt_info.seg_32bit == 0 && ldt_info.limit_in_pages == 0
+                            && ldt_info.seg_not_present == 1 && ldt_info.useable == 0)))
+                /* allow LDTs to be cleared by the user */
+                entry = 0;
+        else
+                /* we must set the "Accessed" bit as IVE doesn't emulate it */
+                entry = IA32_SEG_DESCRIPTOR(ldt_info.base_addr, ldt_info.limit,
+                                            (((ldt_info.read_exec_only ^ 1) << 1)
+                                             | (ldt_info.contents << 2)) | 1,
+                                            1, 3, ldt_info.seg_not_present ^ 1,
+                                            (oldmode ? 0 : ldt_info.useable),
+                                            ldt_info.seg_32bit,
+                                            ldt_info.limit_in_pages);
+        /*
+         * Install the new entry.  We know we're accessing valid (mapped) user-level
+         * memory, but we still need to guard against out-of-memory, hence we must use
+         * put_user().
+         */
+        ret = __put_user(entry, (__u64 __user *) IA32_LDT_OFFSET + ldt_info.entry_number);
+        ia32_load_segment_descriptors(current);
+        return ret;
+}
+
+asmlinkage int
+sys32_modify_ldt (int func, unsigned int ptr, unsigned int bytecount)
+{
+        int ret = -ENOSYS;
+
+        switch (func) {
+              case 0:
+                ret = read_ldt(compat_ptr(ptr), bytecount);
+                break;
+              case 1:
+                ret = write_ldt(compat_ptr(ptr), bytecount, 1);
+                break;
+              case 2:
+                ret = read_default_ldt(compat_ptr(ptr), bytecount);
+                break;
+              case 0x11:
+                ret = write_ldt(compat_ptr(ptr), bytecount, 0);
+                break;
+        }
+        return ret;
+}