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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/ia64/ia32/ia32_ldt.c
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/ia64/ia32/ia32_ldt.c')
-rw-r--r--arch/ia64/ia32/ia32_ldt.c147
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;
+}