x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 560 insertions, 0 deletions

diff --git a/fs/nls/nls_base.c b/fs/nls/nls_base.c
new file mode 100644
index 000000000..a5c3a9f1b
--- /dev/null
+++ b/fs/nls/nls_base.c
@@ -0,0 +1,560 @@
+/*
+ * linux/fs/nls/nls_base.c
+ *
+ * Native language support--charsets and unicode translations.
+ * By Gordon Chaffee 1996, 1997
+ *
+ * Unicode based case conversion 1999 by Wolfram Pienkoss
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/nls.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/kmod.h>
+#include <linux/spinlock.h>
+#include <asm/byteorder.h>
+
+static struct nls_table default_table;
+static struct nls_table *tables = &default_table;
+static DEFINE_SPINLOCK(nls_lock);
+
+/*
+ * Sample implementation from Unicode home page.
+ * http://www.stonehand.com/unicode/standard/fss-utf.html
+ */
+struct utf8_table {
+	int     cmask;
+	int     cval;
+	int     shift;
+	long    lmask;
+	long    lval;
+};
+
+static const struct utf8_table utf8_table[] =
+{
+    {0x80,  0x00,   0*6,    0x7F,           0,         /* 1 byte sequence */},
+    {0xE0,  0xC0,   1*6,    0x7FF,          0x80,      /* 2 byte sequence */},
+    {0xF0,  0xE0,   2*6,    0xFFFF,         0x800,     /* 3 byte sequence */},
+    {0xF8,  0xF0,   3*6,    0x1FFFFF,       0x10000,   /* 4 byte sequence */},
+    {0xFC,  0xF8,   4*6,    0x3FFFFFF,      0x200000,  /* 5 byte sequence */},
+    {0xFE,  0xFC,   5*6,    0x7FFFFFFF,     0x4000000, /* 6 byte sequence */},
+    {0,						       /* end of table    */}
+};
+
+#define UNICODE_MAX	0x0010ffff
+#define PLANE_SIZE	0x00010000
+
+#define SURROGATE_MASK	0xfffff800
+#define SURROGATE_PAIR	0x0000d800
+#define SURROGATE_LOW	0x00000400
+#define SURROGATE_BITS	0x000003ff
+
+int utf8_to_utf32(const u8 *s, int inlen, unicode_t *pu)
+{
+	unsigned long l;
+	int c0, c, nc;
+	const struct utf8_table *t;
+  
+	nc = 0;
+	c0 = *s;
+	l = c0;
+	for (t = utf8_table; t->cmask; t++) {
+		nc++;
+		if ((c0 & t->cmask) == t->cval) {
+			l &= t->lmask;
+			if (l < t->lval || l > UNICODE_MAX ||
+					(l & SURROGATE_MASK) == SURROGATE_PAIR)
+				return -EILSEQ;
+
+			*pu = (unicode_t) l;
+			return nc;
+		}
+		if (inlen <= nc)
+			return -EOVERFLOW;
+
+		s++;
+		c = (*s ^ 0x80) & 0xFF;
+		if (c & 0xC0)
+			return -EILSEQ;
+
+		l = (l << 6) | c;
+	}
+	return -EILSEQ;
+}
+EXPORT_SYMBOL(utf8_to_utf32);
+
+int utf32_to_utf8(unicode_t u, u8 *s, int maxout)
+{
+	unsigned long l;
+	int c, nc;
+	const struct utf8_table *t;
+
+	if (!s)
+		return 0;
+
+	l = u;
+	if (l > UNICODE_MAX || (l & SURROGATE_MASK) == SURROGATE_PAIR)
+		return -EILSEQ;
+
+	nc = 0;
+	for (t = utf8_table; t->cmask && maxout; t++, maxout--) {
+		nc++;
+		if (l <= t->lmask) {
+			c = t->shift;
+			*s = (u8) (t->cval | (l >> c));
+			while (c > 0) {
+				c -= 6;
+				s++;
+				*s = (u8) (0x80 | ((l >> c) & 0x3F));
+			}
+			return nc;
+		}
+	}
+	return -EOVERFLOW;
+}
+EXPORT_SYMBOL(utf32_to_utf8);
+
+static inline void put_utf16(wchar_t *s, unsigned c, enum utf16_endian endian)
+{
+	switch (endian) {
+	default:
+		*s = (wchar_t) c;
+		break;
+	case UTF16_LITTLE_ENDIAN:
+		*s = __cpu_to_le16(c);
+		break;
+	case UTF16_BIG_ENDIAN:
+		*s = __cpu_to_be16(c);
+		break;
+	}
+}
+
+int utf8s_to_utf16s(const u8 *s, int inlen, enum utf16_endian endian,
+		wchar_t *pwcs, int maxout)
+{
+	u16 *op;
+	int size;
+	unicode_t u;
+
+	op = pwcs;
+	while (inlen > 0 && maxout > 0 && *s) {
+		if (*s & 0x80) {
+			size = utf8_to_utf32(s, inlen, &u);
+			if (size < 0)
+				return -EINVAL;
+			s += size;
+			inlen -= size;
+
+			if (u >= PLANE_SIZE) {
+				if (maxout < 2)
+					break;
+				u -= PLANE_SIZE;
+				put_utf16(op++, SURROGATE_PAIR |
+						((u >> 10) & SURROGATE_BITS),
+						endian);
+				put_utf16(op++, SURROGATE_PAIR |
+						SURROGATE_LOW |
+						(u & SURROGATE_BITS),
+						endian);
+				maxout -= 2;
+			} else {
+				put_utf16(op++, u, endian);
+				maxout--;
+			}
+		} else {
+			put_utf16(op++, *s++, endian);
+			inlen--;
+			maxout--;
+		}
+	}
+	return op - pwcs;
+}
+EXPORT_SYMBOL(utf8s_to_utf16s);
+
+static inline unsigned long get_utf16(unsigned c, enum utf16_endian endian)
+{
+	switch (endian) {
+	default:
+		return c;
+	case UTF16_LITTLE_ENDIAN:
+		return __le16_to_cpu(c);
+	case UTF16_BIG_ENDIAN:
+		return __be16_to_cpu(c);
+	}
+}
+
+int utf16s_to_utf8s(const wchar_t *pwcs, int inlen, enum utf16_endian endian,
+		u8 *s, int maxout)
+{
+	u8 *op;
+	int size;
+	unsigned long u, v;
+
+	op = s;
+	while (inlen > 0 && maxout > 0) {
+		u = get_utf16(*pwcs, endian);
+		if (!u)
+			break;
+		pwcs++;
+		inlen--;
+		if (u > 0x7f) {
+			if ((u & SURROGATE_MASK) == SURROGATE_PAIR) {
+				if (u & SURROGATE_LOW) {
+					/* Ignore character and move on */
+					continue;
+				}
+				if (inlen <= 0)
+					break;
+				v = get_utf16(*pwcs, endian);
+				if ((v & SURROGATE_MASK) != SURROGATE_PAIR ||
+						!(v & SURROGATE_LOW)) {
+					/* Ignore character and move on */
+					continue;
+				}
+				u = PLANE_SIZE + ((u & SURROGATE_BITS) << 10)
+						+ (v & SURROGATE_BITS);
+				pwcs++;
+				inlen--;
+			}
+			size = utf32_to_utf8(u, op, maxout);
+			if (size < 0) {
+				if (size == -EILSEQ) {
+					/* Ignore character and move on */
+					continue;
+				}
+				/*
+				 * Stop filling the buffer with data once a character
+				 * does not fit anymore.
+				 */
+				break;
+			} else {
+				op += size;
+				maxout -= size;
+			}
+		} else {
+			*op++ = (u8) u;
+			maxout--;
+		}
+	}
+	return op - s;
+}
+EXPORT_SYMBOL(utf16s_to_utf8s);
+
+int __register_nls(struct nls_table *nls, struct module *owner)
+{
+	struct nls_table ** tmp = &tables;
+
+	if (nls->next)
+		return -EBUSY;
+
+	nls->owner = owner;
+	spin_lock(&nls_lock);
+	while (*tmp) {
+		if (nls == *tmp) {
+			spin_unlock(&nls_lock);
+			return -EBUSY;
+		}
+		tmp = &(*tmp)->next;
+	}
+	nls->next = tables;
+	tables = nls;
+	spin_unlock(&nls_lock);
+	return 0;	
+}
+EXPORT_SYMBOL(__register_nls);
+
+int unregister_nls(struct nls_table * nls)
+{
+	struct nls_table ** tmp = &tables;
+
+	spin_lock(&nls_lock);
+	while (*tmp) {
+		if (nls == *tmp) {
+			*tmp = nls->next;
+			spin_unlock(&nls_lock);
+			return 0;
+		}
+		tmp = &(*tmp)->next;
+	}
+	spin_unlock(&nls_lock);
+	return -EINVAL;
+}
+
+static struct nls_table *find_nls(const char *charset)
+{
+	struct nls_table *nls;
+	spin_lock(&nls_lock);
+	for (nls = tables; nls; nls = nls->next) {
+		if (!strcmp(nls->charset, charset))
+			break;
+		if (nls->alias && !strcmp(nls->alias, charset))
+			break;
+	}
+	if (nls && !try_module_get(nls->owner))
+		nls = NULL;
+	spin_unlock(&nls_lock);
+	return nls;
+}
+
+struct nls_table *load_nls(const char *charset)
+{
+	return try_then_request_module(find_nls(charset), "nls_%s", charset);
+}
+
+void unload_nls(struct nls_table *nls)
+{
+	if (nls)
+		module_put(nls->owner);
+}
+
+static const wchar_t charset2uni[256] = {
+	/* 0x00*/
+	0x0000, 0x0001, 0x0002, 0x0003,
+	0x0004, 0x0005, 0x0006, 0x0007,
+	0x0008, 0x0009, 0x000a, 0x000b,
+	0x000c, 0x000d, 0x000e, 0x000f,
+	/* 0x10*/
+	0x0010, 0x0011, 0x0012, 0x0013,
+	0x0014, 0x0015, 0x0016, 0x0017,
+	0x0018, 0x0019, 0x001a, 0x001b,
+	0x001c, 0x001d, 0x001e, 0x001f,
+	/* 0x20*/
+	0x0020, 0x0021, 0x0022, 0x0023,
+	0x0024, 0x0025, 0x0026, 0x0027,
+	0x0028, 0x0029, 0x002a, 0x002b,
+	0x002c, 0x002d, 0x002e, 0x002f,
+	/* 0x30*/
+	0x0030, 0x0031, 0x0032, 0x0033,
+	0x0034, 0x0035, 0x0036, 0x0037,
+	0x0038, 0x0039, 0x003a, 0x003b,
+	0x003c, 0x003d, 0x003e, 0x003f,
+	/* 0x40*/
+	0x0040, 0x0041, 0x0042, 0x0043,
+	0x0044, 0x0045, 0x0046, 0x0047,
+	0x0048, 0x0049, 0x004a, 0x004b,
+	0x004c, 0x004d, 0x004e, 0x004f,
+	/* 0x50*/
+	0x0050, 0x0051, 0x0052, 0x0053,
+	0x0054, 0x0055, 0x0056, 0x0057,
+	0x0058, 0x0059, 0x005a, 0x005b,
+	0x005c, 0x005d, 0x005e, 0x005f,
+	/* 0x60*/
+	0x0060, 0x0061, 0x0062, 0x0063,
+	0x0064, 0x0065, 0x0066, 0x0067,
+	0x0068, 0x0069, 0x006a, 0x006b,
+	0x006c, 0x006d, 0x006e, 0x006f,
+	/* 0x70*/
+	0x0070, 0x0071, 0x0072, 0x0073,
+	0x0074, 0x0075, 0x0076, 0x0077,
+	0x0078, 0x0079, 0x007a, 0x007b,
+	0x007c, 0x007d, 0x007e, 0x007f,
+	/* 0x80*/
+	0x0080, 0x0081, 0x0082, 0x0083,
+	0x0084, 0x0085, 0x0086, 0x0087,
+	0x0088, 0x0089, 0x008a, 0x008b,
+	0x008c, 0x008d, 0x008e, 0x008f,
+	/* 0x90*/
+	0x0090, 0x0091, 0x0092, 0x0093,
+	0x0094, 0x0095, 0x0096, 0x0097,
+	0x0098, 0x0099, 0x009a, 0x009b,
+	0x009c, 0x009d, 0x009e, 0x009f,
+	/* 0xa0*/
+	0x00a0, 0x00a1, 0x00a2, 0x00a3,
+	0x00a4, 0x00a5, 0x00a6, 0x00a7,
+	0x00a8, 0x00a9, 0x00aa, 0x00ab,
+	0x00ac, 0x00ad, 0x00ae, 0x00af,
+	/* 0xb0*/
+	0x00b0, 0x00b1, 0x00b2, 0x00b3,
+	0x00b4, 0x00b5, 0x00b6, 0x00b7,
+	0x00b8, 0x00b9, 0x00ba, 0x00bb,
+	0x00bc, 0x00bd, 0x00be, 0x00bf,
+	/* 0xc0*/
+	0x00c0, 0x00c1, 0x00c2, 0x00c3,
+	0x00c4, 0x00c5, 0x00c6, 0x00c7,
+	0x00c8, 0x00c9, 0x00ca, 0x00cb,
+	0x00cc, 0x00cd, 0x00ce, 0x00cf,
+	/* 0xd0*/
+	0x00d0, 0x00d1, 0x00d2, 0x00d3,
+	0x00d4, 0x00d5, 0x00d6, 0x00d7,
+	0x00d8, 0x00d9, 0x00da, 0x00db,
+	0x00dc, 0x00dd, 0x00de, 0x00df,
+	/* 0xe0*/
+	0x00e0, 0x00e1, 0x00e2, 0x00e3,
+	0x00e4, 0x00e5, 0x00e6, 0x00e7,
+	0x00e8, 0x00e9, 0x00ea, 0x00eb,
+	0x00ec, 0x00ed, 0x00ee, 0x00ef,
+	/* 0xf0*/
+	0x00f0, 0x00f1, 0x00f2, 0x00f3,
+	0x00f4, 0x00f5, 0x00f6, 0x00f7,
+	0x00f8, 0x00f9, 0x00fa, 0x00fb,
+	0x00fc, 0x00fd, 0x00fe, 0x00ff,
+};
+
+static const unsigned char page00[256] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
+	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
+	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 0x18-0x1f */
+	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 0x20-0x27 */
+	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 0x28-0x2f */
+	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 0x30-0x37 */
+	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 0x38-0x3f */
+	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, /* 0x40-0x47 */
+	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, /* 0x48-0x4f */
+	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, /* 0x50-0x57 */
+	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 0x58-0x5f */
+	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 0x60-0x67 */
+	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 0x68-0x6f */
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 0x70-0x77 */
+	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
+
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 0x80-0x87 */
+	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 0x88-0x8f */
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 0x90-0x97 */
+	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 0x98-0x9f */
+	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* 0xa0-0xa7 */
+	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* 0xa8-0xaf */
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* 0xb0-0xb7 */
+	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* 0xb8-0xbf */
+	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, /* 0xc0-0xc7 */
+	0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, /* 0xc8-0xcf */
+	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, /* 0xd0-0xd7 */
+	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, /* 0xd8-0xdf */
+	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* 0xe0-0xe7 */
+	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* 0xe8-0xef */
+	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* 0xf0-0xf7 */
+	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
+};
+
+static const unsigned char *const page_uni2charset[256] = {
+	page00
+};
+
+static const unsigned char charset2lower[256] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
+	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
+	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 0x18-0x1f */
+	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 0x20-0x27 */
+	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 0x28-0x2f */
+	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 0x30-0x37 */
+	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 0x38-0x3f */
+	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 0x40-0x47 */
+	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 0x48-0x4f */
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 0x50-0x57 */
+	0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 0x58-0x5f */
+	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, /* 0x60-0x67 */
+	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, /* 0x68-0x6f */
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, /* 0x70-0x77 */
+	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
+
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 0x80-0x87 */
+	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 0x88-0x8f */
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 0x90-0x97 */
+	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 0x98-0x9f */
+	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* 0xa0-0xa7 */
+	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* 0xa8-0xaf */
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* 0xb0-0xb7 */
+	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* 0xb8-0xbf */
+	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, /* 0xc0-0xc7 */
+	0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, /* 0xc8-0xcf */
+	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, /* 0xd0-0xd7 */
+	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, /* 0xd8-0xdf */
+	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* 0xe0-0xe7 */
+	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* 0xe8-0xef */
+	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* 0xf0-0xf7 */
+	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
+};
+
+static const unsigned char charset2upper[256] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
+	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
+	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 0x18-0x1f */
+	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, /* 0x20-0x27 */
+	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, /* 0x28-0x2f */
+	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, /* 0x30-0x37 */
+	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, /* 0x38-0x3f */
+	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, /* 0x40-0x47 */
+	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, /* 0x48-0x4f */
+	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, /* 0x50-0x57 */
+	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, /* 0x58-0x5f */
+	0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, /* 0x60-0x67 */
+	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, /* 0x68-0x6f */
+	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, /* 0x70-0x77 */
+	0x58, 0x59, 0x5a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
+
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /* 0x80-0x87 */
+	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 0x88-0x8f */
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, /* 0x90-0x97 */
+	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 0x98-0x9f */
+	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, /* 0xa0-0xa7 */
+	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, /* 0xa8-0xaf */
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, /* 0xb0-0xb7 */
+	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, /* 0xb8-0xbf */
+	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, /* 0xc0-0xc7 */
+	0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, /* 0xc8-0xcf */
+	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, /* 0xd0-0xd7 */
+	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, /* 0xd8-0xdf */
+	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, /* 0xe0-0xe7 */
+	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, /* 0xe8-0xef */
+	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, /* 0xf0-0xf7 */
+	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
+};
+
+
+static int uni2char(wchar_t uni, unsigned char *out, int boundlen)
+{
+	const unsigned char *uni2charset;
+	unsigned char cl = uni & 0x00ff;
+	unsigned char ch = (uni & 0xff00) >> 8;
+
+	if (boundlen <= 0)
+		return -ENAMETOOLONG;
+
+	uni2charset = page_uni2charset[ch];
+	if (uni2charset && uni2charset[cl])
+		out[0] = uni2charset[cl];
+	else
+		return -EINVAL;
+	return 1;
+}
+
+static int char2uni(const unsigned char *rawstring, int boundlen, wchar_t *uni)
+{
+	*uni = charset2uni[*rawstring];
+	if (*uni == 0x0000)
+		return -EINVAL;
+	return 1;
+}
+
+static struct nls_table default_table = {
+	.charset	= "default",
+	.uni2char	= uni2char,
+	.char2uni	= char2uni,
+	.charset2lower	= charset2lower,
+	.charset2upper	= charset2upper,
+};
+
+/* Returns a simple default translation table */
+struct nls_table *load_nls_default(void)
+{
+	struct nls_table *default_nls;
+	
+	default_nls = load_nls(CONFIG_NLS_DEFAULT);
+	if (default_nls != NULL)
+		return default_nls;
+	else
+		return &default_table;
+}
+
+EXPORT_SYMBOL(unregister_nls);
+EXPORT_SYMBOL(unload_nls);
+EXPORT_SYMBOL(load_nls);
+EXPORT_SYMBOL(load_nls_default);
+
+MODULE_DESCRIPTION("Base file system native language support");
+MODULE_LICENSE("Dual BSD/GPL");