]> pilppa.com Git - linux-2.6-omap-h63xx.git/commitdiff
[S390] Make user-copy operations run-time configurable.
authorGerald Schaefer <geraldsc@de.ibm.com>
Wed, 20 Sep 2006 13:59:42 +0000 (15:59 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Wed, 20 Sep 2006 13:59:42 +0000 (15:59 +0200)
Introduces a struct uaccess_ops which allows setting user-copy
operations at run-time.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/kernel/s390_ksyms.c
arch/s390/kernel/setup.c
arch/s390/lib/Makefile
arch/s390/lib/uaccess.S [deleted file]
arch/s390/lib/uaccess64.S [deleted file]
arch/s390/lib/uaccess_std.c [new file with mode: 0644]
include/asm-s390/futex.h
include/asm-s390/uaccess.h

index c73a45467fa45f0164a537f2dbb2282660e2570b..9f19e833a56253535af44a1481284fffe9682360 100644 (file)
@@ -25,12 +25,6 @@ EXPORT_SYMBOL(_oi_bitmap);
 EXPORT_SYMBOL(_ni_bitmap);
 EXPORT_SYMBOL(_zb_findmap);
 EXPORT_SYMBOL(_sb_findmap);
-EXPORT_SYMBOL(__copy_from_user_asm);
-EXPORT_SYMBOL(__copy_to_user_asm);
-EXPORT_SYMBOL(__copy_in_user_asm);
-EXPORT_SYMBOL(__clear_user_asm);
-EXPORT_SYMBOL(__strncpy_from_user_asm);
-EXPORT_SYMBOL(__strnlen_user_asm);
 EXPORT_SYMBOL(diag10);
 
 /*
index f2a9165ca4f8688df3fbec1bbeb3291b1cddb8d6..e229af59976c5aa4d3c389b59d10d78228bf7445 100644 (file)
 #include <asm/ptrace.h>
 #include <asm/sections.h>
 
+/*
+ * User copy operations.
+ */
+struct uaccess_ops uaccess;
+EXPORT_SYMBOL_GPL(uaccess);
+
 /*
  * Machine setup..
  */
@@ -641,6 +647,7 @@ setup_arch(char **cmdline_p)
 
        memory_end = memory_size;
 
+       memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
        parse_early_param();
 
 #ifndef CONFIG_64BIT
index e05d087a6eae3b0d5d8cb2cadb3d0c3aa719de17..96c82424d88be7a1a3c40aead573cc7c1f8047df 100644 (file)
@@ -4,6 +4,5 @@
 
 EXTRA_AFLAGS := -traditional
 
-lib-y += delay.o string.o
-lib-y += $(if $(CONFIG_64BIT),uaccess64.o,uaccess.o)
+lib-y += delay.o string.o uaccess_std.o
 lib-$(CONFIG_SMP) += spinlock.o
diff --git a/arch/s390/lib/uaccess.S b/arch/s390/lib/uaccess.S
deleted file mode 100644 (file)
index 8372752..0000000
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- *  arch/s390/lib/uaccess.S
- *    __copy_{from|to}_user functions.
- *
- *  s390
- *    Copyright (C) 2000,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
- *    Authors(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
- *
- *  These functions have standard call interface
- */
-
-#include <linux/errno.h>
-#include <asm/lowcore.h>
-#include <asm/asm-offsets.h>
-
-        .text
-        .align 4
-        .globl __copy_from_user_asm
-       # %r2 = to, %r3 = n, %r4 = from
-__copy_from_user_asm:
-       slr     %r0,%r0
-0:     mvcp    0(%r3,%r2),0(%r4),%r0
-       jnz     1f
-       slr     %r2,%r2
-       br      %r14
-1:     la      %r2,256(%r2)
-       la      %r4,256(%r4)
-       ahi     %r3,-256
-2:     mvcp    0(%r3,%r2),0(%r4),%r0
-       jnz     1b
-3:     slr     %r2,%r2
-       br      %r14
-4:     lhi     %r0,-4096
-       lr      %r5,%r4
-       slr     %r5,%r0
-       nr      %r5,%r0         # %r5 = (%r4 + 4096) & -4096
-       slr     %r5,%r4         # %r5 = #bytes to next user page boundary
-       clr     %r3,%r5         # copy crosses next page boundary ?
-       jnh     6f              # no, the current page faulted
-       # move with the reduced length which is < 256
-5:     mvcp    0(%r5,%r2),0(%r4),%r0
-       slr     %r3,%r5
-6:     lr      %r2,%r3
-       br      %r14
-        .section __ex_table,"a"
-       .long   0b,4b
-       .long   2b,4b
-       .long   5b,6b
-        .previous
-
-        .align 4
-        .text
-        .globl __copy_to_user_asm
-       # %r2 = from, %r3 = n, %r4 = to
-__copy_to_user_asm:
-       slr     %r0,%r0
-0:     mvcs    0(%r3,%r4),0(%r2),%r0
-       jnz     1f
-       slr     %r2,%r2
-       br      %r14
-1:     la      %r2,256(%r2)
-       la      %r4,256(%r4)
-       ahi     %r3,-256
-2:     mvcs    0(%r3,%r4),0(%r2),%r0
-       jnz     1b
-3:     slr     %r2,%r2
-       br      %r14
-4:     lhi     %r0,-4096
-       lr      %r5,%r4
-       slr     %r5,%r0
-       nr      %r5,%r0         # %r5 = (%r4 + 4096) & -4096
-       slr     %r5,%r4         # %r5 = #bytes to next user page boundary
-       clr     %r3,%r5         # copy crosses next page boundary ?
-       jnh     6f              # no, the current page faulted
-       # move with the reduced length which is < 256
-5:     mvcs    0(%r5,%r4),0(%r2),%r0
-       slr     %r3,%r5
-6:     lr      %r2,%r3
-       br      %r14
-        .section __ex_table,"a"
-       .long   0b,4b
-       .long   2b,4b
-       .long   5b,6b
-        .previous
-
-        .align 4
-        .text
-        .globl __copy_in_user_asm
-       # %r2 = from, %r3 = n, %r4 = to
-__copy_in_user_asm:
-       ahi     %r3,-1
-       jo      6f
-       sacf    256
-       bras    %r1,4f
-0:     ahi     %r3,257
-1:     mvc     0(1,%r4),0(%r2)
-       la      %r2,1(%r2)
-       la      %r4,1(%r4)
-       ahi     %r3,-1
-       jnz     1b
-2:     lr      %r2,%r3
-       br      %r14
-3:     mvc     0(256,%r4),0(%r2)
-       la      %r2,256(%r2)
-       la      %r4,256(%r4)
-4:     ahi     %r3,-256
-       jnm     3b
-5:     ex      %r3,4(%r1)
-       sacf    0
-6:     slr     %r2,%r2
-       br      %r14
-        .section __ex_table,"a"
-       .long   1b,2b
-       .long   3b,0b
-       .long   5b,0b
-        .previous
-
-        .align 4
-        .text
-        .globl __clear_user_asm
-       # %r2 = to, %r3 = n
-__clear_user_asm:
-       bras    %r5,0f
-       .long   empty_zero_page
-0:     l       %r5,0(%r5)
-       slr     %r0,%r0
-1:     mvcs    0(%r3,%r2),0(%r5),%r0
-       jnz     2f
-       slr     %r2,%r2
-       br      %r14
-2:     la      %r2,256(%r2)
-       ahi     %r3,-256
-3:     mvcs    0(%r3,%r2),0(%r5),%r0
-       jnz     2b
-4:     slr     %r2,%r2
-       br      %r14
-5:     lhi     %r0,-4096
-       lr      %r4,%r2
-       slr     %r4,%r0
-       nr      %r4,%r0         # %r4 = (%r2 + 4096) & -4096
-       slr     %r4,%r2         # %r4 = #bytes to next user page boundary
-       clr     %r3,%r4         # clear crosses next page boundary ?
-       jnh     7f              # no, the current page faulted
-       # clear with the reduced length which is < 256
-6:     mvcs    0(%r4,%r2),0(%r5),%r0
-       slr     %r3,%r4
-7:     lr      %r2,%r3
-       br      %r14
-        .section __ex_table,"a"
-       .long   1b,5b
-       .long   3b,5b
-       .long   6b,7b
-        .previous
-
-        .align 4
-        .text
-        .globl __strncpy_from_user_asm
-       # %r2 = count, %r3 = dst, %r4 = src
-__strncpy_from_user_asm:
-       lhi     %r0,0
-       lr      %r1,%r4
-       la      %r4,0(%r4)      # clear high order bit from %r4
-       la      %r2,0(%r2,%r4)  # %r2 points to first byte after string
-       sacf    256
-0:     srst    %r2,%r1
-       jo      0b
-       sacf    0
-       lr      %r1,%r2
-       jh      1f              # \0 found in string ?
-       ahi     %r1,1           # include \0 in copy
-1:     slr     %r1,%r4         # %r1 = copy length (without \0)
-       slr     %r2,%r4         # %r2 = return length (including \0)
-2:     mvcp    0(%r1,%r3),0(%r4),%r0
-       jnz     3f
-       br      %r14
-3:     la      %r3,256(%r3)
-       la      %r4,256(%r4)
-       ahi     %r1,-256
-       mvcp    0(%r1,%r3),0(%r4),%r0
-       jnz     3b
-       br      %r14
-4:     sacf    0
-       lhi     %r2,-EFAULT
-       br      %r14
-       .section __ex_table,"a"
-       .long   0b,4b
-       .previous
-
-        .align 4
-        .text
-        .globl __strnlen_user_asm
-       # %r2 = count, %r3 = src
-__strnlen_user_asm:
-       lhi     %r0,0
-       lr      %r1,%r3
-       la      %r3,0(%r3)      # clear high order bit from %r4
-       la      %r2,0(%r2,%r3)  # %r2 points to first byte after string
-       sacf    256
-0:     srst    %r2,%r1
-       jo      0b
-       sacf    0
-       ahi     %r2,1           # strnlen_user result includes the \0
-                               # or return count+1 if \0 not found
-       slr     %r2,%r3
-       br      %r14
-2:     sacf    0
-       slr     %r2,%r2         # return 0 on exception
-       br      %r14
-       .section __ex_table,"a"
-       .long   0b,2b
-       .previous
diff --git a/arch/s390/lib/uaccess64.S b/arch/s390/lib/uaccess64.S
deleted file mode 100644 (file)
index 1f755be..0000000
+++ /dev/null
@@ -1,207 +0,0 @@
-/*
- *  arch/s390x/lib/uaccess.S
- *    __copy_{from|to}_user functions.
- *
- *  s390
- *    Copyright (C) 2000,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
- *    Authors(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
- *
- *  These functions have standard call interface
- */
-
-#include <linux/errno.h>
-#include <asm/lowcore.h>
-#include <asm/asm-offsets.h>
-
-        .text
-        .align 4
-        .globl __copy_from_user_asm
-       # %r2 = to, %r3 = n, %r4 = from
-__copy_from_user_asm:
-       slgr    %r0,%r0
-0:     mvcp    0(%r3,%r2),0(%r4),%r0
-       jnz     1f
-       slgr    %r2,%r2
-       br      %r14
-1:     la      %r2,256(%r2)
-       la      %r4,256(%r4)
-       aghi    %r3,-256
-2:     mvcp    0(%r3,%r2),0(%r4),%r0
-       jnz     1b
-3:     slgr    %r2,%r2
-       br      %r14
-4:     lghi    %r0,-4096
-       lgr     %r5,%r4
-       slgr    %r5,%r0
-       ngr     %r5,%r0         # %r5 = (%r4 + 4096) & -4096
-       slgr    %r5,%r4         # %r5 = #bytes to next user page boundary
-       clgr    %r3,%r5         # copy crosses next page boundary ?
-       jnh     6f              # no, the current page faulted
-       # move with the reduced length which is < 256
-5:     mvcp    0(%r5,%r2),0(%r4),%r0
-       slgr    %r3,%r5
-6:     lgr     %r2,%r3
-       br      %r14
-        .section __ex_table,"a"
-       .quad   0b,4b
-       .quad   2b,4b
-       .quad   5b,6b
-        .previous
-
-        .align 4
-        .text
-        .globl __copy_to_user_asm
-       # %r2 = from, %r3 = n, %r4 = to
-__copy_to_user_asm:
-       slgr    %r0,%r0
-0:     mvcs    0(%r3,%r4),0(%r2),%r0
-       jnz     1f
-       slgr    %r2,%r2
-       br      %r14
-1:     la      %r2,256(%r2)
-       la      %r4,256(%r4)
-       aghi    %r3,-256
-2:     mvcs    0(%r3,%r4),0(%r2),%r0
-       jnz     1b
-3:     slgr    %r2,%r2
-       br      %r14
-4:     lghi    %r0,-4096
-       lgr     %r5,%r4
-       slgr    %r5,%r0
-       ngr     %r5,%r0         # %r5 = (%r4 + 4096) & -4096
-       slgr    %r5,%r4         # %r5 = #bytes to next user page boundary
-       clgr    %r3,%r5         # copy crosses next page boundary ?
-       jnh     6f              # no, the current page faulted
-       # move with the reduced length which is < 256
-5:     mvcs    0(%r5,%r4),0(%r2),%r0
-       slgr    %r3,%r5
-6:     lgr     %r2,%r3
-       br      %r14
-        .section __ex_table,"a"
-       .quad   0b,4b
-       .quad   2b,4b
-       .quad   5b,6b
-        .previous
-
-        .align 4
-        .text
-        .globl __copy_in_user_asm
-       # %r2 = from, %r3 = n, %r4 = to
-__copy_in_user_asm:
-       aghi    %r3,-1
-       jo      6f
-       sacf    256
-       bras    %r1,4f
-0:     aghi    %r3,257
-1:     mvc     0(1,%r4),0(%r2)
-       la      %r2,1(%r2)
-       la      %r4,1(%r4)
-       aghi    %r3,-1
-       jnz     1b
-2:     lgr     %r2,%r3
-       br      %r14
-3:     mvc     0(256,%r4),0(%r2)
-       la      %r2,256(%r2)
-       la      %r4,256(%r4)
-4:     aghi    %r3,-256
-       jnm     3b
-5:     ex      %r3,4(%r1)
-       sacf    0
-6:     slgr    %r2,%r2
-       br      14
-        .section __ex_table,"a"
-       .quad   1b,2b
-       .quad   3b,0b
-       .quad   5b,0b
-        .previous
-
-        .align 4
-        .text
-        .globl __clear_user_asm
-       # %r2 = to, %r3 = n
-__clear_user_asm:
-       slgr    %r0,%r0
-       larl    %r5,empty_zero_page
-1:     mvcs    0(%r3,%r2),0(%r5),%r0
-       jnz     2f
-       slgr    %r2,%r2
-       br      %r14
-2:     la      %r2,256(%r2)
-       aghi    %r3,-256
-3:     mvcs    0(%r3,%r2),0(%r5),%r0
-       jnz     2b
-4:     slgr    %r2,%r2
-       br      %r14
-5:     lghi    %r0,-4096
-       lgr     %r4,%r2
-       slgr    %r4,%r0
-       ngr     %r4,%r0         # %r4 = (%r2 + 4096) & -4096
-       slgr    %r4,%r2         # %r4 = #bytes to next user page boundary
-       clgr    %r3,%r4         # clear crosses next page boundary ?
-       jnh     7f              # no, the current page faulted
-       # clear with the reduced length which is < 256
-6:     mvcs    0(%r4,%r2),0(%r5),%r0
-       slgr    %r3,%r4
-7:     lgr     %r2,%r3
-       br      %r14
-        .section __ex_table,"a"
-       .quad   1b,5b
-       .quad   3b,5b
-       .quad   6b,7b
-        .previous
-
-        .align 4
-        .text
-        .globl __strncpy_from_user_asm
-       # %r2 = count, %r3 = dst, %r4 = src
-__strncpy_from_user_asm:
-       lghi    %r0,0
-       lgr     %r1,%r4
-       la      %r2,0(%r2,%r4)  # %r2 points to first byte after string
-       sacf    256
-0:     srst    %r2,%r1
-       jo      0b
-       sacf    0
-       lgr     %r1,%r2
-       jh      1f              # \0 found in string ?
-       aghi    %r1,1           # include \0 in copy
-1:     slgr    %r1,%r4         # %r1 = copy length (without \0)
-       slgr    %r2,%r4         # %r2 = return length (including \0)
-2:     mvcp    0(%r1,%r3),0(%r4),%r0
-       jnz     3f
-       br      %r14
-3:     la      %r3,256(%r3)
-       la      %r4,256(%r4)
-       aghi    %r1,-256
-       mvcp    0(%r1,%r3),0(%r4),%r0
-       jnz     3b
-       br      %r14
-4:     sacf    0
-       lghi    %r2,-EFAULT
-       br      %r14
-       .section __ex_table,"a"
-       .quad   0b,4b
-       .previous
-
-        .align 4
-        .text
-        .globl __strnlen_user_asm
-       # %r2 = count, %r3 = src
-__strnlen_user_asm:
-       lghi    %r0,0
-       lgr     %r1,%r3
-       la      %r2,0(%r2,%r3)  # %r2 points to first byte after string
-       sacf    256
-0:     srst    %r2,%r1
-       jo      0b
-       sacf    0
-       aghi    %r2,1           # strnlen_user result includes the \0
-                               # or return count+1 if \0 not found
-       slgr    %r2,%r3
-       br      %r14
-2:     sacf    0
-       slgr    %r2,%r2         # return 0 on exception
-       br      %r14
-       .section __ex_table,"a"
-       .quad   0b,2b
-       .previous
diff --git a/arch/s390/lib/uaccess_std.c b/arch/s390/lib/uaccess_std.c
new file mode 100644 (file)
index 0000000..9a4d4a2
--- /dev/null
@@ -0,0 +1,340 @@
+/*
+ *  arch/s390/lib/uaccess_std.c
+ *
+ *  Standard user space access functions based on mvcp/mvcs and doing
+ *  interesting things in the secondary space mode.
+ *
+ *    Copyright (C) IBM Corp. 2006
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ *              Gerald Schaefer (gerald.schaefer@de.ibm.com)
+ */
+
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <asm/uaccess.h>
+#include <asm/futex.h>
+
+#ifndef __s390x__
+#define AHI    "ahi"
+#define ALR    "alr"
+#define CLR    "clr"
+#define LHI    "lhi"
+#define SLR    "slr"
+#else
+#define AHI    "aghi"
+#define ALR    "algr"
+#define CLR    "clgr"
+#define LHI    "lghi"
+#define SLR    "slgr"
+#endif
+
+size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
+{
+       unsigned long tmp1, tmp2;
+
+       tmp1 = -256UL;
+       asm volatile(
+               "0: mvcp  0(%0,%2),0(%1),%3\n"
+               "   jz    5f\n"
+               "1:"ALR"  %0,%3\n"
+               "   la    %1,256(%1)\n"
+               "   la    %2,256(%2)\n"
+               "2: mvcp  0(%0,%2),0(%1),%3\n"
+               "   jnz   1b\n"
+               "   j     5f\n"
+               "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
+               "  "LHI"  %3,-4096\n"
+               "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
+               "  "SLR"  %4,%1\n"
+               "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
+               "   jnh   6f\n"
+               "4: mvcp  0(%4,%2),0(%1),%3\n"
+               "  "SLR"  %0,%4\n"
+               "   j     6f\n"
+               "5:"SLR"  %0,%0\n"
+               "6: \n"
+               EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
+               : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+               : : "cc", "memory");
+       return size;
+}
+
+size_t copy_from_user_std_small(size_t size, const void __user *ptr, void *x)
+{
+       unsigned long tmp1, tmp2;
+
+       tmp1 = 0UL;
+       asm volatile(
+               "0: mvcp  0(%0,%2),0(%1),%3\n"
+               "  "SLR"  %0,%0\n"
+               "   j     3f\n"
+               "1: la    %4,255(%1)\n" /* %4 = ptr + 255 */
+               "  "LHI"  %3,-4096\n"
+               "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
+               "  "SLR"  %4,%1\n"
+               "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
+               "   jnh   3f\n"
+               "2: mvcp  0(%4,%2),0(%1),%3\n"
+               "  "SLR"  %0,%4\n"
+               "3:\n"
+               EX_TABLE(0b,1b) EX_TABLE(2b,3b)
+               : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+               : : "cc", "memory");
+       return size;
+}
+
+size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
+{
+       unsigned long tmp1, tmp2;
+
+       tmp1 = -256UL;
+       asm volatile(
+               "0: mvcs  0(%0,%1),0(%2),%3\n"
+               "   jz    5f\n"
+               "1:"ALR"  %0,%3\n"
+               "   la    %1,256(%1)\n"
+               "   la    %2,256(%2)\n"
+               "2: mvcs  0(%0,%1),0(%2),%3\n"
+               "   jnz   1b\n"
+               "   j     5f\n"
+               "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
+               "  "LHI"  %3,-4096\n"
+               "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
+               "  "SLR"  %4,%1\n"
+               "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
+               "   jnh   6f\n"
+               "4: mvcs  0(%4,%1),0(%2),%3\n"
+               "  "SLR"  %0,%4\n"
+               "   j     6f\n"
+               "5:"SLR"  %0,%0\n"
+               "6: \n"
+               EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
+               : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+               : : "cc", "memory");
+       return size;
+}
+
+size_t copy_to_user_std_small(size_t size, void __user *ptr, const void *x)
+{
+       unsigned long tmp1, tmp2;
+
+       tmp1 = 0UL;
+       asm volatile(
+               "0: mvcs  0(%0,%1),0(%2),%3\n"
+               "  "SLR"  %0,%0\n"
+               "   j     3f\n"
+               "1: la    %4,255(%1)\n" /* ptr + 255 */
+               "  "LHI"  %3,-4096\n"
+               "   nr    %4,%3\n"      /* (ptr + 255) & -4096UL */
+               "  "SLR"  %4,%1\n"
+               "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
+               "   jnh   3f\n"
+               "2: mvcs  0(%4,%1),0(%2),%3\n"
+               "  "SLR"  %0,%4\n"
+               "3:\n"
+               EX_TABLE(0b,1b) EX_TABLE(2b,3b)
+               : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+               : : "cc", "memory");
+       return size;
+}
+
+size_t copy_in_user_std(size_t size, void __user *to, const void __user *from)
+{
+       unsigned long tmp1;
+
+       asm volatile(
+               "  "AHI"  %0,-1\n"
+               "   jo    5f\n"
+               "   sacf  256\n"
+               "   bras  %3,3f\n"
+               "0:"AHI"  %0,257\n"
+               "1: mvc   0(1,%1),0(%2)\n"
+               "   la    %1,1(%1)\n"
+               "   la    %2,1(%2)\n"
+               "  "AHI"  %0,-1\n"
+               "   jnz   1b\n"
+               "   j     5f\n"
+               "2: mvc   0(256,%1),0(%2)\n"
+               "   la    %1,256(%1)\n"
+               "   la    %2,256(%2)\n"
+               "3:"AHI"  %0,-256\n"
+               "   jnm   2b\n"
+               "4: ex    %0,1b-0b(%3)\n"
+               "   sacf  0\n"
+               "5: "SLR"  %0,%0\n"
+               "6:\n"
+               EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+               : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
+               : : "cc", "memory");
+       return size;
+}
+
+size_t clear_user_std(size_t size, void __user *to)
+{
+       unsigned long tmp1, tmp2;
+
+       asm volatile(
+               "  "AHI"  %0,-1\n"
+               "   jo    5f\n"
+               "   sacf  256\n"
+               "   bras  %3,3f\n"
+               "   xc    0(1,%1),0(%1)\n"
+               "0:"AHI"  %0,257\n"
+               "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
+               "   srl   %2,12\n"
+               "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
+               "  "SLR"  %2,%1\n"
+               "  "CLR"  %0,%2\n"      /* clear crosses next page boundary? */
+               "   jnh   5f\n"
+               "  "AHI"  %2,-1\n"
+               "1: ex    %2,0(%3)\n"
+               "  "AHI"  %2,1\n"
+               "  "SLR"  %0,%2\n"
+               "   j     5f\n"
+               "2: xc    0(256,%1),0(%1)\n"
+               "   la    %1,256(%1)\n"
+               "3:"AHI"  %0,-256\n"
+               "   jnm   2b\n"
+               "4: ex    %0,0(%3)\n"
+               "   sacf  0\n"
+               "5: "SLR"  %0,%0\n"
+               "6:\n"
+               EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+               : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
+               : : "cc", "memory");
+       return size;
+}
+
+size_t strnlen_user_std(size_t size, const char __user *src)
+{
+       register unsigned long reg0 asm("0") = 0UL;
+       unsigned long tmp1, tmp2;
+
+       asm volatile(
+               "   la    %2,0(%1)\n"
+               "   la    %3,0(%0,%1)\n"
+               "  "SLR"  %0,%0\n"
+               "   sacf  256\n"
+               "0: srst  %3,%2\n"
+               "   jo    0b\n"
+               "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
+               "  "SLR"  %0,%1\n"
+               "1: sacf  0\n"
+               EX_TABLE(0b,1b)
+               : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
+               : "d" (reg0) : "cc", "memory");
+       return size;
+}
+
+size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
+{
+       register unsigned long reg0 asm("0") = 0UL;
+       unsigned long tmp1, tmp2;
+
+       asm volatile(
+               "   la    %3,0(%1)\n"
+               "   la    %4,0(%0,%1)\n"
+               "   sacf  256\n"
+               "0: srst  %4,%3\n"
+               "   jo    0b\n"
+               "   sacf  0\n"
+               "   la    %0,0(%4)\n"
+               "   jh    1f\n"         /* found \0 in string ? */
+               "  "AHI"  %4,1\n"       /* include \0 in copy */
+               "1:"SLR"  %0,%1\n"      /* %0 = return length (without \0) */
+               "  "SLR"  %4,%1\n"      /* %4 = copy length (including \0) */
+               "2: mvcp  0(%4,%2),0(%1),%5\n"
+               "   jz    9f\n"
+               "3:"AHI"  %4,-256\n"
+               "   la    %1,256(%1)\n"
+               "   la    %2,256(%2)\n"
+               "4: mvcp  0(%4,%2),0(%1),%5\n"
+               "   jnz   3b\n"
+               "   j     9f\n"
+               "7: sacf  0\n"
+               "8:"LHI"  %0,%6\n"
+               "9:\n"
+               EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
+               : "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
+               : "d" (reg0), "K" (-EFAULT) : "cc", "memory");
+       return size;
+}
+
+#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)     \
+       asm volatile(                                                   \
+               "   sacf  256\n"                                        \
+               "0: l     %1,0(%6)\n"                                   \
+               "1:"insn                                                \
+               "2: cs    %1,%2,0(%6)\n"                                \
+               "3: jl    1b\n"                                         \
+               "   lhi   %0,0\n"                                       \
+               "4: sacf  0\n"                                          \
+               EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
+               : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
+                 "=m" (*uaddr)                                         \
+               : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
+                 "m" (*uaddr) : "cc");
+
+int futex_atomic_op(int op, int __user *uaddr, int oparg, int *old)
+{
+       int oldval = 0, newval, ret;
+
+       inc_preempt_count();
+
+       switch (op) {
+       case FUTEX_OP_SET:
+               __futex_atomic_op("lr %2,%5\n",
+                                 ret, oldval, newval, uaddr, oparg);
+               break;
+       case FUTEX_OP_ADD:
+               __futex_atomic_op("lr %2,%1\nar %2,%5\n",
+                                 ret, oldval, newval, uaddr, oparg);
+               break;
+       case FUTEX_OP_OR:
+               __futex_atomic_op("lr %2,%1\nor %2,%5\n",
+                                 ret, oldval, newval, uaddr, oparg);
+               break;
+       case FUTEX_OP_ANDN:
+               __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
+                                 ret, oldval, newval, uaddr, oparg);
+               break;
+       case FUTEX_OP_XOR:
+               __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
+                                 ret, oldval, newval, uaddr, oparg);
+               break;
+       default:
+               ret = -ENOSYS;
+       }
+       dec_preempt_count();
+       *old = oldval;
+       return ret;
+}
+
+int futex_atomic_cmpxchg(int __user *uaddr, int oldval, int newval)
+{
+       int ret;
+
+       asm volatile(
+               "   sacf 256\n"
+               "   cs   %1,%4,0(%5)\n"
+               "0: lr   %0,%1\n"
+               "1: sacf 0\n"
+               EX_TABLE(0b,1b)
+               : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
+               : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
+               : "cc", "memory" );
+       return ret;
+}
+
+struct uaccess_ops uaccess_std = {
+       .copy_from_user = copy_from_user_std,
+       .copy_from_user_small = copy_from_user_std_small,
+       .copy_to_user = copy_to_user_std,
+       .copy_to_user_small = copy_to_user_std_small,
+       .copy_in_user = copy_in_user_std,
+       .clear_user = clear_user_std,
+       .strnlen_user = strnlen_user_std,
+       .strncpy_from_user = strncpy_from_user_std,
+       .futex_atomic_op = futex_atomic_op,
+       .futex_atomic_cmpxchg = futex_atomic_cmpxchg,
+};
index ffedf14f89f68077696c29cffe1df2dc43ec15db..5e261e1de6719bb99a638421e63eec8c02e5f79a 100644 (file)
@@ -7,75 +7,21 @@
 #include <asm/errno.h>
 #include <asm/uaccess.h>
 
-#ifndef __s390x__
-#define __futex_atomic_fixup \
-                    ".section __ex_table,\"a\"\n"                      \
-                    "   .align 4\n"                                    \
-                    "   .long  0b,4b,2b,4b,3b,4b\n"                    \
-                    ".previous"
-#else /* __s390x__ */
-#define __futex_atomic_fixup \
-                    ".section __ex_table,\"a\"\n"                      \
-                    "   .align 8\n"                                    \
-                    "   .quad  0b,4b,2b,4b,3b,4b\n"                    \
-                    ".previous"
-#endif /* __s390x__ */
-
-#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)     \
-       asm volatile("   sacf 256\n"                                    \
-                    "0: l   %1,0(%6)\n"                                \
-                    "1: " insn                                         \
-                    "2: cs  %1,%2,0(%6)\n"                             \
-                    "3: jl  1b\n"                                      \
-                    "   lhi %0,0\n"                                    \
-                    "4: sacf 0\n"                                      \
-                    __futex_atomic_fixup                               \
-                    : "=d" (ret), "=&d" (oldval), "=&d" (newval),      \
-                      "=m" (*uaddr)                                    \
-                    : "0" (-EFAULT), "d" (oparg), "a" (uaddr),         \
-                      "m" (*uaddr) : "cc" );
-
 static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
 {
        int op = (encoded_op >> 28) & 7;
        int cmp = (encoded_op >> 24) & 15;
        int oparg = (encoded_op << 8) >> 20;
        int cmparg = (encoded_op << 20) >> 20;
-       int oldval = 0, newval, ret;
+       int oldval, ret;
+
        if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
                oparg = 1 << oparg;
 
        if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
                return -EFAULT;
 
-       inc_preempt_count();
-
-       switch (op) {
-       case FUTEX_OP_SET:
-               __futex_atomic_op("lr %2,%5\n",
-                                 ret, oldval, newval, uaddr, oparg);
-               break;
-       case FUTEX_OP_ADD:
-               __futex_atomic_op("lr %2,%1\nar %2,%5\n",
-                                 ret, oldval, newval, uaddr, oparg);
-               break;
-       case FUTEX_OP_OR:
-               __futex_atomic_op("lr %2,%1\nor %2,%5\n",
-                                 ret, oldval, newval, uaddr, oparg);
-               break;
-       case FUTEX_OP_ANDN:
-               __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
-                                 ret, oldval, newval, uaddr, oparg);
-               break;
-       case FUTEX_OP_XOR:
-               __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
-                                 ret, oldval, newval, uaddr, oparg);
-               break;
-       default:
-               ret = -ENOSYS;
-       }
-
-       dec_preempt_count();
+       ret = uaccess.futex_atomic_op(op, uaddr, oparg, &oldval);
 
        if (!ret) {
                switch (cmp) {
@@ -91,32 +37,13 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
        return ret;
 }
 
-static inline int
-futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
+static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr,
+                                               int oldval, int newval)
 {
-       int ret;
-
        if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
                return -EFAULT;
-       asm volatile("   sacf 256\n"
-                    "   cs   %1,%4,0(%5)\n"
-                    "0: lr   %0,%1\n"
-                    "1: sacf 0\n"
-#ifndef __s390x__
-                    ".section __ex_table,\"a\"\n"
-                    "   .align 4\n"
-                    "   .long  0b,1b\n"
-                    ".previous"
-#else /* __s390x__ */
-                    ".section __ex_table,\"a\"\n"
-                    "   .align 8\n"
-                    "   .quad  0b,1b\n"
-                    ".previous"
-#endif /* __s390x__ */
-                    : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
-                    : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
-                    : "cc", "memory" );
-       return oldval;
+
+       return uaccess.futex_atomic_cmpxchg(uaddr, oldval, newval);
 }
 
 #endif /* __KERNEL__ */
index 0b7c0ca4c3d7730b8e342bf368e2a5179c8a0cda..39a2716ae18840a9cca7fa4b159ca4e6d202bdf1 100644 (file)
@@ -47,7 +47,7 @@
                S390_lowcore.user_asce : S390_lowcore.kernel_asce;      \
        asm volatile ("lctlg 7,7,%0" : : "m" (__pto) );                 \
 })
-#else
+#else /* __s390x__ */
 #define set_fs(x) \
 ({                                                                     \
        unsigned long __pto;                                            \
@@ -56,7 +56,7 @@
                S390_lowcore.user_asce : S390_lowcore.kernel_asce;      \
        asm volatile ("lctl  7,7,%0" : : "m" (__pto) );                 \
 })
-#endif
+#endif /* __s390x__ */
 
 #define segment_eq(a,b) ((a).ar4 == (b).ar4)
 
@@ -85,76 +85,50 @@ struct exception_table_entry
         unsigned long insn, fixup;
 };
 
-#ifndef __s390x__
-#define __uaccess_fixup \
-       ".section .fixup,\"ax\"\n"      \
-       "2: lhi    %0,%4\n"             \
-       "   bras   1,3f\n"              \
-       "   .long  1b\n"                \
-       "3: l      1,0(1)\n"            \
-       "   br     1\n"                 \
-       ".previous\n"                   \
-       ".section __ex_table,\"a\"\n"   \
-       "   .align 4\n"                 \
-       "   .long  0b,2b\n"             \
-       ".previous"
-#define __uaccess_clobber "cc", "1"
-#else /* __s390x__ */
-#define __uaccess_fixup \
-       ".section .fixup,\"ax\"\n"      \
-       "2: lghi   %0,%4\n"             \
-       "   jg     1b\n"                \
-       ".previous\n"                   \
-       ".section __ex_table,\"a\"\n"   \
-       "   .align 8\n"                 \
-       "   .quad  0b,2b\n"             \
-       ".previous"
-#define __uaccess_clobber "cc"
-#endif /* __s390x__ */
+struct uaccess_ops {
+       size_t (*copy_from_user)(size_t, const void __user *, void *);
+       size_t (*copy_from_user_small)(size_t, const void __user *, void *);
+       size_t (*copy_to_user)(size_t, void __user *, const void *);
+       size_t (*copy_to_user_small)(size_t, void __user *, const void *);
+       size_t (*copy_in_user)(size_t, void __user *, const void __user *);
+       size_t (*clear_user)(size_t, void __user *);
+       size_t (*strnlen_user)(size_t, const char __user *);
+       size_t (*strncpy_from_user)(size_t, const char __user *, char *);
+       int (*futex_atomic_op)(int op, int __user *, int oparg, int *old);
+       int (*futex_atomic_cmpxchg)(int __user *, int old, int new);
+};
+
+extern struct uaccess_ops uaccess;
+extern struct uaccess_ops uaccess_std;
+
+static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
+{
+       size = uaccess.copy_to_user_small(size, ptr, x);
+       return size ? -EFAULT : size;
+}
+
+static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
+{
+       size = uaccess.copy_from_user_small(size, ptr, x);
+       return size ? -EFAULT : size;
+}
 
 /*
  * These are the main single-value transfer routines.  They automatically
  * use the right size if we just have the right pointer type.
  */
-#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
-#define __put_user_asm(x, ptr, err) \
-({                                                             \
-       err = 0;                                                \
-       asm volatile(                                           \
-               "0: mvcs  0(%1,%2),%3,%0\n"                     \
-               "1:\n"                                          \
-               __uaccess_fixup                                 \
-               : "+&d" (err)                                   \
-               : "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x),     \
-                 "K" (-EFAULT)                                 \
-               : __uaccess_clobber );                          \
-})
-#else
-#define __put_user_asm(x, ptr, err) \
-({                                                             \
-       err = 0;                                                \
-       asm volatile(                                           \
-               "0: mvcs  0(%1,%2),0(%3),%0\n"                  \
-               "1:\n"                                          \
-               __uaccess_fixup                                 \
-               : "+&d" (err)                                   \
-               : "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)),  \
-                 "K" (-EFAULT), "m" (x)                        \
-               : __uaccess_clobber );                          \
-})
-#endif
-
 #define __put_user(x, ptr) \
 ({                                                             \
        __typeof__(*(ptr)) __x = (x);                           \
-       int __pu_err;                                           \
+       int __pu_err = -EFAULT;                                 \
         __chk_user_ptr(ptr);                                    \
        switch (sizeof (*(ptr))) {                              \
        case 1:                                                 \
        case 2:                                                 \
        case 4:                                                 \
        case 8:                                                 \
-               __put_user_asm(__x, ptr, __pu_err);             \
+               __pu_err = __put_user_fn(sizeof (*(ptr)),       \
+                                        ptr, &__x);            \
                break;                                          \
        default:                                                \
                __put_user_bad();                               \
@@ -172,60 +146,36 @@ struct exception_table_entry
 
 extern int __put_user_bad(void) __attribute__((noreturn));
 
-#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
-#define __get_user_asm(x, ptr, err) \
-({                                                             \
-       err = 0;                                                \
-       asm volatile (                                          \
-               "0: mvcp  %O1(%2,%R1),0(%3),%0\n"               \
-               "1:\n"                                          \
-               __uaccess_fixup                                 \
-               : "+&d" (err), "=Q" (x)                         \
-               : "d" (sizeof(*(ptr))), "a" (ptr),              \
-                 "K" (-EFAULT)                                 \
-               : __uaccess_clobber );                          \
-})
-#else
-#define __get_user_asm(x, ptr, err) \
-({                                                             \
-       err = 0;                                                \
-       asm volatile (                                          \
-               "0: mvcp  0(%2,%5),0(%3),%0\n"                  \
-               "1:\n"                                          \
-               __uaccess_fixup                                 \
-               : "+&d" (err), "=m" (x)                         \
-               : "d" (sizeof(*(ptr))), "a" (ptr),              \
-                 "K" (-EFAULT), "a" (&(x))                     \
-               : __uaccess_clobber );                          \
-})
-#endif
-
 #define __get_user(x, ptr)                                     \
 ({                                                             \
-       int __gu_err;                                           \
-        __chk_user_ptr(ptr);                                    \
+       int __gu_err = -EFAULT;                                 \
+       __chk_user_ptr(ptr);                                    \
        switch (sizeof(*(ptr))) {                               \
        case 1: {                                               \
                unsigned char __x;                              \
-               __get_user_asm(__x, ptr, __gu_err);             \
+               __gu_err = __get_user_fn(sizeof (*(ptr)),       \
+                                        ptr, &__x);            \
                (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
                break;                                          \
        };                                                      \
        case 2: {                                               \
                unsigned short __x;                             \
-               __get_user_asm(__x, ptr, __gu_err);             \
+               __gu_err = __get_user_fn(sizeof (*(ptr)),       \
+                                        ptr, &__x);            \
                (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
                break;                                          \
        };                                                      \
        case 4: {                                               \
                unsigned int __x;                               \
-               __get_user_asm(__x, ptr, __gu_err);             \
+               __gu_err = __get_user_fn(sizeof (*(ptr)),       \
+                                        ptr, &__x);            \
                (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
                break;                                          \
        };                                                      \
        case 8: {                                               \
                unsigned long long __x;                         \
-               __get_user_asm(__x, ptr, __gu_err);             \
+               __gu_err = __get_user_fn(sizeof (*(ptr)),       \
+                                        ptr, &__x);            \
                (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
                break;                                          \
        };                                                      \
@@ -247,8 +197,6 @@ extern int __get_user_bad(void) __attribute__((noreturn));
 #define __put_user_unaligned __put_user
 #define __get_user_unaligned __get_user
 
-extern long __copy_to_user_asm(const void *from, long n, void __user *to);
-
 /**
  * __copy_to_user: - Copy a block of data into user space, with less checking.
  * @to:   Destination address, in user space.
@@ -266,7 +214,10 @@ extern long __copy_to_user_asm(const void *from, long n, void __user *to);
 static inline unsigned long
 __copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-       return __copy_to_user_asm(from, n, to);
+       if (__builtin_constant_p(n) && (n <= 256))
+               return uaccess.copy_to_user_small(n, to, from);
+       else
+               return uaccess.copy_to_user(n, to, from);
 }
 
 #define __copy_to_user_inatomic __copy_to_user
@@ -294,8 +245,6 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
        return n;
 }
 
-extern long __copy_from_user_asm(void *to, long n, const void __user *from);
-
 /**
  * __copy_from_user: - Copy a block of data from user space, with less checking.
  * @to:   Destination address, in kernel space.
@@ -316,7 +265,10 @@ extern long __copy_from_user_asm(void *to, long n, const void __user *from);
 static inline unsigned long
 __copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-       return __copy_from_user_asm(to, n, from);
+       if (__builtin_constant_p(n) && (n <= 256))
+               return uaccess.copy_from_user_small(n, from, to);
+       else
+               return uaccess.copy_from_user(n, from, to);
 }
 
 /**
@@ -346,13 +298,10 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
        return n;
 }
 
-extern unsigned long __copy_in_user_asm(const void __user *from, long n,
-                                                       void __user *to);
-
 static inline unsigned long
 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
 {
-       return __copy_in_user_asm(from, n, to);
+       return uaccess.copy_in_user(n, to, from);
 }
 
 static inline unsigned long
@@ -360,34 +309,28 @@ copy_in_user(void __user *to, const void __user *from, unsigned long n)
 {
        might_sleep();
        if (__access_ok(from,n) && __access_ok(to,n))
-               n = __copy_in_user_asm(from, n, to);
+               n = __copy_in_user(to, from, n);
        return n;
 }
 
 /*
  * Copy a null terminated string from userspace.
  */
-extern long __strncpy_from_user_asm(long count, char *dst,
-                                       const char __user *src);
-
 static inline long
 strncpy_from_user(char *dst, const char __user *src, long count)
 {
         long res = -EFAULT;
         might_sleep();
         if (access_ok(VERIFY_READ, src, 1))
-                res = __strncpy_from_user_asm(count, dst, src);
+               res = uaccess.strncpy_from_user(count, src, dst);
         return res;
 }
 
-
-extern long __strnlen_user_asm(long count, const char __user *src);
-
 static inline unsigned long
 strnlen_user(const char __user * src, unsigned long n)
 {
        might_sleep();
-       return __strnlen_user_asm(n, src);
+       return uaccess.strnlen_user(n, src);
 }
 
 /**
@@ -410,12 +353,10 @@ strnlen_user(const char __user * src, unsigned long n)
  * Zero Userspace
  */
 
-extern long __clear_user_asm(void __user *to, long n);
-
 static inline unsigned long
 __clear_user(void __user *to, unsigned long n)
 {
-       return __clear_user_asm(to, n);
+       return uaccess.clear_user(n, to);
 }
 
 static inline unsigned long
@@ -423,7 +364,7 @@ clear_user(void __user *to, unsigned long n)
 {
        might_sleep();
        if (access_ok(VERIFY_WRITE, to, n))
-               n = __clear_user_asm(to, n);
+               n = uaccess.clear_user(n, to);
        return n;
 }