[S390] Use alternative user-copy operations for new hardware.

This introduces new user-copy operations which are optimized for
copying more than 256 Bytes on new hardware.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

4 files changed, 175 insertions, 1 deletions

diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 1ebaa338aa7e..a8bdd96494c7 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -250,6 +250,19 @@ startup_continue:
         oi      7(%r12),0x80            # set IDTE flag
 0:
 
+#
+# find out if we have the MVCOS instruction
+#
+        la      %r1,0f-.LPG1(%r13)      # set program check address
+        stg     %r1,__LC_PGM_NEW_PSW+8
+        .short  0xc800                  # mvcos 0(%r0),0(%r0),%r0
+        .short  0x0000
+        .short  0x0000
+0:      tm      0x8f,0x13               # special-operation exception?
+        bno     1f-.LPG1(%r13)          # if yes, MVCOS is present
+        oi      6(%r12),2               # set MVCOS flag
+1:
+
         lpswe .Lentry-.LPG1(13)         # jump to _stext in primary-space,
                                         # virtual and never return ...
         .align 16
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index e229af59976c..e3d9325f6022 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -647,7 +647,11 @@ setup_arch(char **cmdline_p)
 
         memory_end = memory_size;
 
-        memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
+        if (MACHINE_HAS_MVCOS)
+                memcpy(&uaccess, &uaccess_mvcos, sizeof(uaccess));
+        else
+                memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
+
         parse_early_param();
 
 #ifndef CONFIG_64BIT
diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index 96c82424d88b..c42ffedfdb49 100644
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -5,4 +5,5 @@
 EXTRA_AFLAGS := -traditional
 
 lib-y += delay.o string.o uaccess_std.o
+lib-$(CONFIG_64BIT) += uaccess_mvcos.o
 lib-$(CONFIG_SMP) += spinlock.o
diff --git a/arch/s390/lib/uaccess_mvcos.c b/arch/s390/lib/uaccess_mvcos.c
new file mode 100644
index 000000000000..86c96d6c191a
--- /dev/null
+++ b/arch/s390/lib/uaccess_mvcos.c
@@ -0,0 +1,156 @@
+/*
+ *  arch/s390/lib/uaccess_mvcos.c
+ *
+ *  Optimized user space space access functions based on mvcos.
+ *
+ *    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_mvcos(size_t size, const void __user *ptr, void *x)
+{
+        register unsigned long reg0 asm("0") = 0x81UL;
+        unsigned long tmp1, tmp2;
+
+        tmp1 = -4096UL;
+        asm volatile(
+                "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
+                "   jz    4f\n"
+                "1:"ALR"  %0,%3\n"
+                "  "SLR"  %1,%3\n"
+                "  "SLR"  %2,%3\n"
+                "   j     0b\n"
+                "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
+                "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
+                "  "SLR"  %4,%1\n"
+                "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
+                "   jnh   5f\n"
+                "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
+                "  "SLR"  %0,%4\n"
+                "   j     5f\n"
+                "4:"SLR"  %0,%0\n"
+                "5: \n"
+                EX_TABLE(0b,2b) EX_TABLE(3b,5b)
+                : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+                : "d" (reg0) : "cc", "memory");
+        return size;
+}
+
+size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
+{
+        register unsigned long reg0 asm("0") = 0x810000UL;
+        unsigned long tmp1, tmp2;
+
+        tmp1 = -4096UL;
+        asm volatile(
+                "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
+                "   jz    4f\n"
+                "1:"ALR"  %0,%3\n"
+                "  "SLR"  %1,%3\n"
+                "  "SLR"  %2,%3\n"
+                "   j     0b\n"
+                "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
+                "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
+                "  "SLR"  %4,%1\n"
+                "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
+                "   jnh   5f\n"
+                "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
+                "  "SLR"  %0,%4\n"
+                "   j     5f\n"
+                "4:"SLR"  %0,%0\n"
+                "5: \n"
+                EX_TABLE(0b,2b) EX_TABLE(3b,5b)
+                : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+                : "d" (reg0) : "cc", "memory");
+        return size;
+}
+
+size_t copy_in_user_mvcos(size_t size, void __user *to, const void __user *from)
+{
+        register unsigned long reg0 asm("0") = 0x810081UL;
+        unsigned long tmp1, tmp2;
+
+        tmp1 = -4096UL;
+        /* FIXME: copy with reduced length. */
+        asm volatile(
+                "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
+                "   jz    2f\n"
+                "1:"ALR"  %0,%3\n"
+                "  "SLR"  %1,%3\n"
+                "  "SLR"  %2,%3\n"
+                "   j     0b\n"
+                "2:"SLR"  %0,%0\n"
+                "3: \n"
+                EX_TABLE(0b,3b)
+                : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
+                : "d" (reg0) : "cc", "memory");
+        return size;
+}
+
+size_t clear_user_mvcos(size_t size, void __user *to)
+{
+        register unsigned long reg0 asm("0") = 0x810000UL;
+        unsigned long tmp1, tmp2;
+
+        tmp1 = -4096UL;
+        asm volatile(
+                "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
+                "   jz    4f\n"
+                "1:"ALR"  %0,%2\n"
+                "  "SLR"  %1,%2\n"
+                "   j     0b\n"
+                "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
+                "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
+                "  "SLR"  %3,%1\n"
+                "  "CLR"  %0,%3\n"      /* copy crosses next page boundary? */
+                "   jnh   5f\n"
+                "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
+                "  "SLR"  %0,%3\n"
+                "   j     5f\n"
+                "4:"SLR"  %0,%0\n"
+                "5: \n"
+                EX_TABLE(0b,2b) EX_TABLE(3b,5b)
+                : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
+                : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
+        return size;
+}
+
+extern size_t copy_from_user_std_small(size_t, const void __user *, void *);
+extern size_t copy_to_user_std_small(size_t, void __user *, const void *);
+extern size_t strnlen_user_std(size_t, const char __user *);
+extern size_t strncpy_from_user_std(size_t, const char __user *, char *);
+extern int futex_atomic_op(int, int __user *, int, int *);
+extern int futex_atomic_cmpxchg(int __user *, int, int);
+
+struct uaccess_ops uaccess_mvcos = {
+        .copy_from_user = copy_from_user_mvcos,
+        .copy_from_user_small = copy_from_user_std_small,
+        .copy_to_user = copy_to_user_mvcos,
+        .copy_to_user_small = copy_to_user_std_small,
+        .copy_in_user = copy_in_user_mvcos,
+        .clear_user = clear_user_mvcos,
+        .strnlen_user = strnlen_user_std,
+        .strncpy_from_user = strncpy_from_user_std,
+        .futex_atomic_op = futex_atomic_op,
+        .futex_atomic_cmpxchg = futex_atomic_cmpxchg,
+};