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-rw-r--r--arch/s390/lib/uaccess.c448
1 files changed, 448 insertions, 0 deletions
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
new file mode 100644
index 000000000..fcfd78f99
--- /dev/null
+++ b/arch/s390/lib/uaccess.c
@@ -0,0 +1,448 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Standard user space access functions based on mvcp/mvcs and doing
+ * interesting things in the secondary space mode.
+ *
+ * Copyright IBM Corp. 2006,2014
+ * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ * Gerald Schaefer (gerald.schaefer@de.ibm.com)
+ */
+
+#include <linux/jump_label.h>
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <asm/mmu_context.h>
+#include <asm/facility.h>
+
+#ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
+static DEFINE_STATIC_KEY_FALSE(have_mvcos);
+
+static int __init uaccess_init(void)
+{
+ if (test_facility(27))
+ static_branch_enable(&have_mvcos);
+ return 0;
+}
+early_initcall(uaccess_init);
+
+static inline int copy_with_mvcos(void)
+{
+ if (static_branch_likely(&have_mvcos))
+ return 1;
+ return 0;
+}
+#else
+static inline int copy_with_mvcos(void)
+{
+ return 1;
+}
+#endif
+
+void set_fs(mm_segment_t fs)
+{
+ current->thread.mm_segment = fs;
+ if (fs == USER_DS) {
+ __ctl_load(S390_lowcore.user_asce, 1, 1);
+ clear_cpu_flag(CIF_ASCE_PRIMARY);
+ } else {
+ __ctl_load(S390_lowcore.kernel_asce, 1, 1);
+ set_cpu_flag(CIF_ASCE_PRIMARY);
+ }
+ if (fs & 1) {
+ if (fs == USER_DS_SACF)
+ __ctl_load(S390_lowcore.user_asce, 7, 7);
+ else
+ __ctl_load(S390_lowcore.kernel_asce, 7, 7);
+ set_cpu_flag(CIF_ASCE_SECONDARY);
+ }
+}
+EXPORT_SYMBOL(set_fs);
+
+mm_segment_t enable_sacf_uaccess(void)
+{
+ mm_segment_t old_fs;
+ unsigned long asce, cr;
+ unsigned long flags;
+
+ old_fs = current->thread.mm_segment;
+ if (old_fs & 1)
+ return old_fs;
+ /* protect against a concurrent page table upgrade */
+ local_irq_save(flags);
+ current->thread.mm_segment |= 1;
+ asce = S390_lowcore.kernel_asce;
+ if (likely(old_fs == USER_DS)) {
+ __ctl_store(cr, 1, 1);
+ if (cr != S390_lowcore.kernel_asce) {
+ __ctl_load(S390_lowcore.kernel_asce, 1, 1);
+ set_cpu_flag(CIF_ASCE_PRIMARY);
+ }
+ asce = S390_lowcore.user_asce;
+ }
+ __ctl_store(cr, 7, 7);
+ if (cr != asce) {
+ __ctl_load(asce, 7, 7);
+ set_cpu_flag(CIF_ASCE_SECONDARY);
+ }
+ local_irq_restore(flags);
+ return old_fs;
+}
+EXPORT_SYMBOL(enable_sacf_uaccess);
+
+void disable_sacf_uaccess(mm_segment_t old_fs)
+{
+ current->thread.mm_segment = old_fs;
+ if (old_fs == USER_DS && test_facility(27)) {
+ __ctl_load(S390_lowcore.user_asce, 1, 1);
+ clear_cpu_flag(CIF_ASCE_PRIMARY);
+ }
+}
+EXPORT_SYMBOL(disable_sacf_uaccess);
+
+static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
+ unsigned long size)
+{
+ register unsigned long reg0 asm("0") = 0x01UL;
+ unsigned long tmp1, tmp2;
+
+ tmp1 = -4096UL;
+ asm volatile(
+ "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
+ "6: jz 4f\n"
+ "1: algr %0,%3\n"
+ " slgr %1,%3\n"
+ " slgr %2,%3\n"
+ " j 0b\n"
+ "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
+ " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
+ " slgr %4,%1\n"
+ " clgr %0,%4\n" /* copy crosses next page boundary? */
+ " jnh 5f\n"
+ "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
+ "7: slgr %0,%4\n"
+ " j 5f\n"
+ "4: slgr %0,%0\n"
+ "5:\n"
+ EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
+ : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+ : "d" (reg0) : "cc", "memory");
+ return size;
+}
+
+static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
+ unsigned long size)
+{
+ unsigned long tmp1, tmp2;
+ mm_segment_t old_fs;
+
+ old_fs = enable_sacf_uaccess();
+ tmp1 = -256UL;
+ asm volatile(
+ " sacf 0\n"
+ "0: mvcp 0(%0,%2),0(%1),%3\n"
+ "7: jz 5f\n"
+ "1: algr %0,%3\n"
+ " la %1,256(%1)\n"
+ " la %2,256(%2)\n"
+ "2: mvcp 0(%0,%2),0(%1),%3\n"
+ "8: jnz 1b\n"
+ " j 5f\n"
+ "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
+ " lghi %3,-4096\n"
+ " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
+ " slgr %4,%1\n"
+ " clgr %0,%4\n" /* copy crosses next page boundary? */
+ " jnh 6f\n"
+ "4: mvcp 0(%4,%2),0(%1),%3\n"
+ "9: slgr %0,%4\n"
+ " j 6f\n"
+ "5: slgr %0,%0\n"
+ "6: sacf 768\n"
+ EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
+ EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
+ : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+ : : "cc", "memory");
+ disable_sacf_uaccess(old_fs);
+ return size;
+}
+
+unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ if (copy_with_mvcos())
+ return copy_from_user_mvcos(to, from, n);
+ return copy_from_user_mvcp(to, from, n);
+}
+EXPORT_SYMBOL(raw_copy_from_user);
+
+static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
+ unsigned long size)
+{
+ register unsigned long reg0 asm("0") = 0x010000UL;
+ unsigned long tmp1, tmp2;
+
+ tmp1 = -4096UL;
+ asm volatile(
+ "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
+ "6: jz 4f\n"
+ "1: algr %0,%3\n"
+ " slgr %1,%3\n"
+ " slgr %2,%3\n"
+ " j 0b\n"
+ "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
+ " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
+ " slgr %4,%1\n"
+ " clgr %0,%4\n" /* copy crosses next page boundary? */
+ " jnh 5f\n"
+ "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
+ "7: slgr %0,%4\n"
+ " j 5f\n"
+ "4: slgr %0,%0\n"
+ "5:\n"
+ EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
+ : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+ : "d" (reg0) : "cc", "memory");
+ return size;
+}
+
+static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
+ unsigned long size)
+{
+ unsigned long tmp1, tmp2;
+ mm_segment_t old_fs;
+
+ old_fs = enable_sacf_uaccess();
+ tmp1 = -256UL;
+ asm volatile(
+ " sacf 0\n"
+ "0: mvcs 0(%0,%1),0(%2),%3\n"
+ "7: jz 5f\n"
+ "1: algr %0,%3\n"
+ " la %1,256(%1)\n"
+ " la %2,256(%2)\n"
+ "2: mvcs 0(%0,%1),0(%2),%3\n"
+ "8: jnz 1b\n"
+ " j 5f\n"
+ "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
+ " lghi %3,-4096\n"
+ " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
+ " slgr %4,%1\n"
+ " clgr %0,%4\n" /* copy crosses next page boundary? */
+ " jnh 6f\n"
+ "4: mvcs 0(%4,%1),0(%2),%3\n"
+ "9: slgr %0,%4\n"
+ " j 6f\n"
+ "5: slgr %0,%0\n"
+ "6: sacf 768\n"
+ EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
+ EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
+ : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
+ : : "cc", "memory");
+ disable_sacf_uaccess(old_fs);
+ return size;
+}
+
+unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ if (copy_with_mvcos())
+ return copy_to_user_mvcos(to, from, n);
+ return copy_to_user_mvcs(to, from, n);
+}
+EXPORT_SYMBOL(raw_copy_to_user);
+
+static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
+ unsigned long size)
+{
+ register unsigned long reg0 asm("0") = 0x010001UL;
+ 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: algr %0,%3\n"
+ " slgr %1,%3\n"
+ " slgr %2,%3\n"
+ " j 0b\n"
+ "2:slgr %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;
+}
+
+static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
+ unsigned long size)
+{
+ mm_segment_t old_fs;
+ unsigned long tmp1;
+
+ old_fs = enable_sacf_uaccess();
+ asm volatile(
+ " sacf 256\n"
+ " aghi %0,-1\n"
+ " jo 5f\n"
+ " bras %3,3f\n"
+ "0: aghi %0,257\n"
+ "1: mvc 0(1,%1),0(%2)\n"
+ " la %1,1(%1)\n"
+ " la %2,1(%2)\n"
+ " aghi %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: aghi %0,-256\n"
+ " jnm 2b\n"
+ "4: ex %0,1b-0b(%3)\n"
+ "5: slgr %0,%0\n"
+ "6: sacf 768\n"
+ EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+ : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
+ : : "cc", "memory");
+ disable_sacf_uaccess(old_fs);
+ return size;
+}
+
+unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
+{
+ if (copy_with_mvcos())
+ return copy_in_user_mvcos(to, from, n);
+ return copy_in_user_mvc(to, from, n);
+}
+EXPORT_SYMBOL(raw_copy_in_user);
+
+static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
+{
+ register unsigned long reg0 asm("0") = 0x010000UL;
+ unsigned long tmp1, tmp2;
+
+ tmp1 = -4096UL;
+ asm volatile(
+ "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
+ " jz 4f\n"
+ "1: algr %0,%2\n"
+ " slgr %1,%2\n"
+ " j 0b\n"
+ "2: la %3,4095(%1)\n"/* %4 = to + 4095 */
+ " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
+ " slgr %3,%1\n"
+ " clgr %0,%3\n" /* copy crosses next page boundary? */
+ " jnh 5f\n"
+ "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
+ " slgr %0,%3\n"
+ " j 5f\n"
+ "4: slgr %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;
+}
+
+static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
+{
+ mm_segment_t old_fs;
+ unsigned long tmp1, tmp2;
+
+ old_fs = enable_sacf_uaccess();
+ asm volatile(
+ " sacf 256\n"
+ " aghi %0,-1\n"
+ " jo 5f\n"
+ " bras %3,3f\n"
+ " xc 0(1,%1),0(%1)\n"
+ "0: aghi %0,257\n"
+ " la %2,255(%1)\n" /* %2 = ptr + 255 */
+ " srl %2,12\n"
+ " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
+ " slgr %2,%1\n"
+ " clgr %0,%2\n" /* clear crosses next page boundary? */
+ " jnh 5f\n"
+ " aghi %2,-1\n"
+ "1: ex %2,0(%3)\n"
+ " aghi %2,1\n"
+ " slgr %0,%2\n"
+ " j 5f\n"
+ "2: xc 0(256,%1),0(%1)\n"
+ " la %1,256(%1)\n"
+ "3: aghi %0,-256\n"
+ " jnm 2b\n"
+ "4: ex %0,0(%3)\n"
+ "5: slgr %0,%0\n"
+ "6: sacf 768\n"
+ EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
+ : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
+ : : "cc", "memory");
+ disable_sacf_uaccess(old_fs);
+ return size;
+}
+
+unsigned long __clear_user(void __user *to, unsigned long size)
+{
+ if (copy_with_mvcos())
+ return clear_user_mvcos(to, size);
+ return clear_user_xc(to, size);
+}
+EXPORT_SYMBOL(__clear_user);
+
+static inline unsigned long strnlen_user_srst(const char __user *src,
+ unsigned long size)
+{
+ register unsigned long reg0 asm("0") = 0;
+ unsigned long tmp1, tmp2;
+
+ asm volatile(
+ " la %2,0(%1)\n"
+ " la %3,0(%0,%1)\n"
+ " slgr %0,%0\n"
+ " sacf 256\n"
+ "0: srst %3,%2\n"
+ " jo 0b\n"
+ " la %0,1(%3)\n" /* strnlen_user results includes \0 */
+ " slgr %0,%1\n"
+ "1: sacf 768\n"
+ EX_TABLE(0b,1b)
+ : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
+ : "d" (reg0) : "cc", "memory");
+ return size;
+}
+
+unsigned long __strnlen_user(const char __user *src, unsigned long size)
+{
+ mm_segment_t old_fs;
+ unsigned long len;
+
+ if (unlikely(!size))
+ return 0;
+ old_fs = enable_sacf_uaccess();
+ len = strnlen_user_srst(src, size);
+ disable_sacf_uaccess(old_fs);
+ return len;
+}
+EXPORT_SYMBOL(__strnlen_user);
+
+long __strncpy_from_user(char *dst, const char __user *src, long size)
+{
+ size_t done, len, offset, len_str;
+
+ if (unlikely(size <= 0))
+ return 0;
+ done = 0;
+ do {
+ offset = (size_t)src & (L1_CACHE_BYTES - 1);
+ len = min(size - done, L1_CACHE_BYTES - offset);
+ if (copy_from_user(dst, src, len))
+ return -EFAULT;
+ len_str = strnlen(dst, len);
+ done += len_str;
+ src += len_str;
+ dst += len_str;
+ } while ((len_str == len) && (done < size));
+ return done;
+}
+EXPORT_SYMBOL(__strncpy_from_user);
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