v4.19.13 snapshot.
diff --git a/arch/x86/lib/string_32.c b/arch/x86/lib/string_32.c
new file mode 100644
index 0000000..d15fdae
--- /dev/null
+++ b/arch/x86/lib/string_32.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Most of the string-functions are rather heavily hand-optimized,
+ * see especially strsep,strstr,str[c]spn. They should work, but are not
+ * very easy to understand. Everything is done entirely within the register
+ * set, making the functions fast and clean. String instructions have been
+ * used through-out, making for "slightly" unclear code :-)
+ *
+ * AK: On P4 and K7 using non string instruction implementations might be faster
+ * for large memory blocks. But most of them are unlikely to be used on large
+ * strings.
+ */
+
+#include <linux/string.h>
+#include <linux/export.h>
+
+#ifdef __HAVE_ARCH_STRCPY
+char *strcpy(char *dest, const char *src)
+{
+ int d0, d1, d2;
+ asm volatile("1:\tlodsb\n\t"
+ "stosb\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b"
+ : "=&S" (d0), "=&D" (d1), "=&a" (d2)
+ : "0" (src), "1" (dest) : "memory");
+ return dest;
+}
+EXPORT_SYMBOL(strcpy);
+#endif
+
+#ifdef __HAVE_ARCH_STRNCPY
+char *strncpy(char *dest, const char *src, size_t count)
+{
+ int d0, d1, d2, d3;
+ asm volatile("1:\tdecl %2\n\t"
+ "js 2f\n\t"
+ "lodsb\n\t"
+ "stosb\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b\n\t"
+ "rep\n\t"
+ "stosb\n"
+ "2:"
+ : "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
+ : "0" (src), "1" (dest), "2" (count) : "memory");
+ return dest;
+}
+EXPORT_SYMBOL(strncpy);
+#endif
+
+#ifdef __HAVE_ARCH_STRCAT
+char *strcat(char *dest, const char *src)
+{
+ int d0, d1, d2, d3;
+ asm volatile("repne\n\t"
+ "scasb\n\t"
+ "decl %1\n"
+ "1:\tlodsb\n\t"
+ "stosb\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b"
+ : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
+ : "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu) : "memory");
+ return dest;
+}
+EXPORT_SYMBOL(strcat);
+#endif
+
+#ifdef __HAVE_ARCH_STRNCAT
+char *strncat(char *dest, const char *src, size_t count)
+{
+ int d0, d1, d2, d3;
+ asm volatile("repne\n\t"
+ "scasb\n\t"
+ "decl %1\n\t"
+ "movl %8,%3\n"
+ "1:\tdecl %3\n\t"
+ "js 2f\n\t"
+ "lodsb\n\t"
+ "stosb\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b\n"
+ "2:\txorl %2,%2\n\t"
+ "stosb"
+ : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
+ : "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu), "g" (count)
+ : "memory");
+ return dest;
+}
+EXPORT_SYMBOL(strncat);
+#endif
+
+#ifdef __HAVE_ARCH_STRCMP
+int strcmp(const char *cs, const char *ct)
+{
+ int d0, d1;
+ int res;
+ asm volatile("1:\tlodsb\n\t"
+ "scasb\n\t"
+ "jne 2f\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b\n\t"
+ "xorl %%eax,%%eax\n\t"
+ "jmp 3f\n"
+ "2:\tsbbl %%eax,%%eax\n\t"
+ "orb $1,%%al\n"
+ "3:"
+ : "=a" (res), "=&S" (d0), "=&D" (d1)
+ : "1" (cs), "2" (ct)
+ : "memory");
+ return res;
+}
+EXPORT_SYMBOL(strcmp);
+#endif
+
+#ifdef __HAVE_ARCH_STRNCMP
+int strncmp(const char *cs, const char *ct, size_t count)
+{
+ int res;
+ int d0, d1, d2;
+ asm volatile("1:\tdecl %3\n\t"
+ "js 2f\n\t"
+ "lodsb\n\t"
+ "scasb\n\t"
+ "jne 3f\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b\n"
+ "2:\txorl %%eax,%%eax\n\t"
+ "jmp 4f\n"
+ "3:\tsbbl %%eax,%%eax\n\t"
+ "orb $1,%%al\n"
+ "4:"
+ : "=a" (res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
+ : "1" (cs), "2" (ct), "3" (count)
+ : "memory");
+ return res;
+}
+EXPORT_SYMBOL(strncmp);
+#endif
+
+#ifdef __HAVE_ARCH_STRCHR
+char *strchr(const char *s, int c)
+{
+ int d0;
+ char *res;
+ asm volatile("movb %%al,%%ah\n"
+ "1:\tlodsb\n\t"
+ "cmpb %%ah,%%al\n\t"
+ "je 2f\n\t"
+ "testb %%al,%%al\n\t"
+ "jne 1b\n\t"
+ "movl $1,%1\n"
+ "2:\tmovl %1,%0\n\t"
+ "decl %0"
+ : "=a" (res), "=&S" (d0)
+ : "1" (s), "0" (c)
+ : "memory");
+ return res;
+}
+EXPORT_SYMBOL(strchr);
+#endif
+
+#ifdef __HAVE_ARCH_STRLEN
+size_t strlen(const char *s)
+{
+ int d0;
+ size_t res;
+ asm volatile("repne\n\t"
+ "scasb"
+ : "=c" (res), "=&D" (d0)
+ : "1" (s), "a" (0), "0" (0xffffffffu)
+ : "memory");
+ return ~res - 1;
+}
+EXPORT_SYMBOL(strlen);
+#endif
+
+#ifdef __HAVE_ARCH_MEMCHR
+void *memchr(const void *cs, int c, size_t count)
+{
+ int d0;
+ void *res;
+ if (!count)
+ return NULL;
+ asm volatile("repne\n\t"
+ "scasb\n\t"
+ "je 1f\n\t"
+ "movl $1,%0\n"
+ "1:\tdecl %0"
+ : "=D" (res), "=&c" (d0)
+ : "a" (c), "0" (cs), "1" (count)
+ : "memory");
+ return res;
+}
+EXPORT_SYMBOL(memchr);
+#endif
+
+#ifdef __HAVE_ARCH_MEMSCAN
+void *memscan(void *addr, int c, size_t size)
+{
+ if (!size)
+ return addr;
+ asm volatile("repnz; scasb\n\t"
+ "jnz 1f\n\t"
+ "dec %%edi\n"
+ "1:"
+ : "=D" (addr), "=c" (size)
+ : "0" (addr), "1" (size), "a" (c)
+ : "memory");
+ return addr;
+}
+EXPORT_SYMBOL(memscan);
+#endif
+
+#ifdef __HAVE_ARCH_STRNLEN
+size_t strnlen(const char *s, size_t count)
+{
+ int d0;
+ int res;
+ asm volatile("movl %2,%0\n\t"
+ "jmp 2f\n"
+ "1:\tcmpb $0,(%0)\n\t"
+ "je 3f\n\t"
+ "incl %0\n"
+ "2:\tdecl %1\n\t"
+ "cmpl $-1,%1\n\t"
+ "jne 1b\n"
+ "3:\tsubl %2,%0"
+ : "=a" (res), "=&d" (d0)
+ : "c" (s), "1" (count)
+ : "memory");
+ return res;
+}
+EXPORT_SYMBOL(strnlen);
+#endif