Fixed MTP to work with TWRP

arch/x86/include/asm/checksum_32.h

@@ -0,0 +1,202 @@
+#ifndef _ASM_X86_CHECKSUM_32_H
+#define _ASM_X86_CHECKSUM_32_H
+
+#include <linux/in6.h>
+
+#include <asm/uaccess.h>
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
+
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums, and handles user-space pointer exceptions correctly, when needed.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+
+asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
+					    int len, __wsum sum,
+					    int *src_err_ptr, int *dst_err_ptr);
+
+/*
+ *	Note: when you get a NULL pointer exception here this means someone
+ *	passed in an incorrect kernel address to one of these functions.
+ *
+ *	If you use these functions directly please don't forget the
+ *	access_ok().
+ */
+static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst,
+					       int len, __wsum sum)
+{
+	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
+}
+
+static inline __wsum csum_partial_copy_from_user(const void __user *src,
+						 void *dst,
+						 int len, __wsum sum,
+						 int *err_ptr)
+{
+	__wsum ret;
+
+	might_sleep();
+	stac();
+	ret = csum_partial_copy_generic((__force void *)src, dst,
+					len, sum, err_ptr, NULL);
+	clac();
+
+	return ret;
+}
+
+/*
+ *	This is a version of ip_compute_csum() optimized for IP headers,
+ *	which always checksum on 4 octet boundaries.
+ *
+ *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
+ *	Arnt Gulbrandsen.
+ */
+static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
+{
+	unsigned int sum;
+
+	asm volatile("movl (%1), %0	;\n"
+		     "subl $4, %2	;\n"
+		     "jbe 2f		;\n"
+		     "addl 4(%1), %0	;\n"
+		     "adcl 8(%1), %0	;\n"
+		     "adcl 12(%1), %0;\n"
+		     "1:	adcl 16(%1), %0	;\n"
+		     "lea 4(%1), %1	;\n"
+		     "decl %2	;\n"
+		     "jne 1b		;\n"
+		     "adcl $0, %0	;\n"
+		     "movl %0, %2	;\n"
+		     "shrl $16, %0	;\n"
+		     "addw %w2, %w0	;\n"
+		     "adcl $0, %0	;\n"
+		     "notl %0	;\n"
+		     "2:		;\n"
+	/* Since the input registers which are loaded with iph and ihl
+	   are modified, we must also specify them as outputs, or gcc
+	   will assume they contain their original values. */
+		     : "=r" (sum), "=r" (iph), "=r" (ihl)
+		     : "1" (iph), "2" (ihl)
+		     : "memory");
+	return (__force __sum16)sum;
+}
+
+/*
+ *	Fold a partial checksum
+ */
+
+static inline __sum16 csum_fold(__wsum sum)
+{
+	asm("addl %1, %0		;\n"
+	    "adcl $0xffff, %0	;\n"
+	    : "=r" (sum)
+	    : "r" ((__force u32)sum << 16),
+	      "0" ((__force u32)sum & 0xffff0000));
+	return (__force __sum16)(~(__force u32)sum >> 16);
+}
+
+static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+					unsigned short len,
+					unsigned short proto,
+					__wsum sum)
+{
+	asm("addl %1, %0	;\n"
+	    "adcl %2, %0	;\n"
+	    "adcl %3, %0	;\n"
+	    "adcl $0, %0	;\n"
+	    : "=r" (sum)
+	    : "g" (daddr), "g"(saddr),
+	      "g" ((len + proto) << 8), "0" (sum));
+	return sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+					unsigned short len,
+					unsigned short proto,
+					__wsum sum)
+{
+	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+
+static inline __sum16 ip_compute_csum(const void *buff, int len)
+{
+    return csum_fold(csum_partial(buff, len, 0));
+}
+
+#define _HAVE_ARCH_IPV6_CSUM
+static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+				      const struct in6_addr *daddr,
+				      __u32 len, unsigned short proto,
+				      __wsum sum)
+{
+	asm("addl 0(%1), %0	;\n"
+	    "adcl 4(%1), %0	;\n"
+	    "adcl 8(%1), %0	;\n"
+	    "adcl 12(%1), %0	;\n"
+	    "adcl 0(%2), %0	;\n"
+	    "adcl 4(%2), %0	;\n"
+	    "adcl 8(%2), %0	;\n"
+	    "adcl 12(%2), %0	;\n"
+	    "adcl %3, %0	;\n"
+	    "adcl %4, %0	;\n"
+	    "adcl $0, %0	;\n"
+	    : "=&r" (sum)
+	    : "r" (saddr), "r" (daddr),
+	      "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
+	    : "memory");
+
+	return csum_fold(sum);
+}
+
+/*
+ *	Copy and checksum to user
+ */
+#define HAVE_CSUM_COPY_USER
+static inline __wsum csum_and_copy_to_user(const void *src,
+					   void __user *dst,
+					   int len, __wsum sum,
+					   int *err_ptr)
+{
+	__wsum ret;
+
+	might_sleep();
+	if (access_ok(VERIFY_WRITE, dst, len)) {
+		stac();
+		ret = csum_partial_copy_generic(src, (__force void *)dst,
+						len, sum, NULL, err_ptr);
+		clac();
+		return ret;
+	}
+
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return (__force __wsum)-1; /* invalid checksum */
+}
+
+#endif /* _ASM_X86_CHECKSUM_32_H */