From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Thu, 17 Apr 2014 12:16:03 +0000 (+0200)
Subject: s390/uaccess: provide inline variants of get_user/put_user
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c9ca78415ac1cbb0e9846111d5f01376266cf6f3;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

s390/uaccess: provide inline variants of get_user/put_user

This shortens the code by ~17k (performace_defconfig, march=z196).
The number of exception table entries however increases from 164
entries to 2500 entries (+~18k).
However the executed code is shorter and also faster since we save
the branches to the out-of-line copy_to/from_user implementations.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 1be64a1506d0..cd4c68e0398d 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -132,6 +132,34 @@ unsigned long __must_check __copy_to_user(void __user *to, const void *from,
 #define __copy_to_user_inatomic __copy_to_user
 #define __copy_from_user_inatomic __copy_from_user
 
+#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
+
+#define __put_get_user_asm(to, from, size, spec)		\
+({								\
+	register unsigned long __reg0 asm("0") = spec;		\
+	int __rc;						\
+								\
+	asm volatile(						\
+		"0:	mvcos	%1,%3,%2\n"			\
+		"1:	xr	%0,%0\n"			\
+		"2:\n"						\
+		".pushsection .fixup, \"ax\"\n"			\
+		"3:	lhi	%0,%5\n"			\
+		"	jg	2b\n"				\
+		".popsection\n"					\
+		EX_TABLE(0b,3b) EX_TABLE(1b,3b)			\
+		: "=d" (__rc), "=Q" (*(to))			\
+		: "d" (size), "Q" (*(from)),			\
+		  "d" (__reg0), "K" (-EFAULT)			\
+		: "cc");					\
+	__rc;							\
+})
+
+#define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL)
+#define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL)
+
+#else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
+
 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 {
 	size = __copy_to_user(ptr, x, size);
@@ -144,6 +172,8 @@ static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long s
 	return size ? -EFAULT : 0;
 }
 
+#endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
+
 /*
  * These are the main single-value transfer routines.  They automatically
  * use the right size if we just have the right pointer type.