(no subject)

[John Paul Adrian Glaubitz]

Hi!

This is my attempt of implementing a 64-bit get_user() for SH to address the
build problem when CONFIG_INFINIBAND_USER_ACCESS is enabled.

I have carefully looked at the existing implementations of __get_user_asm(),
__put_user_asm() and the 64-bit __put_user_u64() to come up with the 64-bit
__get_user_u64().

I'm admittedly not an expert when it comes to writing GCC contraints, so the
code might be completely wrong. However, it builds fine without warnings
and fixes the aforementioned issue for me.

Hopefully someone from the more experienced group of kernel developers can
review my code and help me get it into proper shape for submission.

Thanks,
Adrian

--
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

[PATCH] sh: Implement __get_user_u64() required for 64-bit get_user()

[John Paul Adrian Glaubitz]

Trying to build the kernel with CONFIG_INFINIBAND_USER_ACCESS enabled fails

     ERROR: "__get_user_unknown" [drivers/infiniband/core/ib_uverbs.ko] undefined!

with on SH since the kernel misses a 64-bit implementation of get_user().

Implement the missing 64-bit get_user() as __get_user_u64(), matching the
already existing __put_user_u64() which implements the 64-bit put_user().

Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
---
 arch/sh/include/asm/uaccess_32.h | 49 ++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/arch/sh/include/asm/uaccess_32.h b/arch/sh/include/asm/uaccess_32.h
index 624cf55acc27..8bc1cb50f8bf 100644
--- a/arch/sh/include/asm/uaccess_32.h
+++ b/arch/sh/include/asm/uaccess_32.h
@@ -26,6 +26,9 @@ do {								\
 	case 4:							\
 		__get_user_asm(x, ptr, retval, "l");		\
 		break;						\
+	case 8:							\
+		__get_user_u64(x, ptr, retval);			\
+		break;						\
 	default:						\
 		__get_user_unknown();				\
 		break;						\
@@ -66,6 +69,52 @@ do {							\
 
 extern void __get_user_unknown(void);
 
+#if defined(CONFIG_CPU_LITTLE_ENDIAN)
+#define __get_user_u64(x, addr, err) \
+({ \
+__asm__ __volatile__( \
+	"1:\n\t" \
+	"mov.l	%2,%R1\n\t" \
+	"mov.l	%T2,%S1\n\t" \
+	"2:\n" \
+	".section	.fixup,\"ax\"\n" \
+	"3:\n\t" \
+	"mov	#0, %1\n\t" \
+	"mov.l	4f, %0\n\t" \
+	"jmp	@%0\n\t" \
+	" mov	%3, %0\n\t" \
+	".balign	4\n" \
+	"4:	.long	2b\n\t" \
+	".previous\n" \
+	".section	__ex_table,\"a\"\n\t" \
+	".long	1b, 3b\n\t" \
+	".previous" \
+	:"=&r" (err), "=&r" (x) \
+	:"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
+#else
+#define __get_user_u64(x, addr, err) \
+({ \
+__asm__ __volatile__( \
+	"1:\n\t" \
+	"mov.l	%2,%S1\n\t" \
+	"mov.l	%T2,%R1\n\t" \
+	"2:\n" \
+	".section	.fixup,\"ax\"\n" \
+	"3:\n\t" \
+	"mov	#0, %1\n\t" \
+	"mov.l	4f, %0\n\t" \
+	"jmp	@%0\n\t" \
+	" mov	%3, %0\n\t" \
+	".balign	4\n" \
+	"4:	.long	2b\n\t" \
+	".previous\n" \
+	".section	__ex_table,\"a\"\n\t" \
+	".long	1b, 3b\n\t" \
+	".previous" \
+	:"=&r" (err), "=&r" (x) \
+	:"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
+#endif
+
 #define __put_user_size(x,ptr,size,retval)		\
 do {							\
 	retval = 0;					\
-- 
2.27.0.rc2