linux-kernel - [PATCH v2] sh: Implement __get_user_u64() required for 64-bit get

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Date:   Sun, 31 May 2020 12:47:16 +0200
From:   John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>
To:     linux-sh@...r.kernel.org
Cc:     Rich Felker <dalias@...c.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Michael Karcher <kernel@...rcher.dialup.fu-berlin.de>,
        linux-kernel@...r.kernel.org,
        John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>
Subject: [PATCH v2] sh: Implement __get_user_u64() required for 64-bit get_user()

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@...sik.fu-berlin.de>
---
 arch/sh/include/asm/uaccess_32.h | 51 ++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

 Changes since v1:
 - Replace single mov instruction for exception handling
   in case of invalid load

diff --git a/arch/sh/include/asm/uaccess_32.h b/arch/sh/include/asm/uaccess_32.h
index 624cf55acc27..35f6c1e40ec3 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 +69,54 @@ 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,%R1\n\t"   \
+	"mov  #0,%S1\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,%S1\n\t"   \
+	"mov  #0,%R1\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