asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch

Now we specify the minimal version of GCC as 5.1 and Clang/LLVM as 11.0.0
in Documentation/process/changes.rst, __CHAR_BIT__ and __SIZEOF_LONG__ are
usable, it is probably fine to unify the definition of __BITS_PER_LONG as
(__CHAR_BIT__ * __SIZEOF_LONG__) in asm-generic uapi bitsperlong.h.

In order to keep safe and avoid regression, only unify uapi bitsperlong.h
for some archs such as arm64, riscv and loongarch which are using newer
toolchains that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__.
Suggested-by: Xi Ruoyao <xry111@xry111.site>
Link: https://lore.kernel.org/all/d3e255e4746de44c9903c4433616d44ffcf18d1b.camel@xry111.site/Suggested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/linux-arch/a3a4f48a-07d4-4ed9-bc53-5d383428bdd2@app.fastmail.com/Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm64/include/uapi/asm/bitsperlong.h

-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/*
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_BITSPERLONG_H
-#define __ASM_BITSPERLONG_H
-
-#define __BITS_PER_LONG 64
-
-#include <asm-generic/bitsperlong.h>
-
-#endif	/* __ASM_BITSPERLONG_H */

arch/loongarch/include/uapi/asm/bitsperlong.h

-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef __ASM_LOONGARCH_BITSPERLONG_H
-#define __ASM_LOONGARCH_BITSPERLONG_H
-
-#define __BITS_PER_LONG (__SIZEOF_LONG__ * 8)
-
-#include <asm-generic/bitsperlong.h>
-
-#endif /* __ASM_LOONGARCH_BITSPERLONG_H */

arch/riscv/include/uapi/asm/bitsperlong.h

-/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
-/*
- * Copyright (C) 2012 ARM Ltd.
- * Copyright (C) 2015 Regents of the University of California
- */
-
-#ifndef _UAPI_ASM_RISCV_BITSPERLONG_H
-#define _UAPI_ASM_RISCV_BITSPERLONG_H
-
-#define __BITS_PER_LONG (__SIZEOF_POINTER__ * 8)
-
-#include <asm-generic/bitsperlong.h>
-
-#endif /* _UAPI_ASM_RISCV_BITSPERLONG_H */

include/uapi/asm-generic/bitsperlong.h

@@ -2,6 +2,17 @@
 #ifndef _UAPI__ASM_GENERIC_BITS_PER_LONG
 #define _UAPI__ASM_GENERIC_BITS_PER_LONG
 
+#ifndef __BITS_PER_LONG
+/*
+ * In order to keep safe and avoid regression, only unify uapi
+ * bitsperlong.h for some archs which are using newer toolchains
+ * that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__.
+ * See the following link for more info:
+ * https://lore.kernel.org/linux-arch/b9624545-2c80-49a1-ac3c-39264a591f7b@app.fastmail.com/
+ */
+#if defined(__CHAR_BIT__) && defined(__SIZEOF_LONG__)
+#define __BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__)
+#else
 /*
  * There seems to be no way of detecting this automatically from user
  * space, so 64 bit architectures should override this in their
@@ -9,8 +20,8 @@
  * both 32 and 64 bit user space must not rely on CONFIG_64BIT
  * to decide it, but rather check a compiler provided macro.
  */
-#ifndef __BITS_PER_LONG
 #define __BITS_PER_LONG 32
 #endif
+#endif
 
 #endif /* _UAPI__ASM_GENERIC_BITS_PER_LONG */

tools/arch/arm64/include/uapi/asm/bitsperlong.h

-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/*
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_BITSPERLONG_H
-#define __ASM_BITSPERLONG_H
-
-#define __BITS_PER_LONG 64
-
-#include <asm-generic/bitsperlong.h>
-
-#endif	/* __ASM_BITSPERLONG_H */

tools/arch/loongarch/include/uapi/asm/bitsperlong.h

-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef __ASM_LOONGARCH_BITSPERLONG_H
-#define __ASM_LOONGARCH_BITSPERLONG_H
-
-#define __BITS_PER_LONG (__SIZEOF_LONG__ * 8)
-
-#include <asm-generic/bitsperlong.h>
-
-#endif /* __ASM_LOONGARCH_BITSPERLONG_H */

tools/arch/riscv/include/uapi/asm/bitsperlong.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2012 ARM Ltd.
- * Copyright (C) 2015 Regents of the University of California
- */
-
-#ifndef _UAPI_ASM_RISCV_BITSPERLONG_H
-#define _UAPI_ASM_RISCV_BITSPERLONG_H
-
-#define __BITS_PER_LONG (__SIZEOF_POINTER__ * 8)
-
-#include <asm-generic/bitsperlong.h>
-
-#endif /* _UAPI_ASM_RISCV_BITSPERLONG_H */

tools/include/uapi/asm-generic/bitsperlong.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #ifndef _UAPI__ASM_GENERIC_BITS_PER_LONG
 #define _UAPI__ASM_GENERIC_BITS_PER_LONG
 
+#ifndef __BITS_PER_LONG
+/*
+ * In order to keep safe and avoid regression, only unify uapi
+ * bitsperlong.h for some archs which are using newer toolchains
+ * that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__.
+ * See the following link for more info:
+ * https://lore.kernel.org/linux-arch/b9624545-2c80-49a1-ac3c-39264a591f7b@app.fastmail.com/
+ */
+#if defined(__CHAR_BIT__) && defined(__SIZEOF_LONG__)
+#define __BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__)
+#else
 /*
  * There seems to be no way of detecting this automatically from user
  * space, so 64 bit architectures should override this in their
@@ -8,8 +20,8 @@
  * both 32 and 64 bit user space must not rely on CONFIG_64BIT
  * to decide it, but rather check a compiler provided macro.
  */
-#ifndef __BITS_PER_LONG
 #define __BITS_PER_LONG 32
 #endif
+#endif
 
 #endif /* _UAPI__ASM_GENERIC_BITS_PER_LONG */

tools/include/uapi/asm/bitsperlong.h

 /* SPDX-License-Identifier: GPL-2.0 */
 #if defined(__i386__) || defined(__x86_64__)
 #include "../../../arch/x86/include/uapi/asm/bitsperlong.h"
-#elif defined(__aarch64__)
-#include "../../../arch/arm64/include/uapi/asm/bitsperlong.h"
 #elif defined(__powerpc__)
 #include "../../../arch/powerpc/include/uapi/asm/bitsperlong.h"
 #elif defined(__s390__)
@@ -13,12 +11,8 @@
 #include "../../../arch/mips/include/uapi/asm/bitsperlong.h"
 #elif defined(__ia64__)
 #include "../../../arch/ia64/include/uapi/asm/bitsperlong.h"
-#elif defined(__riscv)
-#include "../../../arch/riscv/include/uapi/asm/bitsperlong.h"
 #elif defined(__alpha__)
 #include "../../../arch/alpha/include/uapi/asm/bitsperlong.h"
-#elif defined(__loongarch__)
-#include "../../../arch/loongarch/include/uapi/asm/bitsperlong.h"
 #else
 #include <asm-generic/bitsperlong.h>
 #endif