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Date: Tue, 19 Dec 2023 18:09:51 +0000
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Subject: [PATCH v4 1/2] kernel.h: removed REPEAT_BYTE from kernel.h
From: Tanzir Hasan <tanzirh@google.com>
To: Kees Cook <keescook@chromium.org>, Nick DeSaulniers <nnn@google.com>
Cc: Andy Shevchenko <andy@kernel.org>, linux-hardening@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, 
	llvm@lists.linux.dev, Al Viro <viro@zeniv.linux.org.uk>, 
	Andy Shevchenko <andy.shevchenko@gmail.com>, Tanzir Hasan <tanzirh@google.com>
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This patch creates wordpart.h and includes it in asm/word-at-a-time.h
for the all architectures. WORD_AT_A_TIME_CONSTANTS depends on kernel.h
because of REPEAT_BYTE. Moving this to another header and including it
where necessary allows us to not include the bloated kernel.h. Making
this implicit dependency on REPEAT_BYTE explicit allows for later
improvements in the lib/string.c inclusion list.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Tanzir Hasan <tanzirh@google.com>
---
 arch/arm/include/asm/word-at-a-time.h     |  2 +-
 arch/arm64/include/asm/word-at-a-time.h   |  2 +-
 arch/powerpc/include/asm/word-at-a-time.h |  2 +-
 arch/riscv/include/asm/word-at-a-time.h   |  2 +-
 arch/s390/include/asm/word-at-a-time.h    |  2 +-
 arch/sh/include/asm/word-at-a-time.h      |  1 +
 arch/x86/include/asm/word-at-a-time.h     |  1 +
 fs/namei.c                                |  2 +-
 include/asm-generic/word-at-a-time.h      |  2 +-
 include/linux/kernel.h                    |  7 -------
 include/linux/wordpart.h                  | 17 +++++++++++++++++
 11 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/arch/arm/include/asm/word-at-a-time.h b/arch/arm/include/asm/word-at-a-time.h
index 352ab213520d..e08304996121 100644
--- a/arch/arm/include/asm/word-at-a-time.h
+++ b/arch/arm/include/asm/word-at-a-time.h
@@ -8,7 +8,7 @@
  * Little-endian word-at-a-time zero byte handling.
  * Heavily based on the x86 algorithm.
  */
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 
 struct word_at_a_time {
 	const unsigned long one_bits, high_bits;
diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h
index f3b151ed0d7a..bd8cfbc2b9c3 100644
--- a/arch/arm64/include/asm/word-at-a-time.h
+++ b/arch/arm64/include/asm/word-at-a-time.h
@@ -9,7 +9,7 @@
 
 #ifndef __AARCH64EB__
 
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 
 struct word_at_a_time {
 	const unsigned long one_bits, high_bits;
diff --git a/arch/powerpc/include/asm/word-at-a-time.h b/arch/powerpc/include/asm/word-at-a-time.h
index 30a12d208687..26e4f718a674 100644
--- a/arch/powerpc/include/asm/word-at-a-time.h
+++ b/arch/powerpc/include/asm/word-at-a-time.h
@@ -5,7 +5,7 @@
  * Word-at-a-time interfaces for PowerPC.
  */
 
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 #include <asm/asm-compat.h>
 #include <asm/extable.h>
 
diff --git a/arch/riscv/include/asm/word-at-a-time.h b/arch/riscv/include/asm/word-at-a-time.h
index 7c086ac6ecd4..94bec2f7ba53 100644
--- a/arch/riscv/include/asm/word-at-a-time.h
+++ b/arch/riscv/include/asm/word-at-a-time.h
@@ -9,7 +9,7 @@
 #define _ASM_RISCV_WORD_AT_A_TIME_H
 
 
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 
 struct word_at_a_time {
 	const unsigned long one_bits, high_bits;
diff --git a/arch/s390/include/asm/word-at-a-time.h b/arch/s390/include/asm/word-at-a-time.h
index 2579f1694b82..55e66d9371d6 100644
--- a/arch/s390/include/asm/word-at-a-time.h
+++ b/arch/s390/include/asm/word-at-a-time.h
@@ -2,7 +2,7 @@
 #ifndef _ASM_WORD_AT_A_TIME_H
 #define _ASM_WORD_AT_A_TIME_H
 
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 #include <asm/asm-extable.h>
 #include <asm/bitsperlong.h>
 
diff --git a/arch/sh/include/asm/word-at-a-time.h b/arch/sh/include/asm/word-at-a-time.h
index 4aa398455b94..663658cea69a 100644
--- a/arch/sh/include/asm/word-at-a-time.h
+++ b/arch/sh/include/asm/word-at-a-time.h
@@ -5,6 +5,7 @@
 #ifdef CONFIG_CPU_BIG_ENDIAN
 # include <asm-generic/word-at-a-time.h>
 #else
+#include <linux/wordpart.h>
 /*
  * Little-endian version cribbed from x86.
  */
diff --git a/arch/x86/include/asm/word-at-a-time.h b/arch/x86/include/asm/word-at-a-time.h
index 46b4f1f7f354..c002c864a63e 100644
--- a/arch/x86/include/asm/word-at-a-time.h
+++ b/arch/x86/include/asm/word-at-a-time.h
@@ -3,6 +3,7 @@
 #define _ASM_WORD_AT_A_TIME_H
 
 #include <linux/kernel.h>
+#include <linux/wordpart.h>
 
 /*
  * This is largely generic for little-endian machines, but the
diff --git a/fs/namei.c b/fs/namei.c
index 71c13b2990b4..03db8ca3f394 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -17,7 +17,7 @@
 
 #include <linux/init.h>
 #include <linux/export.h>
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/filelock.h>
diff --git a/include/asm-generic/word-at-a-time.h b/include/asm-generic/word-at-a-time.h
index 95a1d214108a..6f088b2b0b03 100644
--- a/include/asm-generic/word-at-a-time.h
+++ b/include/asm-generic/word-at-a-time.h
@@ -2,7 +2,7 @@
 #ifndef _ASM_WORD_AT_A_TIME_H
 #define _ASM_WORD_AT_A_TIME_H
 
-#include <linux/kernel.h>
+#include <linux/wordpart.h>
 #include <asm/byteorder.h>
 
 #ifdef __BIG_ENDIAN
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d9ad21058eed..162660af5b7d 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -39,13 +39,6 @@
 
 #define STACK_MAGIC	0xdeadbeef
 
-/**
- * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
- * @x: value to repeat
- *
- * NOTE: @x is not checked for > 0xff; larger values produce odd results.
- */
-#define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))
 
 /* generic data direction definitions */
 #define READ			0
diff --git a/include/linux/wordpart.h b/include/linux/wordpart.h
new file mode 100644
index 000000000000..6a5ed5d54ba2
--- /dev/null
+++ b/include/linux/wordpart.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Google LLC <tanzirh@google.com>
+ */
+
+#ifndef _LINUX_WORDPART_H
+#define _LINUX_WORDPART_H
+/**
+ * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
+ * @x: value to repeat
+ *
+ * NOTE: @x is not checked for > 0xff; larger values produce odd results.
+ */
+#define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))
+
+#endif // _LINUX_WORDPART_H
+

-- 
2.43.0.472.g3155946c3a-goog