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From: KP Singh <>
Subject: [PATCH v9 1/4] kernel: Add helper macros for loop unrolling
Date: Wed,  7 Feb 2024 13:49:15 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

This helps in easily initializing blocks of code (e.g. static calls and

UNROLL(N, MACRO, __VA_ARGS__) calls MACRO N times with the first
argument as the index of the iteration. This allows string pasting to
create unique tokens for variable names, function calls etc.

As an example:

	#include <linux/unroll.h>

	#define MACRO(N, a, b)            \
		int add_##N(int a, int b) \
		{                         \
			return a + b + N; \

	UNROLL(2, MACRO, x, y)

expands to:

	int add_0(int x, int y)
		return x + y + 0;

	int add_1(int x, int y)
		return x + y + 1;

Reviewed-by: Kees Cook <>
Reviewed-by: Casey Schaufler <>
Acked-by: Song Liu <>
Acked-by: Andrii Nakryiko <>
Signed-off-by: KP Singh <>
 include/linux/unroll.h | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 include/linux/unroll.h

diff --git a/include/linux/unroll.h b/include/linux/unroll.h
new file mode 100644
index 000000000000..d42fd6366373
--- /dev/null
+++ b/include/linux/unroll.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+ * Copyright (C) 2023 Google LLC.
+ */
+#ifndef __UNROLL_H
+#define __UNROLL_H
+#include <linux/args.h>
+#define UNROLL(N, MACRO, args...) CONCATENATE(__UNROLL_, N)(MACRO, args)
+#define __UNROLL_0(MACRO, args...)
+#define __UNROLL_1(MACRO, args...)  __UNROLL_0(MACRO, args)  MACRO(0, args)
+#define __UNROLL_2(MACRO, args...)  __UNROLL_1(MACRO, args)  MACRO(1, args)
+#define __UNROLL_3(MACRO, args...)  __UNROLL_2(MACRO, args)  MACRO(2, args)
+#define __UNROLL_4(MACRO, args...)  __UNROLL_3(MACRO, args)  MACRO(3, args)
+#define __UNROLL_5(MACRO, args...)  __UNROLL_4(MACRO, args)  MACRO(4, args)
+#define __UNROLL_6(MACRO, args...)  __UNROLL_5(MACRO, args)  MACRO(5, args)
+#define __UNROLL_7(MACRO, args...)  __UNROLL_6(MACRO, args)  MACRO(6, args)
+#define __UNROLL_8(MACRO, args...)  __UNROLL_7(MACRO, args)  MACRO(7, args)
+#define __UNROLL_9(MACRO, args...)  __UNROLL_8(MACRO, args)  MACRO(8, args)
+#define __UNROLL_10(MACRO, args...) __UNROLL_9(MACRO, args)  MACRO(9, args)
+#define __UNROLL_11(MACRO, args...) __UNROLL_10(MACRO, args) MACRO(10, args)
+#define __UNROLL_12(MACRO, args...) __UNROLL_11(MACRO, args) MACRO(11, args)
+#define __UNROLL_13(MACRO, args...) __UNROLL_12(MACRO, args) MACRO(12, args)
+#define __UNROLL_14(MACRO, args...) __UNROLL_13(MACRO, args) MACRO(13, args)
+#define __UNROLL_15(MACRO, args...) __UNROLL_14(MACRO, args) MACRO(14, args)
+#define __UNROLL_16(MACRO, args...) __UNROLL_15(MACRO, args) MACRO(15, args)
+#define __UNROLL_17(MACRO, args...) __UNROLL_16(MACRO, args) MACRO(16, args)
+#define __UNROLL_18(MACRO, args...) __UNROLL_17(MACRO, args) MACRO(17, args)
+#define __UNROLL_19(MACRO, args...) __UNROLL_18(MACRO, args) MACRO(18, args)
+#define __UNROLL_20(MACRO, args...) __UNROLL_19(MACRO, args) MACRO(19, args)
+#endif /* __UNROLL_H */

  reply	other threads:[~2024-02-07 12:49 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-07 12:49 [PATCH v9 0/4] Reduce overhead of LSMs with static calls KP Singh
2024-02-07 12:49 ` KP Singh [this message]
2024-02-07 12:49 ` [PATCH v9 2/4] security: Count the LSMs enabled at compile time KP Singh
2024-02-07 12:49 ` [PATCH v9 3/4] security: Replace indirect LSM hook calls with static calls KP Singh
2024-04-11  0:38   ` Paul Moore
2024-04-11  7:12     ` KP Singh
2024-04-12 15:39       ` Paul Moore
2024-02-07 12:49 ` [PATCH v9 4/4] bpf: Only enable BPF LSM hooks when an LSM program is attached KP Singh
2024-04-11  0:38   ` Paul Moore
2024-05-05 16:25     ` KP Singh

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