[PATCH AUTOSEL 6.17-6.1] arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c
Sasha Levin
sashal at kernel.org
Mon Oct 6 11:17:35 PDT 2025
From: Menglong Dong <menglong8.dong at gmail.com>
[ Upstream commit 35561bab768977c9e05f1f1a9bc00134c85f3e28 ]
The include/generated/asm-offsets.h is generated in Kbuild during
compiling from arch/SRCARCH/kernel/asm-offsets.c. When we want to
generate another similar offset header file, circular dependency can
happen.
For example, we want to generate a offset file include/generated/test.h,
which is included in include/sched/sched.h. If we generate asm-offsets.h
first, it will fail, as include/sched/sched.h is included in asm-offsets.c
and include/generated/test.h doesn't exist; If we generate test.h first,
it can't success neither, as include/generated/asm-offsets.h is included
by it.
In x86_64, the macro COMPILE_OFFSETS is used to avoid such circular
dependency. We can generate asm-offsets.h first, and if the
COMPILE_OFFSETS is defined, we don't include the "generated/test.h".
And we define the macro COMPILE_OFFSETS for all the asm-offsets.c for this
purpose.
Signed-off-by: Menglong Dong <dongml2 at chinatelecom.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz at infradead.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
LLM Generated explanations, may be completely bogus:
Based on my thorough investigation, I can now provide a comprehensive
analysis of this commit.
## **Backport Analysis: COMPILE_OFFSETS Commit**
**Backport Status: YES** (with important conditions)
### Summary
This commit adds `#define COMPILE_OFFSETS` to all architecture-specific
asm-offsets.c files. It is a **preparatory infrastructure patch** that
enables the generation of additional offset header files while avoiding
circular dependency issues during the kernel build process.
### Critical Context
This commit (upstream: 35561bab76897) is **inseparable** from its
companion commit:
- **378b7708194ff**: "sched: Make migrate_{en,dis}able() inline"
These two commits form a **mandatory pair** where:
1. The COMPILE_OFFSETS commit prepares the build infrastructure
2. The migrate_enable/disable commit actually uses this infrastructure
to generate `include/generated/rq-offsets.h`
### Why This Should Be Backported
1. **Already being backported**: The companion commit (378b7708194ff) is
already tagged for stable backport (as commit d0e888caa43cc shows `[
Upstream commit 378b7708194fff77c9020392067329931c3fcc04 ]`)
2. **Build dependency**: Without this COMPILE_OFFSETS commit, the
migrate_enable/disable backport will **fail to build** due to
circular dependency:
- `asm-offsets.c` includes `<linux/sched.h>`
- `<linux/sched.h>` will include `<generated/rq-offsets.h>`
- But `rq-offsets.h` doesn't exist yet when generating `asm-
offsets.h`
- The COMPILE_OFFSETS macro allows conditional inclusion to break
this cycle
3. **Performance improvement for BPF**: The complete patch series
improves BPF FENTRY performance from ~113M/s to ~150M/s (27-32%
improvement) by inlining migrate_enable/disable functions
4. **Low risk**: This commit only adds a simple `#define` to each asm-
offsets.c file with no functional changes to any existing code paths
### Code Changes Analysis
The changes are identical across all 23 architectures:
- **alpha, arc, arm, arm64, csky, hexagon, loongarch, m68k, microblaze,
mips, nios2, openrisc, parisc, powerpc, riscv, s390, sh, sparc, um,
xtensa**
Each file receives:
```c
+#define COMPILE_OFFSETS
```
This macro is used in header files (specifically
`include/linux/sched.h`) to conditionally guard includes:
```c
#ifndef COMPILE_OFFSETS
#include <generated/rq-offsets.h>
#endif
```
### Dependencies
- **Must be backported together with**: commit 378b7708194ff
- **Order matters**: COMPILE_OFFSETS must be applied first (or in same
merge)
- **No standalone value**: This commit has no effect without the follow-
up changes
### Risk Assessment
- **Risk Level**: Low
- **Regression Potential**: Minimal - only adds a preprocessor
definition
- **Testing**: Should build-test on all architectures
- **Compatibility**: X86_64 already had this pattern since 2011 (commit
b82fef82d567)
### References
- Upstream commits: 35561bab76897 (this one) → 378b7708194ff (migrate
inline)
- Author: Menglong Dong <dongml2 at chinatelecom.cn>
- Maintainer: Peter Zijlstra (Intel) <peterz at infradead.org>
- Subsystem: Scheduler / Build infrastructure
**Conclusion**: This is a mandatory prerequisite patch that must be
backported alongside its companion commit to avoid build breakage. The
stable maintainers should ensure both patches are applied together in
the correct order.
arch/alpha/kernel/asm-offsets.c | 1 +
arch/arc/kernel/asm-offsets.c | 1 +
arch/arm/kernel/asm-offsets.c | 2 ++
arch/arm64/kernel/asm-offsets.c | 1 +
arch/csky/kernel/asm-offsets.c | 1 +
arch/hexagon/kernel/asm-offsets.c | 1 +
arch/loongarch/kernel/asm-offsets.c | 2 ++
arch/m68k/kernel/asm-offsets.c | 1 +
arch/microblaze/kernel/asm-offsets.c | 1 +
arch/mips/kernel/asm-offsets.c | 2 ++
arch/nios2/kernel/asm-offsets.c | 1 +
arch/openrisc/kernel/asm-offsets.c | 1 +
arch/parisc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/riscv/kernel/asm-offsets.c | 1 +
arch/s390/kernel/asm-offsets.c | 1 +
arch/sh/kernel/asm-offsets.c | 1 +
arch/sparc/kernel/asm-offsets.c | 1 +
arch/um/kernel/asm-offsets.c | 2 ++
arch/xtensa/kernel/asm-offsets.c | 1 +
20 files changed, 24 insertions(+)
diff --git a/arch/alpha/kernel/asm-offsets.c b/arch/alpha/kernel/asm-offsets.c
index e9dad60b147f3..1ebb058904992 100644
--- a/arch/alpha/kernel/asm-offsets.c
+++ b/arch/alpha/kernel/asm-offsets.c
@@ -4,6 +4,7 @@
* This code generates raw asm output which is post-processed to extract
* and format the required data.
*/
+#define COMPILE_OFFSETS
#include <linux/types.h>
#include <linux/stddef.h>
diff --git a/arch/arc/kernel/asm-offsets.c b/arch/arc/kernel/asm-offsets.c
index f77deb7991757..2978da85fcb65 100644
--- a/arch/arc/kernel/asm-offsets.c
+++ b/arch/arc/kernel/asm-offsets.c
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*/
+#define COMPILE_OFFSETS
#include <linux/sched.h>
#include <linux/mm.h>
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 123f4a8ef4466..2101938d27fcb 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -7,6 +7,8 @@
* This code generates raw asm output which is post-processed to extract
* and format the required data.
*/
+#define COMPILE_OFFSETS
+
#include <linux/compiler.h>
#include <linux/sched.h>
#include <linux/mm.h>
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 30d4bbe68661f..b6367ff3a49ca 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -6,6 +6,7 @@
* 2001-2002 Keith Owens
* Copyright (C) 2012 ARM Ltd.
*/
+#define COMPILE_OFFSETS
#include <linux/arm_sdei.h>
#include <linux/sched.h>
diff --git a/arch/csky/kernel/asm-offsets.c b/arch/csky/kernel/asm-offsets.c
index d1e9035794733..5525c8e7e1d9e 100644
--- a/arch/csky/kernel/asm-offsets.c
+++ b/arch/csky/kernel/asm-offsets.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#define COMPILE_OFFSETS
#include <linux/sched.h>
#include <linux/kernel_stat.h>
diff --git a/arch/hexagon/kernel/asm-offsets.c b/arch/hexagon/kernel/asm-offsets.c
index 03a7063f94561..50eea9fa6f137 100644
--- a/arch/hexagon/kernel/asm-offsets.c
+++ b/arch/hexagon/kernel/asm-offsets.c
@@ -8,6 +8,7 @@
*
* Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
*/
+#define COMPILE_OFFSETS
#include <linux/compat.h>
#include <linux/types.h>
diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/asm-offsets.c
index db1e4bb26b6a0..3017c71576009 100644
--- a/arch/loongarch/kernel/asm-offsets.c
+++ b/arch/loongarch/kernel/asm-offsets.c
@@ -4,6 +4,8 @@
*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
+#define COMPILE_OFFSETS
+
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
diff --git a/arch/m68k/kernel/asm-offsets.c b/arch/m68k/kernel/asm-offsets.c
index 906d732305374..67a1990f9d748 100644
--- a/arch/m68k/kernel/asm-offsets.c
+++ b/arch/m68k/kernel/asm-offsets.c
@@ -9,6 +9,7 @@
* #defines from the assembly-language output.
*/
+#define COMPILE_OFFSETS
#define ASM_OFFSETS_C
#include <linux/stddef.h>
diff --git a/arch/microblaze/kernel/asm-offsets.c b/arch/microblaze/kernel/asm-offsets.c
index 104c3ac5f30c8..b4b67d58e7f6a 100644
--- a/arch/microblaze/kernel/asm-offsets.c
+++ b/arch/microblaze/kernel/asm-offsets.c
@@ -7,6 +7,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
+#define COMPILE_OFFSETS
#include <linux/init.h>
#include <linux/stddef.h>
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index 1e29efcba46e5..5debd9a3854a9 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -9,6 +9,8 @@
* Kevin Kissell, kevink at mips.com and Carsten Langgaard, carstenl at mips.com
* Copyright (C) 2000 MIPS Technologies, Inc.
*/
+#define COMPILE_OFFSETS
+
#include <linux/compat.h>
#include <linux/types.h>
#include <linux/sched.h>
diff --git a/arch/nios2/kernel/asm-offsets.c b/arch/nios2/kernel/asm-offsets.c
index e3d9b7b6fb48a..88190b503ce5d 100644
--- a/arch/nios2/kernel/asm-offsets.c
+++ b/arch/nios2/kernel/asm-offsets.c
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2011 Tobias Klauser <tklauser at distanz.ch>
*/
+#define COMPILE_OFFSETS
#include <linux/stddef.h>
#include <linux/sched.h>
diff --git a/arch/openrisc/kernel/asm-offsets.c b/arch/openrisc/kernel/asm-offsets.c
index 710651d5aaae1..3cc826f2216b1 100644
--- a/arch/openrisc/kernel/asm-offsets.c
+++ b/arch/openrisc/kernel/asm-offsets.c
@@ -18,6 +18,7 @@
* compile this file to assembler, and then extract the
* #defines from the assembly-language output.
*/
+#define COMPILE_OFFSETS
#include <linux/signal.h>
#include <linux/sched.h>
diff --git a/arch/parisc/kernel/asm-offsets.c b/arch/parisc/kernel/asm-offsets.c
index 757816a7bd4b2..9abfe65492c65 100644
--- a/arch/parisc/kernel/asm-offsets.c
+++ b/arch/parisc/kernel/asm-offsets.c
@@ -13,6 +13,7 @@
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
* Copyright (C) 2003 James Bottomley <jejb at parisc-linux.org>
*/
+#define COMPILE_OFFSETS
#include <linux/types.h>
#include <linux/sched.h>
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index b3048f6d3822c..a4bc80b30410a 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -8,6 +8,7 @@
* compile this file to assembler, and then extract the
* #defines from the assembly-language output.
*/
+#define COMPILE_OFFSETS
#include <linux/compat.h>
#include <linux/signal.h>
diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index 6e8c0d6feae9e..7d42d3b8a32a7 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -3,6 +3,7 @@
* Copyright (C) 2012 Regents of the University of California
* Copyright (C) 2017 SiFive
*/
+#define COMPILE_OFFSETS
#include <linux/kbuild.h>
#include <linux/mm.h>
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 95ecad9c7d7d2..a8915663e917f 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -4,6 +4,7 @@
* This code generates raw asm output which is post-processed to extract
* and format the required data.
*/
+#define COMPILE_OFFSETS
#include <linux/kbuild.h>
#include <linux/sched.h>
diff --git a/arch/sh/kernel/asm-offsets.c b/arch/sh/kernel/asm-offsets.c
index a0322e8328456..429b6a7631468 100644
--- a/arch/sh/kernel/asm-offsets.c
+++ b/arch/sh/kernel/asm-offsets.c
@@ -8,6 +8,7 @@
* compile this file to assembler, and then extract the
* #defines from the assembly-language output.
*/
+#define COMPILE_OFFSETS
#include <linux/stddef.h>
#include <linux/types.h>
diff --git a/arch/sparc/kernel/asm-offsets.c b/arch/sparc/kernel/asm-offsets.c
index 3d9b9855dce91..6e660bde48dd8 100644
--- a/arch/sparc/kernel/asm-offsets.c
+++ b/arch/sparc/kernel/asm-offsets.c
@@ -10,6 +10,7 @@
*
* On sparc, thread_info data is static and TI_XXX offsets are computed by hand.
*/
+#define COMPILE_OFFSETS
#include <linux/sched.h>
#include <linux/mm_types.h>
diff --git a/arch/um/kernel/asm-offsets.c b/arch/um/kernel/asm-offsets.c
index 1fb12235ab9c8..a69873aa697f4 100644
--- a/arch/um/kernel/asm-offsets.c
+++ b/arch/um/kernel/asm-offsets.c
@@ -1 +1,3 @@
+#define COMPILE_OFFSETS
+
#include <sysdep/kernel-offsets.h>
diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c
index da38de20ae598..cfbced95e944a 100644
--- a/arch/xtensa/kernel/asm-offsets.c
+++ b/arch/xtensa/kernel/asm-offsets.c
@@ -11,6 +11,7 @@
*
* Chris Zankel <chris at zankel.net>
*/
+#define COMPILE_OFFSETS
#include <asm/processor.h>
#include <asm/coprocessor.h>
--
2.51.0
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