The patch titled
Subject: percpu: repurpose __percpu tag as a named address space qualifier
has been added to the -mm mm-unstable branch. Its filename is
percpu-repurpose-__percpu-tag-as-a-named-address-space-qualifier.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/percpu-repurpose-__percpu-tag-as-a-named-address-space-qualifier.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Uros Bizjak <ubizjak@xxxxxxxxx>
Subject: percpu: repurpose __percpu tag as a named address space qualifier
Date: Sun, 8 Dec 2024 21:45:20 +0100
The patch introduces __percpu_qual define and repurposes __percpu tag as a
named address space qualifier using the new define.
Arches can now conditionally define __percpu_qual as their named address
space qualifier for percpu variables.
Link: https://lkml.kernel.org/r/20241208204708.3742696-6-ubizjak@xxxxxxxxx
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Acked-by: Nadav Amit <nadav.amit@xxxxxxxxx>
Acked-by: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: Waiman Long <longman@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/asm-generic/percpu.h | 13 +++++++++++++
include/linux/compiler_types.h | 2 +-
2 files changed, 14 insertions(+), 1 deletion(-)
--- a/include/asm-generic/percpu.h~percpu-repurpose-__percpu-tag-as-a-named-address-space-qualifier
+++ a/include/asm-generic/percpu.h
@@ -6,6 +6,19 @@
#include <linux/threads.h>
#include <linux/percpu-defs.h>
+/*
+ * __percpu_qual is the qualifier for the percpu named address space.
+ *
+ * Most arches use generic named address space for percpu variables but
+ * some arches define percpu variables in different named address space
+ * (on the x86 arch, percpu variable may be declared as being relative
+ * to the %fs or %gs segments using __seg_fs or __seg_gs named address
+ * space qualifier).
+ */
+#ifndef __percpu_qual
+# define __percpu_qual
+#endif
+
#ifdef CONFIG_SMP
/*
--- a/include/linux/compiler_types.h~percpu-repurpose-__percpu-tag-as-a-named-address-space-qualifier
+++ a/include/linux/compiler_types.h
@@ -57,7 +57,7 @@ static inline void __chk_io_ptr(const vo
# define __user BTF_TYPE_TAG(user)
# endif
# define __iomem
-# define __percpu BTF_TYPE_TAG(percpu)
+# define __percpu __percpu_qual BTF_TYPE_TAG(percpu)
# define __rcu BTF_TYPE_TAG(rcu)
# define __chk_user_ptr(x) (void)0
_
Patches currently in -mm which might be from ubizjak@xxxxxxxxx are
x86-kgdb-use-is_err_pcpu-macro.patch
compilerh-introduce-typeof_unqual-macro.patch
percpu-use-typeof_unqual-in-variable-declarations.patch
percpu-use-typeof_unqual-in-_cpu_ptr-accessors.patch
percpu-repurpose-__percpu-tag-as-a-named-address-space-qualifier.patch
percpu-x86-enable-strict-percpu-checks-via-named-as-qualifiers.patch
