The patch titled
Subject: percpu/x86: enable strict percpu checks via named AS qualifiers
has been added to the -mm mm-unstable branch. Its filename is
percpu-x86-enable-strict-percpu-checks-via-named-as-qualifiers.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/percpu-x86-enable-strict-percpu-checks-via-named-as-qualifiers.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Uros Bizjak <ubizjak@xxxxxxxxx>
Subject: percpu/x86: enable strict percpu checks via named AS qualifiers
Date: Sun, 8 Dec 2024 21:45:21 +0100
This patch declares percpu variables in __seg_gs/__seg_fs named AS and
keeps them named AS qualified until they are dereferenced with percpu
accessor. This approach enables various compiler check for
cross-namespace variable assignments.
Link: https://lkml.kernel.org/r/20241208204708.3742696-7-ubizjak@xxxxxxxxx
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Acked-by: Nadav Amit <nadav.amit@xxxxxxxxx>
Acked-by: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
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>
---
arch/x86/include/asm/percpu.h | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
--- a/arch/x86/include/asm/percpu.h~percpu-x86-enable-strict-percpu-checks-via-named-as-qualifiers
+++ a/arch/x86/include/asm/percpu.h
@@ -95,9 +95,23 @@
#endif /* CONFIG_SMP */
-#define __my_cpu_type(var) typeof(var) __percpu_seg_override
-#define __my_cpu_ptr(ptr) (__my_cpu_type(*(ptr))*)(__force uintptr_t)(ptr)
-#define __my_cpu_var(var) (*__my_cpu_ptr(&(var)))
+/*
+ * XXX: Remove test for __CHECKER__ once
+ * sparse learns about __typeof_unqual__.
+ */
+#if defined(CONFIG_USE_X86_SEG_SUPPORT) && \
+ defined(CONFIG_CC_HAS_TYPEOF_UNQUAL) && !defined(__CHECKER__)
+# define __my_cpu_type(var) typeof(var)
+# define __my_cpu_ptr(ptr) (ptr)
+# define __my_cpu_var(var) (var)
+
+# define __percpu_qual __percpu_seg_override
+#else
+# define __my_cpu_type(var) typeof(var) __percpu_seg_override
+# define __my_cpu_ptr(ptr) (__my_cpu_type(*(ptr))*)(__force uintptr_t)(ptr)
+# define __my_cpu_var(var) (*__my_cpu_ptr(&(var)))
+#endif
+
#define __percpu_arg(x) __percpu_prefix "%" #x
#define __force_percpu_arg(x) __force_percpu_prefix "%" #x
_
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
