[PATCH v3 6/6] percpu/x86: Enable strict percpu checks via named AS qualifiers
From: Uros Bizjak <hidden>
Date: 2024-12-08 20:47:33
Also in:
linux-arch, linux-bcachefs, linux-mm, lkml
Subsystem:
per-cpu memory allocator, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Dennis Zhou, Tejun Heo, Christoph Lameter, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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.
Signed-off-by: Uros Bizjak <redacted>
Acked-by: Nadav Amit <redacted>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <redacted>
Cc: Thomas Gleixner <redacted>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <redacted>
Cc: Peter Zijlstra <peterz@infradead.org>
---
v2: - Add comment to remove test for __CHECKER__ once sparse learns
about __typeof_unqual__.
---
arch/x86/include/asm/percpu.h | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 27f668660abe..1ef08289e667 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/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
--
2.42.0