From: Uros Bizjak Date: Tue, 2 Apr 2024 17:50:38 +0000 (+0200) Subject: x86/percpu: Use __force to cast from __percpu address space X-Git-Tag: v6.10-rc1~198^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a55c1fdad5f61b4bfe42319694b23671a758cb28;p=thirdparty%2Fkernel%2Flinux.git x86/percpu: Use __force to cast from __percpu address space Fix Sparse warning when casting from __percpu address space by using __force in the cast. x86 named address spaces are not considered to be subspaces of the generic (flat) address space, so explicit casts are required to convert pointers between these address spaces and the generic address space (the application should cast to uintptr_t and apply the segment base offset). The cast to uintptr_t removes __percpu address space tag and Sparse reports: warning: cast removes address space '__percpu' of expression Use __force to inform Sparse that the cast is intentional. Fixes: 9a462b9eafa6 ("x86/percpu: Use compiler segment prefix qualifier") Reported-by: Charlemagne Lasse Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/20240402175058.52649-1-ubizjak@gmail.com Closes: https://lore.kernel.org/lkml/CAFGhKbzev7W4aHwhFPWwMZQEHenVgZUj7=aunFieVqZg3mt14A@mail.gmail.com/ --- diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 1f6404e0c4283..20696df5d5678 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -77,7 +77,7 @@ #define arch_raw_cpu_ptr(_ptr) \ ({ \ unsigned long tcp_ptr__ = __raw_my_cpu_offset; \ - tcp_ptr__ += (unsigned long)(_ptr); \ + tcp_ptr__ += (__force unsigned long)(_ptr); \ (typeof(*(_ptr)) __kernel __force *)tcp_ptr__; \ }) #else @@ -96,8 +96,8 @@ #endif /* CONFIG_SMP */ #define __my_cpu_type(var) typeof(var) __percpu_seg_override -#define __my_cpu_ptr(ptr) (__my_cpu_type(*ptr) *)(uintptr_t)(ptr) -#define __my_cpu_var(var) (*__my_cpu_ptr(&var)) +#define __my_cpu_ptr(ptr) (__my_cpu_type(*ptr)*)(__force uintptr_t)(ptr) +#define __my_cpu_var(var) (*__my_cpu_ptr(&(var))) #define __percpu_arg(x) __percpu_prefix "%" #x #define __force_percpu_arg(x) __force_percpu_prefix "%" #x