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Date: Thu, 4 Apr 2024 11:42:02 +0200
From: Uros Bizjak <ubizjak@...il.com>
To: x86@...nel.org,
linux-kernel@...r.kernel.org
Cc: Uros Bizjak <ubizjak@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Andy Lutomirski <luto@...nel.org>,
Brian Gerst <brgerst@...il.com>,
Denys Vlasenko <dvlasenk@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Josh Poimboeuf <jpoimboe@...hat.com>
Subject: [PATCH v2 2/3] x86/percpu: Rewrite x86_this_cpu_test_bit() and friends as macros
Rewrite the whole family of x86_this_cpu_test_bit() functions
as macros, so standard __my_cpu_var() and raw_cpu_read() macros
can be used on percpu variables. This approach considerably
simplifies implementation of functions and also introduces
standard checks on accessed percpu variables.
No functional changes intended.
Signed-off-by: Uros Bizjak <ubizjak@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
---
v2: Split from the original v1 patch.
---
arch/um/include/asm/cpufeature.h | 3 +-
arch/x86/include/asm/cpufeature.h | 3 +-
arch/x86/include/asm/percpu.h | 54 +++++++++++++------------------
3 files changed, 25 insertions(+), 35 deletions(-)
diff --git a/arch/um/include/asm/cpufeature.h b/arch/um/include/asm/cpufeature.h
index 66fe06db872f..1eb8b834fbec 100644
--- a/arch/um/include/asm/cpufeature.h
+++ b/arch/um/include/asm/cpufeature.h
@@ -38,8 +38,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
#define this_cpu_has(bit) \
(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
- x86_this_cpu_test_bit(bit, \
- (unsigned long __percpu *)&cpu_info.x86_capability))
+ x86_this_cpu_test_bit(bit, cpu_info.x86_capability))
/*
* This macro is for detection of features which need kernel
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index f95e1c8b7c01..7d527467ab9c 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -127,8 +127,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
#define this_cpu_has(bit) \
(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
- x86_this_cpu_test_bit(bit, \
- (unsigned long __percpu *)&cpu_info.x86_capability))
+ x86_this_cpu_test_bit(bit, cpu_info.x86_capability))
/*
* This macro is for detection of features which need kernel
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index cbfbbe836ee2..d6ff0db32209 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -96,7 +96,7 @@
#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_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
@@ -568,37 +568,29 @@ do { \
#define this_cpu_read_stable_8(pcp) ({ BUILD_BUG(); (typeof(pcp))0; })
#endif
-static __always_inline bool x86_this_cpu_constant_test_bit(unsigned int nr,
- const unsigned long __percpu *addr)
-{
- unsigned long __percpu *a =
- (unsigned long __percpu *)addr + nr / BITS_PER_LONG;
+#define x86_this_cpu_constant_test_bit(_nr, _var) \
+({ \
+ unsigned long __percpu *addr__ = \
+ (unsigned long __percpu *)&(_var) + ((_nr) / BITS_PER_LONG); \
+ !!((1UL << ((_nr) % BITS_PER_LONG)) & raw_cpu_read(*addr__)); \
+})
-#ifdef CONFIG_X86_64
- return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_8(*a)) != 0;
-#else
- return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_4(*a)) != 0;
-#endif
-}
-
-static inline bool x86_this_cpu_variable_test_bit(int nr,
- const unsigned long __percpu *addr)
-{
- bool oldbit;
-
- asm volatile("btl %[nr], " __percpu_arg([var])
- CC_SET(c)
- : CC_OUT(c) (oldbit)
- : [var] "m" (*__my_cpu_ptr((unsigned long __percpu *)(addr))),
- [nr] "Ir" (nr));
-
- return oldbit;
-}
-
-#define x86_this_cpu_test_bit(nr, addr) \
- (__builtin_constant_p((nr)) \
- ? x86_this_cpu_constant_test_bit((nr), (addr)) \
- : x86_this_cpu_variable_test_bit((nr), (addr)))
+#define x86_this_cpu_variable_test_bit(_nr, _var) \
+({ \
+ bool oldbit; \
+ \
+ asm volatile("btl %[nr], " __percpu_arg([var]) \
+ CC_SET(c) \
+ : CC_OUT(c) (oldbit) \
+ : [var] "m" (__my_cpu_var(_var)), \
+ [nr] "rI" (_nr)); \
+ oldbit; \
+})
+
+#define x86_this_cpu_test_bit(_nr, _var) \
+ (__builtin_constant_p(_nr) \
+ ? x86_this_cpu_constant_test_bit(_nr, _var) \
+ : x86_this_cpu_variable_test_bit(_nr, _var))
#include <asm-generic/percpu.h>
--
2.44.0
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