cregit-Linux how code gets into the kernel

Release 4.12 include/asm-generic/cmpxchg.h

/*
 * Generic UP xchg and cmpxchg using interrupt disablement.  Does not
 * support SMP.
 */

#ifndef __ASM_GENERIC_CMPXCHG_H

#define __ASM_GENERIC_CMPXCHG_H

#ifdef CONFIG_SMP
#error "Cannot use generic cmpxchg on SMP"
#endif

#include <linux/types.h>
#include <linux/irqflags.h>

#ifndef xchg

/*
 * This function doesn't exist, so you'll get a linker error if
 * something tries to do an invalidly-sized xchg().
 */
extern void __xchg_called_with_bad_pointer(void);


static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size) { unsigned long ret, flags; switch (size) { case 1: #ifdef __xchg_u8 return __xchg_u8(x, ptr); #else local_irq_save(flags); ret = *(volatile u8 *)ptr; *(volatile u8 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u8 */ case 2: #ifdef __xchg_u16 return __xchg_u16(x, ptr); #else local_irq_save(flags); ret = *(volatile u16 *)ptr; *(volatile u16 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u16 */ case 4: #ifdef __xchg_u32 return __xchg_u32(x, ptr); #else local_irq_save(flags); ret = *(volatile u32 *)ptr; *(volatile u32 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u32 */ #ifdef CONFIG_64BIT case 8: #ifdef __xchg_u64 return __xchg_u64(x, ptr); #else local_irq_save(flags); ret = *(volatile u64 *)ptr; *(volatile u64 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u64 */ #endif /* CONFIG_64BIT */ default: __xchg_called_with_bad_pointer(); return x; } }

Contributors

PersonTokensPropCommitsCommitProp
David Howells253100.00%1100.00%
Total253100.00%1100.00%

#define xchg(ptr, x) ({ \ ((__typeof__(*(ptr))) \ __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ }) #endif /* xchg */ /* * Atomic compare and exchange. */ #include <asm-generic/cmpxchg-local.h> #ifndef cmpxchg_local #define cmpxchg_local(ptr, o, n) ({ \ ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ (unsigned long)(n), sizeof(*(ptr)))); \ }) #endif #ifndef cmpxchg64_local #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) #endif #define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) #define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) #endif /* __ASM_GENERIC_CMPXCHG_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
David Howells28379.05%228.57%
Mathieu Desnoyers3810.61%114.29%
Jonas Bonn318.66%114.29%
Paul Gortmaker30.84%114.29%
Marek Vašut20.56%114.29%
Sebastian Andrzej Siewior10.28%114.29%
Total358100.00%7100.00%
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