mirror of
git://git.musl-libc.org/musl
synced 2024-12-15 03:05:15 +00:00
df0b5a4940
this behavior (opening fds 0-2 for a suid program) is explicitly allowed (but not required) by POSIX to protect badly-written suid programs from clobbering files they later open. this commit does add some cost in startup code, but the availability of auxv and the security flag will be useful elsewhere in the future. in particular auxv is needed for static-linked vdso support, which is still waiting to be committed (sorry nik!)
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
#ifndef _INTERNAL_ATOMIC_H
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#define _INTERNAL_ATOMIC_H
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#include <stdint.h>
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static inline int a_ctz_64(uint64_t x)
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{
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int r;
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__asm__( "bsf %1,%0 ; jnz 1f ; bsf %2,%0 ; addl $32,%0\n1:"
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: "=r"(r) : "r"((unsigned)x), "r"((unsigned)(x>>32)) );
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return r;
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}
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static inline int a_ctz_l(unsigned long x)
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{
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long r;
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__asm__( "bsf %1,%0" : "=r"(r) : "r"(x) );
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return r;
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}
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static inline void a_and_64(volatile uint64_t *p, uint64_t v)
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{
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__asm__( "lock ; andl %1, (%0) ; lock ; andl %2, 4(%0)"
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: : "r"((long *)p), "r"((unsigned)v), "r"((unsigned)(v>>32)) : "memory" );
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}
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static inline void a_or_64(volatile uint64_t *p, uint64_t v)
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{
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__asm__( "lock ; orl %1, (%0) ; lock ; orl %2, 4(%0)"
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: : "r"((long *)p), "r"((unsigned)v), "r"((unsigned)(v>>32)) : "memory" );
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}
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static inline void a_store_l(volatile void *p, long x)
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{
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__asm__( "movl %1, %0" : "=m"(*(long *)p) : "r"(x) : "memory" );
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}
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static inline void a_or_l(volatile void *p, long v)
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{
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__asm__( "lock ; orl %1, %0"
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: "=m"(*(long *)p) : "r"(v) : "memory" );
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}
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static inline void *a_cas_p(volatile void *p, void *t, void *s)
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{
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__asm__( "lock ; cmpxchg %3, %1"
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: "=a"(t), "=m"(*(long *)p) : "a"(t), "r"(s) : "memory" );
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return t;
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}
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static inline long a_cas_l(volatile void *p, long t, long s)
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{
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__asm__( "lock ; cmpxchg %3, %1"
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: "=a"(t), "=m"(*(long *)p) : "a"(t), "r"(s) : "memory" );
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return t;
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}
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static inline int a_cas(volatile int *p, int t, int s)
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{
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__asm__( "lock ; cmpxchg %3, %1"
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: "=a"(t), "=m"(*p) : "a"(t), "r"(s) : "memory" );
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return t;
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}
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static inline void *a_swap_p(void *volatile *x, void *v)
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{
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__asm__( "xchg %0, %1" : "=r"(v), "=m"(*(void **)x) : "0"(v) : "memory" );
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return v;
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}
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static inline long a_swap_l(volatile void *x, long v)
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{
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__asm__( "xchg %0, %1" : "=r"(v), "=m"(*(long *)x) : "0"(v) : "memory" );
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return v;
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}
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static inline void a_or(volatile void *p, int v)
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{
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__asm__( "lock ; orl %1, %0"
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: "=m"(*(int *)p) : "r"(v) : "memory" );
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}
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static inline void a_and(volatile void *p, int v)
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{
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__asm__( "lock ; andl %1, %0"
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: "=m"(*(int *)p) : "r"(v) : "memory" );
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}
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static inline int a_swap(volatile int *x, int v)
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{
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__asm__( "xchg %0, %1" : "=r"(v), "=m"(*x) : "0"(v) : "memory" );
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return v;
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}
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#define a_xchg a_swap
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static inline int a_fetch_add(volatile int *x, int v)
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{
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__asm__( "lock ; xadd %0, %1" : "=r"(v), "=m"(*x) : "0"(v) : "memory" );
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return v;
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}
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static inline void a_inc(volatile int *x)
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{
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__asm__( "lock ; incl %0" : "=m"(*x) : "m"(*x) : "memory" );
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}
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static inline void a_dec(volatile int *x)
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{
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__asm__( "lock ; decl %0" : "=m"(*x) : "m"(*x) : "memory" );
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}
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static inline void a_store(volatile int *p, int x)
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{
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__asm__( "movl %1, %0" : "=m"(*p) : "r"(x) : "memory" );
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}
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static inline void a_spin()
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{
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__asm__ __volatile__( "pause" : : : "memory" );
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}
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static inline void a_crash()
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{
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__asm__ __volatile__( "hlt" : : : "memory" );
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}
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#endif
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