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alpha: no need to include asm/xchg.h twice
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We used to generate different helpers for local and full
{cmp,}xchg(); these days the barriers are in arch_{cmp,}xchg()
instead and generated helpers are identical for local and
full cases.  No need for those parametrized includes of
asm/xchg.h - we might as well insert its contents directly
in asm/cmpxchg.h and do it only once.

Signed-off-by: Al Viro <[email protected]>
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Al Viro authored and arndb committed Aug 19, 2024
1 parent 47ac09b commit 7193b5c
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239 changes: 223 additions & 16 deletions arch/alpha/include/asm/cmpxchg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3,25 +3,240 @@
#define _ALPHA_CMPXCHG_H

/*
* Atomic exchange routines.
* Atomic exchange.
* Since it can be used to implement critical sections
* it must clobber "memory" (also for interrupts in UP).
*/

#define ____xchg(type, args...) __arch_xchg ## type ## _local(args)
#define ____cmpxchg(type, args...) __cmpxchg ## type ## _local(args)
#include <asm/xchg.h>
static inline unsigned long
____xchg_u8(volatile char *m, unsigned long val)
{
unsigned long ret, tmp, addr64;

__asm__ __volatile__(
" andnot %4,7,%3\n"
" insbl %1,%4,%1\n"
"1: ldq_l %2,0(%3)\n"
" extbl %2,%4,%0\n"
" mskbl %2,%4,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%3)\n"
" beq %2,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
: "r" ((long)m), "1" (val) : "memory");

return ret;
}

static inline unsigned long
____xchg_u16(volatile short *m, unsigned long val)
{
unsigned long ret, tmp, addr64;

__asm__ __volatile__(
" andnot %4,7,%3\n"
" inswl %1,%4,%1\n"
"1: ldq_l %2,0(%3)\n"
" extwl %2,%4,%0\n"
" mskwl %2,%4,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%3)\n"
" beq %2,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
: "r" ((long)m), "1" (val) : "memory");

return ret;
}

static inline unsigned long
____xchg_u32(volatile int *m, unsigned long val)
{
unsigned long dummy;

__asm__ __volatile__(
"1: ldl_l %0,%4\n"
" bis $31,%3,%1\n"
" stl_c %1,%2\n"
" beq %1,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (val), "=&r" (dummy), "=m" (*m)
: "rI" (val), "m" (*m) : "memory");

return val;
}

static inline unsigned long
____xchg_u64(volatile long *m, unsigned long val)
{
unsigned long dummy;

__asm__ __volatile__(
"1: ldq_l %0,%4\n"
" bis $31,%3,%1\n"
" stq_c %1,%2\n"
" beq %1,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
: "=&r" (val), "=&r" (dummy), "=m" (*m)
: "rI" (val), "m" (*m) : "memory");

return val;
}

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

static __always_inline unsigned long
____xchg(volatile void *ptr, unsigned long x, int size)
{
return
size == 1 ? ____xchg_u8(ptr, x) :
size == 2 ? ____xchg_u16(ptr, x) :
size == 4 ? ____xchg_u32(ptr, x) :
size == 8 ? ____xchg_u64(ptr, x) :
(__xchg_called_with_bad_pointer(), x);
}

/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*/

static inline unsigned long
____cmpxchg_u8(volatile char *m, unsigned char old, unsigned char new)
{
unsigned long prev, tmp, cmp, addr64;

__asm__ __volatile__(
" andnot %5,7,%4\n"
" insbl %1,%5,%1\n"
"1: ldq_l %2,0(%4)\n"
" extbl %2,%5,%0\n"
" cmpeq %0,%6,%3\n"
" beq %3,2f\n"
" mskbl %2,%5,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%4)\n"
" beq %2,3f\n"
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
: "r" ((long)m), "Ir" (old), "1" (new) : "memory");

return prev;
}

static inline unsigned long
____cmpxchg_u16(volatile short *m, unsigned short old, unsigned short new)
{
unsigned long prev, tmp, cmp, addr64;

__asm__ __volatile__(
" andnot %5,7,%4\n"
" inswl %1,%5,%1\n"
"1: ldq_l %2,0(%4)\n"
" extwl %2,%5,%0\n"
" cmpeq %0,%6,%3\n"
" beq %3,2f\n"
" mskwl %2,%5,%2\n"
" or %1,%2,%2\n"
" stq_c %2,0(%4)\n"
" beq %2,3f\n"
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
: "r" ((long)m), "Ir" (old), "1" (new) : "memory");

return prev;
}

static inline unsigned long
____cmpxchg_u32(volatile int *m, int old, int new)
{
unsigned long prev, cmp;

__asm__ __volatile__(
"1: ldl_l %0,%5\n"
" cmpeq %0,%3,%1\n"
" beq %1,2f\n"
" mov %4,%1\n"
" stl_c %1,%2\n"
" beq %1,3f\n"
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r"(prev), "=&r"(cmp), "=m"(*m)
: "r"((long) old), "r"(new), "m"(*m) : "memory");

return prev;
}

static inline unsigned long
____cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
{
unsigned long prev, cmp;

__asm__ __volatile__(
"1: ldq_l %0,%5\n"
" cmpeq %0,%3,%1\n"
" beq %1,2f\n"
" mov %4,%1\n"
" stq_c %1,%2\n"
" beq %1,3f\n"
"2:\n"
".subsection 2\n"
"3: br 1b\n"
".previous"
: "=&r"(prev), "=&r"(cmp), "=m"(*m)
: "r"((long) old), "r"(new), "m"(*m) : "memory");

return prev;
}

/* This function doesn't exist, so you'll get a linker error
if something tries to do an invalid cmpxchg(). */
extern void __cmpxchg_called_with_bad_pointer(void);

static __always_inline unsigned long
____cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
int size)
{
return
size == 1 ? ____cmpxchg_u8(ptr, old, new) :
size == 2 ? ____cmpxchg_u16(ptr, old, new) :
size == 4 ? ____cmpxchg_u32(ptr, old, new) :
size == 8 ? ____cmpxchg_u64(ptr, old, new) :
(__cmpxchg_called_with_bad_pointer(), old);
}

#define xchg_local(ptr, x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
(__typeof__(*(ptr))) __arch_xchg_local((ptr), (unsigned long)_x_,\
(__typeof__(*(ptr))) ____xchg((ptr), (unsigned long)_x_, \
sizeof(*(ptr))); \
})

#define arch_cmpxchg_local(ptr, o, n) \
({ \
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
(__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_, \
(__typeof__(*(ptr))) ____cmpxchg((ptr), (unsigned long)_o_, \
(unsigned long)_n_, \
sizeof(*(ptr))); \
})
Expand All @@ -32,12 +247,6 @@
cmpxchg_local((ptr), (o), (n)); \
})

#undef ____xchg
#undef ____cmpxchg
#define ____xchg(type, args...) __arch_xchg ##type(args)
#define ____cmpxchg(type, args...) __cmpxchg ##type(args)
#include <asm/xchg.h>

/*
* The leading and the trailing memory barriers guarantee that these
* operations are fully ordered.
Expand All @@ -48,7 +257,7 @@
__typeof__(*(ptr)) _x_ = (x); \
smp_mb(); \
__ret = (__typeof__(*(ptr))) \
__arch_xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \
____xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \
smp_mb(); \
__ret; \
})
Expand All @@ -59,7 +268,7 @@
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
smp_mb(); \
__ret = (__typeof__(*(ptr))) __cmpxchg((ptr), \
__ret = (__typeof__(*(ptr))) ____cmpxchg((ptr), \
(unsigned long)_o_, (unsigned long)_n_, sizeof(*(ptr)));\
smp_mb(); \
__ret; \
Expand All @@ -71,6 +280,4 @@
arch_cmpxchg((ptr), (o), (n)); \
})

#undef ____cmpxchg

#endif /* _ALPHA_CMPXCHG_H */
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