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sparc32: drop unused atomic24 support
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atomic24 support was used to semaphores in the past - but is no longer used.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Sam Ravnborg authored and David S. Miller committed Dec 27, 2011
1 parent 371de6e commit 348738a
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Showing 3 changed files with 0 additions and 161 deletions.
100 changes: 0 additions & 100 deletions arch/sparc/include/asm/atomic_32.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,106 +52,6 @@ extern void atomic_set(atomic_t *, int);
#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)


/* This is the old 24-bit implementation. It's still used internally
* by some sparc-specific code, notably the semaphore implementation.
*/
typedef struct { volatile int counter; } atomic24_t;

#ifndef CONFIG_SMP

#define ATOMIC24_INIT(i) { (i) }
#define atomic24_read(v) ((v)->counter)
#define atomic24_set(v, i) (((v)->counter) = i)

#else
/* We do the bulk of the actual work out of line in two common
* routines in assembler, see arch/sparc/lib/atomic.S for the
* "fun" details.
*
* For SMP the trick is you embed the spin lock byte within
* the word, use the low byte so signedness is easily retained
* via a quick arithmetic shift. It looks like this:
*
* ----------------------------------------
* | signed 24-bit counter value | lock | atomic_t
* ----------------------------------------
* 31 8 7 0
*/

#define ATOMIC24_INIT(i) { ((i) << 8) }

static inline int atomic24_read(const atomic24_t *v)
{
int ret = v->counter;

while(ret & 0xff)
ret = v->counter;

return ret >> 8;
}

#define atomic24_set(v, i) (((v)->counter) = ((i) << 8))
#endif

static inline int __atomic24_add(int i, atomic24_t *v)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
register int tmp1 asm("g3");
register int tmp2 asm("g4");
register int tmp3 asm("g7");

ptr = &v->counter;
increment = i;

__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_add\n\t"
" add %%o7, 8, %%o7\n"
: "=&r" (increment), "=r" (tmp1), "=r" (tmp2), "=r" (tmp3)
: "0" (increment), "r" (ptr)
: "memory", "cc");

return increment;
}

static inline int __atomic24_sub(int i, atomic24_t *v)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
register int tmp1 asm("g3");
register int tmp2 asm("g4");
register int tmp3 asm("g7");

ptr = &v->counter;
increment = i;

__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_sub\n\t"
" add %%o7, 8, %%o7\n"
: "=&r" (increment), "=r" (tmp1), "=r" (tmp2), "=r" (tmp3)
: "0" (increment), "r" (ptr)
: "memory", "cc");

return increment;
}

#define atomic24_add(i, v) ((void)__atomic24_add((i), (v)))
#define atomic24_sub(i, v) ((void)__atomic24_sub((i), (v)))

#define atomic24_dec_return(v) __atomic24_sub(1, (v))
#define atomic24_inc_return(v) __atomic24_add(1, (v))

#define atomic24_sub_and_test(i, v) (__atomic24_sub((i), (v)) == 0)
#define atomic24_dec_and_test(v) (__atomic24_sub(1, (v)) == 0)

#define atomic24_inc(v) ((void)__atomic24_add(1, (v)))
#define atomic24_dec(v) ((void)__atomic24_sub(1, (v)))

#define atomic24_add_negative(i, v) (__atomic24_add((i), (v)) < 0)

/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec() barrier()
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55 changes: 0 additions & 55 deletions arch/sparc/lib/atomic_32.S
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Original file line number Diff line number Diff line change
Expand Up @@ -40,60 +40,5 @@ ___xchg32_sun4md:
mov %g4, %o7
#endif

/* Read asm-sparc/atomic.h carefully to understand how this works for SMP.
* Really, some things here for SMP are overly clever, go read the header.
*/
.globl ___atomic24_add
___atomic24_add:
rd %psr, %g3 ! Keep the code small, old way was stupid
nop; nop; nop; ! Let the bits set
or %g3, PSR_PIL, %g7 ! Disable interrupts
wr %g7, 0x0, %psr ! Set %psr
nop; nop; nop; ! Let the bits set
#ifdef CONFIG_SMP
1: ldstub [%g1 + 3], %g7 ! Spin on the byte lock for SMP.
orcc %g7, 0x0, %g0 ! Did we get it?
bne 1b ! Nope...
ld [%g1], %g7 ! Load locked atomic24_t
sra %g7, 8, %g7 ! Get signed 24-bit integer
add %g7, %g2, %g2 ! Add in argument
sll %g2, 8, %g7 ! Transpose back to atomic24_t
st %g7, [%g1] ! Clever: This releases the lock as well.
#else
ld [%g1], %g7 ! Load locked atomic24_t
add %g7, %g2, %g2 ! Add in argument
st %g2, [%g1] ! Store it back
#endif
wr %g3, 0x0, %psr ! Restore original PSR_PIL
nop; nop; nop; ! Let the bits set
jmpl %o7, %g0 ! NOTE: not + 8, see callers in atomic.h
mov %g4, %o7 ! Restore %o7

.globl ___atomic24_sub
___atomic24_sub:
rd %psr, %g3 ! Keep the code small, old way was stupid
nop; nop; nop; ! Let the bits set
or %g3, PSR_PIL, %g7 ! Disable interrupts
wr %g7, 0x0, %psr ! Set %psr
nop; nop; nop; ! Let the bits set
#ifdef CONFIG_SMP
1: ldstub [%g1 + 3], %g7 ! Spin on the byte lock for SMP.
orcc %g7, 0x0, %g0 ! Did we get it?
bne 1b ! Nope...
ld [%g1], %g7 ! Load locked atomic24_t
sra %g7, 8, %g7 ! Get signed 24-bit integer
sub %g7, %g2, %g2 ! Subtract argument
sll %g2, 8, %g7 ! Transpose back to atomic24_t
st %g7, [%g1] ! Clever: This releases the lock as well
#else
ld [%g1], %g7 ! Load locked atomic24_t
sub %g7, %g2, %g2 ! Subtract argument
st %g2, [%g1] ! Store it back
#endif
wr %g3, 0x0, %psr ! Restore original PSR_PIL
nop; nop; nop; ! Let the bits set
jmpl %o7, %g0 ! NOTE: not + 8, see callers in atomic.h
mov %g4, %o7 ! Restore %o7

.globl __atomic_end
__atomic_end:
6 changes: 0 additions & 6 deletions arch/sparc/lib/ksyms.c
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Expand Up @@ -62,8 +62,6 @@ extern void ___rw_read_enter(void);
extern void ___rw_read_try(void);
extern void ___rw_read_exit(void);
extern void ___rw_write_enter(void);
extern void ___atomic24_add(void);
extern void ___atomic24_sub(void);

/* Alias functions whose names begin with "." and export the aliases.
* The module references will be fixed up by module_frob_arch_sections.
Expand Down Expand Up @@ -97,10 +95,6 @@ EXPORT_SYMBOL(___rw_read_exit);
EXPORT_SYMBOL(___rw_write_enter);
#endif

/* Atomic operations. */
EXPORT_SYMBOL(___atomic24_add);
EXPORT_SYMBOL(___atomic24_sub);

EXPORT_SYMBOL(__ashrdi3);
EXPORT_SYMBOL(__ashldi3);
EXPORT_SYMBOL(__lshrdi3);
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