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0f58189d4a
As noticed by Mikulas Patocka, the backoff macros don't completely nop out for UP builds, we still get a branch always and a delay slot nop. Fix this by making the branch to the backoff spin loop selective, then we can nop out the spin loop completely. Signed-off-by: David S. Miller <davem@davemloft.net>
134 lines
3 KiB
ArmAsm
134 lines
3 KiB
ArmAsm
/* atomic.S: These things are too big to do inline.
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*
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* Copyright (C) 1999, 2007 David S. Miller (davem@davemloft.net)
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*/
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#include <asm/asi.h>
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#include <asm/backoff.h>
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.text
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/* Two versions of the atomic routines, one that
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* does not return a value and does not perform
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* memory barriers, and a second which returns
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* a value and does the barriers.
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*/
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.globl atomic_add
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.type atomic_add,#function
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atomic_add: /* %o0 = increment, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: lduw [%o1], %g1
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add %g1, %o0, %g7
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cas [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %icc, BACKOFF_LABEL(2f, 1b)
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nop
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retl
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nop
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic_add, .-atomic_add
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.globl atomic_sub
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.type atomic_sub,#function
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atomic_sub: /* %o0 = decrement, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: lduw [%o1], %g1
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sub %g1, %o0, %g7
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cas [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %icc, BACKOFF_LABEL(2f, 1b)
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nop
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retl
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nop
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic_sub, .-atomic_sub
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.globl atomic_add_ret
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.type atomic_add_ret,#function
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atomic_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: lduw [%o1], %g1
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add %g1, %o0, %g7
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cas [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %icc, BACKOFF_LABEL(2f, 1b)
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add %g1, %o0, %g1
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retl
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sra %g1, 0, %o0
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic_add_ret, .-atomic_add_ret
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.globl atomic_sub_ret
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.type atomic_sub_ret,#function
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atomic_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: lduw [%o1], %g1
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sub %g1, %o0, %g7
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cas [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %icc, BACKOFF_LABEL(2f, 1b)
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sub %g1, %o0, %g1
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retl
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sra %g1, 0, %o0
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic_sub_ret, .-atomic_sub_ret
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.globl atomic64_add
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.type atomic64_add,#function
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atomic64_add: /* %o0 = increment, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: ldx [%o1], %g1
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add %g1, %o0, %g7
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casx [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
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nop
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retl
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nop
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic64_add, .-atomic64_add
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.globl atomic64_sub
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.type atomic64_sub,#function
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atomic64_sub: /* %o0 = decrement, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: ldx [%o1], %g1
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sub %g1, %o0, %g7
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casx [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
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nop
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retl
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nop
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic64_sub, .-atomic64_sub
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.globl atomic64_add_ret
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.type atomic64_add_ret,#function
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atomic64_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: ldx [%o1], %g1
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add %g1, %o0, %g7
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casx [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
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nop
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retl
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add %g1, %o0, %o0
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic64_add_ret, .-atomic64_add_ret
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.globl atomic64_sub_ret
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.type atomic64_sub_ret,#function
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atomic64_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
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BACKOFF_SETUP(%o2)
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1: ldx [%o1], %g1
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sub %g1, %o0, %g7
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casx [%o1], %g1, %g7
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cmp %g1, %g7
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bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
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nop
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retl
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sub %g1, %o0, %o0
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2: BACKOFF_SPIN(%o2, %o3, 1b)
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.size atomic64_sub_ret, .-atomic64_sub_ret
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