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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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7d9794e752
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rich Felker <dalias@libc.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-sh@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
#ifndef __ASM_SH_ATOMIC_LLSC_H
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#define __ASM_SH_ATOMIC_LLSC_H
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/*
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* SH-4A note:
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*
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* We basically get atomic_xxx_return() for free compared with
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* atomic_xxx(). movli.l/movco.l require r0 due to the instruction
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* encoding, so the retval is automatically set without having to
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* do any special work.
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*/
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/*
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* To get proper branch prediction for the main line, we must branch
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* forward to code at the end of this object's .text section, then
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* branch back to restart the operation.
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*/
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#define ATOMIC_OP(op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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unsigned long tmp; \
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\
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__asm__ __volatile__ ( \
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"1: movli.l @%2, %0 ! atomic_" #op "\n" \
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" " #op " %1, %0 \n" \
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" movco.l %0, @%2 \n" \
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" bf 1b \n" \
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: "=&z" (tmp) \
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: "r" (i), "r" (&v->counter) \
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: "t"); \
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}
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#define ATOMIC_OP_RETURN(op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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unsigned long temp; \
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\
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__asm__ __volatile__ ( \
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"1: movli.l @%2, %0 ! atomic_" #op "_return \n" \
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" " #op " %1, %0 \n" \
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" movco.l %0, @%2 \n" \
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" bf 1b \n" \
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" synco \n" \
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: "=&z" (temp) \
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: "r" (i), "r" (&v->counter) \
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: "t"); \
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\
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return temp; \
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}
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#define ATOMIC_FETCH_OP(op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned long res, temp; \
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\
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__asm__ __volatile__ ( \
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"1: movli.l @%3, %0 ! atomic_fetch_" #op " \n" \
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" mov %0, %1 \n" \
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" " #op " %2, %0 \n" \
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" movco.l %0, @%3 \n" \
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" bf 1b \n" \
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" synco \n" \
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: "=&z" (temp), "=&z" (res) \
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: "r" (i), "r" (&v->counter) \
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: "t"); \
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\
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return res; \
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}
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#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
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ATOMIC_OPS(add)
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ATOMIC_OPS(sub)
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#undef ATOMIC_OPS
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#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
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ATOMIC_OPS(and)
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ATOMIC_OPS(or)
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ATOMIC_OPS(xor)
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#undef ATOMIC_OPS
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#undef ATOMIC_FETCH_OP
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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#endif /* __ASM_SH_ATOMIC_LLSC_H */
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