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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b791d1193a
On some CPUs, it is more efficient to disable and enable interrupts in the kernel rather than use ll/sc for atomic operations. But if we were to set cpu_has_llsc to false, we would break the userspace futex interface (in asm/futex.h). We separate the two concepts, with a new predicate kernel_uses_llsc, that lets us disable the kernel's use of ll/sc while still allowing the futex code to use it. Also there were a couple of cases in bitops.h where we were using ll/sc unconditionally even if cpu_has_llsc were false. Signed-off-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
222 lines
5.9 KiB
C
222 lines
5.9 KiB
C
#ifndef _ARCH_MIPS_LOCAL_H
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#define _ARCH_MIPS_LOCAL_H
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#include <linux/percpu.h>
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#include <linux/bitops.h>
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#include <asm/atomic.h>
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#include <asm/cmpxchg.h>
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#include <asm/war.h>
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typedef struct
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{
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atomic_long_t a;
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} local_t;
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#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
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#define local_read(l) atomic_long_read(&(l)->a)
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#define local_set(l, i) atomic_long_set(&(l)->a, (i))
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#define local_add(i, l) atomic_long_add((i), (&(l)->a))
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#define local_sub(i, l) atomic_long_sub((i), (&(l)->a))
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#define local_inc(l) atomic_long_inc(&(l)->a)
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#define local_dec(l) atomic_long_dec(&(l)->a)
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/*
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* Same as above, but return the result value
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*/
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static __inline__ long local_add_return(long i, local_t * l)
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{
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unsigned long result;
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1:" __LL "%1, %2 # local_add_return \n"
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" addu %0, %1, %3 \n"
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__SC "%0, %2 \n"
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" beqzl %0, 1b \n"
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" addu %0, %1, %3 \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
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: "Ir" (i), "m" (l->a.counter)
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: "memory");
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} else if (kernel_uses_llsc) {
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1:" __LL "%1, %2 # local_add_return \n"
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" addu %0, %1, %3 \n"
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__SC "%0, %2 \n"
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" beqz %0, 1b \n"
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" addu %0, %1, %3 \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
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: "Ir" (i), "m" (l->a.counter)
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: "memory");
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} else {
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unsigned long flags;
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local_irq_save(flags);
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result = l->a.counter;
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result += i;
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l->a.counter = result;
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local_irq_restore(flags);
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}
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return result;
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}
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static __inline__ long local_sub_return(long i, local_t * l)
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{
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unsigned long result;
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1:" __LL "%1, %2 # local_sub_return \n"
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" subu %0, %1, %3 \n"
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__SC "%0, %2 \n"
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" beqzl %0, 1b \n"
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" subu %0, %1, %3 \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
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: "Ir" (i), "m" (l->a.counter)
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: "memory");
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} else if (kernel_uses_llsc) {
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1:" __LL "%1, %2 # local_sub_return \n"
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" subu %0, %1, %3 \n"
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__SC "%0, %2 \n"
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" beqz %0, 1b \n"
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" subu %0, %1, %3 \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
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: "Ir" (i), "m" (l->a.counter)
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: "memory");
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} else {
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unsigned long flags;
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local_irq_save(flags);
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result = l->a.counter;
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result -= i;
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l->a.counter = result;
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local_irq_restore(flags);
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}
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return result;
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}
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#define local_cmpxchg(l, o, n) \
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((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
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#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
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/**
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* local_add_unless - add unless the number is a given value
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* @l: pointer of type local_t
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* @a: the amount to add to l...
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* @u: ...unless l is equal to u.
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*
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* Atomically adds @a to @l, so long as it was not @u.
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* Returns non-zero if @l was not @u, and zero otherwise.
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*/
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#define local_add_unless(l, a, u) \
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({ \
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long c, old; \
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c = local_read(l); \
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while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \
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c = old; \
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c != (u); \
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})
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#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
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#define local_dec_return(l) local_sub_return(1, (l))
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#define local_inc_return(l) local_add_return(1, (l))
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/*
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* local_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @l: pointer of type local_t
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*
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* Atomically subtracts @i from @l and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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#define local_sub_and_test(i, l) (local_sub_return((i), (l)) == 0)
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/*
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* local_inc_and_test - increment and test
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* @l: pointer of type local_t
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*
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* Atomically increments @l by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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#define local_inc_and_test(l) (local_inc_return(l) == 0)
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/*
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* local_dec_and_test - decrement by 1 and test
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* @l: pointer of type local_t
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*
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* Atomically decrements @l by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
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/*
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* local_add_negative - add and test if negative
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* @l: pointer of type local_t
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* @i: integer value to add
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*
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* Atomically adds @i to @l and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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#define local_add_negative(i, l) (local_add_return(i, (l)) < 0)
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/* Use these for per-cpu local_t variables: on some archs they are
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* much more efficient than these naive implementations. Note they take
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* a variable, not an address.
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*/
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#define __local_inc(l) ((l)->a.counter++)
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#define __local_dec(l) ((l)->a.counter++)
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#define __local_add(i, l) ((l)->a.counter+=(i))
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#define __local_sub(i, l) ((l)->a.counter-=(i))
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/* Need to disable preemption for the cpu local counters otherwise we could
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still access a variable of a previous CPU in a non atomic way. */
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#define cpu_local_wrap_v(l) \
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({ local_t res__; \
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preempt_disable(); \
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res__ = (l); \
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preempt_enable(); \
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res__; })
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#define cpu_local_wrap(l) \
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({ preempt_disable(); \
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l; \
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preempt_enable(); }) \
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#define cpu_local_read(l) cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
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#define cpu_local_set(l, i) cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
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#define cpu_local_inc(l) cpu_local_wrap(local_inc(&__get_cpu_var(l)))
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#define cpu_local_dec(l) cpu_local_wrap(local_dec(&__get_cpu_var(l)))
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#define cpu_local_add(i, l) cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
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#define cpu_local_sub(i, l) cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
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#define __cpu_local_inc(l) cpu_local_inc(l)
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#define __cpu_local_dec(l) cpu_local_dec(l)
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#define __cpu_local_add(i, l) cpu_local_add((i), (l))
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#define __cpu_local_sub(i, l) cpu_local_sub((i), (l))
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#endif /* _ARCH_MIPS_LOCAL_H */
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