tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
alpha: futex implementation
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
authored by
Ivan Kokshaysky
and committed by
Linus Torvalds
77b4cf5c
08a42e86
+116
-4
+2
arch/alpha/include/asm/barrier.h
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arch/alpha/include/asm/barrier.h
···
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__asm__ __volatile__("mb": : :"memory")
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#ifdef CONFIG_SMP
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#define __ASM_SMP_MB "\tmb\n"
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#define smp_read_barrier_depends() read_barrier_depends()
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#else
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#define __ASM_SMP_MB
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#define smp_mb() barrier()
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#define smp_rmb() barrier()
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#define smp_wmb() barrier()
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arch/alpha/include/asm/futex.h
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arch/alpha/include/asm/futex.h
···
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#ifndef _ASM_FUTEX_H
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#define _ASM_FUTEX_H
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#ifndef _ASM_ALPHA_FUTEX_H
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#define _ASM_ALPHA_FUTEX_H
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#include <asm-generic/futex.h>
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#ifdef __KERNEL__
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#endif
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#include <linux/futex.h>
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#include <linux/uaccess.h>
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#include <asm/errno.h>
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#include <asm/barrier.h>
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#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
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__asm__ __volatile__( \
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__ASM_SMP_MB \
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"1: ldl_l %0,0(%2)\n" \
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insn \
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"2: stl_c %1,0(%2)\n" \
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" beq %1,4f\n" \
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" mov $31,%1\n" \
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"3: .subsection 2\n" \
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"4: br 1b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .long 1b-.\n" \
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" lda $31,3b-1b(%1)\n" \
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" .long 2b-.\n" \
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" lda $31,3b-2b(%1)\n" \
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" .previous\n" \
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: "=&r" (oldval), "=&r"(ret) \
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: "r" (uaddr), "r"(oparg) \
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: "memory")
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static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
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{
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int op = (encoded_op >> 28) & 7;
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int cmp = (encoded_op >> 24) & 15;
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int oparg = (encoded_op << 8) >> 20;
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int cmparg = (encoded_op << 20) >> 20;
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int oldval = 0, ret;
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if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
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oparg = 1 << oparg;
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if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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return -EFAULT;
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pagefault_disable();
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switch (op) {
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case FUTEX_OP_SET:
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__futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ADD:
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__futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_OR:
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__futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ANDN:
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__futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_XOR:
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__futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
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break;
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default:
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ret = -ENOSYS;
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}
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pagefault_enable();
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if (!ret) {
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switch (cmp) {
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case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
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case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
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case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
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case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
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case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
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case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
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default: ret = -ENOSYS;
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}
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}
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return ret;
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}
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static inline int
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futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
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{
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int prev, cmp;
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if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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return -EFAULT;
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__asm__ __volatile__ (
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__ASM_SMP_MB
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"1: ldl_l %0,0(%2)\n"
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" cmpeq %0,%3,%1\n"
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" beq %1,3f\n"
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" mov %4,%1\n"
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"2: stl_c %1,0(%2)\n"
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" beq %1,4f\n"
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"3: .subsection 2\n"
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"4: br 1b\n"
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" .previous\n"
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" .section __ex_table,\"a\"\n"
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" .long 1b-.\n"
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" lda $31,3b-1b(%0)\n"
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" .long 2b-.\n"
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" lda $31,3b-2b(%0)\n"
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" .previous\n"
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: "=&r"(prev), "=&r"(cmp)
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: "r"(uaddr), "r"((long)oldval), "r"(newval)
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: "memory");
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return prev;
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}
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#endif /* __KERNEL__ */
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#endif /* _ASM_ALPHA_FUTEX_H */