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4f41c2b456
There are only two uaccess variants on s390 left: the version that is used if the mvcos instruction is available, and the page table walk variant. So there is no need for expensive indirect function calls. By default the mvcos variant will be called. If the mvcos instruction is not available it will call the page table walk variant. For minimal performance impact the "if (mvcos_is_available)" is implemented with a jump label, which will be a six byte nop on machines with mvcos. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
#ifndef _ASM_S390_FUTEX_H
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#define _ASM_S390_FUTEX_H
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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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int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval);
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int __futex_atomic_op_inuser(int op, u32 __user *uaddr, int oparg, int *old);
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static inline int futex_atomic_op_inuser(int encoded_op, u32 __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, ret;
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if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
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oparg = 1 << oparg;
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pagefault_disable();
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ret = __futex_atomic_op_inuser(op, uaddr, oparg, &oldval);
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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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#endif /* _ASM_S390_FUTEX_H */
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