Commit fc1d4c9c authored by Kaz Kojima's avatar Kaz Kojima Committed by Paul Mundt
Browse files

sh: Fix up futex implementation. 



SH is able to support a complete futex implementation on UP by way
of gUSA. However, IRQ toggling must be done for the old CPUs that
don't have movli.l/movco.l (LL/SC) instructions. Provide a default
implementation that does this, so it's possible to optimize for
newer CPUs.

Follows the same scheme as the current asm-sh/atomic-*.h headers.

Signed-off-by: default avatarKaz Kojima <kkojima@rr.iij4u.or.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent eee4c469

include/asm-sh/futex-irq.h

0 → 100644
+111 −0
Original line number Diff line number Diff line 
#ifndef __ASM_SH_FUTEX_IRQ_H

#define __ASM_SH_FUTEX_IRQ_H



#include <asm/system.h>



static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr,

					   int *oldval)

{

	unsigned long flags;

	int ret;



	local_irq_save(flags);



	ret = get_user(*oldval, uaddr);

	if (!ret)

		ret = put_user(oparg, uaddr);



	local_irq_restore(flags);



	return ret;

}



static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr,

					   int *oldval)

{

	unsigned long flags;

	int ret;



	local_irq_save(flags);



	ret = get_user(*oldval, uaddr);

	if (!ret)

		ret = put_user(*oldval + oparg, uaddr);



	local_irq_restore(flags);



	return ret;

}



static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr,

					  int *oldval)

{

	unsigned long flags;

	int ret;



	local_irq_save(flags);



	ret = get_user(*oldval, uaddr);

	if (!ret)

		ret = put_user(*oldval | oparg, uaddr);



	local_irq_restore(flags);



	return ret;

}



static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr,

					   int *oldval)

{

	unsigned long flags;

	int ret;



	local_irq_save(flags);



	ret = get_user(*oldval, uaddr);

	if (!ret)

		ret = put_user(*oldval & oparg, uaddr);



	local_irq_restore(flags);



	return ret;

}



static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr,

					   int *oldval)

{

	unsigned long flags;

	int ret;



	local_irq_save(flags);



	ret = get_user(*oldval, uaddr);

	if (!ret)

		ret = put_user(*oldval ^ oparg, uaddr);



	local_irq_restore(flags);



	return ret;

}



static inline int atomic_futex_op_cmpxchg_inatomic(int __user *uaddr,

						   int oldval, int newval)

{

	unsigned long flags;

	int ret, prev = 0;



	local_irq_save(flags);



	ret = get_user(prev, uaddr);

	if (!ret && oldval == prev)

		ret = put_user(newval, uaddr);



	local_irq_restore(flags);



	if (ret)

		return ret;



	return prev;

}



#endif /* __ASM_SH_FUTEX_IRQ_H */

include/asm-sh/futex.h

+75 −4
Original line number Diff line number Diff line 
#ifndef _ASM_FUTEX_H

#define _ASM_FUTEX_H

#ifndef __ASM_SH_FUTEX_H

#define __ASM_SH_FUTEX_H



#include <asm-generic/futex.h>

#ifdef __KERNEL__



#endif
 
#include <linux/futex.h>

#include <asm/errno.h>

#include <asm/uaccess.h>



/* XXX: UP variants, fix for SH-4A and SMP.. */

#include <asm/futex-irq.h>



static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)

{

	int op = (encoded_op >> 28) & 7;

	int cmp = (encoded_op >> 24) & 15;

	int oparg = (encoded_op << 8) >> 20;

	int cmparg = (encoded_op << 20) >> 20;

	int oldval = 0, ret;



	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))

		oparg = 1 << oparg;



	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))

		return -EFAULT;



	pagefault_disable();



	switch (op) {

	case FUTEX_OP_SET:

		ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);

		break;

	case FUTEX_OP_ADD:

		ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);

		break;

	case FUTEX_OP_OR:

		ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);

		break;

	case FUTEX_OP_ANDN:

		ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);

		break;

	case FUTEX_OP_XOR:

		ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);

		break;

	default:

		ret = -ENOSYS;

		break;

	}



	pagefault_enable();



	if (!ret) {

		switch (cmp) {

		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;

		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;

		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;

		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;

		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;

		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;

		default: ret = -ENOSYS;

		}

	}



	return ret;

}



static inline int

futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)

{

	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))

		return -EFAULT;



	return atomic_futex_op_cmpxchg_inatomic(uaddr, oldval, newval);

}



#endif /* __KERNEL__ */

#endif /* __ASM_SH_FUTEX_H */

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