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microblaze: Futex support 

Microblaze v7.20 provides new lwx, swx instructions which bring
possibility to implement lock rutines.

There are some tests in open posix thread LTP part but current
toolchain not support it.

Signed-off-by: Michal Simek <monstr@monstr.eu>
This commit is contained in:
Michal Simek 2009-10-19 11:58:44 +02:00
parent d68bf9705a
commit fd3db0a675
1 changed files with 126 additions and 1 deletions
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127
arch/microblaze/include/asm/futex.h
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@ -1 +1,126 @@
#include <asm-generic/futex.h>
#ifndef _ASM_MICROBLAZE_FUTEX_H
#define _ASM_MICROBLAZE_FUTEX_H
#ifdef __KERNEL__
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
({ \
__asm__ __volatile__ ( \
"1: lwx %0, %2, r0; " \
insn \
"2: swx %1, %2, r0; \
addic %1, r0, 0; \
bnei %1, 1b; \
3: \
.section .fixup,\"ax\"; \
4: brid 3b; \
addik %1, r0, %3; \
.previous; \
.section __ex_table,\"a\"; \
.word 1b,4b,2b,4b; \
.previous;" \
: "=&r" (oldval), "=&r" (ret) \
: "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
); \
})
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:
__futex_atomic_op("or %1,%4,%4;", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("add %1,%0,%4;", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("or %1,%0,%4;", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("and %1,%0,%4;", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("xor %1,%0,%4;", ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
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)
{
int prev, cmp;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
__asm__ __volatile__ ("1: lwx %0, %2, r0; \
cmp %1, %0, %3; \
beqi %1, 3f; \
2: swx %4, %2, r0; \
addic %1, r0, 0; \
bnei %1, 1b; \
3: \
.section .fixup,\"ax\"; \
4: brid 3b; \
addik %0, r0, %5; \
.previous; \
.section __ex_table,\"a\"; \
.word 1b,4b,2b,4b; \
.previous;" \
: "=&r" (prev), "=&r"(cmp) \
: "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT));
return prev;
}
#endif /* __KERNEL__ */
#endif