android_kernel_xiaomi_sm8350/include/asm-sparc64/futex.h
David S. Miller c7fed9d750 [SPARC64]: Fix futex_atomic_cmpxchg_inatomic implementation.
I copied the logic from ll/sc arch implementations, but that
was wrong and makes no sense at all.  Just do a straight
compare-exchange instruction, just like x86.

Based upon bug reports from Dennis Gilmore and Fabio Massimo.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-11-01 16:30:39 -08:00

109 lines
2.6 KiB
C

#ifndef _SPARC64_FUTEX_H
#define _SPARC64_FUTEX_H
#include <linux/futex.h>
#include <asm/errno.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#define __futex_cas_op(insn, ret, oldval, uaddr, oparg) \
__asm__ __volatile__( \
"\n1: lduwa [%3] %%asi, %2\n" \
" " insn "\n" \
"2: casa [%3] %%asi, %2, %1\n" \
" cmp %2, %1\n" \
" bne,pn %%icc, 1b\n" \
" mov 0, %0\n" \
"3:\n" \
" .section .fixup,#alloc,#execinstr\n" \
" .align 4\n" \
"4: ba 3b\n" \
" mov %5, %0\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .align 4\n" \
" .word 1b, 4b\n" \
" .word 2b, 4b\n" \
" .previous\n" \
: "=&r" (ret), "=&r" (oldval), "=&r" (tem) \
: "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
: "memory")
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, tem;
if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(int))))
return -EFAULT;
if (unlikely((((unsigned long) uaddr) & 0x3UL)))
return -EINVAL;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
inc_preempt_count();
switch (op) {
case FUTEX_OP_SET:
__futex_cas_op("mov\t%4, %1", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_cas_op("add\t%2, %4, %1", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_cas_op("or\t%2, %4, %1", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_cas_op("and\t%2, %4, %1", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_XOR:
__futex_cas_op("xor\t%2, %4, %1", ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
dec_preempt_count();
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)
{
__asm__ __volatile__(
"\n1: casa [%3] %%asi, %2, %0\n"
"2:\n"
" .section .fixup,#alloc,#execinstr\n"
" .align 4\n"
"3: ba 2b\n"
" mov %4, %0\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .align 4\n"
" .word 1b, 3b\n"
" .previous\n"
: "=r" (newval)
: "0" (newval), "r" (oldval), "r" (uaddr), "i" (-EFAULT)
: "memory");
return newval;
}
#endif /* !(_SPARC64_FUTEX_H) */