openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

xtensa: implement robust futex atomic uaccess ops 

This enables the set_robust_list(2) system call.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Chris Zankel <chris@zankel.net>
This commit is contained in:
Baruch Siach 2013-11-18 06:46:43 +02:00 committed by Chris Zankel
parent a6e16b9aaf
commit 220c062688
2 changed files with 147 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/xtensa/include/asm/Kbuild
View File

@ -8,7 +8,6 @@ generic-y += emergency-restart.h
generic-y += errno.h
generic-y += exec.h
generic-y += fcntl.h
generic-y += futex.h
generic-y += hardirq.h
generic-y += ioctl.h
generic-y += irq_regs.h

147
arch/xtensa/include/asm/futex.h Normal file
View File

@ -0,0 +1,147 @@
/*
* Atomic futex routines
*
* Based on the PowerPC implementataion
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Copyright (C) 2013 TangoTec Ltd.
*
* Baruch Siach <baruch@tkos.co.il>
*/
#ifndef _ASM_XTENSA_FUTEX_H
#define _ASM_XTENSA_FUTEX_H
#ifdef __KERNEL__
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
__asm__ __volatile( \
"1: l32i %0, %2, 0\n" \
insn "\n" \
" wsr %0, scompare1\n" \
"2: s32c1i %1, %2, 0\n" \
" bne %1, %0, 1b\n" \
" movi %1, 0\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
" .align 4\n" \
"4: .long 3b\n" \
"5: l32r %0, 4b\n" \
" movi %1, %3\n" \
" jx %0\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .long 1b,5b,2b,5b\n" \
" .previous\n" \
: "=&r" (oldval), "=&r" (ret) \
: "r" (uaddr), "I" (-EFAULT), "r" (oparg) \
: "memory")
static inline int futex_atomic_op_inuser(int encoded_op, u32 __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(u32)))
return -EFAULT;
#if !XCHAL_HAVE_S32C1I
return -ENOSYS;
#endif
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %1, %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)
return ret;
switch (cmp) {
case FUTEX_OP_CMP_EQ: return (oldval == cmparg);
case FUTEX_OP_CMP_NE: return (oldval != cmparg);
case FUTEX_OP_CMP_LT: return (oldval < cmparg);
case FUTEX_OP_CMP_GE: return (oldval >= cmparg);
case FUTEX_OP_CMP_LE: return (oldval <= cmparg);
case FUTEX_OP_CMP_GT: return (oldval > cmparg);
}
return -ENOSYS;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
u32 prev;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
#if !XCHAL_HAVE_S32C1I
return -ENOSYS;
#endif
__asm__ __volatile__ (
" # futex_atomic_cmpxchg_inatomic\n"
"1: l32i %1, %3, 0\n"
" mov %0, %5\n"
" wsr %1, scompare1\n"
"2: s32c1i %0, %3, 0\n"
"3:\n"
" .section .fixup,\"ax\"\n"
" .align 4\n"
"4: .long 3b\n"
"5: l32r %1, 4b\n"
" movi %0, %6\n"
" jx %1\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .long 1b,5b,2b,5b\n"
" .previous\n"
: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
: "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT)
: "memory");
*uval = prev;
return ret;
}
#endif /* __KERNEL__ */
#endif /* _ASM_XTENSA_FUTEX_H */