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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (C) 2018 Turing Robotic Industries Inc.
* Copyright (C) 2022 Dmitry Chagin <dchagin@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/elf_common.h>
#include <machine/asm.h>
#include <machine/param.h>
#include <machine/vmparam.h>
#include <sys/errno.h>
#include "assym.inc"
.macro check_user_access user_arg, limit, bad_addr_func
ldr x7, =(\limit)
cmp x\user_arg, x7
b.cs \bad_addr_func
.endm
futex_fault:
SET_FAULT_HANDLER(xzr, x1)
EXIT_USER_ACCESS_CHECK(w0, x1)
futex_fault_nopcb:
mov x0, #EFAULT
ret
#define LINUX_FUTEX_MAX_LOOPS 128
/*
* int oparg, uint32_t *uaddr, int *oldval
*
* Return 0 on success, errno on failure,
* EAGAIN is returned if LL/SC operation fails.
*
* XXX. VM_MAXUSER_ADDRESS is not applicable here, should be replaced
* by something like LINUX_SHAREDPAGE.
*/
/* (int *)uaddr2 = oparg */
ENTRY(futex_xchgl)
check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
adr x9, futex_fault /* Load the fault handler */
SET_FAULT_HANDLER(x9, x4) /* And set it */
ENTER_USER_ACCESS(w9, x4)
mov w5, #LINUX_FUTEX_MAX_LOOPS
prfm pstl1strm, [x1]
mov w6, w0 /* Save oparg */
1: ldxr w4, [x1] /* Load oldval from uaddr */
stlxr w0, w6, [x1] /* Store oparg to uaddr */
cbz w0, 3f /* Exit on success */
sub w5, w5, w0 /* Dec loop counter, w0 is 1 */
cbnz w5, 1b /* Loop */
mov x0, #EAGAIN /* Store of newval failed */
3: dmb ish
EXIT_USER_ACCESS(w9)
SET_FAULT_HANDLER(xzr, x9) /* Reset the fault handler */
str w4, [x2] /* Store oldval */
ret
END(futex_xchgl)
/* (int *)uaddr2 += oparg */
ENTRY(futex_addl)
check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
adr x9, futex_fault
SET_FAULT_HANDLER(x9, x4)
ENTER_USER_ACCESS(w9, x4)
mov w5, #LINUX_FUTEX_MAX_LOOPS
prfm pstl1strm, [x1]
mov w6, w0
1: ldxr w4, [x1]
add w3, w4, w6 /* oldval + oparg */
stlxr w0, w3, [x1]
cbz w0, 3f
sub w5, w5, w0
cbnz w5, 1b
mov x0, #EAGAIN
3: dmb ish
EXIT_USER_ACCESS(w9)
SET_FAULT_HANDLER(xzr, x9)
str w4, [x2]
ret
END(futex_addl)
/* (int *)uaddr2 |= oparg */
ENTRY(futex_orl)
check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
adr x9, futex_fault
SET_FAULT_HANDLER(x9, x4)
ENTER_USER_ACCESS(w9, x4)
mov w5, #LINUX_FUTEX_MAX_LOOPS
prfm pstl1strm, [x1]
mov w6, w0
1: ldxr w4, [x1]
orr w3, w4, w6 /* oldavl |= oparg */
stlxr w0, w3, [x1]
cbz w0, 3f
sub w5, w5, w0
cbnz w5, 1b
mov x0, #EAGAIN
3: dmb ish
EXIT_USER_ACCESS(w9)
SET_FAULT_HANDLER(xzr, x9)
str w4, [x2]
ret
END(futex_orl)
/* (int *)uaddr2 &= oparg */
ENTRY(futex_andl)
check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
adr x9, futex_fault
SET_FAULT_HANDLER(x9, x4)
ENTER_USER_ACCESS(w9, x4)
mov w5, #LINUX_FUTEX_MAX_LOOPS
prfm pstl1strm, [x1]
mov w6, w0
1: ldxr w4, [x1]
and w3, w4, w6 /* oldval &= oparg */
stlxr w0, w3, [x1]
cbz w0, 3f
sub w5, w5, w0
cbnz w5, 1b
mov x0, #EAGAIN
3: dmb ish
EXIT_USER_ACCESS(w9)
SET_FAULT_HANDLER(xzr, x9)
str w4, [x2]
ret
END(futex_andl)
/* (int *)uaddr2 ^= oparg */
ENTRY(futex_xorl)
check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
adr x9, futex_fault
SET_FAULT_HANDLER(x9, x4)
ENTER_USER_ACCESS(w9, x4)
mov w5, #LINUX_FUTEX_MAX_LOOPS
prfm pstl1strm, [x1]
mov w6, w0
1: ldxr w4, [x1]
eor w3, w4, w6 /* oldval ^= oparg */
stlxr w0, w3, [x1]
cbz w0, 3f
sub w5, w5, w0
cbnz w5, 1b
mov x0, #EAGAIN
3: dmb ish
EXIT_USER_ACCESS(w9)
SET_FAULT_HANDLER(xzr, x9)
str w4, [x2]
ret
END(futex_xorl)
GNU_PROPERTY_AARCH64_FEATURE_1_NOTE(GNU_PROPERTY_AARCH64_FEATURE_1_VAL)
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