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diff --git a/sys/arm64/linux/linux_support.s b/sys/arm64/linux/linux_support.s
--- a/sys/arm64/linux/linux_support.s
+++ b/sys/arm64/linux/linux_support.s
@@ -2,6 +2,7 @@
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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
@@ -27,36 +28,151 @@
* $FreeBSD$
*/
-#include "linux_assym.h"
#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+#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
+
/*
- * LINUXTODO: implement futex_*
+ * 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)
- brk #0
+ 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)
- brk #0
+ 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)
- brk #0
+ 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)
- brk #0
+ 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)
- brk #0
+ 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)

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