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Add muldiv/rd_tsc support for arm64 platform. 

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: If35459be78e023346a140184401172f8e023c7f9
PiperOrigin-RevId: 231638020
This commit is contained in:
Haibo Xu 2019-01-30 11:48:02 -08:00 committed by Shentubot
parent f03c7e48e7
commit cedff8d3ae
5 changed files with 167 additions and 1 deletions
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5
pkg/sentry/time/BUILD
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@ -1,6 +1,6 @@
load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
package(licenses = ["notice"]) # Apache 2.0
package(licenses = ["notice"]) # Apache 2.0, portions BSD
load("//tools/go_generics:defs.bzl", "go_template_instance")
@ -18,15 +18,18 @@ go_template_instance(
go_library(
name = "time",
srcs = [
"arith_arm64.go",
"calibrated_clock.go",
"clock_id.go",
"clocks.go",
"muldiv_amd64.s",
"muldiv_arm64.s",
"parameters.go",
"sampler.go",
"sampler_unsafe.go",
"seqatomic_parameters.go",
"tsc_amd64.s",
"tsc_arm64.s",
],
importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/time",
visibility = ["//pkg/sentry:internal"],

27
pkg/sentry/time/LICENSE Normal file
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@ -0,0 +1,27 @@
Copyright (c) 2009 The Go Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* 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.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
OWNER 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.

70
pkg/sentry/time/arith_arm64.go Normal file
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@ -0,0 +1,70 @@
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file provides a generic Go implementation of uint128 divided by uint64.
// The code is derived from Go's generic math/big.divWW_g
// (src/math/big/arith.go), but is only used on ARM64.
package time
import "math/bits"
type word uint
const (
_W = bits.UintSize // word size in bits
_W2 = _W / 2 // half word size in bits
_B2 = 1 << _W2 // half digit base
_M2 = _B2 - 1 // half digit mask
)
// nlz returns the number of leading zeros in x.
// Wraps bits.LeadingZeros call for convenience.
func nlz(x word) uint {
return uint(bits.LeadingZeros(uint(x)))
}
// q = (u1<<_W + u0 - r)/y
// Adapted from Warren, Hacker's Delight, p. 152.
func divWW(u1, u0, v word) (q, r word) {
if u1 >= v {
return 1<<_W - 1, 1<<_W - 1
}
s := nlz(v)
v <<= s
vn1 := v >> _W2
vn0 := v & _M2
un32 := u1<<s | u0>>(_W-s)
un10 := u0 << s
un1 := un10 >> _W2
un0 := un10 & _M2
q1 := un32 / vn1
rhat := un32 - q1*vn1
for q1 >= _B2 || q1*vn0 > _B2*rhat+un1 {
q1--
rhat += vn1
if rhat >= _B2 {
break
}
}
un21 := un32*_B2 + un1 - q1*v
q0 := un21 / vn1
rhat = un21 - q0*vn1
for q0 >= _B2 || q0*vn0 > _B2*rhat+un0 {
q0--
rhat += vn1
if rhat >= _B2 {
break
}
}
return q1*_B2 + q0, (un21*_B2 + un0 - q0*v) >> s
}

44
pkg/sentry/time/muldiv_arm64.s Normal file
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@ -0,0 +1,44 @@
// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "textflag.h"
// Documentation is available in parameters.go.
//
// func muldiv64(value, multiplier, divisor uint64) (uint64, bool)
TEXT ·muldiv64(SB),NOSPLIT,$40-33
MOVD value+0(FP), R0
MOVD multiplier+8(FP), R1
MOVD divisor+16(FP), R2
UMULH R0, R1, R3
MUL R0, R1, R4
CMP R2, R3
BHS overflow
MOVD R3, 8(RSP)
MOVD R4, 16(RSP)
MOVD R2, 24(RSP)
CALL ·divWW(SB)
MOVD 32(RSP), R0
MOVD R0, result+24(FP)
MOVD $1, R0
MOVB R0, ok+32(FP)
RET
overflow:
MOVD ZR, result+24(FP)
MOVB ZR, ok+32(FP)
RET

22
pkg/sentry/time/tsc_arm64.s Normal file
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@ -0,0 +1,22 @@
// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "textflag.h"
TEXT ·Rdtsc(SB),NOSPLIT,$0-8
// Get the virtual counter.
ISB $15
WORD $0xd53be040 //MRS CNTVCT_EL0, R0
MOVD R0, ret+0(FP)
RET