crashpad/snapshot/cpu_context_test.cc
Mark Mentovai 6278690abe Update copyright boilerplate, 2022 edition (Crashpad)
sed -i '' -E -e 's/Copyright (.+) The Crashpad Authors\. All rights reserved\.$/Copyright \1 The Crashpad Authors/' $(git grep -El 'Copyright (.+) The Crashpad Authors\. All rights reserved\.$')

Bug: chromium:1098010
Change-Id: I8d6138469ddbe3d281a5d83f64cf918ec2491611
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3878262
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>
2022-09-06 23:54:07 +00:00

349 lines
14 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// Copyright 2014 The Crashpad Authors
//
// 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 "snapshot/cpu_context.h"
#include <stddef.h>
#include <string.h>
#include <sys/types.h>
#include <iterator>
#include "gtest/gtest.h"
#include "test/hex_string.h"
namespace crashpad {
namespace test {
namespace {
enum ExponentValue {
kExponentAllZero = 0,
kExponentAllOne,
kExponentNormal,
};
enum FractionValue {
kFractionAllZero = 0,
kFractionNormal,
};
//! \brief Initializes an x87 register to a known bit pattern.
//!
//! \param[out] st_mm The x87 register to initialize. The reserved portion of
//! the register is always zeroed out.
//! \param[in] exponent_value The bit pattern to use for the exponent. If this
//! is kExponentAllZero, the sign bit will be set to `1`, and if this is
//! kExponentAllOne, the sign bit will be set to `0`. This tests that the
//! implementation doesnt erroneously consider the sign bit to be part of
//! the exponent. This may also be kExponentNormal, indicating that the
//! exponent shall neither be all zeroes nor all ones.
//! \param[in] j_bit The value to use for the “J bit” (“integer bit”).
//! \param[in] fraction_value If kFractionAllZero, the fraction will be zeroed
//! out. If kFractionNormal, the fraction will not be all zeroes.
void SetX87Register(CPUContextX86::X87Register* st,
ExponentValue exponent_value,
bool j_bit,
FractionValue fraction_value) {
switch (exponent_value) {
case kExponentAllZero:
(*st)[9] = 0x80;
(*st)[8] = 0;
break;
case kExponentAllOne:
(*st)[9] = 0x7f;
(*st)[8] = 0xff;
break;
case kExponentNormal:
(*st)[9] = 0x55;
(*st)[8] = 0x55;
break;
}
uint8_t fraction_pattern = fraction_value == kFractionAllZero ? 0 : 0x55;
memset(st, fraction_pattern, 8);
if (j_bit) {
(*st)[7] |= 0x80;
} else {
(*st)[7] &= ~0x80;
}
}
//! \brief Initializes an x87 register to a known bit pattern.
//!
//! This behaves as SetX87Register() but also clears the reserved portion of the
//! field as used in the `fxsave` format.
void SetX87OrMMXRegister(CPUContextX86::X87OrMMXRegister* st_mm,
ExponentValue exponent_value,
bool j_bit,
FractionValue fraction_value) {
SetX87Register(&st_mm->st, exponent_value, j_bit, fraction_value);
memset(st_mm->st_reserved, 0, sizeof(st_mm->st_reserved));
}
TEST(CPUContextX86, FxsaveToFsave) {
// Establish a somewhat plausible fxsave state. Use nonzero values for
// reserved fields and things that arent present in fsave.
CPUContextX86::Fxsave fxsave;
fxsave.fcw = 0x027f; // mask exceptions, 53-bit precision, round to nearest
fxsave.fsw = 1 << 11; // top = 1: logical 0-7 maps to physical 1-7, 0
fxsave.ftw = 0x1f; // physical 5-7 (logical 4-6) empty
fxsave.reserved_1 = 0x5a;
fxsave.fop = 0x1fe; // fsin
fxsave.fpu_ip = 0x76543210;
fxsave.fpu_cs = 0x0007;
fxsave.reserved_2 = 0x5a5a;
fxsave.fpu_dp = 0xfedcba98;
fxsave.fpu_ds = 0x000f;
fxsave.reserved_3 = 0x5a5a;
fxsave.mxcsr = 0x1f80;
fxsave.mxcsr_mask = 0xffff;
SetX87Register(
&fxsave.st_mm[0].st, kExponentNormal, true, kFractionAllZero); // valid
SetX87Register(
&fxsave.st_mm[1].st, kExponentAllZero, false, kFractionAllZero); // zero
SetX87Register(
&fxsave.st_mm[2].st, kExponentAllOne, true, kFractionAllZero); // spec.
SetX87Register(
&fxsave.st_mm[3].st, kExponentAllOne, true, kFractionNormal); // spec.
SetX87Register(
&fxsave.st_mm[4].st, kExponentAllZero, false, kFractionAllZero);
SetX87Register(
&fxsave.st_mm[5].st, kExponentAllZero, false, kFractionAllZero);
SetX87Register(
&fxsave.st_mm[6].st, kExponentAllZero, false, kFractionAllZero);
SetX87Register(
&fxsave.st_mm[7].st, kExponentNormal, true, kFractionNormal); // valid
for (size_t index = 0; index < std::size(fxsave.st_mm); ++index) {
memset(&fxsave.st_mm[index].st_reserved,
0x5a,
sizeof(fxsave.st_mm[index].st_reserved));
}
memset(&fxsave.xmm, 0x5a, sizeof(fxsave) - offsetof(decltype(fxsave), xmm));
CPUContextX86::Fsave fsave;
CPUContextX86::FxsaveToFsave(fxsave, &fsave);
// Everything should have come over from fxsave. Reserved fields should be
// zero.
EXPECT_EQ(fsave.fcw, fxsave.fcw);
EXPECT_EQ(fsave.reserved_1, 0);
EXPECT_EQ(fsave.fsw, fxsave.fsw);
EXPECT_EQ(fsave.reserved_2, 0);
EXPECT_EQ(fsave.ftw, 0xfe90); // FxsaveToFsaveTagWord
EXPECT_EQ(fsave.reserved_3, 0);
EXPECT_EQ(fsave.fpu_ip, fxsave.fpu_ip);
EXPECT_EQ(fsave.fpu_cs, fxsave.fpu_cs);
EXPECT_EQ(fsave.fop, fxsave.fop);
EXPECT_EQ(fsave.fpu_dp, fxsave.fpu_dp);
EXPECT_EQ(fsave.fpu_ds, fxsave.fpu_ds);
EXPECT_EQ(fsave.reserved_4, 0);
for (size_t index = 0; index < std::size(fsave.st); ++index) {
EXPECT_EQ(BytesToHexString(fsave.st[index], std::size(fsave.st[index])),
BytesToHexString(fxsave.st_mm[index].st,
std::size(fxsave.st_mm[index].st)))
<< "index " << index;
}
}
TEST(CPUContextX86, FsaveToFxsave) {
// Establish a somewhat plausible fsave state. Use nonzero values for
// reserved fields.
CPUContextX86::Fsave fsave;
fsave.fcw = 0x0300; // unmask exceptions, 64-bit precision, round to nearest
fsave.reserved_1 = 0xa5a5;
fsave.fsw = 2 << 11; // top = 2: logical 0-7 maps to physical 2-7, 0-1
fsave.reserved_2 = 0xa5a5;
fsave.ftw = 0xa9ff; // physical 0-3 (logical 6-7, 0-1) empty; physical 4
// (logical 2) zero; physical 5-7 (logical 3-5) special
fsave.reserved_3 = 0xa5a5;
fsave.fpu_ip = 0x456789ab;
fsave.fpu_cs = 0x1013;
fsave.fop = 0x01ee; // fldz
fsave.fpu_dp = 0x0123cdef;
fsave.fpu_ds = 0x2017;
fsave.reserved_4 = 0xa5a5;
SetX87Register(&fsave.st[0], kExponentAllZero, false, kFractionNormal);
SetX87Register(&fsave.st[1], kExponentAllZero, true, kFractionNormal);
SetX87Register(
&fsave.st[2], kExponentAllZero, false, kFractionAllZero); // zero
SetX87Register(
&fsave.st[3], kExponentAllZero, true, kFractionAllZero); // spec.
SetX87Register(
&fsave.st[4], kExponentAllZero, false, kFractionNormal); // spec.
SetX87Register(
&fsave.st[5], kExponentAllZero, true, kFractionNormal); // spec.
SetX87Register(&fsave.st[6], kExponentAllZero, false, kFractionAllZero);
SetX87Register(&fsave.st[7], kExponentAllZero, true, kFractionAllZero);
CPUContextX86::Fxsave fxsave;
CPUContextX86::FsaveToFxsave(fsave, &fxsave);
// Everything in fsave should have come over from there. Fields not present in
// fsave and reserved fields should be zero.
EXPECT_EQ(fxsave.fcw, fsave.fcw);
EXPECT_EQ(fxsave.fsw, fsave.fsw);
EXPECT_EQ(fxsave.ftw, 0xf0); // FsaveToFxsaveTagWord
EXPECT_EQ(fxsave.reserved_1, 0);
EXPECT_EQ(fxsave.fop, fsave.fop);
EXPECT_EQ(fxsave.fpu_ip, fsave.fpu_ip);
EXPECT_EQ(fxsave.fpu_cs, fsave.fpu_cs);
EXPECT_EQ(fxsave.reserved_2, 0);
EXPECT_EQ(fxsave.fpu_dp, fsave.fpu_dp);
EXPECT_EQ(fxsave.fpu_ds, fsave.fpu_ds);
EXPECT_EQ(fxsave.reserved_3, 0);
EXPECT_EQ(fxsave.mxcsr, 0u);
EXPECT_EQ(fxsave.mxcsr_mask, 0u);
for (size_t index = 0; index < std::size(fxsave.st_mm); ++index) {
EXPECT_EQ(BytesToHexString(fxsave.st_mm[index].st,
std::size(fxsave.st_mm[index].st)),
BytesToHexString(fsave.st[index], std::size(fsave.st[index])))
<< "index " << index;
EXPECT_EQ(BytesToHexString(fxsave.st_mm[index].st_reserved,
std::size(fxsave.st_mm[index].st_reserved)),
std::string(std::size(fxsave.st_mm[index].st_reserved) * 2, '0'))
<< "index " << index;
}
size_t unused_len = sizeof(fxsave) - offsetof(decltype(fxsave), xmm);
EXPECT_EQ(BytesToHexString(fxsave.xmm, unused_len),
std::string(unused_len * 2, '0'));
// Since the fsave format is a subset of the fxsave format, fsave-fxsave-fsave
// should round-trip cleanly.
CPUContextX86::Fsave fsave_2;
CPUContextX86::FxsaveToFsave(fxsave, &fsave_2);
// Clear the reserved fields in the original fsave structure, since theyre
// expected to be clear in the copy.
fsave.reserved_1 = 0;
fsave.reserved_2 = 0;
fsave.reserved_3 = 0;
fsave.reserved_4 = 0;
EXPECT_EQ(memcmp(&fsave, &fsave_2, sizeof(fsave)), 0);
}
TEST(CPUContextX86, FxsaveToFsaveTagWord) {
// The fsave tag word uses bit pattern 00 for valid, 01 for zero, 10 for
// “special”, and 11 for empty. Like the fxsave tag word, it is arranged by
// physical register. The fxsave tag word determines whether a register is
// empty, and analysis of the x87 register content distinguishes between
// valid, zero, and special. In the initializations below, comments show
// whether a register is expected to be considered valid, zero, or special,
// except where the tag word is expected to indicate that it is empty. Each
// combination appears twice: once where the fxsave tag word indicates a
// nonempty register, and once again where it indicates an empty register.
uint16_t fsw = 0 << 11; // top = 0: logical 0-7 maps to physical 0-7
uint8_t fxsave_tag = 0x0f; // physical 4-7 (logical 4-7) empty
CPUContextX86::X87OrMMXRegister st_mm[8];
SetX87OrMMXRegister(
&st_mm[0], kExponentNormal, false, kFractionNormal); // spec.
SetX87OrMMXRegister(
&st_mm[1], kExponentNormal, true, kFractionNormal); // valid
SetX87OrMMXRegister(
&st_mm[2], kExponentNormal, false, kFractionAllZero); // spec.
SetX87OrMMXRegister(
&st_mm[3], kExponentNormal, true, kFractionAllZero); // valid
SetX87OrMMXRegister(&st_mm[4], kExponentNormal, false, kFractionNormal);
SetX87OrMMXRegister(&st_mm[5], kExponentNormal, true, kFractionNormal);
SetX87OrMMXRegister(&st_mm[6], kExponentNormal, false, kFractionAllZero);
SetX87OrMMXRegister(&st_mm[7], kExponentNormal, true, kFractionAllZero);
EXPECT_EQ(CPUContextX86::FxsaveToFsaveTagWord(fsw, fxsave_tag, st_mm),
0xff22);
fsw = 2 << 11; // top = 2: logical 0-7 maps to physical 2-7, 0-1
fxsave_tag = 0xf0; // physical 0-3 (logical 6-7, 0-1) empty
SetX87OrMMXRegister(&st_mm[0], kExponentAllZero, false, kFractionNormal);
SetX87OrMMXRegister(&st_mm[1], kExponentAllZero, true, kFractionNormal);
SetX87OrMMXRegister(
&st_mm[2], kExponentAllZero, false, kFractionAllZero); // zero
SetX87OrMMXRegister(
&st_mm[3], kExponentAllZero, true, kFractionAllZero); // spec.
SetX87OrMMXRegister(
&st_mm[4], kExponentAllZero, false, kFractionNormal); // spec.
SetX87OrMMXRegister(
&st_mm[5], kExponentAllZero, true, kFractionNormal); // spec.
SetX87OrMMXRegister(&st_mm[6], kExponentAllZero, false, kFractionAllZero);
SetX87OrMMXRegister(&st_mm[7], kExponentAllZero, true, kFractionAllZero);
EXPECT_EQ(CPUContextX86::FxsaveToFsaveTagWord(fsw, fxsave_tag, st_mm),
0xa9ff);
fsw = 5 << 11; // top = 5: logical 0-7 maps to physical 5-7, 0-4
fxsave_tag = 0x5a; // physical 0, 2, 5, and 7 (logical 5, 0, 2, and 3) empty
SetX87OrMMXRegister(&st_mm[0], kExponentAllOne, false, kFractionNormal);
SetX87OrMMXRegister(
&st_mm[1], kExponentAllOne, true, kFractionNormal); // spec.
SetX87OrMMXRegister(&st_mm[2], kExponentAllOne, false, kFractionAllZero);
SetX87OrMMXRegister(&st_mm[3], kExponentAllOne, true, kFractionAllZero);
SetX87OrMMXRegister(
&st_mm[4], kExponentAllOne, false, kFractionNormal); // spec.
SetX87OrMMXRegister(&st_mm[5], kExponentAllOne, true, kFractionNormal);
SetX87OrMMXRegister(
&st_mm[6], kExponentAllOne, false, kFractionAllZero); // spec.
SetX87OrMMXRegister(
&st_mm[7], kExponentAllOne, true, kFractionAllZero); // spec.
EXPECT_EQ(CPUContextX86::FxsaveToFsaveTagWord(fsw, fxsave_tag, st_mm),
0xeebb);
// This set set is just a mix of all of the possible tag types in a single
// register file.
fsw = 1 << 11; // top = 1: logical 0-7 maps to physical 1-7, 0
fxsave_tag = 0x1f; // physical 5-7 (logical 4-6) empty
SetX87OrMMXRegister(
&st_mm[0], kExponentNormal, true, kFractionAllZero); // valid
SetX87OrMMXRegister(
&st_mm[1], kExponentAllZero, false, kFractionAllZero); // zero
SetX87OrMMXRegister(
&st_mm[2], kExponentAllOne, true, kFractionAllZero); // spec.
SetX87OrMMXRegister(
&st_mm[3], kExponentAllOne, true, kFractionNormal); // spec.
SetX87OrMMXRegister(&st_mm[4], kExponentAllZero, false, kFractionAllZero);
SetX87OrMMXRegister(&st_mm[5], kExponentAllZero, false, kFractionAllZero);
SetX87OrMMXRegister(&st_mm[6], kExponentAllZero, false, kFractionAllZero);
SetX87OrMMXRegister(
&st_mm[7], kExponentNormal, true, kFractionNormal); // valid
EXPECT_EQ(CPUContextX86::FxsaveToFsaveTagWord(fsw, fxsave_tag, st_mm),
0xfe90);
// In this set, everything is valid.
fsw = 0 << 11; // top = 0: logical 0-7 maps to physical 0-7
fxsave_tag = 0xff; // nothing empty
for (size_t index = 0; index < std::size(st_mm); ++index) {
SetX87OrMMXRegister(&st_mm[index], kExponentNormal, true, kFractionAllZero);
}
EXPECT_EQ(CPUContextX86::FxsaveToFsaveTagWord(fsw, fxsave_tag, st_mm), 0);
// In this set, everything is empty. The registers shouldnt be consulted at
// all, so theyre left alone from the previous set.
fsw = 0 << 11; // top = 0: logical 0-7 maps to physical 0-7
fxsave_tag = 0; // everything empty
EXPECT_EQ(CPUContextX86::FxsaveToFsaveTagWord(fsw, fxsave_tag, st_mm),
0xffff);
}
TEST(CPUContextX86, FsaveToFxsaveTagWord) {
// The register sets that these x87 tag words might apply to are given in the
// FxsaveToFsaveTagWord test above.
EXPECT_EQ(CPUContextX86::FsaveToFxsaveTagWord(0xff22), 0x0f);
EXPECT_EQ(CPUContextX86::FsaveToFxsaveTagWord(0xa9ff), 0xf0);
EXPECT_EQ(CPUContextX86::FsaveToFxsaveTagWord(0xeebb), 0x5a);
EXPECT_EQ(CPUContextX86::FsaveToFxsaveTagWord(0xfe90), 0x1f);
EXPECT_EQ(CPUContextX86::FsaveToFxsaveTagWord(0x0000), 0xff);
EXPECT_EQ(CPUContextX86::FsaveToFxsaveTagWord(0xffff), 0x00);
}
} // namespace
} // namespace test
} // namespace crashpad