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a3d2a9ec92ad4406ccf51ff45a4a1d2aa16eaa69
gem5/src/arch/arm/process.cc
Gabe Black a3d2a9ec92 arch, base: Stop assuming object files have three segments. 
The ObjectFile class has hardcoded assumptions that there are three
segments, text, bss and data. There are some files which have one
"segment" like raw files, where the entire file's contents are
considered a single segment. There are also ELF files which can have
an arbitrary number of segments, and those segments can hold any
number of sections, including the text, data and/or bss sections.

Removing this assumption frees up some object file formats from having
to twist themselves to fit in that structure, possibly introducing
ambiguities when some segments may fulfill multiple roles.

Change-Id: I976e06a3a90ef852b17a6485e2595b006b2090d5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21463
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
2019-10-10 01:25:17 +00:00

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/*
* Copyright (c) 2010, 2012, 2017-2018 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2007-2008 The Florida State University
* 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 the copyright holders 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.
*
* Authors: Stephen Hines
* Ali Saidi
*/
#include "arch/arm/process.hh"
#include "arch/arm/isa_traits.hh"
#include "arch/arm/types.hh"
#include "base/loader/elf_object.hh"
#include "base/loader/object_file.hh"
#include "base/logging.hh"
#include "cpu/thread_context.hh"
#include "debug/Stack.hh"
#include "mem/page_table.hh"
#include "params/Process.hh"
#include "sim/aux_vector.hh"
#include "sim/byteswap.hh"
#include "sim/process_impl.hh"
#include "sim/syscall_return.hh"
#include "sim/system.hh"
using namespace std;
using namespace ArmISA;
ArmProcess::ArmProcess(ProcessParams *params, ObjectFile *objFile,
ObjectFile::Arch _arch)
: Process(params,
new EmulationPageTable(params->name, params->pid, PageBytes),
objFile),
arch(_arch)
{
fatal_if(params->useArchPT, "Arch page tables not implemented.");
}
ArmProcess32::ArmProcess32(ProcessParams *params, ObjectFile *objFile,
ObjectFile::Arch _arch)
: ArmProcess(params, objFile, _arch)
{
Addr brk_point = roundUp(objFile->maxSegmentAddr(), PageBytes);
Addr stack_base = 0xbf000000L;
Addr max_stack_size = 8 * 1024 * 1024;
Addr next_thread_stack_base = stack_base - max_stack_size;
Addr mmap_end = 0x40000000L;
memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
next_thread_stack_base, mmap_end);
}
ArmProcess64::ArmProcess64(ProcessParams *params, ObjectFile *objFile,
ObjectFile::Arch _arch)
: ArmProcess(params, objFile, _arch)
{
Addr brk_point = roundUp(objFile->maxSegmentAddr(), PageBytes);
Addr stack_base = 0x7fffff0000L;
Addr max_stack_size = 8 * 1024 * 1024;
Addr next_thread_stack_base = stack_base - max_stack_size;
Addr mmap_end = 0x4000000000L;
memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
next_thread_stack_base, mmap_end);
}
void
ArmProcess32::initState()
{
Process::initState();
argsInit<uint32_t>(PageBytes, INTREG_SP);
for (int i = 0; i < contextIds.size(); i++) {
ThreadContext * tc = system->getThreadContext(contextIds[i]);
CPACR cpacr = tc->readMiscReg(MISCREG_CPACR);
// Enable the floating point coprocessors.
cpacr.cp10 = 0x3;
cpacr.cp11 = 0x3;
tc->setMiscReg(MISCREG_CPACR, cpacr);
// Generically enable floating point support.
FPEXC fpexc = tc->readMiscReg(MISCREG_FPEXC);
fpexc.en = 1;
tc->setMiscReg(MISCREG_FPEXC, fpexc);
}
}
void
ArmProcess64::initState()
{
Process::initState();
argsInit<uint64_t>(PageBytes, INTREG_SP0);
for (int i = 0; i < contextIds.size(); i++) {
ThreadContext * tc = system->getThreadContext(contextIds[i]);
CPSR cpsr = tc->readMiscReg(MISCREG_CPSR);
cpsr.mode = MODE_EL0T;
tc->setMiscReg(MISCREG_CPSR, cpsr);
CPACR cpacr = tc->readMiscReg(MISCREG_CPACR_EL1);
// Enable the floating point coprocessors.
cpacr.cp10 = 0x3;
cpacr.cp11 = 0x3;
// Enable SVE.
cpacr.zen = 0x3;
tc->setMiscReg(MISCREG_CPACR_EL1, cpacr);
// Generically enable floating point support.
FPEXC fpexc = tc->readMiscReg(MISCREG_FPEXC);
fpexc.en = 1;
tc->setMiscReg(MISCREG_FPEXC, fpexc);
}
}
uint32_t
ArmProcess32::armHwcapImpl() const
{
enum ArmCpuFeature {
Arm_Swp = 1 << 0,
Arm_Half = 1 << 1,
Arm_Thumb = 1 << 2,
Arm_26Bit = 1 << 3,
Arm_FastMult = 1 << 4,
Arm_Fpa = 1 << 5,
Arm_Vfp = 1 << 6,
Arm_Edsp = 1 << 7,
Arm_Java = 1 << 8,
Arm_Iwmmxt = 1 << 9,
Arm_Crunch = 1 << 10,
Arm_ThumbEE = 1 << 11,
Arm_Neon = 1 << 12,
Arm_Vfpv3 = 1 << 13,
Arm_Vfpv3d16 = 1 << 14
};
return Arm_Swp | Arm_Half | Arm_Thumb | Arm_FastMult |
Arm_Vfp | Arm_Edsp | Arm_ThumbEE | Arm_Neon |
Arm_Vfpv3 | Arm_Vfpv3d16;
}
uint32_t
ArmProcess64::armHwcapImpl() const
{
// In order to know what these flags mean, please refer to Linux
// /Documentation/arm64/elf_hwcaps.txt text file.
enum ArmCpuFeature {
Arm_Fp = 1 << 0,
Arm_Asimd = 1 << 1,
Arm_Evtstrm = 1 << 2,
Arm_Aes = 1 << 3,
Arm_Pmull = 1 << 4,
Arm_Sha1 = 1 << 5,
Arm_Sha2 = 1 << 6,
Arm_Crc32 = 1 << 7,
Arm_Atomics = 1 << 8,
Arm_Fphp = 1 << 9,
Arm_Asimdhp = 1 << 10,
Arm_Cpuid = 1 << 11,
Arm_Asimdrdm = 1 << 12,
Arm_Jscvt = 1 << 13,
Arm_Fcma = 1 << 14,
Arm_Lrcpc = 1 << 15,
Arm_Dcpop = 1 << 16,
Arm_Sha3 = 1 << 17,
Arm_Sm3 = 1 << 18,
Arm_Sm4 = 1 << 19,
Arm_Asimddp = 1 << 20,
Arm_Sha512 = 1 << 21,
Arm_Sve = 1 << 22,
Arm_Asimdfhm = 1 << 23,
Arm_Dit = 1 << 24,
Arm_Uscat = 1 << 25,
Arm_Ilrcpc = 1 << 26,
Arm_Flagm = 1 << 27
};
uint32_t hwcap = 0;
ThreadContext *tc = system->getThreadContext(contextIds[0]);
const AA64PFR0 pf_r0 = tc->readMiscReg(MISCREG_ID_AA64PFR0_EL1);
hwcap |= (pf_r0.fp == 0) ? Arm_Fp : 0;
hwcap |= (pf_r0.fp == 1) ? Arm_Fphp | Arm_Fp : 0;
hwcap |= (pf_r0.advsimd == 0) ? Arm_Asimd : 0;
hwcap |= (pf_r0.advsimd == 1) ? Arm_Asimdhp | Arm_Asimd : 0;
hwcap |= (pf_r0.sve >= 1) ? Arm_Sve : 0;
hwcap |= (pf_r0.dit >= 1) ? Arm_Dit : 0;
const AA64ISAR0 isa_r0 = tc->readMiscReg(MISCREG_ID_AA64ISAR0_EL1);
hwcap |= (isa_r0.aes >= 1) ? Arm_Aes : 0;
hwcap |= (isa_r0.aes >= 2) ? Arm_Pmull : 0;
hwcap |= (isa_r0.sha1 >= 1) ? Arm_Sha1 : 0;
hwcap |= (isa_r0.sha2 >= 1) ? Arm_Sha2 : 0;
hwcap |= (isa_r0.sha2 >= 2) ? Arm_Sha512 : 0;
hwcap |= (isa_r0.crc32 >= 1) ? Arm_Crc32 : 0;
hwcap |= (isa_r0.atomic >= 1) ? Arm_Atomics : 0;
hwcap |= (isa_r0.rdm >= 1) ? Arm_Asimdrdm : 0;
hwcap |= (isa_r0.sha3 >= 1) ? Arm_Sha3 : 0;
hwcap |= (isa_r0.sm3 >= 1) ? Arm_Sm3 : 0;
hwcap |= (isa_r0.sm4 >= 1) ? Arm_Sm4 : 0;
hwcap |= (isa_r0.dp >= 1) ? Arm_Asimddp : 0;
hwcap |= (isa_r0.fhm >= 1) ? Arm_Asimdfhm : 0;
hwcap |= (isa_r0.ts >= 1) ? Arm_Flagm : 0;
const AA64ISAR1 isa_r1 = tc->readMiscReg(MISCREG_ID_AA64ISAR1_EL1);
hwcap |= (isa_r1.dpb >= 1) ? Arm_Dcpop : 0;
hwcap |= (isa_r1.jscvt >= 1) ? Arm_Jscvt : 0;
hwcap |= (isa_r1.fcma >= 1) ? Arm_Fcma : 0;
hwcap |= (isa_r1.lrcpc >= 1) ? Arm_Lrcpc : 0;
hwcap |= (isa_r1.lrcpc >= 2) ? Arm_Ilrcpc : 0;
const AA64MMFR2 mm_fr2 = tc->readMiscReg(MISCREG_ID_AA64MMFR2_EL1);
hwcap |= (mm_fr2.at >= 1) ? Arm_Uscat : 0;
return hwcap;
}
template <class IntType>
void
ArmProcess::argsInit(int pageSize, IntRegIndex spIndex)
{
int intSize = sizeof(IntType);
std::vector<AuxVector<IntType>> auxv;
string filename;
if (argv.size() < 1)
filename = "";
else
filename = argv[0];
//We want 16 byte alignment
uint64_t align = 16;
// Patch the ld_bias for dynamic executables.
updateBias();
// load object file into target memory
objFile->loadSegments(initVirtMem);
//Setup the auxilliary vectors. These will already have endian conversion.
//Auxilliary vectors are loaded only for elf formatted executables.
ElfObject * elfObject = dynamic_cast<ElfObject *>(objFile);
if (elfObject) {
if (objFile->getOpSys() == ObjectFile::Linux) {
IntType features = armHwcap<IntType>();
//Bits which describe the system hardware capabilities
//XXX Figure out what these should be
auxv.emplace_back(M5_AT_HWCAP, features);
//Frequency at which times() increments
auxv.emplace_back(M5_AT_CLKTCK, 0x64);
//Whether to enable "secure mode" in the executable
auxv.emplace_back(M5_AT_SECURE, 0);
// Pointer to 16 bytes of random data
auxv.emplace_back(M5_AT_RANDOM, 0);
//The filename of the program
auxv.emplace_back(M5_AT_EXECFN, 0);
//The string "v71" -- ARM v7 architecture
auxv.emplace_back(M5_AT_PLATFORM, 0);
}
//The system page size
auxv.emplace_back(M5_AT_PAGESZ, ArmISA::PageBytes);
// For statically linked executables, this is the virtual address of
// the program header tables if they appear in the executable image
auxv.emplace_back(M5_AT_PHDR, elfObject->programHeaderTable());
// This is the size of a program header entry from the elf file.
auxv.emplace_back(M5_AT_PHENT, elfObject->programHeaderSize());
// This is the number of program headers from the original elf file.
auxv.emplace_back(M5_AT_PHNUM, elfObject->programHeaderCount());
// This is the base address of the ELF interpreter; it should be
// zero for static executables or contain the base address for
// dynamic executables.
auxv.emplace_back(M5_AT_BASE, getBias());
//XXX Figure out what this should be.
auxv.emplace_back(M5_AT_FLAGS, 0);
//The entry point to the program
auxv.emplace_back(M5_AT_ENTRY, objFile->entryPoint());
//Different user and group IDs
auxv.emplace_back(M5_AT_UID, uid());
auxv.emplace_back(M5_AT_EUID, euid());
auxv.emplace_back(M5_AT_GID, gid());
auxv.emplace_back(M5_AT_EGID, egid());
}
//Figure out how big the initial stack nedes to be
// A sentry NULL void pointer at the top of the stack.
int sentry_size = intSize;
string platform = "v71";
int platform_size = platform.size() + 1;
// Bytes for AT_RANDOM above, we'll just keep them 0
int aux_random_size = 16; // as per the specification
// The aux vectors are put on the stack in two groups. The first group are
// the vectors that are generated as the elf is loaded. The second group
// are the ones that were computed ahead of time and include the platform
// string.
int aux_data_size = filename.size() + 1;
int env_data_size = 0;
for (int i = 0; i < envp.size(); ++i) {
env_data_size += envp[i].size() + 1;
}
int arg_data_size = 0;
for (int i = 0; i < argv.size(); ++i) {
arg_data_size += argv[i].size() + 1;
}
int info_block_size =
sentry_size + env_data_size + arg_data_size +
aux_data_size + platform_size + aux_random_size;
//Each auxilliary vector is two 4 byte words
int aux_array_size = intSize * 2 * (auxv.size() + 1);
int envp_array_size = intSize * (envp.size() + 1);
int argv_array_size = intSize * (argv.size() + 1);
int argc_size = intSize;
//Figure out the size of the contents of the actual initial frame
int frame_size =
info_block_size +
aux_array_size +
envp_array_size +
argv_array_size +
argc_size;
//There needs to be padding after the auxiliary vector data so that the
//very bottom of the stack is aligned properly.
int partial_size = frame_size;
int aligned_partial_size = roundUp(partial_size, align);
int aux_padding = aligned_partial_size - partial_size;
int space_needed = frame_size + aux_padding;
memState->setStackMin(memState->getStackBase() - space_needed);
memState->setStackMin(roundDown(memState->getStackMin(), align));
memState->setStackSize(memState->getStackBase() - memState->getStackMin());
// map memory
allocateMem(roundDown(memState->getStackMin(), pageSize),
roundUp(memState->getStackSize(), pageSize));
// map out initial stack contents
IntType sentry_base = memState->getStackBase() - sentry_size;
IntType aux_data_base = sentry_base - aux_data_size;
IntType env_data_base = aux_data_base - env_data_size;
IntType arg_data_base = env_data_base - arg_data_size;
IntType platform_base = arg_data_base - platform_size;
IntType aux_random_base = platform_base - aux_random_size;
IntType auxv_array_base = aux_random_base - aux_array_size - aux_padding;
IntType envp_array_base = auxv_array_base - envp_array_size;
IntType argv_array_base = envp_array_base - argv_array_size;
IntType argc_base = argv_array_base - argc_size;
DPRINTF(Stack, "The addresses of items on the initial stack:\n");
DPRINTF(Stack, "0x%x - aux data\n", aux_data_base);
DPRINTF(Stack, "0x%x - env data\n", env_data_base);
DPRINTF(Stack, "0x%x - arg data\n", arg_data_base);
DPRINTF(Stack, "0x%x - random data\n", aux_random_base);
DPRINTF(Stack, "0x%x - platform base\n", platform_base);
DPRINTF(Stack, "0x%x - auxv array\n", auxv_array_base);
DPRINTF(Stack, "0x%x - envp array\n", envp_array_base);
DPRINTF(Stack, "0x%x - argv array\n", argv_array_base);
DPRINTF(Stack, "0x%x - argc \n", argc_base);
DPRINTF(Stack, "0x%x - stack min\n", memState->getStackMin());
// write contents to stack
// figure out argc
IntType argc = argv.size();
IntType guestArgc = ArmISA::htog(argc);
//Write out the sentry void *
IntType sentry_NULL = 0;
initVirtMem.writeBlob(sentry_base, &sentry_NULL, sentry_size);
//Fix up the aux vectors which point to other data
for (int i = auxv.size() - 1; i >= 0; i--) {
if (auxv[i].type == M5_AT_PLATFORM) {
auxv[i].val = platform_base;
initVirtMem.writeString(platform_base, platform.c_str());
} else if (auxv[i].type == M5_AT_EXECFN) {
auxv[i].val = aux_data_base;
initVirtMem.writeString(aux_data_base, filename.c_str());
} else if (auxv[i].type == M5_AT_RANDOM) {
auxv[i].val = aux_random_base;
// Just leave the value 0, we don't want randomness
}
}
//Copy the aux stuff
Addr auxv_array_end = auxv_array_base;
for (const auto &aux: auxv) {
initVirtMem.write(auxv_array_end, aux, GuestByteOrder);
auxv_array_end += sizeof(aux);
}
//Write out the terminating zeroed auxillary vector
const AuxVector<IntType> zero(0, 0);
initVirtMem.write(auxv_array_end, zero);
auxv_array_end += sizeof(zero);
copyStringArray(envp, envp_array_base, env_data_base, initVirtMem);
copyStringArray(argv, argv_array_base, arg_data_base, initVirtMem);
initVirtMem.writeBlob(argc_base, &guestArgc, intSize);
ThreadContext *tc = system->getThreadContext(contextIds[0]);
//Set the stack pointer register
tc->setIntReg(spIndex, memState->getStackMin());
//A pointer to a function to run when the program exits. We'll set this
//to zero explicitly to make sure this isn't used.
tc->setIntReg(ArgumentReg0, 0);
//Set argument regs 1 and 2 to argv[0] and envp[0] respectively
if (argv.size() > 0) {
tc->setIntReg(ArgumentReg1, arg_data_base + arg_data_size -
argv[argv.size() - 1].size() - 1);
} else {
tc->setIntReg(ArgumentReg1, 0);
}
if (envp.size() > 0) {
tc->setIntReg(ArgumentReg2, env_data_base + env_data_size -
envp[envp.size() - 1].size() - 1);
} else {
tc->setIntReg(ArgumentReg2, 0);
}
PCState pc;
pc.thumb(arch == ObjectFile::Thumb);
pc.nextThumb(pc.thumb());
pc.aarch64(arch == ObjectFile::Arm64);
pc.nextAArch64(pc.aarch64());
pc.set(getStartPC() & ~mask(1));
tc->pcState(pc);
//Align the "stackMin" to a page boundary.
memState->setStackMin(roundDown(memState->getStackMin(), pageSize));
}
RegVal
ArmProcess32::getSyscallArg(ThreadContext *tc, int &i)
{
assert(i < 6);
return tc->readIntReg(ArgumentReg0 + i++);
}
RegVal
ArmProcess64::getSyscallArg(ThreadContext *tc, int &i)
{
assert(i < 8);
return tc->readIntReg(ArgumentReg0 + i++);
}
RegVal
ArmProcess32::getSyscallArg(ThreadContext *tc, int &i, int width)
{
assert(width == 32 || width == 64);
if (width == 32)
return getSyscallArg(tc, i);
// 64 bit arguments are passed starting in an even register
if (i % 2 != 0)
i++;
// Registers r0-r6 can be used
assert(i < 5);
uint64_t val;
val = tc->readIntReg(ArgumentReg0 + i++);
val |= ((uint64_t)tc->readIntReg(ArgumentReg0 + i++) << 32);
return val;
}
RegVal
ArmProcess64::getSyscallArg(ThreadContext *tc, int &i, int width)
{
return getSyscallArg(tc, i);
}
void
ArmProcess32::setSyscallArg(ThreadContext *tc, int i, RegVal val)
{
assert(i < 6);
tc->setIntReg(ArgumentReg0 + i, val);
}
void
ArmProcess64::setSyscallArg(ThreadContext *tc, int i, RegVal val)
{
assert(i < 8);
tc->setIntReg(ArgumentReg0 + i, val);
}
void
ArmProcess32::setSyscallReturn(ThreadContext *tc, SyscallReturn sysret)
{
if (objFile->getOpSys() == ObjectFile::FreeBSD) {
// Decode return value
if (sysret.encodedValue() >= 0)
// FreeBSD checks the carry bit to determine if syscall is succeeded
tc->setCCReg(CCREG_C, 0);
else {
sysret = -sysret.encodedValue();
}
}
tc->setIntReg(ReturnValueReg, sysret.encodedValue());
}
void
ArmProcess64::setSyscallReturn(ThreadContext *tc, SyscallReturn sysret)
{
if (objFile->getOpSys() == ObjectFile::FreeBSD) {
// Decode return value
if (sysret.encodedValue() >= 0)
// FreeBSD checks the carry bit to determine if syscall is succeeded
tc->setCCReg(CCREG_C, 0);
else {
sysret = -sysret.encodedValue();
}
}
tc->setIntReg(ReturnValueReg, sysret.encodedValue());
}
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