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gem5: expose syscall emulation with --user

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Then also expose QEMU user mode with --user. Docs not perfect yet,
would require a build alternative for userland/ for -static and or
passing options before the QEMU userland executable with a new CLI.
This commit is contained in:
Ciro Santilli 六四事件 法轮功
2018-10-29 23:00:01 +00:00
parent e267435f6a
commit a29b5a41fb
4 changed files with 232 additions and 184 deletions
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54
README.adoc
View File

@@ -7647,7 +7647,7 @@ The reason this is cool, is that `ls` is not statically compiled, but since we h
In other words, much cooler than:
....
./run-toolchain --arch arm gcc -- -static "$(./getvar kernel_modules_src_dir)/user/hello.c"
./run-toolchain --arch arm gcc -- -static "$(./getvar userland_src_dir)/hello.c"
qemu-arm a.out
....
@@ -7686,9 +7686,22 @@ FATAL: kernel too old
but it must be using the kernel version given by glibc, since we didn't hit that error on uclibc.
==== QEMU user mode integration
We have a nice user mode integration under way.
It is already usable with:
....
./build-qemu --user
./run --user path/to/static/executable -- arg1 "arg 2" arg3
....
TODO: factor <<qemu-user-mode>> with this:
==== gem5 syscall emulation mode
Analogous to <<qemu-user-mode>>, but less usable.
Analogous to <<qemu-user-mode>>, but less usable:
* https://stackoverflow.com/questions/48986597/when-should-you-use-full-system-fs-vs-syscall-emulation-se-with-userland-program
* https://stackoverflow.com/questions/48959349/how-to-solve-fatal-kernel-too-old-when-running-gem5-in-syscall-emulation-se-m
@@ -7698,12 +7711,12 @@ First we try some `-static` sanity checks.
Works and prints `hello`:
....
./run-toolchain --arch x86_64 gcc -- -static -o x86_64.out "$(./getvar kernel_modules_src_dir)/user/hello.c"
./run-toolchain --arch arm gcc -- -static -o arm.out "$(./getvar kernel_modules_src_dir)/user/hello.c"
./run-toolchain --arch aarch64 gcc -- -static -o aarch64.out "$(./getvar kernel_modules_src_dir)/user/hello.c"
./run --arch x86_64 --gem5 --gem5-script se --exec-image ./x86_64.out
./run --arch arm --gem5 --gem5-script se --exec-image ./arm.out
./run --arch aarch64 --gem5 --gem5-script se --exec-image ./aarch64.out
./run-toolchain --arch x86_64 gcc -- -static -o x86_64.out "$(./getvar userland_src_dir)/hello.c"
./run-toolchain --arch arm gcc -- -static -o arm.out "$(./getvar userland_src_dir)/hello.c"
./run-toolchain --arch aarch64 gcc -- -static -o aarch64.out "$(./getvar userland_src_dir)/hello.c"
./run --arch x86_64 --gem5 --user ./x86_64.out
./run --arch arm --gem5 --user ./arm.out
./run --arch aarch64 --gem5 --user ./aarch64.out
....
But I think this is unreliable, and only works because we are using uclibc which does not check the kernel version as glibc does: https://stackoverflow.com/questions/48959349/how-to-solve-fatal-kernel-too-old-when-running-gem5-in-syscall-emulation-se-m/50542301#50542301
@@ -7711,9 +7724,9 @@ But I think this is unreliable, and only works because we are using uclibc which
Ignoring that insanity, we then try it with dynamically linked executables:
....
./run --arch x86_64 --gem5 --gem5-script se --exec-image "$(./getvar --arch x86_64 --gem5 target_dir)/hello.out"
./run --arch arm --gem5 --gem5-script se --exec-image "$(./getvar --arch arm --gem5 target_dir)/hello.out"
./run --arch aarch64 --gem5 --gem5-script se --exec-image "$(./getvar --arch aarch64 --gem5 target_dir)/hello.out"
./run --arch x86_64 --gem5 --user "$(./getvar --arch x86_64 --gem5 target_dir)/hello.out"
./run --arch arm --gem5 --user "$(./getvar --arch arm --gem5 target_dir)/hello.out"
./run --arch aarch64 --gem5 --user "$(./getvar --arch aarch64 --gem5 target_dir)/hello.out"
....
But at 185c2730cc78d5adda683d76c0e3b35e7cb534f0 they fail with:
@@ -7736,6 +7749,12 @@ Then I was told that it is has never been tested outside of x86_64:
* https://stackoverflow.com/questions/50542222/how-to-run-a-dynamically-linked-executable-syscall-emulation-mode-se-py-in-gem5
* https://www.mail-archive.com/gem5-users@gem5.org/msg15585.html
===== gem5 syscall emulation mode CLI options
....
./run --gem5 --user ./aarch64.out -- --options 'op1 "op 2" op3'
....
==== User mode vs full system benchmark
Let's see if user mode runs considerably faster than full system or not.
@@ -7743,16 +7762,21 @@ Let's see if user mode runs considerably faster than full system or not.
gem5 user mode:
....
./build-buildroot --config 'BR2_PACKAGE_DHRYSTONE=y' --arch arm
make \
-B \
-C "$(./getvar --arch arm build_dir)/dhrystone-2" \
CC="$(./run-toolchain --arch arm --dry gcc)" \
CFLAGS=-static \
;
time \
"$(./getvar --arch arm --gem5 exec)" \
"$(./getvar --arch arm gem5_se_file)" \
-c "$(./getvar --arch arm build_dir)/dhrystone-2/dhrystone" \
-o 100000 \
./run \
--arch arm \
--gem5 \
--user \
"$(./getvar --arch arm build_dir)/dhrystone-2/dhrystone" \
-- \
--options 100000 \
;
....

12
build-qemu
View File

@@ -6,6 +6,12 @@ import common
class QemuComponent(common.Component):
def add_parser_arguments(self, parser):
parser.add_argument(
'--user',
default=False,
action='store_true',
help='Build QEMU user mode instead of system.',
)
parser.add_argument(
'extra_config_args',
default=[],
@@ -20,12 +26,16 @@ class QemuComponent(common.Component):
verbose = ['V=1']
else:
verbose = []
if args.user:
target_list = '{}-linux-user'.format(args.arch)
else:
target_list = '{}-softmmu'.format(args.arch)
common.run_cmd(
[
os.path.join(common.qemu_src_dir, 'configure'),
'--enable-debug',
'--enable-trace-backends=simple',
'--target-list={}-softmmu'.format(args.arch),
'--target-list={}'.format(target_list),
'--enable-sdl',
'--with-sdlabi=2.0',
] +

1
common.py
View File

@@ -792,7 +792,6 @@ def setup(parser):
# Kernel modules.
this_module.kernel_modules_build_base_dir = os.path.join(this_module.out_dir, 'kernel_modules')
this_module.kernel_modules_build_dir = os.path.join(this_module.kernel_modules_build_base_dir, args.arch)
this_module.kernel_modules_build_subdir = os.path.join(this_module.kernel_modules_build_dir, kernel_modules_subdir)
this_module.kernel_modules_build_host_dir = os.path.join(this_module.kernel_modules_build_base_dir, 'host')
this_module.userland_build_dir = os.path.join(this_module.out_dir, 'userland', args.arch)
this_module.out_rootfs_overlay_dir = os.path.join(this_module.out_dir, 'rootfs_overlay', args.arch)

59
run
View File

@@ -16,11 +16,10 @@ defaults = {
'debug_vm': False,
'eval': None,
'extra_emulator_args': [],
'exec_image': None,
'gem5_exe_args': '',
'gem5_script': 'fs',
'gem5_readfile': '',
'gem5_restore': None,
'gem5_script': 'fs',
'graphic': False,
'initramfs': False,
'initrd': False,
@@ -36,6 +35,7 @@ defaults = {
'tmux': False,
'tmux_args': '',
'trace': None,
'user': None,
'vnc': False,
}
@@ -104,6 +104,7 @@ def main(args, extra_args=None):
'Tried to use: ' + common.image)
if common.image is None:
raise Exception('Baremetal ELF file not found. Tried:\n' + '\n'.join(paths))
cmd = debug_vm.copy()
if args.gem5:
if args.baremetal is None:
if not os.path.exists(common.rootfs_raw_file):
@@ -128,8 +129,7 @@ def main(args, extra_args=None):
extra_env['M5_PATH'] = common.gem5_system_dir
# https://stackoverflow.com/questions/52312070/how-to-modify-a-file-under-src-python-and-run-it-without-rebuilding-in-gem5/52312071#52312071
extra_env['M5_OVERRIDE_PY_SOURCE'] = 'true'
cmd = (
debug_vm +
cmd.extend(
[
common.executable,
'--debug-file=trace.txt',
@@ -139,6 +139,9 @@ def main(args, extra_args=None):
'-d', common.m5out_dir
]
)
if args.user is not None:
cmd.extend([common.gem5_se_file, '-c', args.user])
else:
if args.gem5_script == 'fs':
# TODO port
if args.gem5_restore is not None:
@@ -185,12 +188,28 @@ def main(args, extra_args=None):
'--kernel', common.image,
'--little-cpus', '2'
])
elif args.gem5_script == 'se':
assert(args.exec_image is not None)
cmd.extend([common.gem5_se_file, '-c', args.exec_image])
if args.debug_guest:
# https://stackoverflow.com/questions/49296092/how-to-make-gem5-wait-for-gdb-to-connect-to-reliably-break-at-start-kernel-of-th
cmd.extend(['--param', 'system.cpu[0].wait_for_remote_gdb = True'])
else:
qemu_user_and_system_options = [
'-trace', 'enable={},file={}'.format(trace_type, common.qemu_trace_file),
]
if args.user is not None:
if args.debug_guest:
debug_args = ['-g', str(common.gdb_port)]
else:
debug_args = []
cmd.extend(
[
os.path.join(common.qemu_build_dir, '{}-linux-user'.format(args.arch), 'qemu-{}'.format(args.arch)),
] +
qemu_user_and_system_options +
debug_args +
[
args.user
]
)
else:
if not os.path.exists(common.image):
raise_image_not_found()
@@ -213,8 +232,7 @@ def main(args, extra_args=None):
extra_emulator_args.append('-enable-kvm')
if args.kgdb:
extra_emulator_args.extend(['-serial', 'tcp::{},server,nowait'.format(common.gdb_port)])
cmd = (
debug_vm +
cmd.extend(
[
qemu_executable,
'-device', 'rtl8139,netdev=net0',
@@ -225,12 +243,12 @@ def main(args, extra_args=None):
'-netdev', 'user,hostfwd=tcp::{}-:{},hostfwd=tcp::{}-:22,id=net0'.format(common.qemu_hostfwd_generic_port, common.qemu_hostfwd_generic_port, common.qemu_hostfwd_ssh_port),
'-no-reboot',
'-smp', str(args.cpus),
'-trace', 'enable={},file={}'.format(trace_type, common.qemu_trace_file),
'-virtfs', 'local,path={},mount_tag=host_data,security_model=mapped,id=host_data'.format(common.p9_dir),
'-virtfs', 'local,path={},mount_tag=host_out,security_model=mapped,id=host_out'.format(common.out_dir),
'-virtfs', 'local,path={},mount_tag=host_out_rootfs_overlay,security_model=mapped,id=host_out_rootfs_overlay'.format(common.out_rootfs_overlay_dir),
'-virtfs', 'local,path={},mount_tag=host_rootfs_overlay,security_model=mapped,id=host_rootfs_overlay'.format(common.rootfs_overlay_dir),
] +
qemu_user_and_system_options +
serial_monitor +
vnc
)
@@ -290,8 +308,7 @@ def main(args, extra_args=None):
else:
cpu = 'cortex-a57'
append = ['-append', '{} {}'.format(root, kernel_cli)]
cmd = (
cmd +
cmd.extend(
[
# highmem=off needed since v3.0.0 due to:
# http://lists.nongnu.org/archive/html/qemu-discuss/2018-08/msg00034.html
@@ -360,15 +377,6 @@ def get_argparse():
help='''\
Replace the normal init with a minimal init that just evals the given string.
See: https://github.com/cirosantilli/linux-kernel-module-cheat#replace-init
'''
)
parser.add_argument(
'--exec-image', default=defaults['gem5_script'],
help='''\
Set which executable image to use. Currently only used for gem5 se.py
which has no sensible default. Maybe we could also select the --baremetal
executable with this, might be a nicer interface. We could definitely use
this to override the default Linux kernel image.
'''
)
parser.add_argument(
@@ -410,7 +418,7 @@ gem.op5 --debug-flags=Exec fs.py --cpu-type=HPI --caches
'''
)
parser.add_argument(
'--gem5-script', default=defaults['gem5_script'], choices=['fs', 'se', 'biglittle'],
'--gem5-script', default=defaults['gem5_script'], choices=['fs', 'biglittle'],
help='Which gem5 script to use'
)
parser.add_argument(
@@ -488,6 +496,13 @@ to use this option:
* on the split:
** if on QEMU and `-d` is given, GDB
** if on gem5, the gem5 terminal
'''
)
parser.add_argument(
'--user', default=defaults['user'],
help='''\
Run the given userland executable in user mode instead of full system mode.
In gem5, user mode is called Syscall Emulation (SE) mode and uses se.py.
'''
)
parser.add_argument(