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319 commits

Author SHA1 Message Date
Andreas Kling
33e3e8d63d UserspaceEmulator: Add the getrandom() syscall 2020-07-15 23:44:51 +02:00
Andreas Kling
1873b8f3e4 UserspaceEmulator: Fix bogus use of "errno" in shbuf related syscalls 
When we're making direct syscalls, there's no "errno" involved.
Thanks to Sergey for spotting these.
 2020-07-15 23:43:38 +02:00
Andreas Kling
092f643119 UserspaceEmulator: Log invalid and double free() calls :^) 
We can easily catch free() on never-malloced addresses, as well as
double calls to free() on the same address, so let's do it!
 2020-07-15 23:25:20 +02:00
Andreas Kling
c314292319 UserspaceEmulator: Catch use-after-frees by tracking malloc/free :^) 
This patch introduces a "MallocTracer" to the UserspaceEmulator.
If this object is present on the Emulator, it can be notified whenever
the emulated program does a malloc() or free().

The notifications come in via a magic instruction sequence that we
embed in the LibC malloc() and free() functions. The sequence is:

    "salc x2, push reg32 x2, pop reg32 x3"

The data about the malloc/free operation is in the three pushes.
We make sure the sequence is harmless when running natively.

Memory accesses on MmapRegion are then audited to see if they fall
inside a known-to-be-freed malloc chunk. If so, we complain loud
and red in the debugger output. :^)

This is very, very cool! :^)

It's also a whole lot slower than before, since now we're auditing
memory accesses against a new set of metadata. This will need to be
optimized (and running in this mode should be opt-in, perhaps even
a separate program, etc.)
 2020-07-15 23:25:20 +02:00
Andreas Kling
c8b496162d UserspaceEmulator: Add some more syscalls :^) 
Here's set_process_icon(), gettimeofday() and clock_gettime().
 2020-07-15 18:47:45 +02:00
Andreas Kling
feebe3f42e UserspaceEmulator: Add partial support for the SHLD/SHRD instructions 
We don't support all the addressing modes yet, but it won't be very
hard to add the rest of them when needed.
 2020-07-15 18:47:45 +02:00
Andreas Kling
2da44dba44 UserspaceEmulator: Add support for shared buffers (shbuf) 
We track these separately from regular mmap() regions, as they have
slightly different behaviors.
 2020-07-15 18:47:45 +02:00
Andreas Kling
0ce4d3e942 UserspaceEmulator: Dump backtrace on FPU instruction 2020-07-15 18:47:45 +02:00
Andreas Kling
76b2a2789b UserspaceEmulator: Implement MUL_RM32 2020-07-15 18:47:45 +02:00
Andreas Kling
029fe56d69 UserspaceEmulator: Implement the 32-bit BSWAP instruction :^) 2020-07-15 18:47:45 +02:00
Andreas Kling
339f12e8a2 UserspaceEmulator: Implement an assortment of system calls 
Here goes mkdir(), unlink(), socket(), getsockopt(), fchmod()
bind(), connect(), listen(), select() and recvfrom().

They're not perfect but they seem to work. :^)
 2020-07-15 18:47:45 +02:00
Andreas Kling
0781868092 UserspaceEmulator: Implement IDIV_RM32 2020-07-15 13:42:15 +02:00
Andreas Kling
400a252720 UserspaceEmulator: Implement the CBW/CDQ/CWD/CWDE instructions 2020-07-15 13:42:15 +02:00
Andreas Kling
6a926a8c61 LibX86+UserspaceEmulator: Don't store a32 in MemoryOrRegisterReference 
The a32 bit tells us whether a memory address is 32-bit or not.
We already have this information in Instruction, so just plumb that
around instead of double-caching the bit.
 2020-07-15 13:42:15 +02:00
Sergey Bugaev
e12b591509 UserspaceEmulator: Implement virt$pipe() 2020-07-15 13:41:46 +02:00
Andreas Kling
ef84865c8c LibX86+UserspaceEmulator: Devirtualize and inline more instruction code 
Use some template hacks to force GCC to inline more of the instruction
decoding stuff into the UserspaceEmulator main execution loop.

This is my last optimization for today, and we've gone from ~60 seconds
when running "UserspaceEmulator UserspaceEmulator id" to ~8 seconds :^)
 2020-07-13 21:00:51 +02:00
Andreas Kling
f608b9d89a UserspaceEmulator: Mark some generic instructions ALWAYS_INLINE :^) 2020-07-13 20:47:45 +02:00
Andreas Kling
2f81c20002 UserspaceEmulator: Move the SoftCPU stream virtuals to the header 
They don't actually get inlined yet, but at least this devirtualizes
them which is nice.
 2020-07-13 20:41:48 +02:00
Andreas Kling
a27473cbc2 UserspaceEmulator+LibX86: Turn on -O3 optimization for emulation code 
Since this code is performance-sensitive, let's have the compiler do
whatever it can to help us with the most important files.

This yields a ~8% speedup.
 2020-07-13 20:23:00 +02:00
Andreas Kling
8656835935 UserspaceEmulator: Add a very simple instruction fetch cache 
To avoid MMU region lookup on every single instruction fetch, we now
cache a raw pointer to the current instruction. This gets automatically
invalidated when we jump somewhere, but as long as we're executing
sequentially, instruction fetches will hit the cache and bypass all
the region lookup stuff.

This is about a ~2x speedup. :^)
 2020-07-13 20:14:14 +02:00
Andreas Kling
a83fe7f82d UserspaceEmulator: Add the POPFD instruction 
I'm not sure the mask I'm using here is completely correct, but it's
not terribly important since we're a userspace-only emulator anyway.
 2020-07-13 13:50:22 +02:00
Andreas Kling
dba6f9b24b UserspaceEmulator: Add the NOT instruction (with bonus: NOP!) 2020-07-13 13:50:22 +02:00
Andreas Kling
5ecbfd8451 UserspaceEmulator: Add the STC/CLC and STD/CLD instructions 2020-07-13 13:50:22 +02:00
Andreas Kling
9f293054e8 UserspaceEmulator: Implement the ADC instruction 2020-07-13 13:50:22 +02:00
Andreas Kling
6230c60296 UserspaceEmulator: Make SBB actually respect the SoftCPU carry flag 
We were forgetting to set the host CPU's carry flag before executing
the SBB instruction. This made the result a bit unpredictable. :^)
 2020-07-13 13:50:22 +02:00
Andreas Kling
a9f92e5d75 UserspaceEmulator: Remove an unnecessary step in some instructions 
We don't need to move the result of shifts around like this, we can
just use inline assembly outputs to make it end up in the right place.
 2020-07-13 13:50:22 +02:00
Andreas Kling
80d3306840 UserspaceEmulator: Fix wrong ESI/EDI step sizes in MOVSW and MOVSD 2020-07-13 13:50:22 +02:00
Andreas Kling
e0580e2975 UserspaceEmulator: Add some more syscalls 
We can now unmap mapped memory, among other things. This is all very
ad-hoc as I'm trying to run UserspaceEmulator inside itself. :^)
 2020-07-13 13:50:22 +02:00
Andreas Kling
9b6464010f UserspaceEmulator: Add basic support for memory-mapped files 
MmapRegion now supports using an mmap'ed file descriptor as backing.
 2020-07-13 13:50:22 +02:00
Andreas Kling
63d3f5d19b UserspaceEmulator: Implement the PUSHFD instruction 2020-07-13 13:50:22 +02:00
Andreas Kling
f6ad5edab0 UserspaceEmulator: Make mmap'ed memory track read/write protection 
Here's the first time we get a taste of better information than the
real hardware can give us: unlike x86 CPUs, we can actually support
write-only memory, so now we do!

While this isn't immediately useful, it's still pretty cool. :^)
 2020-07-13 13:50:22 +02:00
Andreas Kling
27c1690504 UserspaceEmulator: Pass arguments through to emulated process 
Ultimately we'll want to support passing some options to the emulator
as well, but for now just pass all arguments (except argv[0] of course)
through to the emulated process.

This is still not perfect, but slightly better than what we had before.
 2020-07-13 13:50:22 +02:00
Andreas Kling
3d42b85969 UserspaceEmulator: Move SimpleRegion to its own files 2020-07-13 13:50:22 +02:00
Andreas Kling
4d3787ae33 UserspaceEmulator: Support the fstat() and get_process_name() syscalls 
For now, we just pretend that the process name is "EMULATED". We can
probably do better though. :^)
 2020-07-13 13:50:22 +02:00
Andreas Kling
617655db0d UserspaceEmulator: Move exit() syscall logging to debug output 
We want the emulated program to appear without noise in the terminal.
 2020-07-12 21:37:54 +02:00
Andreas Kling
1d32c66dde UserspaceEmulator: Put some syscall logging behind DEBUG_SPAM 2020-07-12 21:37:54 +02:00
Andreas Kling
95a42efc62 UserspaceEmulator: Implement enough syscalls to get /bin/id running :^) 2020-07-12 21:37:54 +02:00
Andreas Kling
1b196df4c4 UserspaceEmulator: Implement/stub out various syscalls 
Moving forward on getting /bin/id to run inside the emulator. :^)
 2020-07-12 21:37:54 +02:00
Andreas Kling
56d3a949e6 UserspaceEmulator: Disable per-instruction trace dumps for now 
With tracing turned on, it's just too slow when doing big operations
like initializing malloc freelists.
 2020-07-12 21:37:54 +02:00
Andreas Kling
079021a607 UserspaceEmulator: Put the executable name in argv[0] :^) 
The emulated program can now find its own name in argv[0]. Very cool!
 2020-07-12 21:37:54 +02:00
Andreas Kling
ddf7b817df UserspaceEmulator: Add Emulator::dump_backtrace() 
This gives you a nice, symbolicated backtrace at the current EIP. :^)
 2020-07-12 21:37:54 +02:00
Andreas Kling
584923445c UserspaceEmulator: "Add" a couple of syscalls 
This patch adds gettid() and stubs out pledge() and unveil() for now.
 2020-07-12 21:37:54 +02:00
Andreas Kling
e461e3c8b0 UserspaceEmulator: Fix missing sign extension in PUSH_imm8 2020-07-12 17:44:14 +02:00
Andreas Kling
94f07660e9 UserspaceEmulator: Add some convenient SoftMMU APIs for copying data 
We'll soon want to copy data in and out of the SoftMMU memory space.
 2020-07-12 17:42:57 +02:00
Andreas Kling
274ac3c628 UserspaceEmulator: Implement the XADD instruction 2020-07-12 15:35:01 +02:00
Andreas Kling
04695957e2 UserspaceEmulator: Implement the MOVSX instruction 2020-07-12 15:33:29 +02:00
Andreas Kling
8940916232 UserspaceEmulator: Implement JMP_RM32 2020-07-12 14:54:30 +02:00
Andreas Kling
a424208399 UserspaceEmulator: Implement DIV_RM32 
Not using inline assembly for this one since flags are undefined after
a DIV instruction anyway.
 2020-07-12 14:53:19 +02:00
Andreas Kling
062e2f8614 UserspaceEmulator: Implement the XCHG instruction 2020-07-12 14:45:46 +02:00
Andreas Kling
536ca0f8c9 UserspaceEmulator: Implement some more MOV variants 2020-07-12 14:45:35 +02:00