Let's adapt this class a bit better to how it's actually being used.
Instead of having valid/invalid states and storing an error in case
it's invalid, a MappedFile is now always valid, and the factory
function that creates it will return an OSError if mapping fails.
Unlike zero-extend moves, the upper bytes are not just zeroed,
but rather are based on the sign bit of the source, which means
if the source is tainted, so should the upper bytes be.
This was a goofy kernel API where you could assign an icon_id (int) to
a process which referred to a global shbuf with a 16x16 icon bitmap
inside it.
Instead of this, programs that want to display a process icon now
retrieve it from the process executable instead.
Problem:
- C functions with no arguments require a single `void` in the argument list.
Solution:
- Put the `void` in the argument list of functions in C header files.
We were using ring 0 selectors everywhere (the bottom 3 bits of a
selector determines the ring.) This doesn't really make any practical
difference since UE doesn't run code in other rings anyway, but let's
have correct-looking segment selectors. :^)
Make it possible to bail out of ELF::Image::for_each_program_header()
and then do exactly that if something goes wrong during executable
loading in the kernel.
Also make the errors we return slightly more nuanced than just ENOEXEC.
This commit gets rid of ELF::Loader entirely since its very ambiguous
purpose was actually to load executables for the kernel, and that is
now handled by the kernel itself.
This patch includes some drive-by cleanup in LibDebug and CrashDaemon
enabled by the fact that we no longer need to keep the ref-counted
ELF::Loader around.
Problem:
- `(void)` simply casts the expression to void. This is understood to
indicate that it is ignored, but this is really a compiler trick to
get the compiler to not generate a warning.
Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.
Note:
- Functions taking a `(void)` argument list have also been changed to
`()` because this is not needed and shows up in the same grep
command.
Keep the debug symbols for shared libraries in memory after we opened
them the first time. This dramatically speeds up symbolication of
backtraces when running dynamically linked programs in UE.
When loading dynamic objects, the emulator loads the interpreter,
generates an auxiliary vector and starts executing the loader.
Additionally, this commits also makes the MallocTracer and backtrace
symbolication work for dynamically loaded programs.
Instead of caching a raw pointer to the next instruction, cache the
region we're fetching instructions from, and a pointer to its base.
This way we don't need to keep invalidating and reloading the cache
whenever the CPU jumps.
By passing the Region& to the auditing functions, we know exactly which
block we are hitting. This allows us to track big mallocations the same
way we already do chunked ones.
This gets rid of the O(n) scan in find_mallocation() for allocations
larger than the maximum malloc chunk size. :^)
These are getting quite hot (~4% of general emulation profile combined)
so let's just devirtualize them and turn the function calls into simple
boolean checks.
Instead of tracking known malloc blocks in a separate hash table,
add an optional malloc metadata pointer to MmapRegion.
This makes finding the malloc metadata for a given pointer extremely
fast since it can piggyback on the page table array. :^)
Not motivated by anything in particular, they just looked easy to fill
in. With this, all arithmetic FI* FPU instructions are implemented.
Switch to the mXXint style in a few more functions, this part is no-op.
This is used by memset() so we get a lot of mileage out of optimizing
this instruction.
Note that we currently audit every individual byte accessed separately.
This could be greatly improved by adding a range auditing mechanism to
MallocTracer.
To make SoftMMU::find_region() O(1), this patch invests 3MiB into a
lookup table where we track each possible page base address and map
them to the SoftMMU::Region corresponding to that address.
This is another large improvement to general emulation performance. :^)
We don't want the next_address pointer losing its alignment somehow.
This whole thing should be replaced at some point, since UE hosted
programs won't be able to run forever with this allocation strategy.
m32int is a 32-bit integer stored in memory, and should not be mistaken
for a floating point number. :^)
Also add missing handling of 64-bit FPU register operands to some of
the RM64 instructions.
There are some destruction order races that can cause hangs while
shutting down UE. Since there's no particular value right now in
destroying the Emulator object properly, just avoid destruction and
add a FIXME about looking into it later.
