Commit graph

12 commits

Author SHA1 Message Date
Andreas Kling
c19b56dc99 Kernel+LibC: Add minherit() and MAP_INHERIT_ZERO
This patch adds the minherit() syscall originally invented by OpenBSD.
Only the MAP_INHERIT_ZERO mode is supported for now. If set on an mmap
region, that region will be zeroed out on fork().
2020-04-12 20:22:26 +02:00
Andreas Kling
31e1af732f Kernel+LibC: Allow sys$mmap() callers to specify address alignment
This is exposed via the non-standard serenity_mmap() call in userspace.
2020-02-16 12:55:56 +01:00
Andreas Kling
94ca55cefd Meta: Add license header to source files
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.

For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.

Going forward, all new source files should include a license header.
2020-01-18 09:45:54 +01:00
Andreas Kling
24c736b0e7 Kernel: Use the Syscall string and buffer types more
While I was updating syscalls to stop passing null-terminated strings,
I added some helpful struct types:

    - StringArgument { const char*; size_t; }
    - ImmutableBuffer<Data, Size> { const Data*; Size; }
    - MutableBuffer<Data, Size> { Data*; Size; }

The Process class has some convenience functions for validating and
optionally extracting the contents from these structs:

    - get_syscall_path_argument(StringArgument)
    - validate_and_copy_string_from_user(StringArgument)
    - validate(ImmutableBuffer)
    - validate(MutableBuffer)

There's still so much code around this and I'm wondering if we should
generate most of it instead. Possible nice little project.
2020-01-11 12:47:47 +01:00
Andreas Kling
a47f0c93de Kernel: Pass name+length to mmap() and remove SmapDisabler 2020-01-06 12:04:55 +01:00
Andreas Kling
33025a8049 Kernel: Pass name+length to set_mmap_name() and remove SmapDisabler 2020-01-06 11:56:59 +01:00
Andreas Kling
7f04334664 Kernel: Remove broken implementation of Unix SHM
This code never worked, as was never used for anything. We can build
a much better SHM implementation on top of TmpFS or similar when we
get to the point when we need one.
2020-01-02 12:44:21 +01:00
Andreas Kling
dbb644f20c Kernel: Start implementing purgeable memory support
It's now possible to get purgeable memory by using mmap(MAP_PURGEABLE).
Purgeable memory has a "volatile" flag that can be set using madvise():

- madvise(..., MADV_SET_VOLATILE)
- madvise(..., MADV_SET_NONVOLATILE)

When in the "volatile" state, the kernel may take away the underlying
physical memory pages at any time, without notifying the owner.
This gives you a guilt discount when caching very large things. :^)

Setting a purgeable region to non-volatile will return whether or not
the memory has been taken away by the kernel while being volatile.
Basically, if madvise(..., MADV_SET_NONVOLATILE) returns 1, that means
the memory was purged while volatile, and whatever was in that piece
of memory needs to be reconstructed before use.
2019-12-09 19:12:38 +01:00
Andreas Kling
bbc2f5205f LibC: Fix wrong syscall identifier for shm_unlink()
I renamed "shm_close" to "shm_unlink" since there's no such thing as
shm_close(), but forgot to update LibC, oops!
2019-11-09 22:42:54 +01:00
Andreas Kling
874ebbe4a5 LibC: shm_unlink() was making an unlink() syscall internally
I guess that tells us how well-tested the SHM implementation is.
2019-11-09 22:42:19 +01:00
Andreas Kling
7d6689055f Kernel+LibC+crash: Add mprotect() syscall
This patch adds the mprotect() syscall to allow changing the protection
flags for memory regions. We don't do any region splitting/merging yet,
so this only works on whole mmap() regions.

Added a "crash -r" flag to verify that we crash when you attempt to
write to read-only memory. :^)
2019-08-12 19:33:24 +02:00
Andreas Kling
04b9dc2d30 Libraries: Create top level directory for libraries.
Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.
2019-07-04 16:16:50 +02:00
Renamed from LibC/mman.cpp (Browse further)