Summary:
PowerPC has two PLT models: BSS-PLT and Secure-PLT. BSS-PLT uses runtime
code generation to generate the PLT stubs. Secure-PLT was introduced with
GCC 4.1 and Binutils 2.17 (base has GCC 4.2.1 and Binutils 2.17), and is a
more secure PLT format, using a read-only linkage table, with the dynamic
linker populating a non-executable index table.
This is the libc, rtld, and kernel support only. The toolchain and build
parts will be updated separately.
Reviewed By: nwhitehorn, bdragon, pfg
Differential Revision: https://reviews.freebsd.org/D20598
MFC after: 1 month
This is in preparation for compiling these files as part of rtld (which is
built with WARNS=6). See https://reviews.freebsd.org/D20663 for more details.
In the case of mmap(), add a HISTORY section. Mention that mmap() and
mprotect()'s documentation predates an implementation. The
implementation first saw wide use in 4.3-Reno, but there seems to be no
easy way to express that in mdoc so stick with 4.4BSD.
Reviewed by: emaste
Requested by: cem
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D20713
A new macro PROT_MAX() alters a protection value so it can be OR'd with
a regular protection value to specify the maximum permissions. If
present, these flags specify the maximum permissions.
While these flags are non-portable, they can be used in portable code
with simple ifdefs to expand PROT_MAX() to 0.
This change allows (e.g.) a region that must be writable during run-time
linking or JIT code generation to be made permanently read+execute after
writes are complete. This complements W^X protections allowing more
precise control by the programmer.
This change alters mprotect argument checking and returns an error when
unhandled protection flags are set. This differs from POSIX (in that
POSIX only specifies an error), but is the documented behavior on Linux
and more closely matches historical mmap behavior.
In addition to explicit setting of the maximum permissions, an
experimental sysctl vm.imply_prot_max causes mmap to assume that the
initial permissions requested should be the maximum when the sysctl is
set to 1. PROT_NONE mappings are excluded from this for compatibility
with rtld and other consumers that use such mappings to reserve
address space before mapping contents into part of the reservation. A
final version this is expected to provide per-binary and per-process
opt-in/out options and this sysctl will go away in its current form.
As such it is undocumented.
Reviewed by: emaste, kib (prior version), markj
Additional suggestions from: alc
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D18880
The man page claims that with O_FSYNC (aka O_SYNC) the kernel will not cache
written data. However, that's not true. Nor does POSIX require it.
Perhaps it was true when that section of the man page was written in r69336
(I haven't checked). But it's not true now. Now the effect is simply that
writes are sent to disk immediately and synchronously, but they're still
cached.
See also: https://pubs.opengroup.org/onlinepubs/9699919799/
See also: ffs_write in sys/ufs/ffs/ffs_vnops.c
Reviewed by: cem
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20641
port number, properly access them by their IPv6 names.
This will make it easier to slice up and compile out address families
in the future.
No functional change intended.
MFC after: 6 weeks
Use the .PATH mechanism instead so keep installing them from lib/libc/gen
While here revert 347961 and 347893 which are no longer needed
Discussed with: manu
Tested by: manu
ok manu@
In all practical situations, the resolver visibility is static.
Requested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: so (emaste)
Differential revision: https://reviews.freebsd.org/D20281
libc was picked as the destination location for these because of the syscalls
that use these files as the lowest level place they are referenced.
Approved by: will (mentor), rgrimes, manu
Differential Revision: https://reviews.freebsd.org/D16728
Historically we have not distinguished between kernel wirings and user
wirings for accounting purposes. User wirings (via mlock(2)) were
subject to a global limit on the number of wired pages, so if large
swaths of physical memory were wired by the kernel, as happens with
the ZFS ARC among other things, the limit could be exceeded, causing
user wirings to fail.
The change adds a new counter, v_user_wire_count, which counts the
number of virtual pages wired by user processes via mlock(2) and
mlockall(2). Only user-wired pages are subject to the system-wide
limit which helps provide some safety against deadlocks. In
particular, while sources of kernel wirings typically support some
backpressure mechanism, there is no way to reclaim user-wired pages
shorting of killing the wiring process. The limit is exported as
vm.max_user_wired, renamed from vm.max_wired, and changed from u_int
to u_long.
The choice to count virtual user-wired pages rather than physical
pages was done for simplicity. There are mechanisms that can cause
user-wired mappings to be destroyed while maintaining a wiring of
the backing physical page; these make it difficult to accurately
track user wirings at the physical page layer.
The change also closes some holes which allowed user wirings to succeed
even when they would cause the system limit to be exceeded. For
instance, mmap() may now fail with ENOMEM in a process that has called
mlockall(MCL_FUTURE) if the new mapping would cause the user wiring
limit to be exceeded.
Note that bhyve -S is subject to the user wiring limit, which defaults
to 1/3 of physical RAM. Users that wish to exceed the limit must tune
vm.max_user_wired.
Reviewed by: kib, ngie (mlock() test changes)
Tested by: pho (earlier version)
MFC after: 45 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19908
The rewrite of strcmp in assembly uses an instruction added in PowerISA
2.05, making it SIGILL on CPUs older than the POWER6, such as the PPC970 in
the PowerMac G5. Revert this until we get clang+lld, or retire the in-tree
binutils in favor of newer binutils with IFUNC support, whichever comes
first.
Summary:
Optimize strcmp for powerpc64.
Data is loaded by double words and cmpb intruction is used to find '\0'.
Some performance gain rates between the current and the optimized solution:
String size (bytes) Gain rate
<=8 0.59%
<=16 1.92%
32 3.02%
64 5.60%
128 10.16%
256 18.05%
512 30.18%
1024 42.82%
Submitted by: alexandre.yamashita_eldorado.org.br,
leonardo.bianconi_eldorado.org.br
Differential Revision: https://reviews.freebsd.org/D15220
Relative performance to rand(3) is sort of irrelevant; they do different things
and a user with sensitivity to RNG performance won't use libc random(3) anyway.
The historical note about bad seeding is long obsolete, referring to a 1996 or
earlier version of FreeBSD.
Sponsored by: Dell EMC Isilon
Initialize `oldlen` to the size of the value, instead of leaving the value
unitialized. Leaving it unitialized seems to work by accident on amd64 when
running 64-bit programs, but not on i386.
This matches patterns in use in other programs.
PR: 237458
Approved by: emaste (mentor; implicit)
MFC after: 1 week
Tested on: ^/head (amd64), ^/stable/11 (i386)
It is a useful arc4random wrapper in the kernel for much the same reasons as
in userspace. Move the source to libkern (because kernel build is
restricted to sys/, but userspace can include any file it likes) and build
kernel and libc versions from the same source file.
Copy the documentation from arc4random_uniform(3) to the section 9 page.
While here, add missing arc4random_buf(9) symlink.
Sponsored by: Dell EMC Isilon
random.3 is only "better" in contrast to rand.3. Both are non-cryptographic
pseudo-random number generators. The opening blurbs of each's DESCRIPTION
section does emphasize this, and correctly directs unfamiliar developers to
arc4random(3). However, the summary (".Nd" or Name description) of random.3
conflicted in tone and message with that warning.
Resolve the conflict by clarifying in the Nd section that random(3) is
non-cryptographic and pseudo-random. Elide the "better" qualifier which
implied a comparison but did not provide a specific object to contrast.
Sponsored by: Dell EMC Isilon
Since inits for the main binary are run from rtld (for some time), the
rtld_exit atexit(3) handler, which is passed from rtld to the program
entry and installed by csu, is installed after any atexit(3) handlers
installed by main binary constructors. This means that rtld_exit() is
fired before main binary handlers.
Typical C++ static constructors are executed from init (either binary
or libs) but use atexit(3) to ensure that destructors are called in
the right order, independent of the linking order. Also, C++
libraries finalizers call __cxa_finalize(3) to flush library'
atexit(3) entries. Since atexit(3) entry is cleared after being run,
this would be mostly innocent, except that, atexit(rtld_exit) done
after main binary constructors, makes destructors from libraries
executed before destructors for main.
Fix by reordering atexit(rtld_exit) before inits for main binary, same
as it happened when inits were called by csu. Do it using new private
libc symbol with pre-defined ABI.
Reported. tested, and reviewed by: kan
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
the file associated with the given file descriptor.
Reviewed by: kib, asomers
Reviewed by: cem, jilles, brooks (they reviewed previous version)
Discussed with: pjd, and many others
Differential Revision: https://reviews.freebsd.org/D14567
There are a few places that use hand crafted versions of the macros
from sys/netinet/in.h making it difficult to actually alter the
values in use by these macros. Correct that by replacing handcrafted
code with proper macro usage.
Reviewed by: karels, kristof
Approved by: bde (mentor)
MFC after: 3 weeks
Sponsored by: John Gilmore
Differential Revision: https://reviews.freebsd.org/D19317
The current logic for CSTD/CXXSTD requires homogenity as far as the
supported C/C++ standards, which is a sensible default. However, when
dealing with differing versions of C++, some code may compile with C++11, but
not C++17 (for instance). So in order to avoid having people convert over their
code to the new standard, give the users the ability to specify the standard on
a per-program basis.
This will allow a user to override the supporting standard for a set of
programs, mixing C++11 with C++14 (for instance).
Reviewed by: asomers
Apprved by: emaste (mentor)
MFC after: 1 month
MFC with: r345708
Differential Revision: https://reviews.freebsd.org/D19738
When a review is closed via Phabricator it updates the patch attached to the
review. I downloaded the raw patch from Phabricator, applied it, and repeated
my mistake from r345704 by accident mixing content from D19732 and D19738.
For my own personal sanity, I will try not to mix reviews like this in the
future.
MFC after: 1 month
MFC with: r345706
Approved by: emaste (mentor, implicit)
CXXSTD was added as the C++ analogue to CSTD.
CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.
This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.
As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.
Notes:
This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.
Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:
Before this commit:
```
CXXFLAGS+= -std=c++14
```
After this commit:
```
CXXSTD= c++14
```
Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
MFC with: r345203, r345704, r345705
Relnotes: yes
Tested with: make tinderbox
Differential Revision: https://reviews.freebsd.org/D19732
I accidentally committed code from two reviews. I will reintroduce the code to
bsd.progs.mk as part of a separate commit from r345704.
Approved by: emaste (mentor, implicit)
MFC after: 2 months
MFC with: r345704
CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.
This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.
As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.
Notes:
This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.
Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:
Before this commit:
```
CXXFLAGS+= -std=c++14
```
After this commit:
```
CXXSTD= c++14
```
Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D19732
If dso uses initial exec TLS mode, rtld tries to allocate TLS in
static space. If there is no space left, the dlopen(3) fails. If space
if allocated, initial content from PT_TLS segment is distributed to
all threads' pcbs, which was missed and caused un-initialized TLS
segment for such dso after dlopen(3).
The mode is auto-detected either due to the relocation used, or if the
DF_STATIC_TLS dynamic flag is set. In the later case, the TLS segment
is tried to allocate earlier, which increases chance of the dlopen(3)
to succeed. LLD was recently fixed to properly emit the flag, ld.bdf
did it always.
Initial test by: dumbbell
Tested by: emaste (amd64), ian (arm)
Tested by: Gerald Aryeetey <aryeeteygerald_rogers.com> (arm64)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D19072
r345620 by kib@ fixed the rtld issue that caused a crash at startup
during resolution of libc's ifuncs with BIND_NOW.
PR: 233333
Sponsored by: The FreeBSD Foundation
r343532 noted the difference between "hw.realmem" and "hw.physmem", which I
was previously unaware of. I discovered that neither sysctl had a
description visible via `sysctl -d', so I found where they were defined and
added suitable descriptions. While in the file, I went ahead and added
descriptions for all the others which lacked them. I also updated sysctl.3
accordingly
Reviewed by: kib, bcr
MFC after: 1 weeks
Sponsored by: Panasas
Differential Revision: https://reviews.freebsd.org/D19007
According to 0mp, macros are not expanded in the argument provided to
-width. Use plain identifiers for width specification.
Noted and reviewed by: 0mp
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Differential revision: https://reviews.freebsd.org/D19308
