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
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Later gcc and clang have deprecated =v (which maps to a specific temp
register) and instead we should just use =r to have the assembler
(hopefully!) save/restore things appropriately after choosing
a register.
Tested:
* AR9344 SoC, with userreg support
* AR9331 SoC, with no userreg support
Sponsored by: Sponsored by: DARPA, AFRL (MIPS TLS user register work)
This work, originally from Stacey Son, uses the MIPS UserReg for
reading the TLS data, and will fall back to the normal syscall path
when it isn't supported.
This code dynamically patches cpu_switch() to bypass the UserReg
instruction so to avoid generating a machine exception.
Thanks to sson for the original work, and to Dan Nelson for
bringing it to date and testing it on MIPS32 with me.
Tested:
* mips64 (sson)
* mips74k (dnelson_1901@yahoo.com) - AR9344 SoC, UserReg support
* mips24k (adrian) - AR9331 SoC, no UserReg support
Obtained from: sson, dnelson_1901@yahoo.com
The amd64, i386, and sparc64 versions were identical, with the one
difference where the former two used inline asm instead of _tcb_get. I
have compared the function before and after replacing the asm with _tcb_get
and found the object files to be identical.
The arm, mips, and powerpc versions were almost identical. The only
difference was the powerpc version used an alignment of 1 where arm and
mips used 16. As this is an increase in alignment is will be safe.
Along with this arm, mips, and powerpc all passed, when initial was true,
the value returned from _tcb_get as the first argument to
_rtld_allocate_tls. This would then return this pointer back to the caller.
We can remove these extra calls by checking if initial is set and setting
the thread control block directly. As this is what the sparc64 code does
we can use it directly.
As after these observations all the architectures can now have identical
code we can merge them into a common file.
Differential Revision: https://reviews.freebsd.org/D1556
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
