Reserved bits in the Floating-Point Control and Status Register (FCSR)
should not be implicitly cleared by fedisableexcept or feenableexcept,
there is no reason to. Among these are the 8 condition codes and one of
the two bits reserved for architecture implementers (bits #22 & #21).
As to the latter, there is no reason to treat any of them as reserved
either, they should be user controllable and settable via __fpu_control
override as the user sees fit. For example in processors implemented by
MIPS Technologies, such as the 5Kf or the 24Kf, these bits are used to
change the treatment of denormalised operands and tiny results: bit #22
is Flush Override (FO) and bit #21 is Flush to Nearest (FN). They cause
non-IEEE-compliant behaviour, but some programs may have a use for such
modes of operation; the library should not obstruct such use just as it
does not for the architectural Flush to Zero (FS) bit (bit #24).
Therefore the change adjusts the reserved mask accordingly and also
documents the distinction between bits 22:21 and 20:18.
This function is now called from dl_open_worker with the GL(dl_load_lock)
lock held and no longer needs local protection. GL(dl_load_lock) also
correctly protects _dl_lookup_symbol_x called here that relies on the
caller to have serialized access to the data structures it uses.
This patch introduces two new convenience functions to set the default
thread attributes used for creating threads. This allows a programmer
to set the default thread attributes just once in a process and then
run pthread_create without additional attributes.
Resolves: #15465
The program name may be unavailable if the user application tampers
with argc and argv[]. Some parts of the dynamic linker caters for
this while others don't, so this patch consolidates the check and
fallback into a single macro and updates all users.
[BZ #15442] This adds support for the inverse interpretation of the
quiet bit of IEEE 754 floating-point NaN data that some processors
use. This includes in particular MIPS architecture processors; the
payload used for the canonical qNaN encoding is updated accordingly
so as not to interfere with the quiet bit.
* sysdeps/unix/sysv/linux/bits/mman-linux.h (MAP_ANONYMOUS):
Allow definition via __MAP_ANONYMOUS.
* sysdeps/unix/sysv/linux/mips/bits/mman.h: Remove all defines
provided by bits/mman-linux.h and include <bits/mman-linux.h>.
(__MAP_ANONYMOUS): Define.
This feature is specifically for the C++ compiler to offload calling
thread_local object destructors on thread program exit, to glibc.
This is to overcome the possible complication of destructors of
thread_local objects getting called after the DSO in which they're
defined is unloaded by the dynamic linker. The DSO is marked as
'unloadable' if it has a constructed thread_local object and marked as
'unloadable' again when all the constructed thread_local objects
defined in it are destroyed.
That convention requires the instruction immediately preceding SYSCALL
to initialize $v0 with the syscall number. Then if a restart triggers,
$v0 will have been clobbered by the syscall interrupted, and needs to be
reinititalized. The kernel will decrement the PC by 4 before switching
back to the user mode so that $v0 has been reloaded before SYSCALL is
executed again. This implies the place $v0 is loaded from must be
preserved across a syscall, e.g. an immediate, static register, stack
slot, etc.
The restriction was lifted with Linux 2.6.36 kernel release and no
special requirements are placed around the SYSCALL instruction anymore,
however we still support older kernel binaries.
