Samuel Thibault [Tue, 2 May 2023 19:29:26 +0000 (21:29 +0200)]
hurd 64bit: Make dev_t word type
dev_t are 64bit on Linux ports, so better increase their size on 64bit
Hurd. It happens that this helps with BZ 23084 there: st_dev has type fsid_t
(quad) and is specified by POSIX to have type dev_t. Making dev_t 64bit
makes these match.
Samuel Thibault [Mon, 1 May 2023 12:48:06 +0000 (14:48 +0200)]
socket: Fix tst-cmsghdr-skeleton.c use of cmsg_len
cmsg_len is supposed to be socklen_t according to standards, but it was made
size_t on Linux, see BZ 16919. For ports that have it socklen_t, SIZE_MAX is
too large. We can however explicitly cast it to the type of cmsg_len so it
will fit according to that type.
hurd: Replace reply port with a dead name on failed interruption
If we're trying to interrupt an interruptible RPC, but the server fails
to respond to our __interrupt_operation () call, we instead destroy the
reply port we were expecting the reply to the RPC on.
Instead of deallocating the name completely, replace it with a dead
name, so the name won't get reused for some other right, and deallocate
it in _hurd_intr_rpc_mach_msg once we return from the signal handler.
Flavio Cruz [Mon, 1 May 2023 00:09:49 +0000 (20:09 -0400)]
Define __mig_strlen to support dynamically sized strings in hurd RPCs
We make lib{mach,hurd}user.so only call __mig_strlen which can be
relocated before libc.so is relocated, similar to what is done with
__mig_memcpy.
Message-Id: <ZE8DTRDpY2hpPZlJ@jupiter.tail36e24.ts.net>
Normally, in static builds, the first code that runs is _start, in e.g.
sysdeps/x86_64/start.S, which quickly calls __libc_start_main, passing
it the argv etc. Among the first things __libc_start_main does is
initializing the tunables (based on env), then CPU features, and then
calls _dl_relocate_static_pie (). Specifically, this runs ifunc
resolvers to pick, based on the CPU features discovered earlier, the
most suitable implementation of "string" functions such as memcpy.
Before that point, calling memcpy (or other ifunc-resolved functions)
will not work.
In the Hurd port, things are more complex. In order to get argv/env for
our process, glibc normally needs to do an RPC to the exec server,
unless our args/env are already located on the stack (which is what
happens to bootstrap processes spawned by GNU Mach). Fetching our
argv/env from the exec server has to be done before the call to
__libc_start_main, since we need to know what our argv/env are to pass
them to __libc_start_main.
On the other hand, the implementation of the RPC (and other initial
setup needed on the Hurd before __libc_start_main can be run) is not
very trivial. In particular, it may (and on x86_64, will) use memcpy.
But as described above, calling memcpy before __libc_start_main can not
work, since the GOT entry for it is not yet initialized at that point.
Work around this by pre-filling the GOT entry with the baseline version
of memcpy, __memcpy_sse2_unaligned. This makes it possible for early
calls to memcpy to just work. The initial value of the GOT entry is
unused on x86_64, and changing it won't interfere with the relocation
being performed later: once _dl_relocate_static_pie () is called, the
baseline version will get replaced with the most suitable one, and that
is what subsequent calls of memcpy are going to call.
[samuel.thibault@ens-lyon.org: Restored same comments as on i386] Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230429201822.2605207-3-bugaevc@gmail.com>
We need to align on uintptr_t to make this work for x86_64,
otherwise things will go wrong when RPCs return errors.
Message-Id: <ZE3aPH7uCEDti47H@jupiter.tail36e24.ts.net>
If the process has set the close-on-exec flag for the file descriptor,
it expects the file descriptor to get closed on exec, even if we replace
what the file descriptor refers to.
If any of the early boot-up tasks calls exit () or returns from main (),
terminate it properly instead of crashing on trying to dereference
_hurd_ports and getting forcibly terminated by the kernel.
We sadly cannot make the __USEPORT macro do the check for _hurd_ports
being unset, because it evaluates to the value of the expression
provided as the second argument, and that can be of any type; so there
is no single suitable fallback value for the macro to evaluate to in
case _hurd_ports is unset. Instead, each use site that wants to care for
this case will have to do its own checking.
H.J. Lu [Thu, 27 Apr 2023 20:06:15 +0000 (13:06 -0700)]
__check_pf: Add a cancellation cleanup handler [BZ #20975]
There are reports for hang in __check_pf:
https://github.com/JoeDog/siege/issues/4
It is reproducible only under specific configurations:
1. Large number of cores (>= 64) and large number of threads (> 3X of
the number of cores) with long lived socket connection.
2. Low power (frequency) mode.
3. Power management is enabled.
While holding lock, __check_pf calls make_request which calls __sendto
and __recvmsg. Since __sendto and __recvmsg are cancellation points,
lock held by __check_pf won't be released and can cause deadlock when
thread cancellation happens in __sendto or __recvmsg. Add a cancellation
cleanup handler for __check_pf to unlock the lock when cancelled by
another thread. This fixes BZ #20975 and the siege hang issue.
Kito Cheng [Tue, 14 Mar 2023 15:19:48 +0000 (23:19 +0800)]
Remap __GLIBC_FLT_EVAL_METHOD to 0 if __FLT_EVAL_METHOD__ is -1
__GLIBC_FLT_EVAL_METHOD will effect the definition of float_t and
double_t, currently we'll set __GLIBC_FLT_EVAL_METHOD to 2 when
__FLT_EVAL_METHOD__ is -1, that means we'll define float_t and double_t
to long double.
However some target isn't natively (HW) support long double like AArch64 and
RISC-V, they defined long double as 128-bits IEEE 754 floating point type.
That means setting __GLIBC_FLT_EVAL_METHOD to 2 will cause very inefficient
code gen for those target who didn't provide native support for long
double, and that's violate the spirit float_t and double_t - most efficient
types at least as wide as float and double.
So this patch propose to remap __GLIBC_FLT_EVAL_METHOD to 0 rather than
2 when __FLT_EVAL_METHOD__ is -1, which means we'll use float/double
rather than long double for float_t and double_t.
Note: __FLT_EVAL_METHOD__ == -1 means the precision is indeterminable,
which means compiler might using indeterminable precision during
optimization/code gen, clang will set this value to -1 when fast
math is enabled.
Note: Default definition float_t and double_t in current glibc:
| __GLIBC_FLT_EVAL_METHOD | float_t | double_t
| 0 or 16 | float | double
| 1 | double | doulbe
| 2 | long double | long double
More complete list see math/math.h
Note: RISC-V has defined ISA extension to support 128-bits IEEE 754
floating point operations, but only rare RISC-V core will implement that.
Related link:
[1] LLVM issue (__FLT_EVAL_METHOD__ is set to -1 with Ofast. #60781):
https://github.com/llvm/llvm-project/issues/60781
[2] Last version of this patch: https://sourceware.org/pipermail/libc-alpha/2023-February/145622.html
Hsiangkai Wang [Tue, 14 Mar 2023 16:25:12 +0000 (00:25 +0800)]
riscv: Resolve symbols directly for symbols with STO_RISCV_VARIANT_CC.
In some cases, we do not want to go through the resolver for function
calls. For example, functions with vector arguments will use vector
registers to pass arguments. In the resolver, we do not save/restore the
vector argument registers for lazy binding efficiency. To avoid ruining
the vector arguments, functions with vector arguments will not go
through the resolver.
To achieve the goal, we will annotate the function symbols with
STO_RISCV_VARIANT_CC flag and add DT_RISCV_VARIANT_CC tag in the dynamic
section. In the first pass on PLT relocations, we do not set up to call
_dl_runtime_resolve. Instead, we resolve the functions directly.
Support for SFrame format is available in Binutils 2.40. The GNU ld merges
the input .sframe sections and creates an output .sframe section in a
segment PT_GNU_SFRAME.
This checks that:
* We can send and receive fds over Unix domain sockets using SCM_RIGHTS;
* msg_controllen, cmsg_level, cmsg_type, cmsg_len are all filled in
correctly on receive;
* Most importantly, the received fd has or has not the close-on-exec
flag set depending on whether we pass MSG_CMSG_CLOEXEC to recvmsg ().
Samuel Thibault [Mon, 24 Apr 2023 22:14:58 +0000 (00:14 +0200)]
hurd: Do not take any flag from the CMSG_DATA
As fixed in 0822e3552a78 ("hurd: Don't pass FD_CLOEXEC in CMSG_DATA"),
senders currently don't have any flag to pass. We shouldn't blindly take
random flags that senders could be erroneously giving us.
This is a new flag that can be passed to recvmsg () to make it
atomically set the CLOEXEC flag on all the file descriptors received
using the SCM_RIGHTS mechanism. This is useful for all the same reasons
that the other XXX_CLOEXEC flags are useful: namely, it provides
atomicity with respect to another thread of the same process calling
(fork and then) exec at the same time.
This flag is already supported on Linux and FreeBSD. The flag's value,
0x40000, is choosen to match FreeBSD's.
Samuel Thibault [Mon, 24 Apr 2023 21:05:15 +0000 (23:05 +0200)]
hurd: Don't pass FD_CLOEXEC in CMSG_DATA
The flags are used by _hurd_intern_fd, which takes O_* flags, not FD_*.
Also, it is of no concern to the receiving process whether or not
the sender process wants to close its copy of sent file descriptor
upon exec, and it should not influence whether or not the received
file descriptor gets the FD_CLOEXEC flag set in the receiving process.
The latter should in fact be dependent on the MSG_CMSG_CLOEXEC flag
being passed to the recvmsg () call, which is going to be implemented
in the following commit.
This is a flag that can be passed to mmap () to request that the mapping
being established should be located in the lower 2 GB area of the
address space, so only the lower 31 (not 32) bits can be set in its
address, and the address can be represented as a 32-bit integer without
truncating it.
This flag is intended to be compatible with Linux, FreeBSD, and Darwin
flags of the same name. Out of those systems, it appears Linux and
FreeBSD take MAP_32BIT to mean "map 31 bit", whereas Darwin allows the
32nd bit to be set in the address as well. The Hurd follows Linux and
FreeBSD behavior.
Unlike on those systems, on the Hurd MAP_32BIT is defined on all
supported architectures (which currently are only i386 and x86_64).
When opening a temporary file without O_CLOEXEC we risk leaking the
file descriptor if another thread calls (fork and then) exec while we
have the fd open. Fix this by consistently passing O_CLOEXEC everywhere
where we open a file for internal use (and not to return it to the user,
in which case the API defines whether or not the close-on-exec flag
shall be set on the returned fd).
Copy strncpy tests for strndup. Covers some basic testcases with random
strings. Remove tests that set the destination's bytes and checked the
resulting buffer's bytes. Remove wide character test support since
wcsndup() doesn't exist.
hurd: Don't migrate reply port into __init1_tcbhead
Properly differentiate between setting up the real TLS with
TLS_INIT_TP, and setting up the early TLS (__init1_tcbhead) in static
builds. In the latter case, don't yet migrate the reply port into the
TCB, and don't yet set __libc_tls_initialized to 1.
This also lets us move the __init1_desc assignment inside
_hurd_tls_init ().
Created tunable to force small pages on stack allocation.
Created tunable glibc.pthread.stack_hugetlb to control when hugepages
can be used for stack allocation.
In case THP are enabled and glibc.pthread.stack_hugetlb is set to
0, glibc will madvise the kernel not to use allow hugepages for stack
allocations.
DJ Delorie [Mon, 3 Apr 2023 21:33:03 +0000 (17:33 -0400)]
malloc: set NON_MAIN_ARENA flag for reclaimed memalign chunk (BZ #30101)
Based on these comments in malloc.c:
size field is or'ed with NON_MAIN_ARENA if the chunk was obtained
from a non-main arena. This is only set immediately before handing
the chunk to the user, if necessary.
The NON_MAIN_ARENA flag is never set for unsorted chunks, so it
does not have to be taken into account in size comparisons.
When we pull a chunk off the unsorted list (or any list) we need to
make sure that flag is set properly before returning the chunk.
Use the rounded-up size for chunk_ok_for_memalign()
Do not scan the arena for reusable chunks if there's no arena.
Account for chunk overhead when determining if a chunk is a reuse
candidate.
mcheck interferes with memalign, so skip mcheck variants of
memalign tests.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
_hurd_thread_sigstate () already handles finding an existing sigstate
before allocating a new one, so just use that. Bonus: this will only
lock the _hurd_siglock once.
Much as the comment says, things on _hurd_subinit assume that _hurd_pid
is already initialized by the time _hurd_subinit is run, so
_hurd_proc_subinit has to run before it. Specifically, init_dtable ()
calls _hurd_port2fd (), which uses _hurd_pid and _hurd_pgrp to set up
ctty handling. With _hurd_subinit running before _hurd_proc_subinit,
ctty setup was broken:
Fix this by running the _hurd_proc_subinit hook in the correct place --
just after _hurd_portarray is set up (so the proc server port is
available in its usual place) and just before running _hurd_subinit.
We must not use the user's reply port (scp->sc_reply_port) for any of
our own RPCs, otherwise various things break. So, use MACH_PORT_DEAD as
a reply port when destroying our reply port, and make sure to do this
after _hurd_sigstate_unlock (), which may do a gsync_wake () RPC.
It is common to have (some of) stdin, stdout and stderr point to the
very same port. We were making the ctty RPCs that _hurd_port2fd () does
for each one of them separately:
Instead, let's detect this case and duplicate the ctty port we already
have. This means we do 1 RPC instead of 3 (and create a single protid
on the server side) if the file is our ctty, and no RPCs instead of 1
if it's not. A clear win!
Optimize the fast paths (x < y) and (x/y < 2^12). Delay handling of special
cases to reduce the number of instructions executed before the fast paths.
Performance improvements for fmod:
Wilco Dijkstra [Tue, 21 Mar 2023 14:00:22 +0000 (14:00 +0000)]
Benchtests: Adjust timing
Adjust iteration counts so benchmarks don't run too slowly or quickly.
Ensure benchmarks take less than 10 seconds on older, slower cores and
more than 0.5 seconds on fast cores.
Sergey Bugaev [Sun, 19 Mar 2023 15:10:07 +0000 (18:10 +0300)]
hurd: Only check for TLS initialization inside rtld or in static builds
When glibc is built as a shared library, TLS is always initialized by
the call of TLS_INIT_TP () macro made inside the dynamic loader, prior
to running the main program (see dl-call_tls_init_tp.h). We can take
advantage of this: we know for sure that __LIBC_NO_TLS () will evaluate
to 0 in all other cases, so let the compiler know that explicitly too.
Also, only define _hurd_tls_init () and TLS_INIT_TP () under the same
conditions (either !SHARED or inside rtld), to statically assert that
this is the case.
Other than a microoptimization, this also helps with avoiding awkward
sharing of the __libc_tls_initialized variable between ld.so and libc.so
that we would have to do otherwise -- we know for sure that no sharing
is required, simply because __libc_tls_initialized would always be set
to true inside libc.so.
Now that the signal code no longer accesses it, the only real user of it
was mig-reply.c, so move the logic for managing the port there.
If we're in SHARED and outside of rtld, we know that __LIBC_NO_TLS ()
always evaluates to 0, and a TLS reply port will always be used, not
__hurd_reply_port0. Still, the compiler does not see that
__hurd_reply_port0 is never used due to its address being taken. To deal
with this, explicitly compile out __hurd_reply_port0 when we know we
won't use it.
Also, instead of accessing the port via THREAD_SELF->reply_port, this
uses THREAD_GETMEM and THREAD_SETMEM directly, avoiding possible
miscompilations.
Samuel Thibault [Tue, 11 Apr 2023 22:12:02 +0000 (00:12 +0200)]
aio: Fix freeing memory
The content of the pool array is initialized only until pool_size,
pointers between pool_size and pool_max_size were not initialized by the
realloc call in get_elem so they should not be freed.
This fixes aio tests crashing at their termination on GNU/Hurd.
Apparently we load libc.so (and thus start using its functions) before
calling TLS_INIT_TP, so libc.so functions should not actually assume
that TLS is always set up.
Sergey Bugaev [Sun, 19 Mar 2023 15:10:10 +0000 (18:10 +0300)]
hurd: Don't leak __hurd_reply_port0
Previously, once we set up TLS, we would implicitly switch from using
__hurd_reply_port0 to reply_port inside the TCB, leaving the former
unused. But we never deallocated it, so it got leaked.
Instead, migrate the port into the new TCB's reply_port slot. This
avoids both the port leak and an extra syscall to create a new reply
port for the TCB.
Sergey Bugaev [Sun, 19 Mar 2023 15:10:08 +0000 (18:10 +0300)]
hurd: Improve reply port handling when exiting signal handlers
If we're doing signals, that means we've already got the signal thread
running, and that implies TLS having been set up. So we know that
__hurd_local_reply_port will resolve to THREAD_SELF->reply_port, and can
access that directly using the THREAD_GETMEM and THREAD_SETMEM macros.
This avoids potential miscompilations, and should also be a tiny bit
faster.
Also, use mach_port_mod_refs () and not mach_port_destroy () to destroy
the receive right. mach_port_destroy () should *never* be used on
mach_task_self (); this can easily lead to port use-after-free
vulnerabilities if the task has any other references to the same port.
Sergey Bugaev [Sun, 19 Mar 2023 15:10:07 +0000 (18:10 +0300)]
hurd: Only check for TLS initialization inside rtld or in static builds
When glibc is built as a shared library, TLS is always initialized by
the call of TLS_INIT_TP () macro made inside the dynamic loader, prior
to running the main program (see dl-call_tls_init_tp.h). We can take
advantage of this: we know for sure that __LIBC_NO_TLS () will evaluate
to 0 in all other cases, so let the compiler know that explicitly too.
Also, only define _hurd_tls_init () and TLS_INIT_TP () under the same
conditions (either !SHARED or inside rtld), to statically assert that
this is the case.
Other than a microoptimization, this also helps with avoiding awkward
sharing of the __libc_tls_initialized variable between ld.so and libc.so
that we would have to do otherwise -- we know for sure that no sharing
is required, simply because __libc_tls_initialized would always be set
to true inside libc.so.
These are just regular local variables that are not accessed in any
funny ways, not even though a pointer. There's absolutely no reason to
declare them volatile. It only ends up hurting the quality of the
generated machine code.
If anything, it would make sense to decalre sigsp as *pointing* to
volatile memory (volatile void *sigsp), but evidently that's not needed
either.
Paul Eggert [Sat, 8 Apr 2023 20:51:26 +0000 (13:51 -0700)]
manual: update AddressSanitizer discussion
* manual/string.texi (Truncating Strings): Update obsolescent
reference and use the more-generic term “AddressSanitizer”.
Mention fortification, too. -fcheck-pointer-bounds is no longer
supported.
Paul Eggert [Sat, 8 Apr 2023 20:51:26 +0000 (13:51 -0700)]
manual: improve string section wording
* manual/string.texi: Editorial fixes. Do not say “text” when
“string” or “string contents” is meant, as a C string can contain
bytes that are not valid text in the current encoding.
When warning about strcat efficiency, warn similarly about strncat
and wcscat. “coping” → “copying”.
Mention at the start of the two problematic sections that problems
are discussed at section end.
projects / thirdparty / glibc.git / log
