the adjustment made is entirely a function of TLS_ABOVE_TP and
TP_OFFSET. aside from avoiding repetition of the TP_OFFSET value and
arithmetic, this change makes pthread_arch.h independent of the
definition of struct __pthread from pthread_impl.h. this in turn will
allow inclusion of pthread_arch.h to be moved to the top of
pthread_impl.h so that it can influence the definition of the
structure.
previously, arch files were very inconsistent about the type used for
the thread pointer. this change unifies the new __get_tp interface to
always use uintptr_t, which is the most correct when performing
arithmetic that may involve addresses outside the actual pointed-to
object (due to TP_OFFSET).
the syscall number is reserved on all targets, but it is not wired up
on all targets, see
linux commit 8f6ccf6159aed1f04c6d179f61f6fb2691261e84
Merge tag 'clone3-v5.3' of ... brauner/linux
linux commit 8f3220a806545442f6f26195bc491520f5276e7c
arch: wire-up clone3() syscall
linux commit 7f192e3cd316ba58c88dfa26796cf77789dd9872
fork: add clone3
see
linux commit 7615d9e1780e26e0178c93c55b73309a5dc093d7
arch: wire-up pidfd_open()
linux commit 32fcb426ec001cb6d5a4a195091a8486ea77e2df
pid: add pidfd_open()
now that all 32-bit archs have 64-bit time_t (and suseconds_t), the
arch-provided _Int64 macro (long or long long, as appropriate) can be
used to define them, and arch-specific definitions are no longer
needed.
these structures can now be defined generically in terms of endianness
and long size. previously, the 32-bit archs all shared a common
definition from the generic bits header, and each 64-bit arch had to
repeat the 64-bit version, with endian conditionals if the arch had
variants of each endianness.
I would prefer getting rid of the preprocessor conditionals for
padding and instead using unnamed bitfield members, like commit
9b2921bea1 did for struct timespec.
however, at present sendmsg, recvmsg, and recvmmsg need access to the
padding members by name to zero them. this could perhaps be cleaned up
in the future.
policy has long been that these definitions are purely a function of
whether long/pointer is 32- or 64-bit, and that they are not allowed
to vary per-arch. move the definition to the shared alltypes.h.in
fragment, using integer constant expressions in terms of sizeof to
vary the array dimensions appropriately. I'm not sure whether this is
more or less ugly than using preprocessor conditionals and two sets of
definitions here, but either way is a lot less ugly than repeating the
same thing for every arch.
LLONG_MAX is uniform for all archs we support and plenty of header and
code level logic assumes it is, so it does not make sense for limits.h
bits mechanism to pretend it's variable.
LONG_BIT can be defined in terms of LONG_MAX; there's no reason to put
it in bits.
by moving LONG_MAX definition to __LONG_MAX in alltypes.h and moving
LLONG_MAX out of bits, there are now no plain-C limits that are
defined in the bits header, so the bits header only needs to be
included in the POSIX or extended profiles. this allows the feature
test macro logic to be removed from the bits header, facilitating a
long-term goal of getting such logic out of bits.
having __LONG_MAX in alltypes.h will allow further generalization of
headers.
archs without a constant PAGESIZE no longer need bits/limits.h at all.
this change is motivated by the intersection of several factors.
presently, despite being a nonstandard header, endian.h is exposing
the unprefixed byte order macros and functions only if _BSD_SOURCE or
_GNU_SOURCE is defined. this is to accommodate use of endian.h from
other headers, including bits headers, which need to define structure
layout in terms of endianness. with time64 switch-over, even more
headers will need to do this.
at the same time, the resolution of Austin Group issue 162 makes
endian.h a standard header for POSIX-future, requiring that it expose
the unprefixed macros and the functions even in standards-conforming
profiles. changes to meet this new requirement would break existing
internal usage of endian.h by causing it to violate namespace where
it's used.
instead, have the arch's alltypes.h define __BYTE_ORDER, either as a
fixed constant or depending on the right arch-specific predefined
macros for determining endianness. explicit literals 1234 and 4321 are
used instead of __LITTLE_ENDIAN and __BIG_ENDIAN so that there's no
danger of getting the wrong result if a macro is undefined and
implicitly evaluates to 0 at the preprocessor level.
the powerpc (32-bit) bits/endian.h being removed had logic for varying
endianness, but our powerpc arch has never supported that and has
always been big-endian-only. this logic is not carried over to the new
__BYTE_ORDER definition in alltypes.h.
now that commit f7f1079796 removed the
legacy i386 conditional definition, va_list is in no way
arch-specific, and has no reason to be in the future. move it to the
shared part of alltypes.h.in
new mount api syscalls were added, same numers on all targets, see
linux commit a07b20004793d8926f78d63eb5980559f7813404
vfs: syscall: Add open_tree(2) to reference or clone a mount
linux commit 2db154b3ea8e14b04fee23e3fdfd5e9d17fbc6ae
vfs: syscall: Add move_mount(2) to move mounts around
linux commit 24dcb3d90a1f67fe08c68a004af37df059d74005
vfs: syscall: Add fsopen() to prepare for superblock creation
linux commit ecdab150fddb42fe6a739335257949220033b782
vfs: syscall: Add fsconfig() for configuring and managing a context
linux commit 93766fbd2696c2c4453dd8e1070977e9cd4e6b6d
vfs: syscall: Add fsmount() to create a mount for a superblock
linux commit cf3cba4a429be43e5527a3f78859b1bfd9ebc5fb
vfs: syscall: Add fspick() to select a superblock for reconfiguration
linux commit 9c8ad7a2ff0bfe58f019ec0abc1fb965114dde7d
uapi, x86: Fix the syscall numbering of the mount API syscalls [ver #2]
linux commit d8076bdb56af5e5918376cd1573a6b0007fc1a89
uapi: Wire up the mount API syscalls on non-x86 arches [ver #2]
previously these differed from generic because they needed their own
definitions of IPC_64. now that it's no longer in public header,
they're identical.
the definition of the IPC_64 macro controls the interface between libc
and the kernel through syscalls; it's not a public API. the meaning is
rather obscure. long ago, Linux's sysvipc *id_ds structures used
16-bit uids/gids and wrong types for a few other fields. this was in
the libc5 era, before glibc. the IPC_64 flag (64 is a misnomer; it's
more like 32) tells the kernel to use the modern[-ish] versions of the
structures.
the definition of IPC_64 has nothing to do with whether the arch is
32- or 64-bit. rather, due to either historical accident or
intentional obnoxiousness, the kernel only accepts and masks off the
0x100 IPC_64 flag conditional on CONFIG_ARCH_WANT_IPC_PARSE_VERSION,
i.e. for archs that want to provide, or that accidentally provided,
both. for archs which don't define this option, no masking is
performed and commands with the 0x100 bit set will fail as invalid. so
ultimately, the definition is just a matter of matching an arbitrary
switch defined per-arch in the kernel.
presently, all archs/ABIs have struct stat matching the kernel
stat[64] type, except mips/mipsn32/mips64 which do conversion hacks in
syscall_arch.h to work around bugs in the kernel type. this patch
completely decouples them and adds a translation step to the success
path of fstatat. at present, this is just a gratuitous copying, but it
opens up multiple possibilities for future support for 64-bit time_t
on 32-bit archs and for cleaned-up/unified ABIs.
for clarity, the mips hacks are not yet removed in this commit, so the
mips kstat structs still correspond to the output of the hacks in
their syscall_arch.h files, not the raw kernel type. a subsequent
commit will fix this.
syscall numbers are now synced up across targets (starting from 403 the
numbers are the same on all targets other than an arch specific offset)
IPC syscalls sem*, shm*, msg* got added where they were missing (except
for semop: only semtimedop got added), the new semctl, shmctl, msgctl
imply IPC_64, see
linux commit 0d6040d4681735dfc47565de288525de405a5c99
arch: add split IPC system calls where needed
new 64bit time_t syscall variants got added on 32bit targets, see
linux commit 48166e6ea47d23984f0b481ca199250e1ce0730a
y2038: add 64-bit time_t syscalls to all 32-bit architectures
new async io syscalls got added, see
linux commit 2b188cc1bb857a9d4701ae59aa7768b5124e262e
Add io_uring IO interface
linux commit edafccee56ff31678a091ddb7219aba9b28bc3cb
io_uring: add support for pre-mapped user IO buffers
a new syscall got added that uses the fd of /proc/<pid> as a stable
handle for processes: allows sending signals without pid reuse issues,
intended to eventually replace rt_sigqueueinfo, kill, tgkill and
rt_tgsigqueueinfo, see
linux commit 3eb39f47934f9d5a3027fe00d906a45fe3a15fad
signal: add pidfd_send_signal() syscall
on some targets (arm, m68k, s390x, sh) some previously missing syscall
numbers got added as well.
this will allow the compiler to cache and reuse the result, meaning we
no longer have to take care not to load it more than once for the sake
of archs where the load may be expensive.
depends on commit 1c84c99913 for
correctness, since otherwise the compiler could hoist loads during
stage 3 of dynamic linking before the initial thread-pointer setup.
these were overlooked in the declarations overhaul work because they
are not properly declared, and the current framework even allows their
declared types to vary by arch. at some point this should be cleaned
up, but I'm not sure what the right way would be.
sys/ptrace.h is target specific, use bits/ptrace.h to add target
specific macro definitions.
these macros are kept in the generic sys/ptrace.h even though some
targets don't support them:
PTRACE_GETREGS
PTRACE_SETREGS
PTRACE_GETFPREGS
PTRACE_SETFPREGS
PTRACE_GETFPXREGS
PTRACE_SETFPXREGS
so no macro definition got removed in this patch on any target. only
s390x has a numerically conflicting macro definition (PTRACE_SINGLEBLOCK).
the PT_ aliases follow glibc headers, otherwise the definitions come
from linux uapi headers except ones that are skipped in glibc and
there is no real kernel support (s390x PTRACE_*_AREA) or need special
type definitions (mips PTRACE_*_WATCH_*) or only relevant for linux
2.4 compatibility (PTRACE_OLDSETOPTIONS).
PAGESIZE is actually the version defined in POSIX base, with PAGE_SIZE
being in the XSI option. use PAGESIZE as the underlying definition to
facilitate making exposure of PAGE_SIZE conditional.
counts leading zero bits of a 64bit int, undefined on zero input.
(has nothing to do with atomics, added to atomic.h so target specific
helper functions are together.)
there is a logarithmic generic implementation and another in terms of
a 32bit a_clz_32 on targets where that's available.
when _GNU_SOURCE is defined, which is always the case when compiling
c++ with gcc, these macros for the the indices in gregset_t are
exposed and likely to clash with applications. by using enum constants
rather than macros defined with integer literals, we can make the
clash slightly less likely to break software. the macros are still
defined in case anything checks for them with #ifdef, but they're
defined to expand to themselves so that non-file-scope (e.g.
namespaced) identifiers by the same names still work.
for the sake of avoiding mistakes, the changes were generated with sed
via the command:
sed -i -e 's/#define *\(REG_[A-Z_0-9]\{1,\}\) *\([0-9]\{1,\}\)'\
'/enum { \1 = \2 };\n#define \1 \1/' \
arch/i386/bits/signal.h arch/x86_64/bits/signal.h arch/x32/bits/signal.h
gdb can only backtrace/unwind across signal handlers if it recognizes
the sa_restorer trampoline. for x86_64, gdb first attempts to
determine the symbol name for the function in which the program
counter resides and match it against "__restore_rt". if no name can be
found (e.g. in the case of a stripped binary), the exact instruction
sequence is matched instead.
when matching the function name, however, gdb's unwind code wrongly
considers the interval [sym,sym+size] rather than [sym,sym+size).
thus, if __restore_rt begins immediately after another function, gdb
wrongly identifies pc as lying within the previous adjacent function.
this patch adds a nop before __restore_rt to preclude that
possibility. it also removes the symbol name __restore and replaces it
with a macro since the stability of whether gdb identifies the
function as __restore_rt or __restore is not clear.
for the no-symbols case, the instruction sequence is changed to use
%rax rather than %eax to match what gdb expects.
based on patch by Szabolcs Nagy, with extended description and
corresponding x32 changes added.
placing the opening brace on the same line as the struct keyword/tag
is the style I prefer and seems to be the prevailing practice in more
recent additions.
these changes were generated by the command:
find include/ arch/*/bits -name '*.h' \
-exec sed -i '/^struct [^;{]*$/{N;s/\n/ /;}' {} +
and subsequently checked by hand to ensure that the regex did not pick
up any false positives.
the syscalls take an additional flag argument, they were added in commit
f17d8b35452cab31a70d224964cd583fb2845449 and a RWF_HIPRI priority hint
flag was added to linux/fs.h in 97be7ebe53915af504fb491fb99f064c7cf3cb09.
the syscall is not allocated for microblaze and sh yet.
commits e24984efd5 and
16b55298dc inadvertently disabled the
a_spin implementations for i386, x86_64, and x32 by defining a macro
named a_pause instead of a_spin. this should not have caused any
functional regression, but it inhibited cpu relaxation while spinning
for locks.
bug reported by George Kulakowski.
it was introduced for offloading copying between regular files
in linux commit 29732938a6289a15e907da234d6692a2ead71855
(microblaze and sh does not yet have the syscall number.)
currently five targets use the same mman.h constants and the rest
share most constants too, so move them to sys/mman.h before the
bits/mman.h include where the differences can be corrected by
redefinition of the macros.
this fixes two minor bugs: POSIX_MADV_DONTNEED was wrong on most
targets (it should be the same as MADV_DONTNEED), and sh defined
the x86-only MAP_32BIT mmap flag.
all bits headers that were identical for a number of 'clean' archs are
moved to the new arch/generic tree. in addition, a few headers that
differed only cosmetically from the new generic version are removed.
additional deduplication may be possible in mman.h and in several
headers (limits.h, posix.h, stdint.h) that mostly depend on whether
the arch is 32- or 64-bit, but they are left alone for now because
greater gains are likely possible with more invasive changes to header
logic, which is beyond the scope of this commit.
they lock faulted pages into memory (useful when a small part of a
large mapped file needs efficient access), new in linux v4.4, commit
b0f205c2a3082dd9081f9a94e50658c5fa906ff1
MLOCK_* is not in the POSIX reserved namespace for sys/mman.h
this is mlock with a flags argument, new in linux commit
a8ca5d0ecbdde5cc3d7accacbd69968b0c98764e
as usual microblaze and sh don't have allocated syscall number yet.
new in linux v4.3 added for aarch64, arm, i386, mips, or1k, powerpc,
x32 and x86_64.
membarrier is a system wide memory barrier, moves most of the
synchronization cost to one side, new in kernel commit
5b25b13ab08f616efd566347d809b4ece54570d1
userfaultfd is useful for qemu and is new in kernel commit
8d2afd96c20316d112e04d935d9e09150e988397
switch_endian is powerpc only for switching endianness, new in commit
529d235a0e190ded1d21ccc80a73e625ebcad09b
this commit mostly makes consistent things like spacing, function
ordering in atomic_arch.h, argument names, use of volatile, etc.
a_ctz_l was also removed from x86_64 since atomic.h provides it
automatically using a_ctz_64.
rather than having each arch provide its own atomic.h, there is a new
shared atomic.h in src/internal which pulls arch-specific definitions
from arc/$(ARCH)/atomic_arch.h. the latter can be extremely minimal,
defining only a_cas or new ll/sc type primitives which the shared
atomic.h will use to construct everything else.
this commit avoids making heavy changes to the individual archs'
atomic implementations. definitions which are identical or
near-identical to what the new shared atomic.h would produce have been
removed, but otherwise the changes made are just hooking up the
arch-specific files to the new infrastructure. major changes to take
advantage of the new system will come in subsequent commits.
using the actual mcontext_t definition rather than an overlaid pointer
array both improves correctness/readability and eliminates some ugly
hacks for archs with 64-bit registers bit 32-bit program counter.
also fix UB due to comparison of pointers not in a common array
object.
commit 3c43c0761e fixed missing
synchronization in the atomic store operation for i386 and x86_64, but
opted to use mfence for the barrier on x86_64 where it's always
available. however, in practice mfence is significantly slower than
the barrier approach used on i386 (a nop-like lock orl operation).
this commit changes x86_64 (and x32) to use the faster barrier.
despite being strongly ordered, the x86 memory model does not preclude
reordering of loads across earlier stores. while a plain store
suffices as a release barrier, we actually need a full barrier, since
users of a_store subsequently load a waiter count to determine whether
to issue a futex wait, and using a stale count will result in soft
(fail-to-wake) deadlocks. these deadlocks were observed in malloc and
possible with stdio locks and other libc-internal locking.
on i386, an atomic operation on the caller's stack is used as the
barrier rather than performing the store itself using xchg; this
avoids the need to read the cache line on which the store is being
performed. mfence is used on x86_64 where it's always available, and
could be used on i386 with the appropriate cpu model checks if it's
shown to perform better.
conceptually, and on other archs, these functions take a pointer to
int, but in the i386, x86_64, and x32 versions of atomic.h, they took
a pointer to void instead.
