see
linux commit b0a0c2615f6f199a656ed8549d7dce625d77aa77
epoll: wire up syscall epoll_pwait2
linux commit 58169a52ebc9a733aeb5bea857bc5daa71a301bb
epoll: add syscall epoll_pwait2
epoll_wait with struct timespec timeout instead of int. no time32 variant.
mainly added to linux to allow a central process management service in
android to give MADV_COLD|PAGEOUT hints for other processes, see
linux commit ecb8ac8b1f146915aa6b96449b66dd48984caacc
mm/madvise: introduce process_madvise() syscall: an external memory
hinting API
see
linux commit 9b4feb630e8e9801603f3cab3a36369e3c1cf88d
arch: wire-up close_range()
linux commit 278a5fbaed89dacd04e9d052f4594ffd0e0585de
open: add close_range()
the linux faccessat syscall lacks a flag argument that is necessary
to implement the posix api, see
linux commit c8ffd8bcdd28296a198f237cc595148a8d4adfbe
vfs: add faccessat2 syscall
also added clone3 on sh and m68k, on sh it's still missing (not
yet wired up), but reserved so safe to add.
see
linux commit fddb5d430ad9fa91b49b1d34d0202ffe2fa0e179
open: introduce openat2(2) syscall
linux commit 9a2cef09c801de54feecd912303ace5c27237f12
arch: wire up pidfd_getfd syscall
linux commit 8649c322f75c96e7ced2fec201e123b2b073bf09
pid: Implement pidfd_getfd syscall
linux commit e8bb2a2a1d51511e6b3f7e08125d52ec73c11139
m68k: Wire up clone3() syscall
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).
a number of users performing seccomp filtering have requested use of
the new individual syscall numbers for socket syscalls, rather than
the legacy multiplexed socketcall, since the latter has the arguments
all in memory where they can't participate in filter decisions.
previously, some archs used the multiplexed socketcall if it was
historically all that was available, while other archs used the
separate syscalls. the intent was that the latter set only include
archs that have "always" had separate socket syscalls, at least going
back to linux 2.6.0. however, at least powerpc, powerpc64, and sh were
wrongly included in this set, and thus socket operations completely
failed on old kernels for these archs.
with the changes made here, the separate syscalls are always
preferred, but fallback code is compiled for archs that also define
SYS_socketcall. two such archs, mips (plain o32) and microblaze,
define SYS_socketcall despite never having needed it, so it's now
undefined by their versions of syscall_arch.h to prevent inclusion of
useless fallback code.
some archs, where the separate syscalls were only added after the
addition of SYS_accept4, lack SYS_accept. because socket calls are
always made with zeros in the unused argument positions, it suffices
to just use SYS_accept4 to provide a definition of SYS_accept, and
this is done to make happy the macro machinery that concatenates the
socket call name onto __SC_ and SYS_.
this extends commit 5a105f19b5, removing
timer[fd]_settime and timer[fd]_gettime. the timerfd ones are likely
to have been used in software that started using them before it could
rely on libc exposing functions.
some nontrivial number of applications have historically performed
direct syscalls for these operations rather than using the public
functions. such usage is invalid now that time_t is 64-bit and these
syscalls no longer match the types they are used with, and it was
already harmful before (by suppressing use of vdso).
since syscall() has no type safety, incorrect usage of these syscalls
can't be caught at compile-time. so, without manually inspecting or
running additional tools to check sources, the risk of such errors
slipping through is high.
this patch renames the syscalls on 32-bit archs to clock_gettime32 and
gettimeofday_time32, so that applications using the original names
will fail to build without being fixed.
note that there are a number of other syscalls that may also be unsafe
to use directly after the time64 switchover, but (1) these are the
main two that seem to be in widespread use, and (2) most of the others
continue to have valid usage with a null timeval/timespec argument, as
the argument is an optional timeout or similar.
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.
now that all 32-bit archs have 64-bit time types, the values for the
time-related ioctls can be shared. the mechanism for this is an
arch/generic version of the bits header. archs which don't use the
generic header still need to duplicate the definitions.
x32, which does not use the new time64 values of the macros, already
has its own overrides, so this commit does not affect it.
now that all 32-bit archs have 64-bit time types, the values for the
time-related socket option macros can be treated as universal for
32-bit archs. the sys/socket.h mechanism for this predates
arch/generic and is instead in the top-level header.
x32, which does not use the new time64 values of the macros, already
has its own overrides, so this commit does not affect it.
this commit preserves ABI fully for existing interface boundaries
between libc and libc consumers (applications or libraries), by
retaining existing symbol names for the legacy 32-bit interfaces and
redirecting sources compiled against the new headers to alternate
symbol names. this does not necessarily, however, preserve the
pairwise ABI of libc consumers with one another; where they use
time_t-derived types in their interfaces with one another, it may be
necessary to synchronize updates with each other.
the intent is that ABI resulting from this commit already be stable
and permanent, but it will not be officially so until a release is
made. changes to some header-defined types that do not play any role
in the ABI between libc and its consumers may still be subject to
change.
mechanically, the changes made by this commit for each 32-bit arch are
as follows:
- _REDIR_TIME64 is defined to activate the symbol redirections in
public headers
- COMPAT_SRC_DIRS is defined in arch.mak to activate build of ABI
compat shims to serve as definitions for the original symbol names
- time_t and suseconds_t definitions are changed to long long (64-bit)
- IPC_STAT definition is changed to add the IPC_TIME64 bit (0x100),
triggering conversion of semid_ds, shmid_ds, and msqid_ds split
low/high time bits into new time_t members
- structs semid_ds, shmid_ds, msqid_ds, and stat are modified to add
new 64-bit time_t/timespec members at the end, maintaining existing
layout of other members.
- socket options (SO_*) and ioctl (sockios) command macros are
redefined to use the kernel's "_NEW" values.
in addition, on archs where vdso clock_gettime is used, the
VDSO_CGT_SYM macro definition in syscall_arch.h is changed to use a
new time64 vdso function if available, and a new VDSO_CGT32_SYM macro
is added for use as fallback on kernels lacking time64.
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
commit ffaaa6d230 removed the
corresponding stdarg.h support for compilers without va_list builtins,
but failed to remove the alternate type definition, leaving incorrect
va_list definitions in place with compilers that don't define __GNUC__
with a value >= 3.
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]
otherwise, 32-bit archs that could otherwise share the generic
bits/ipc.h would need to duplicate the struct ipc_perm definition,
obscuring the fact that it's the same. sysvipc is not widely used and
these headers are not commonly included, so there is no performance
gain to be had by limiting the number of indirectly included files
here.
files with the existing time32 definition of IPC_STAT are added to all
current 32-bit archs now, so that when it's changed the change will
show up as a change rather than addition of a new file where it's less
obvious that the value is changing vs the generic one that was used
before.
there are more archs sharing the generic 64-bit version of the struct,
which is uniform and much more reasonable, than sharing the current
"generic" one, and depending on how time64 sysvipc is done for 32-bit
archs, even more may be sharing the "64-bit version" in the future.
so, duplicate the current generic to all archs using it (arm, i386,
m68k, microblaze, or1k) so that the generic can be changed freely.
this is recorded as its own commit mainly as a hint to git tooling, to
assist in copy/move tracking.
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.
we have to avoid using ebx unconditionally in asm constraints for
i386, because gcc 3 and 4 and possibly other simplistic compilers
(pcc?) implement PIC via making ebx a fixed-use register, and disallow
its use for anything else. rather than hard-coding knowledge of which
compilers work (at least gcc 5+ and clang), perform a configure test;
this should give us the good codegen on any new compilers we don't yet
know about.
swapping ebx and edx is kept for 1- and 2-arg syscalls because it
avoids having any spills/stack-frame at all in small functions. for
6-arg, if ebx is directly usable, the complex shuffling introduced in
commit c8798ef974 can be avoided, and
ebp can be loaded the same way ebx is in 5-arg syscalls for compilers
that don't support direct use of ebx.
commit 22e5bbd0de inlined the i386
syscall mechanism, but wrongly assumed memory operands to the 5- and
6-argument syscall asm would be esp-based. however, nothing in the
constraints prevented them from being ebx- or ebp-based, and in those
cases, ebx and ebp could be clobbered before use of the memory operand
was complete. in the 6-argument case, this prevented restoration of
the original register values before the end of the asm block, breaking
the asm contract since ebx and ebp are not marked as clobbered. (they
can't be, because lots of compilers don't accept these registers in
constraints or clobbers if PIC or frame pointer is enabled).
doing this right is complicated by the fact that, after a single push,
no operands which might be memory operands are usable. if they are
esp-based, the value of esp has changed, rendering them invalid.
introduce some new dances to load the registers. for the 5-arg case,
push the operand that may be a memory operand first, and after that,
it doesn't matter if the operand is invalid, since we'll just use the
newly pushed value. for the 6-arg case, we need to put both operands
in memory to begin with, like the old non-inline code prior to commit
22e5bbd0de accepted, so that there's
only one potentially memory-based operand to the asm. this can then be
saved with a single push, and after that the values can be read off
into the registers they're needed in.
there's some size overhead, but still a lot less execution overhead
than the old out-of-line code. doing it better depends on a modern
compiler that lets you use ebx and ebp in asm constraints without
restriction. the failure modes on compilers where this doesn't work
are inconsistent and dangerous (on at least some gcc versions 4.x and
earlier, wrong codegen!), so this is a delicate matter. it can be
addressed later if needed.
this is the first part of a series of patches intended to make
__syscall fully self-contained in the object file produced using
syscall.h, which will make it possible for crt1 code to perform
syscalls.
the (confusingly named) i386 __vsyscall mechanism, which this commit
removes, was introduced before the presence of a valid thread pointer
was mandatory; back then the thread pointer was setup lazily only if
threads were used. the intent was to be able to perform syscalls using
the kernel's fast entry point in the VDSO, which can use the sysenter
(Intel) or syscall (AMD) instruction instead of int $128, but without
inlining an access to the __syscall global at the point of each
syscall, which would incur a significant size cost from PIC setup
everywhere. the mechanism also shuffled registers/calling convention
around to avoid spills of call-saved registers, and to avoid
allocating ebx or ebp via asm constraints, since there are plenty of
broken-but-supported compiler versions which are incapable of
allocating ebx with -fPIC or ebp with -fno-omit-frame-pointer.
the new mechanism preserves the properties of avoiding spills and
avoiding allocation of ebx/ebp in constraints, but does it inline,
using some fairly simple register shuffling, and uses a field of the
thread structure rather than global data for the vdso-provided syscall
code address.
for now, the external __syscall function is refactored not to use the
old __vsyscall so it can be kept, but the intent is to remove it too.
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.
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).
Update atomic.h to provide a_ctz_l in all cases (atomic_arch.h should
now only provide a_ctz_32 and/or a_ctz_64).
The generic version of a_ctz_32 now takes advantage of a_clz_32 if
available and the generic a_ctz_64 now makes use of a_ctz_32.
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.
most of the found naming differences don't matter to musl, because
internally it unifies the syscall names that vary across targets,
but for external code the names should match the kernel uapi.
aarch64:
__NR_fstatat is called __NR_newfstatat in linux.
__NR_or1k_atomic got mistakenly copied from or1k.
arm:
__NR_arm_sync_file_range is an alias for __NR_sync_file_range2
__NR_fadvise64_64 is called __NR_arm_fadvise64_64 in linux,
the old non-arm name is kept too, it should not cause issues.
(powerpc has similar nonstandard fadvise and it uses the
normal name.)
i386:
__NR_madvise1 was removed from linux in commit
303395ac3bf3e2cb488435537d416bc840438fcb 2011-11-11
microblaze:
__NR_fadvise, __NR_fstatat, __NR_pread, __NR_pwrite
had different name in linux.
mips:
__NR_fadvise, __NR_fstatat, __NR_pread, __NR_pwrite, __NR_select
had different name in linux.
mipsn32:
__NR_fstatat is called __NR_newfstatat in linux.
or1k:
__NR__llseek is called __NR_llseek in linux.
the old name is kept too because that's the name musl uses
internally.
powerpc:
__NR_{get,set}res{gid,uid}32 was never present in powerpc linux.
__NR_timerfd was briefly defined in linux but then got renamed.
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
this has been slated for removal for a long time. there is
fundamentally no way to implement stdarg without compiler assistance;
any attempt to do so has serious undefined behavior; its working
depends not just (as a common misconception goes) on ABI, but also on
assumptions about compiler code generation internal to a translation
unit, which is not subject to external ABI constraints.
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.
Szabolcs Nagy
Rich Felker
Andre McCurdy