same changes to the defined macros as in powerpc and generic bits.

same changes as in the generic header.

and BOTHER and IBSHIFT were removed (present in linux uapi but not
in glibc) and TIOCSER_TEMT was added (present in glibc).

add EXTA, EXTB, CIBAUD, CMSPAR, XCASE macros and hide them as well as
CBAUD, ECHOCTL, ECHOPRT, ECHOKE, FLUSHO, PENDIN in standard mode.

the new macros are both in glibc termios.h and in linux asm/termbits.h,
the later also contains IBSHIFT and BOTHER, those were not added.

these are not standard macros, but some of them are in the reserved
namespace so could be exposed, the ones which are not reserved are
CIBAUD, CMSPAR and XCASE (which was removed in issue 6), the rest
got hidden to be consistent with glibc.

arm ioctl.h is the same as the generic one except this macro,
so a workaround solution is used to avoid another ioctl.h copy.

musl does not define these on other targets either.

it seems it was a typo.

TIOCM_ macros were wrongly using the asm-generic/termios.h definitions
instead of the mips specific ones from asm/termios.h

mips and powerpc use their own asm/ioctls.h, not the asm-generic/ioctls.h
and they lack termiox macros that are available on other targets.
see kernel commit 1d65b4a088de407e99714fdc27862449db04fb5c

these are defined in linux asm/ioctls.h.
(powerpc64 and powerpc bits/ioctl.h are now identical)

glibc ioctl.h has it too.

TIOCTTYGSTRUCT, TIOCGHAYESESP, TIOCSHAYESESP and TIOCM_MODEM_BITS
were removed from the linux uapi and not present in glibc ioctl.h

they were slightly different in musl, but should be the same:
the linux uapi and glibc headers are not different.

the (unused) speed fields were omitted when these ports were first
added (within this release cycle, so not present in any release yet)
in accordance with how glibc defines the structure on mips archs.
however their omission does not match existing musl practice/intent.

glibc provides its own, mostly-unified termios structure definition
and performs translation in userspace to match the kernel structure
for the arch, but has gratuitous differences on a few archs like mips,
presumably as a result of historical mistakes. some other libcs use
the kernel definitions directly. musl essentially does that, by
matching the kernel layout in the part of the structure the kernel
will read/write, but leaves additional space at the end for
extensibility. these are nominally the (nonstandard) speed fields and
(on most archs) extra c_cc elements, but since they are not used they
could be repurposed if there's ever a need.

commit 6d38c9cf provided an
arm-specific version of posix_fadvise to address the alternate
argument order the kernel expects on arm, but neglected to address
that powerpc (32-bit) has the same issue. instead of having arch
variant files in duplicate, simply put the alternate version in the
top-level file under the control of a macro defined in syscall_arch.h.

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.

These system calls are already all remapped in an arch-agnostic manner in
src/internal/syscall.h

based on patch submitted by Jaydeep Patil, with minor changes.

mips32r6 and mips64r6 are actually new isas at both the asm source and
opcode levels (pre-r6 code cannot run on r6) and thus need to be
treated as a new subarch. the following changes are made, some of
which yield code generation improvements for non-r6 targets too:

- add subarch logic in configure script and reloc.h files for dynamic
  linker name.

- suppress use of .set mips2 asm directives (used to allow mips2
  atomic instructions on baseline mips1 builds; the kernel has to
  emulate them on mips1) except when actually needed. they cause wrong
  instruction encodings on r6, and pessimize inlining on at least some
  compilers.

- only hard-code sync instruction encoding on mips1.

- use "ZC" constraint instead of "m" constraint for llsc memory
  operands on r6, where the ll/sc instructions no longer accept full
  16-bit offsets.

- only hard-code rdhwr instruction encoding with .word on targets
  (pre-r2) where it may need trap-and-emulate by the kernel.
  otherwise, just use the instruction mnemonic, and allow an arbitrary
  destination register to be used.

commits e24984ef and
16b55298 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.)

add userfaultfd, membarrier and mlock2 system call numbers.

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.

these changes should not affect generated code, but they reflect that
the underlying objects operated on by a_cas_p are supposed to have
type volatile void *, not volatile long. in theory a compiler could
treat the effective type mismatch in the "m" memory operands as
undefined behavior.

apparently clang does not accept matching-register input and output
constraints that differ in size (32-bit vs 64-bit).

based on patch by Jaydeep Patil.

Some PowerPC CPUs (e.g. Freescale MPC85xx) have a completely different
instruction set for floating point operations (SPE).
Executing regular PowerPC floating point instructions results in
"Illegal instruction" errors.

Make it possible to run these devices in soft-float mode.

patch by Mahesh Bodapati and Jaydeep Patil of Imagination
Technologies.

This brings the call to an actually usable speed.
Quick unscientific benchmark: 14ns : 102ns :: vDSO : syscall

at present this is done only for consistency, since this file defines
its own a_cas_p rather than using the new generic one from atomic.h
added in commit 225f6a6b. these
definitions may however be useful if we ever need to add other
pointer-sized atomic operations.

the workaround was for a bug that botched .gpword references to local
labels, applying a nonsensical random offset of -0x4000 to them.

this reverses commit 5e396fb9 and a
removes a similar hack that was added to syscall_cp.s in the later
commit 756c8af8. it turns out one
additional instance of the same idiom, the GETFUNCSYM macro in
arch/mips/reloc.h, was still affected by the assembler bug and does
not admit an easy workaround without making assumptions about how the
macro is used. the previous workarounds made static linking work but
left the early-stage dynamic linker broken and thus had limited
usefulness.

instead, affected users (using binutils versions older than 2.20) will
need to fix the bug on the binutils side; the trivial patch is commit
453f5985b13e35161984bf1bf657bbab11515aa4 in the binutils-gdb
repository.

"Q" input constraint was used for the written object, instead of "=Q"
output constraint.  this should not cause problems because "memory"
is on the clobber list, but "=Q" better documents the intent and more
consistent with the actual asm code.

this changes the generated code, because different registers are used,
but other than the register names nothing should change.

GDB is looking for a pointer to the ldso debug info in the data of the
..rld_map section.
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>

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.

vdso support is available on mips starting with kernel 4.4, see kernel
commit a7f4df4e21 "MIPS: VDSO: Add implementations of gettimeofday()
and clock_gettime()" for details.

In Linux kernel 4.4.0 the mips code returns -ENOSYS in case it can not
handle the vdso call and assumes the libc will call the original
syscall in this case. Handle this case in musl. Currently Linux kernel
4.4.0 handles the following types: CLOCK_REALTIME_COARSE,
CLOCK_MONOTONIC_COARSE, CLOCK_REALTIME and CLOCK_MONOTONIC.

si_errno and si_code are swapped in mips siginfo_t compared to other
archs and some si_code values are different.  This fix is required
for POSIX timers to work.

based on patch by Dmitry Ivanov.

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.