linux(4): Cleanup signal trampolines

This is the first stage of a signal trampolines refactoring.

From trampolines retired emulation of the 'call' instruction, which is
replaced by direct call of a

linux(4): Cleanup signal trampolines

This is the first stage of a signal trampolines refactoring.

From trampolines retired emulation of the 'call' instruction, which is
replaced by direct call of a signal handler. The signal handler address
is in the register.

The previous trampoline implemenatation used semi-Linux-way to call
a signal handler via the 'jmp' instruction. Wherefore the trampoline
emulated a 'call' instruction to into the stack the return address for
signal handler's 'ret' instruction. Wherefore handmade DWARD annotations
was used.

While here rephrased and removed excessive comments.

MFC after: 2 weeks

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linux(4): Retire unneeded initialization

Both uc_flags and uc_link are zeroed above. On amd64 and i386 the
uc_link field is not used at all. The UC_FP_XSTATE bit should be set
in the uc_flags if OS

linux(4): Retire unneeded initialization

Both uc_flags and uc_link are zeroed above. On amd64 and i386 the
uc_link field is not used at all. The UC_FP_XSTATE bit should be set
in the uc_flags if OS xsave knob is turned on (and xsave is implemented).

MFC after: 2 weeks

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linux(4): Implement vdso getcpu for x86.

This is modeled after f2395455 (by kib@).

MFC after: 2 weeks

linux(4): Add compat.linux32.emulate_i386 knob.

Historically 32-bit Linuxulator under amd64 emulated the real i386
behavior. Since 3d8dd983 the old i386 Linux world can't be used under
amd64 Linuxul

linux(4): Add compat.linux32.emulate_i386 knob.

Historically 32-bit Linuxulator under amd64 emulated the real i386
behavior. Since 3d8dd983 the old i386 Linux world can't be used under
amd64 Linuxulator as it don't know anything about amd64 machine (which
is returned now by newuname() syscall). So, add a knob to allow to swith
the behavior and use i386 Linux binaries on amd64.
Set knob to the new behavior as I think this is common to the modern
Linux distros.

Reviewed by: Pau Amma (doc), emaste
Differential revision: https://reviews.freebsd.org/D34708
MFC after: 2 weeks

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linux_copyout_strings: Use PROC_PS_STRINGS().

Reviewed by: markj
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D34173

sysent: Add a sv_psstringssz field to struct sysentvec

The size of the ps_strings structure varies between ABIs, so this is
useful for computing the address of the ps_strings structure relative to
t

sysent: Add a sv_psstringssz field to struct sysentvec

The size of the ps_strings structure varies between ABIs, so this is
useful for computing the address of the ps_strings structure relative to
the top of the stack when stack address randomization is enabled.

Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33704

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exec: Simplify sv_copyout_strings implementations a bit

Simplify control flow around handling of the execpath length and signal
trampoline. Cache the sysentvec pointer in a local variable.

No func

exec: Simplify sv_copyout_strings implementations a bit

Simplify control flow around handling of the execpath length and signal
trampoline. Cache the sysentvec pointer in a local variable.

No functional change intended.

Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33703

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amd64: centralize definitions of CS_SECURE and EFL_SECURE

Requested by markj
Reviewed by: jhb, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: http

amd64: centralize definitions of CS_SECURE and EFL_SECURE

Requested by markj
Reviewed by: jhb, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31954

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linux(4): Add struct clone_args for future clone3 system call.

In preparation for clone3 system call add struct clone_args and use it in
clone implementation.
Move all of clone related bits to the n

linux(4): Add struct clone_args for future clone3 system call.

In preparation for clone3 system call add struct clone_args and use it in
clone implementation.
Move all of clone related bits to the newly created linux_fork.h header.

Differential revision: https://reviews.freebsd.org/D31474
MFC after: 2 weeks

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fork: Allow ABI to specify fork return values for child.

At least Linux x86 ABI's does not use carry bit and expects that the dx register
is preserved. For this add a new sv_set_fork_retval hook and

fork: Allow ABI to specify fork return values for child.

At least Linux x86 ABI's does not use carry bit and expects that the dx register
is preserved. For this add a new sv_set_fork_retval hook and call it from cpu_fork().

Add a short comment about touching dx in x86_set_fork_retval(), for more details
see phab comments from kib@ and imp@.

Reviewed by: kib
Differential revision: https://reviews.freebsd.org/D31472
MFC after: 2 weeks

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linux(4): Allow musl brand to use FUTEX_REQUEUE op.

Initial patch from submitter was adapted by me to prevent unconditional
FUTEX_REQUEUE use.

PR: 255947
Submitted by: Philippe Michaud-Boudreaul

linux(4): Allow musl brand to use FUTEX_REQUEUE op.

Initial patch from submitter was adapted by me to prevent unconditional
FUTEX_REQUEUE use.

PR: 255947
Submitted by: Philippe Michaud-Boudreault
Differential Revision: https://reviews.freebsd.org/D30332

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linux(4): Add arch name to the some printfs.

Reviewed by: emaste
Differential revision: https://reviews.freebsd.org/D30904
MFC after: 2 weeks

linux(4): Fixup the vDSO initialization order.

The vDSO initialisation order should be as follows:
- native abi init via exec_sysvec_init();
- vDSO symbols queued to the linux_vdso_syms list;
- linu

linux(4): Fixup the vDSO initialization order.

The vDSO initialisation order should be as follows:
- native abi init via exec_sysvec_init();
- vDSO symbols queued to the linux_vdso_syms list;
- linux_vdso_install();
- linux_exec_sysvec_init();

As the exec_sysvec_init() called with SI_ORDER_ANY (last) at SI_SUB_EXEC
order, move linux_vdso_install() and linux_exec_sysvec_init() to the
SI_SUB_EXEC+1 order.

Reviewed by: trasz
Differential Revision: https://reviews.freebsd.org/D30902
MFC after 2 weeks

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linux(4): Constify vdso install/deinstall.

In order to reduce diff between arches constify vdso install/deinstall
functions like arm64.

Reviewed by: emaste
Differential revision: https://reviews.f

linux(4): Constify vdso install/deinstall.

In order to reduce diff between arches constify vdso install/deinstall
functions like arm64.

Reviewed by: emaste
Differential revision: https://reviews.freebsd.org/D30901
MFC after: 2 weeks

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linux(4); Almost complete the vDSO.

The vDSO (virtual dynamic shared object) is a small shared library that the
kernel maps R/O into the address space of all Linux processes on image
activation. The

linux(4); Almost complete the vDSO.

The vDSO (virtual dynamic shared object) is a small shared library that the
kernel maps R/O into the address space of all Linux processes on image
activation. The vDSO is a fully formed ELF image, shared by all processes
with the same ABI, has no process private data.

The primary purpose of the vDSO:
- non-executable stack, signal trampolines not copied to the stack;
- signal trampolines unwind, mandatory for the NPTL;
- to avoid contex-switch overhead frequently used system calls can be
implemented in the vDSO: for now gettimeofday, clock_gettime.

The first two have been implemented, so add the implementation of system
calls.

System calls implemenation based on a native timekeeping code with some
limitations:
- ifunc can't be used, as vDSO r/o mapped to the process VA and rtld
can't relocate symbols;
- reading HPET memory is not implemented for now (TODO).

In case on any error vDSO system calls fallback to the kernel system
calls. For unimplemented vDSO system calls added prototypes which call
corresponding kernel system call.

Tested by: trasz (arm64)
Differential revision: https://reviews.freebsd.org/D30900
MFC after: 2 weeks

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linux(4): Modify sv_onexec hook to return an error.

Temporary add stubs to the Linux emulation layer which calls the existing hook.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.

linux(4): Modify sv_onexec hook to return an error.

Temporary add stubs to the Linux emulation layer which calls the existing hook.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D30911
MFC after: 2 weeks

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Pass the syscall number to capsicum permission-denied signals

The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossi

Pass the syscall number to capsicum permission-denied signals

The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossible to
recover in the signal handler after the call has returned. This small
tweak delivers it in the `si_value` field of the signal, which is
sufficient to catch capability violations and emulate them with a call
to a more-privileged process in the signal handler.

This reapplies 3a522ba1bc852c3d4660a4fa32e4a94999d09a47 with a fix for
the static assertion failure on i386.

Approved by: markj (mentor)

Reviewed by: kib, bcr (manpages)

Differential Revision: https://reviews.freebsd.org/D29185

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Revert "Pass the syscall number to capsicum permission-denied signals"

This broke the i386 build.

This reverts commit 3a522ba1bc852c3d4660a4fa32e4a94999d09a47.

Pass the syscall number to capsicum permission-denied signals

The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossi

Pass the syscall number to capsicum permission-denied signals

The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossible to
recover in the signal handler after the call has returned. This small
tweak delivers it in the `si_value` field of the signal, which is
sufficient to catch capability violations and emulate them with a call
to a more-privileged process in the signal handler.

Approved by: markj (mentor)

Reviewed by: kib, bcr (manpages)

Differential Revision: https://reviews.freebsd.org/D29185

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linux(4): implement coredump support

Implement dumping core for Linux binaries on amd64, for both
32- and 64-bit executables. Some bits are still missing.

This is based on a prototype by chuck@.

linux(4): implement coredump support

Implement dumping core for Linux binaries on amd64, for both
32- and 64-bit executables. Some bits are still missing.

This is based on a prototype by chuck@.

Reviewed By: kib
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30019

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Add infrastructure required for Linux coredump support

This adds `sv_elf_core_osabi`, `sv_elf_core_abi_vendor`,
and `sv_elf_core_prepare_notes` fields to `struct sysentvec`,
and modifies imgact_elf.

Add infrastructure required for Linux coredump support

This adds `sv_elf_core_osabi`, `sv_elf_core_abi_vendor`,
and `sv_elf_core_prepare_notes` fields to `struct sysentvec`,
and modifies imgact_elf.c to make use of them instead
of hardcoding FreeBSD-specific values. It also updates all
of the ABI definitions to preserve current behaviour.

This makes it possible to implement non-native ELF coredump
support without unnecessary code duplication. It will be used
for Linux coredumps.

Reviewed By: kib
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30921

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linux(4): Make vDSO defines private.

Hide the vDSO defines to the linux32_sysvec as they are not intended to
be used outside of it. Fix LINUX32_PS_STRINGS, use the size of
struct linux32_ps_strings

linux(4): Make vDSO defines private.

Hide the vDSO defines to the linux32_sysvec as they are not intended to
be used outside of it. Fix LINUX32_PS_STRINGS, use the size of
struct linux32_ps_strings instead of a numeric constant.

MFC after: 2 weeks

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linux(4): Retire linux_kplatform.

Assuming we can't run on i486, i586 class cpu, retire linux_kplatform var
and use hardcoded 'machine' value in linux_newuname().

I have added linux_kplatform for c

linux(4): Retire linux_kplatform.

Assuming we can't run on i486, i586 class cpu, retire linux_kplatform var
and use hardcoded 'machine' value in linux_newuname().

I have added linux_kplatform for consistency with linux_platform which is
placed in to vdso to avoid excess copyout it on stack for AT_PLATFORM at
exec time.

This is the first stage of Linuxulator's vdso revision.

Reviewed by: trasz, imp
Differential Revision: https://reviews.freebsd.org/D30774
MFC after: 2 weeks

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Add quirks for Linux ABI signals handling

Require queueing of the signals with default action, and disable
dequeueing SIGCHLD on wait for live process.

Reported and tested by: dchagin
Reviewed by:

Add quirks for Linux ABI signals handling

Require queueing of the signals with default action, and disable
dequeueing SIGCHLD on wait for live process.

Reported and tested by: dchagin
Reviewed by: dchagin, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30675

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linuxolator: Add compat.linux.setid_allowed knob

PR: 21463
Reported by: kris
Reviewed by: dchagin
Tested by: trasz
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential Revision: https

linuxolator: Add compat.linux.setid_allowed knob

PR: 21463
Reported by: kris
Reviewed by: dchagin
Tested by: trasz
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D28154

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