Clean up the <sys/ucontext.h> <-> <machine/mcontext.h> interface up
a little:
- Define _UC_MD_BIT* constants for the available machine-dependent bits,
and use those constants to define the machine-dependent bits as well
as the machine-independent bits that have machine-dependent values.
- Explicitly generate an error if _UC_TLSBASE, _UC_SETSTACK, or
_UC_CLRSTACK are not defined by <machine/mcontext.h>.

Add missing __{BEGIN,END}_DECLS in order to catch up with
sanitizer_linux_libcdep.cc rev 1.17:

http://cvsweb.netbsd.org/bsdweb.cgi/src/external/gpl3/gcc/dist/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc#rev1.17

Fix build with HAVE_GCC=9.

pass a pointer conversion via uintptr_t *and* the desired type casts.
avoids new GCC 9 warnings with C++ code.

Introduce _UC_MACHINE_FP() as a macro

_UC_MACHINE_FP() is a helper macro to extract from mcontext a frame pointer.

Don't rely on this interface as a compiler might strip frame pointer or
optimize it making this interface unreliable.


For hppa assume a small frame context, for larger frames FP might be located
in a different register (4 instead of 3).

For ia64 there is no strict frame pointer, and registers might rotate.
Reuse 79 following:

./gcc/config/ia64/ia64.h:#define HARD_FRAME_POINTER_REGNUM LOC_REG (79)

Once ia64 will mature, this should be revisited.

A macro can encapsulate a real function for extracting Frame Pointer on
more complex CPUs / ABIs.


For the remaining CPUs, reuse standard register as defined in appropriate ABI.

The direct users of this macro are LLVM and GCC with Sanitizers.

Proposed on tech-userlevel@.

Sponsored by <The NetBSD Foundation>

branches: 1.9.42;
Add TLS support for m68k.

branches: 1.8.4;
Allow storing and receiving the LWP private pointer via ucontext_t
on all platforms except VAX and IA64. Add fast access via register for
AMD64, i386 and SH3 ports. Use this fast access in libpthread to replace
the stack based pthread_self(). Implement skeleton support for Alpha,
HPPA, PowerPC, SPARC and SPARC64, but leave it disabled.

Ports that support this feature provide __HAVE____LWP_GETPRIVATE_FAST in
machine/types.h and a corresponding __lwp_getprivate_fast in
machine/mcontext.h.

This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.

Fix ucontext32_t on AMD64. Add optional compile time assertions for
ucontext_t and ucontext32_t to ensure that they don't change.
Provide the constants for AMD64, ARM, i386, and M68K.

branches: 1.6.22; 1.6.28; 1.6.30;
Remove clause 3 and 4 from TNF licenses

branches: 1.5.74; 1.5.76; 1.5.78;
merge ktrace-lwp.

Add some accessor macros for the ucontext:
* _UC_MACHINE_PC() - access the program counter
* _UC_MACHINE_INTRV() - access the integer return value register
* _UC_MACHINE_SET_PC() - set the program counter (this requires
special handling on some platforms).

SA_SIGINFO support for m68k

branches: 1.2.2;
Merge the nathanw_sa branch.

branches: 1.1.2;
file mcontext.h was initially added on branch nathanw_sa.

Add missing __{BEGIN,END}_DECLS in order to catch up with
sanitizer_linux_libcdep.cc rev 1.17:

http://cvsweb.netbsd.org/bsdweb.cgi/src/external/gpl3/gcc/dist/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc#rev1.17

Fix build with HAVE_GCC=9.

pass a pointer conversion via uintptr_t *and* the desired type casts.
avoids new GCC 9 warnings with C++ code.

Introduce _UC_MACHINE_FP() as a macro

_UC_MACHINE_FP() is a helper macro to extract from mcontext a frame pointer.

Don't rely on this interface as a compiler might strip frame pointer or
optimize it making this interface unreliable.


For hppa assume a small frame context, for larger frames FP might be located
in a different register (4 instead of 3).

For ia64 there is no strict frame pointer, and registers might rotate.
Reuse 79 following:

./gcc/config/ia64/ia64.h:#define HARD_FRAME_POINTER_REGNUM LOC_REG (79)

Once ia64 will mature, this should be revisited.

A macro can encapsulate a real function for extracting Frame Pointer on
more complex CPUs / ABIs.


For the remaining CPUs, reuse standard register as defined in appropriate ABI.

The direct users of this macro are LLVM and GCC with Sanitizers.

Proposed on tech-userlevel@.

Sponsored by <The NetBSD Foundation>

branches: 1.9.42;
Add TLS support for m68k.

branches: 1.8.4;
Allow storing and receiving the LWP private pointer via ucontext_t
on all platforms except VAX and IA64. Add fast access via register for
AMD64, i386 and SH3 ports. Use this fast access in libpthread to replace
the stack based pthread_self(). Implement skeleton support for Alpha,
HPPA, PowerPC, SPARC and SPARC64, but leave it disabled.

Ports that support this feature provide __HAVE____LWP_GETPRIVATE_FAST in
machine/types.h and a corresponding __lwp_getprivate_fast in
machine/mcontext.h.

This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.

Fix ucontext32_t on AMD64. Add optional compile time assertions for
ucontext_t and ucontext32_t to ensure that they don't change.
Provide the constants for AMD64, ARM, i386, and M68K.

branches: 1.6.22; 1.6.28; 1.6.30;
Remove clause 3 and 4 from TNF licenses

branches: 1.5.74; 1.5.76; 1.5.78;
merge ktrace-lwp.

Add some accessor macros for the ucontext:
* _UC_MACHINE_PC() - access the program counter
* _UC_MACHINE_INTRV() - access the integer return value register
* _UC_MACHINE_SET_PC() - set the program counter (this requires
special handling on some platforms).

SA_SIGINFO support for m68k

branches: 1.2.2;
Merge the nathanw_sa branch.

branches: 1.1.2;
file mcontext.h was initially added on branch nathanw_sa.

pass a pointer conversion via uintptr_t *and* the desired type casts.
avoids new GCC 9 warnings with C++ code.

Introduce _UC_MACHINE_FP() as a macro

_UC_MACHINE_FP() is a helper macro to extract from mcontext a frame pointer.

Don't rely on this interface as a compiler might strip frame pointer or
optimize it making this interface unreliable.


For hppa assume a small frame context, for larger frames FP might be located
in a different register (4 instead of 3).

For ia64 there is no strict frame pointer, and registers might rotate.
Reuse 79 following:

./gcc/config/ia64/ia64.h:#define HARD_FRAME_POINTER_REGNUM LOC_REG (79)

Once ia64 will mature, this should be revisited.

A macro can encapsulate a real function for extracting Frame Pointer on
more complex CPUs / ABIs.


For the remaining CPUs, reuse standard register as defined in appropriate ABI.

The direct users of this macro are LLVM and GCC with Sanitizers.

Proposed on tech-userlevel@.

Sponsored by <The NetBSD Foundation>

branches: 1.9.42;
Add TLS support for m68k.

branches: 1.8.4;
Allow storing and receiving the LWP private pointer via ucontext_t
on all platforms except VAX and IA64. Add fast access via register for
AMD64, i386 and SH3 ports. Use this fast access in libpthread to replace
the stack based pthread_self(). Implement skeleton support for Alpha,
HPPA, PowerPC, SPARC and SPARC64, but leave it disabled.

Ports that support this feature provide __HAVE____LWP_GETPRIVATE_FAST in
machine/types.h and a corresponding __lwp_getprivate_fast in
machine/mcontext.h.

This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.

Fix ucontext32_t on AMD64. Add optional compile time assertions for
ucontext_t and ucontext32_t to ensure that they don't change.
Provide the constants for AMD64, ARM, i386, and M68K.

branches: 1.6.22; 1.6.28; 1.6.30;
Remove clause 3 and 4 from TNF licenses

branches: 1.5.74; 1.5.76; 1.5.78;
merge ktrace-lwp.

Add some accessor macros for the ucontext:
* _UC_MACHINE_PC() - access the program counter
* _UC_MACHINE_INTRV() - access the integer return value register
* _UC_MACHINE_SET_PC() - set the program counter (this requires
special handling on some platforms).

SA_SIGINFO support for m68k

branches: 1.2.2;
Merge the nathanw_sa branch.

branches: 1.1.2;
file mcontext.h was initially added on branch nathanw_sa.