powerpc: Fix multiple issues with FP/VSX save/restore

Multiple issues existed within the powerpc FP/VSX save/restore functionality,
leading to register corruption and loss of register contents in sp

powerpc: Fix multiple issues with FP/VSX save/restore

Multiple issues existed within the powerpc FP/VSX save/restore functionality,
leading to register corruption and loss of register contents in specific
scenarios involving high signal load and use of both floating point and VSX
instructions.

Issue #1

On little endian systems the PCB used the wrong location for the shadowed
FP register within the larger VSX register. This appears to have been an
attempt to correct issue #2 without understanding how the vector load/store
instructions actually operate.

Issue #2

On little endian systems, the VSX state save/restore routines swapped 32-bit
words within the 64-bit aliased double word for the associated floating point
register. This was due to the use of a word-oriented load/store vs. doubleword
oriented load/store.

Issue #3

The FPU was turned off in the PCB but not in hardware, leading to a potential
race condition if the same thread was scheduled immediately after sigreturn.

The triggering codebase for this is Go, which makes heavy use of signals and
and generates an unusual mix of floating point and VSX assembler. As a result,
when combined with th powerpc lazy FPU restore, a condition was repeatedly hit
whereby the thread was interrupted in FP+VSX mode, then restored in FP only
mode, thus reliably triggering the issues above.

Also clean up the associated asm() style issue flagged by GitHub Actions.

Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>

MFC after: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/1756

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sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

powerpc: Fix multiple issues with FP/VSX save/restore

Multiple issues existed within the powerpc FP/VSX save/restore functionality,
leading to register corruption and loss of register contents in sp

powerpc: Fix multiple issues with FP/VSX save/restore

Multiple issues existed within the powerpc FP/VSX save/restore functionality,
leading to register corruption and loss of register contents in specific
scenarios involving high signal load and use of both floating point and VSX
instructions.

Issue #1

On little endian systems the PCB used the wrong location for the shadowed
FP register within the larger VSX register. This appears to have been an
attempt to correct issue #2 without understanding how the vector load/store
instructions actually operate.

Issue #2

On little endian systems, the VSX state save/restore routines swapped 32-bit
words within the 64-bit aliased double word for the associated floating point
register. This was due to the use of a word-oriented load/store vs. doubleword
oriented load/store.

Issue #3

The FPU was turned off in the PCB but not in hardware, leading to a potential
race condition if the same thread was scheduled immediately after sigreturn.

The triggering codebase for this is Go, which makes heavy use of signals and
and generates an unusual mix of floating point and VSX assembler. As a result,
when combined with th powerpc lazy FPU restore, a condition was repeatedly hit
whereby the thread was interrupted in FP+VSX mode, then restored in FP only
mode, thus reliably triggering the issues above.

Also clean up the associated asm() style issue flagged by GitHub Actions.

Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>

MFC after: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/1756

show more ...

sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

Merge ^/head r325999 through r326131.

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

show more ...

MFH

Sponsored by: The FreeBSD Foundation

Merge ^/head r295544 through r295600.

POSIX states that #include <signal.h> shall make both mcontext_t and
ucontext_t available. Our code even has XXX comment about this.

Add a bit of compliance by moving struct __ucontext definition i

POSIX states that #include <signal.h> shall make both mcontext_t and
ucontext_t available. Our code even has XXX comment about this.

Add a bit of compliance by moving struct __ucontext definition into
sys/_ucontext.h and including it into signal.h and sys/ucontext.h.

Several machine/ucontext.h headers were changed to use namespace-safe
types (like uint64_t->__uint64_t) to not depend on sys/types.h.
struct __stack_t from sys/signal.h is made always visible in private
namespace to satisfy sys/_ucontext.h requirements.

Apparently mips _types.h pollutes global namespace with f_register_t
type definition. This commit does not try to fix the issue.

PR: 207079
Reported and tested by: Ting-Wei Lan <lantw44@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

show more ...

Merge sync of head

MFH: r278968-r280640

Sponsored by: The FreeBSD Foundation

Merge r278538 through r280226.

Merge from head

Merge ^/head r279893 through r279984.

Provide VSX context in ucontext(3) API.

MFC

Merge head r233826 through r234834.

IFC @ r234692

sys/amd64/include/cpufunc.h
sys/amd64/include/fpu.h
sys/amd64/amd64/fpu.c
sys/amd64/vmm/vmm.c

- Add API to allow vmm FPU state init/save/restore.

FP stuff discussed with: kib

Merge ^/head r325999 through r326131.

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

show more ...

MFH

Sponsored by: The FreeBSD Foundation

Merge ^/head r295544 through r295600.

POSIX states that #include <signal.h> shall make both mcontext_t and
ucontext_t available. Our code even has XXX comment about this.

Add a bit of compliance by moving struct __ucontext definition i

POSIX states that #include <signal.h> shall make both mcontext_t and
ucontext_t available. Our code even has XXX comment about this.

Add a bit of compliance by moving struct __ucontext definition into
sys/_ucontext.h and including it into signal.h and sys/ucontext.h.

Several machine/ucontext.h headers were changed to use namespace-safe
types (like uint64_t->__uint64_t) to not depend on sys/types.h.
struct __stack_t from sys/signal.h is made always visible in private
namespace to satisfy sys/_ucontext.h requirements.

Apparently mips _types.h pollutes global namespace with f_register_t
type definition. This commit does not try to fix the issue.

PR: 207079
Reported and tested by: Ting-Wei Lan <lantw44@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

show more ...

Merge sync of head

MFH: r278968-r280640

Sponsored by: The FreeBSD Foundation