Increase size of pcb_flags to four bytes.

Requested by: bde, jhb

Improve PCB flags handling and make it more robust. Add two new functions
for manipulating pcb_flags. These inline functions are very similar to
atomic_set_char(9) and atomic_clear_char(9) but with

Improve PCB flags handling and make it more robust. Add two new functions
for manipulating pcb_flags. These inline functions are very similar to
atomic_set_char(9) and atomic_clear_char(9) but without unnecessary LOCK
prefix for SMP. Add comments about the rationale[1]. Use these functions
wherever possible. Although there are some places where it is not strictly
necessary (e.g., a PCB is copied to create a new PCB), it is done across
the board for sake of consistency. Turn pcb_full_iret into a PCB flag as
it is safe now. Move rarely used fields before pcb_flags and reduce size
of pcb_flags to one byte. Fix some style(9) nits in pcb.h while I am in
the neighborhood.

Reviewed by: kib
Submitted by: kib[1]
MFC after: 2 months

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Sync: merge r216133 through r216338 from ^/head.

Retire write-only PCB_FULLCTX pcb flag on amd64.

Reminded by: Petr Salinger <Petr.Salinger seznam cz>
Tested by: pho
MFC after: 1 week

Merge svn+ssh://svn.freebsd.org/base/head@211344

Rearrange struct pcb. r177532 (CVS r1.64 of pcb.h) moved pcb_flags to make
better use of cache lines by placing it before pcb_save (now pcb_user_save),
which is moved to the end of pcb since r210777.

- Merge savectx2() with savectx() and struct xpcb with struct pcb. [1]
savectx() is only used for panic dump (dumppcb) and kdb (stoppcbs). Thus,
saving additional information does not hurt and it ma

- Merge savectx2() with savectx() and struct xpcb with struct pcb. [1]
savectx() is only used for panic dump (dumppcb) and kdb (stoppcbs). Thus,
saving additional information does not hurt and it may be even beneficial.
Unfortunately, struct pcb has grown larger to accommodate more data.
Move 512-byte long pcb_user_save to the end of struct pcb while I am here.
- savectx() now saves FPU state unconditionally and copy it to the PCB of
FPU thread if necessary. This gives panic dump and kdb a chance to take
a look at the current FPU state even if the FPU is "supposedly" not used.
- Resuming CPU now unconditionally reinitializes FPU. If the saved FPU
state was irrelevant, it could be in an unknown state.

Suggested by: bde [1]

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Merge svn+ssh://svn.freebsd.org/base/head@208879

Introduce the x86 kernel interfaces to allow kernel code to use
FPU/SSE hardware. Caller should provide a save area that is chained
into the stack of the areas; pcb save_area for usermode FPU state i

Introduce the x86 kernel interfaces to allow kernel code to use
FPU/SSE hardware. Caller should provide a save area that is chained
into the stack of the areas; pcb save_area for usermode FPU state is
on top. The pcb now contains a pointer to the current FPU saved area,
used during FPUDNA handling and context switches. There is also a
facility to allow the kernel thread to use pcb save_area.

Change the dreaded warnings "npxdna in kernel mode!" into the panics
when FPU usage is not registered.

KPI discussed with: fabient
Tested by: pho, fabient
Hardware provided by: Sentex Communications
MFC after: 1 month

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Merge from head

- MFC @196061

Restore the segment registers and segment base MSRs for amd64 syscall
return path only when neither thread was context switched while
executing syscall code nor syscall explicitely modified LDT or MS

Restore the segment registers and segment base MSRs for amd64 syscall
return path only when neither thread was context switched while
executing syscall code nor syscall explicitely modified LDT or MSRs.

Save segment registers in trap handlers before interrupts are enabled,
to not allow context switches to happen before registers are saved.
Use separated byte in pcb for indication of fast/full return, since
pcb_flags are not synchronized with context switches.

The change puts back syscall microbenchmark numbers that were slowed
down after commit of the support for LDT on amd64.

Reviewed by: jeff
Tested (and tested, and tested ...) by: pho
Approved by: re (kensmith)

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- Merge from HEAD

Garbage collect unused stack segment since r190620.

Save and restore segment registers on amd64 when entering and leaving
the kernel on amd64. Fill and read segment registers for mcontext and
signals. Handle traps caused by restoration of the
invalida

Save and restore segment registers on amd64 when entering and leaving
the kernel on amd64. Fill and read segment registers for mcontext and
signals. Handle traps caused by restoration of the
invalidated selectors.

Implement user-mode creation and manipulation of the process-specific
LDT descriptors for amd64, see sysarch(2).

Implement support for TSS i/o port access permission bitmap for amd64.

Context-switch LDT and TSS. Do not save and restore segment registers on
the context switch, that is handled by kernel enter/leave trampolines
now. Remove segment restore code from the signal trampolines for
freebsd/amd64, freebsd/ia32 and linux/i386 for the same reason.

Implement amd64-specific compat shims for sysarch.

Linuxolator (temporary ?) switched to use gsbase for thread_area pointer.

TODO:
Currently, gdb is not adapted to show segment registers from struct reg.
Also, no machine-depended ptrace command is added to set segment
registers for debugged process.

In collaboration with: pho
Discussed with: peter
Reviewed by: jhb
Linuxolator tested by: dchagin

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Initial suspend/resume support for amd64.

This code is heavily inspired by Takanori Watanabe's experimental SMP patch
for i386 and large portion was shamelessly cut and pasted from Peter Wemm's
AP b

Initial suspend/resume support for amd64.

This code is heavily inspired by Takanori Watanabe's experimental SMP patch
for i386 and large portion was shamelessly cut and pasted from Peter Wemm's
AP boot code.

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Update the projects tree to a newer FreeBSD current.

A better fix for handling different FPU initial control words for different
ABIs:
- Store the FPU initial control word in the pcb for each thread.
- When first using the FPU, load the initial control

A better fix for handling different FPU initial control words for different
ABIs:
- Store the FPU initial control word in the pcb for each thread.
- When first using the FPU, load the initial control word after restoring
the clean state if it is not the standard control word.
- Provide a correct control word for Linux/i386 binaries under
FreeBSD/amd64.
- Adjust the control word returned for fpugetregs()/npxgetregs() when a
thread hasn't used the FPU yet to reflect the real initial control
word for the current ABI.
- The Linux/i386 ABI for FreeBSD/i386 now properly sets the right control
word instead of trashing whatever the current state of the FPU is.

Reviewed by: bde

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Move the PCB flag macros up next to the 'pcb_flags' member in the struct.

The pcb_gs32p should be per-cpu, not per-thread pointer. This is
location in GDT where the segment descriptor from pcb_gs32sd is
copied, and the location is in GDT local to CPU.

Noted and reviewed b

The pcb_gs32p should be per-cpu, not per-thread pointer. This is
location in GDT where the segment descriptor from pcb_gs32sd is
copied, and the location is in GDT local to CPU.

Noted and reviewed by: peter
MFC after: 1 week

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Bring back the save/restore of the %ds, %es, %fs and %gs registers for
the 32bit images on amd64.

Change the semantic of the PCB_32BIT pcb flag to request the context
switch code to operate on the s

Bring back the save/restore of the %ds, %es, %fs and %gs registers for
the 32bit images on amd64.

Change the semantic of the PCB_32BIT pcb flag to request the context
switch code to operate on the segment registers. Its previous meaning
of saving or restoring the %gs base offset is assigned to the new
PCB_GS32BIT flag.

FreeBSD 32bit image activator sets the PCB_32BIT flag, while Linux 32bit
emulation sets PCB_32BIT | PCB_GS32BIT.

Reviewed by: peter
MFC after: 2 weeks

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Move pcb_flags to make trivially better use of cache lines.

MFP4: Linux set_thread_area syscall (aka TLS) support for amd64.

Initial version was submitted by Divacky Roman and mostly rewritten by me.

Tested by: emulation

I believe the stack underflows during early development that caused me to
add spare padding at the beginning of the pcb are long gone. Remove the
padding fields.

Kill pcb_rflags. It served no purpose.

Reported by: bde