x86: Eliminate mfence hotpatch for membar_sync.

The more-compatible LOCK ADD $0,-N(%rsp) turns out to be cheaper
than MFENCE anyway. Let's save some space and maintenance and rip
out the hotpatch

x86: Eliminate mfence hotpatch for membar_sync.

The more-compatible LOCK ADD $0,-N(%rsp) turns out to be cheaper
than MFENCE anyway. Let's save some space and maintenance and rip
out the hotpatching for it.

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x86: Every load is a load-acquire, so membar_consumer is a noop.

lfence is only needed for MD logic, such as operations on I/O memory
rather than normal cacheable memory, or special instructions lik

x86: Every load is a load-acquire, so membar_consumer is a noop.

lfence is only needed for MD logic, such as operations on I/O memory
rather than normal cacheable memory, or special instructions like
RDTSC -- never for MI synchronization between threads/CPUs. No need
for hot-patching to do lfence here.

(The x86_lfence function might reasonably be patched on i386 to do
lfence for MD logic, but it isn't now and this doesn't change that.)

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Switch the rest of i386 to the x86_hotpatch mechanism.

Use the hotpatch framework when patching _atomic_cas_64.

Use the hotpatch framework for LFENCE/MFENCE.

Merge the bouyer-xenpvh branch, bringing in Xen PV drivers support under HVM
guests in GENERIC.
Xen support can be disabled at runtime with
boot -c
disable hypervisor

Rewrite the FPU code on x86. This greatly simplifies the logic and removes
the dependency on IPL_HIGH. NVMM is updated accordingly. Posted on
port-amd64 a week ago.

Bump the kernel version to 9.99.1

Rewrite the FPU code on x86. This greatly simplifies the logic and removes
the dependency on IPL_HIGH. NVMM is updated accordingly. Posted on
port-amd64 a week ago.

Bump the kernel version to 9.99.16.

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Welcome XENPVHVM mode.

It is UP only, has xbd(4) and xennet(4) as PV drivers.

The console is com0 at isa and the native portion is very
rudimentary AT architecture, so is probably suboptimal to
run

Welcome XENPVHVM mode.

It is UP only, has xbd(4) and xennet(4) as PV drivers.

The console is com0 at isa and the native portion is very
rudimentary AT architecture, so is probably suboptimal to
run without PV support.

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We reorganise definitions for XEN source support as follows:

XEN - common sources required for baseline XEN support.
XENPV - sources required for support of XEN in PV mode.
XENPVHVM - sources requir

We reorganise definitions for XEN source support as follows:

XEN - common sources required for baseline XEN support.
XENPV - sources required for support of XEN in PV mode.
XENPVHVM - sources required for support for XEN in HVM mode.
XENPVH - sources required for support for XEN in PVH mode.

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i586 and below don't have this 3-byte nop, so use three 1-byte nops,
reported by Nathanial Sloss

Declare INTR_RECURSE_HWFRAME, same as amd64.

Add SMAP support for i386.

Remove DO_DEFERRED_SWITCH and DO_DEFERRED_SWITCH_RETRY, unused.

Use .pushsection (like amd64), and align INTRENTRY.

Switch x86_retpatch[] -> HOTPATCH().

Switch x86_lockpatch[] -> HOTPATCH().

Implement a real hotpatch feature.

Define a HOTPATCH() macro, that puts a label and additional information
in the new .rodata.hotpatch kernel section. In patch.c, scan the section
and patch what nee

Implement a real hotpatch feature.

Define a HOTPATCH() macro, that puts a label and additional information
in the new .rodata.hotpatch kernel section. In patch.c, scan the section
and patch what needs to be. Now it is possible to hotpatch the content of
a macro.

SMAP is switched to use this new system; this saves a call+ret in each
kernel entry/exit point.

Many other operating systems do the same.

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Declare INTRFASTEXIT as a function, like amd64; will be expanded soon.

Remove TRAPLOG from i386. Nowadays there are better instrumentation tools,
in both software and hardware.

style

comment

Selector registers are 16-bit and binutils 2.18 insists that only 16-bit
accesses are permitted on them. Therefore, change movl to movw. No change to
machine code generated.

Access Xen's vcpu info structure per-CPU.
Tested on i386 and amd64 (both dom0 and domU) by me.
Xen2 tested (both dom0 and domU) by bouyer.
OK bouyer

don't bother to check curlwp==NULL.

Merge the bouyer-xeni386 branch to head, at tag bouyer-xeni386-merge1 (the
branch is still active and will see i386PAE support developement).
Sumary of changes:
- switch xeni386 to the x86/x86/pmap.c

Merge the bouyer-xeni386 branch to head, at tag bouyer-xeni386-merge1 (the
branch is still active and will see i386PAE support developement).
Sumary of changes:
- switch xeni386 to the x86/x86/pmap.c, and the xen/x86/x86_xpmap.c
pmap bootstrap.
- merge back most of xen/i386/ to i386/i386
- change the build to reduce diffs between i386 and amd64 in file locations
- remove include files that were identical to the i386/amd64 counterparts,
the build will find them via the xen-ma/machine link.

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