linux.git/arch/ia64/kernel/sal.c, branch master

arch: Remove Itanium (IA-64) architecture

2023-09-11T08:13:17+00:00

The Itanium architecture is obsolete, and an informal survey [0] reveals
that any residual use of Itanium hardware in production is mostly HP-UX
or OpenVMS based. The use of Linux on Itanium appears to be limited to
enthusiasts that occasionally boot a fresh Linux kernel to see whether
things are still working as intended, and perhaps to churn out some
distro packages that are rarely used in practice.

None of the original companies behind Itanium still produce or support
any hardware or software for the architecture, and it is listed as
'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers
that contributed on behalf of those companies (nor anyone else, for that
matter) have been willing to support or maintain the architecture
upstream or even be responsible for applying the odd fix. The Intel
firmware team removed all IA-64 support from the Tianocore/EDK2
reference implementation of EFI in 2018. (Itanium is the original
architecture for which EFI was developed, and the way Linux supports it
deviates significantly from other architectures.) Some distros, such as
Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have
dropped support years ago.

While the argument is being made [1] that there is a 'for the common
good' angle to being able to build and run existing projects such as the
Grid Community Toolkit [2] on Itanium for interoperability testing, the
fact remains that none of those projects are known to be deployed on
Linux/ia64, and very few people actually have access to such a system in
the first place. Even if there were ways imaginable in which Linux/ia64
could be put to good use today, what matters is whether anyone is
actually doing that, and this does not appear to be the case.

There are no emulators widely available, and so boot testing Itanium is
generally infeasible for ordinary contributors. GCC still supports IA-64
but its compile farm [3] no longer has any IA-64 machines. GLIBC would
like to get rid of IA-64 [4] too because it would permit some overdue
code cleanups. In summary, the benefits to the ecosystem of having IA-64
be part of it are mostly theoretical, whereas the maintenance overhead
of keeping it supported is real.

So let's rip off the band aid, and remove the IA-64 arch code entirely.
This follows the timeline proposed by the Debian/ia64 maintainer [5],
which removes support in a controlled manner, leaving IA-64 in a known
good state in the most recent LTS release. Other projects will follow
once the kernel support is removed.

[0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/
[1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/
[2] https://gridcf.org/gct-docs/latest/index.html
[3] https://cfarm.tetaneutral.net/machines/list/
[4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/
[5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/

Acked-by: Tony Luck 
Signed-off-by: Ard Biesheuvel

locking, arch/ia64: Reduce header dependencies by moving XTP bits into the new header

2020-08-06T14:13:13+00:00

We want to remove the #include  from , but for this
we have to move the XTP bits into a separate header first (as these bits
rely on  definitions), and include them in the .c files that rely
on those APIs.

Co-developed-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

ia64: remove now unused machvec indirections

2019-08-16T18:33:57+00:00

With the SGI SN2 machvec removal most of the indirections are unused
now, so remove them.  This includes the entire removal of the mmio
read*/write* macros as the generic ones are identical to the
asm-generic/io.h version.

Signed-off-by: Christoph Hellwig 
Link: https://lkml.kernel.org/r/20190813072514.23299-17-hch@lst.de
Signed-off-by: Tony Luck

ia64: remove support for the SGI SN2 platform

2019-08-16T18:33:57+00:00

The SGI SN2 (early Altix) is a very non-standard IA64 platform that was
at the very high end of even IA64 hardware, and has been discontinued
a long time ago.  Remove it because there no upstream users left, and it
has magic hooks all over the kernel.

Signed-off-by: Christoph Hellwig 
Link: https://lkml.kernel.org/r/20190813072514.23299-16-hch@lst.de
Signed-off-by: Tony Luck

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

[IA64] Update check_sal_cache_flush to use platform_send_ipi()

2008-06-11T23:40:33+00:00

check_sal_cache_flush is used to detect broken firmware that drops
pending interrupts.

The old implementation schedules a timer interrupt for itself in
the future by getting the current value of the Interval Timer
Counter + 1000 cycles, waits for the interrupt to be pended, calls
SAL_CACHE_FLUSH, and finally checks to see if the interrupt is
still pending.

This implementation can cause problems for virtual machine code if
the process of scheduling the timer interrupt takes more than 1000
cycles; the virtual machine can end up sleeping for several hundred
years while waiting for the ITC to wrap around.

The fix is to use platform_send_ipi. The processor will still send
an interrupt to itself, using the IA64_IPI_DM_INT delivery mode,
which causes the IPI to look like an external interrupt. The rest
of the SAL_CACHE_FLUSH + checking to see if the interrupt is still
pending remains unchanged.

This fix has been boot tested successfully on:

	- intel tiger2
	- hp rx6600
	- hp rx5670

The rx5670 has known buggy firmware, where SAL_CACHE_FLUSH drops
pending interrupts. A boot test on this machine showed this message
on the console:

SAL: SAL_CACHE_FLUSH drops interrupts; PAL_CACHE_FLUSH will be used instead

Which proves that the self-inflicted IPI approach is viable. And
as expected, the other tested platforms correctly did not display
the warning.

Signed-off-by: Alex Chiang 
Signed-off-by: Tony Luck

[IA64] allow user to force_pal_cache_flush

2008-05-14T22:42:07+00:00

The sequence executed in check_sal_cache_flush:

	- pend a timer interrupt
	- call SAL_CACHE_FLUSH
	- see if interrupt is still pending

can hang HP machines with buggy SAL_CACHE_FLUSH implementations.

Provide a kernel command-line argument to allow users skip this
check if desired. Using this parameter will force ia64_sal_cache_flush
to call ia64_pal_cache_flush() instead of SAL_CACHE_FLUSH.

Signed-off-by: Alex Chiang 
Signed-off-by: Tony Luck

[IA64] workaround tiger ia64_sal_get_physical_id_info hang

2008-03-04T22:26:50+00:00

This fixes regression introduced in 113134fcbca83619be4c68d0ca66db6093777b5d

Intel Tiger platforms hang when calling SAL_GET_PHYSICAL_ID_INFO
instead of properly returning -1 for unimplemented, so add a
version check.

SGI Altix platforms have an incorrect SAL version hard-coded into
their prom -- they encode 2.9, but actually implement 3.2 -- so
fix it up and allow ia64_sal_get_physical_id_info to keep
working.

Signed-off-by: Alex Chiang 
Acked-by: Russ Anderson 
Signed-off-by: Tony Luck

[IA64] Export three symbols for module use

2008-02-04T23:46:23+00:00

Since kvm/module needs to use some unexported functions in kernel,
so export them with this patch.

Signed-off-by: Zhang Xiantao 
Signed-off-by: Tony Luck

[IA64] spelling fixes: arch/ia64/

2007-05-11T21:55:43+00:00

Spelling and apostrophe fixes in arch/ia64/.

Signed-off-by: Simon Arlott 
Signed-off-by: Tony Luck