linux.git/arch/ia64/kernel/mca.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The Itanium architecture is obsolete, and an informal survey [0] reveals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

kill do_each_thread()

2023-08-21T20:46:25+00:00

Eric has pointed out that we still have 3 users of do_each_thread().
Change them to use for_each_process_thread() and kill this helper.

There is a subtle change, after do_each_thread/while_each_thread g == t ==
&init_task, while after for_each_process_thread() they both point to
nowhere, but this doesn't matter.

> Why is for_each_process_thread() better than do_each_thread()?

Say, for_each_process_thread() is rcu safe, do_each_thread() is not.

And certainly

	for_each_process_thread(p, t) {
		do_something(p, t);
	}

looks better than

	do_each_thread(p, t) {
		do_something(p, t);
	} while_each_thread(p, t);

And again, there are only 3 users of this awkward helper left.  It should
have been killed years ago and in fact I thought it had already been
killed.  It uses while_each_thread() which needs some changes.

Link: https://lkml.kernel.org/r/20230817163708.GA8248@redhat.com
Signed-off-by: Oleg Nesterov 
Reviewed-by: Kees Cook 
Cc: "Christian Brauner (Microsoft)" 
Cc: Eric W. Biederman 
Cc: Jiri Slaby  # tty/serial
Signed-off-by: Andrew Morton

ia64: mca: use strscpy() is more robust and safer

2022-10-12T01:51:10+00:00

The implementation of strscpy() is more robust and safer.  That's now the
recommended way to copy NUL terminated strings.

Link: https://lkml.kernel.org/r/20220930061950.288290-1-xu.xin16@zte.com.cn
Reported-by: Zeal Robot 
Signed-off-by: Xu Panda 
Signed-off-by: xu xin 
Cc: Haowen Bai 
Signed-off-by: Andrew Morton

ia64: mca: drop redundant spinlock initialization

2022-05-13T03:38:37+00:00

mlogbuf_rlock has declared and initialized by DEFINE_SPINLOCK,
so we don't need to spin_lock_init again, drop it.

Link: https://lkml.kernel.org/r/1652176897-4754-1-git-send-email-baihaowen@meizu.com
Signed-off-by: Haowen Bai 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton

sched: Change task_struct::state

2021-06-18T09:43:09+00:00

Change the type and name of task_struct::state. Drop the volatile and
shrink it to an 'unsigned int'. Rename it in order to find all uses
such that we can use READ_ONCE/WRITE_ONCE as appropriate.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Daniel Bristot de Oliveira 
Acked-by: Will Deacon 
Acked-by: Daniel Thompson 
Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org

ia64: mca: always make IA64_MCA_DEBUG an expression

2021-04-30T18:20:35+00:00

At least ia64_mca_log_sal_error_record() expects some statement:

    static void ia64_mca_log_sal_error_record(int sal_info_type)
    {
        ...
        if (irq_safe)
            IA64_MCA_DEBUG("CPU %d: SAL log contains %s error record
",
                smp_processor_id(),
                sal_info_type < ARRAY_SIZE(rec_name) ? rec_name[sal_info_type] : "UNKNOWN");
        ...
    }

Instead of fixing all callers the change expicitly makes IA64_MCA_DEBUG
a non-empty expression.

Link: https://lkml.kernel.org/r/20210328215549.830420-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ia64: mca: allocate early mca with GFP_ATOMIC

2021-03-25T16:22:55+00:00

The sleep warning happens at early boot right at secondary CPU
activation bootup:

    smp: Bringing up secondary CPUs ...
    BUG: sleeping function called from invalid context at mm/page_alloc.c:4942
    in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1
    CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.12.0-rc2-00007-g79e228d0b611-dirty #99
    ..
    Call Trace:
      show_stack+0x90/0xc0
      dump_stack+0x150/0x1c0
      ___might_sleep+0x1c0/0x2a0
      __might_sleep+0xa0/0x160
      __alloc_pages_nodemask+0x1a0/0x600
      alloc_page_interleave+0x30/0x1c0
      alloc_pages_current+0x2c0/0x340
      __get_free_pages+0x30/0xa0
      ia64_mca_cpu_init+0x2d0/0x3a0
      cpu_init+0x8b0/0x1440
      start_secondary+0x60/0x700
      start_ap+0x750/0x780
    Fixed BSP b0 value from CPU 1

As I understand interrupts are not enabled yet and system has a lot of
memory.  There is little chance to sleep and switch to GFP_ATOMIC should
be a no-op.

Link: https://lkml.kernel.org/r/20210315085045.204414-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2021-02-25T18:17:31+00:00

Pull Kbuild updates from Masahiro Yamada:

 - Fix false-positive build warnings for ARCH=ia64 builds

 - Optimize dictionary size for module compression with xz

 - Check the compiler and linker versions in Kconfig

 - Fix misuse of extra-y

 - Support DWARF v5 debug info

 - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
   exceeded the limit

 - Add generic syscall{tbl,hdr}.sh for cleanups across arches

 - Minor cleanups of genksyms

 - Minor cleanups of Kconfig

* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
  initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
  kbuild: remove deprecated 'always' and 'hostprogs-y/m'
  kbuild: parse C= and M= before changing the working directory
  kbuild: reuse this-makefile to define abs_srctree
  kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
  kconfig: omit --oldaskconfig option for 'make config'
  kconfig: fix 'invalid option' for help option
  kconfig: remove dead code in conf_askvalue()
  kconfig: clean up nested if-conditionals in check_conf()
  kconfig: Remove duplicate call to sym_get_string_value()
  Makefile: Remove # characters from compiler string
  Makefile: reuse CC_VERSION_TEXT
  kbuild: check the minimum linker version in Kconfig
  kbuild: remove ld-version macro
  scripts: add generic syscallhdr.sh
  scripts: add generic syscalltbl.sh
  arch: syscalls: remove $(srctree)/ prefix from syscall tables
  arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
  gen_compile_commands: prune some directories
  kbuild: simplify access to the kernel's version
  ...

ia64: remove unneeded header includes from

2021-02-11T20:11:19+00:00

 includes too many unneeded headers.

This commit cuts off a lot of header includes.

What we need to include are:

 -  for DECLARE_PER_CPU(u64, ia64_mca_pal_base)
 -  for NR_CPUS
 -  for u8, u64, size_t, etc.
 -  for KERNEL_STACK_SIZE

The other header includes are actually unneeded.

 previously included 436 headers, and now it includes
only 138. I confirmed  is still self-contained.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Randy Dunlap 
Acked-by: Ard Biesheuvel

ia64: do not typedef struct pal_min_state_area_s

2021-02-11T20:11:19+00:00

Documentation/process/coding-style.rst says:

  Please don't use things like ``vps_t``.
  It's a **mistake** to use typedef for structures and pointers.

This commit converts as follows:

  struct pal_min_state_area_s  ->  struct pal_min_state_area
         pal_min_state_area_t  ->  struct pal_min_state_area

My main motivation for this is to slim down the include directives
of  in the next commit.

Currently,  is required to include  directly
or indirectly due to (pal_min_state_area_t *). Otherwise, it would
have no idea what pal_min_state_area_t is.

Replacing it with (struct pal_min_state_area *) will relax the header
dependency since it is enough to tell it is a pointer to a structure,
and to resolve the size of struct pal_min_state_area. It will make
 independent of .

 typedef's a lot of structures, but it is trivial to
convert the others in the same way.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Randy Dunlap