linux.git/arch/powerpc/kernel/smp.c, branch v6.2

powerpc: allow minimum sized kernel stack frames

2022-12-02T06:54:09+00:00

This affects only 64-bit ELFv2 kernels, and reduces the minimum
asm-created stack frame size from 112 to 32 byte on those kernels.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221127124942.1665522-16-npiggin@gmail.com

powerpc/smp: poll cpu_callin_map more aggressively in __cpu_up()

2022-09-28T09:22:14+00:00

At boot time, it is not necessary to delay between polls of
cpu_callin_map when waiting for a kicked CPU to come up. Remove the
delay intervals, but preserve the overall deadline (five seconds).

At run time, the first poll result is usually negative and we incur a
sleeping wait. If we spin on the callin word for a short time first,
we can reduce __cpu_up() from dozens of milliseconds to under 1ms in
the common case on a P9 LPAR:

$ ppc64_cpu --smt=off
$ bpftrace -e 'kprobe:__cpu_up {
                 @start[tid] = nsecs;
               }
               kretprobe:__cpu_up /@start[tid]/ {
                 @us = hist((nsecs - @start[tid]) / 1000);
                 delete(@start[tid]);
               }' -c 'ppc64_cpu --smt=on'

Before:

@us:
[16K, 32K)        85 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[32K, 64K)        13 |@@@@@@@                                             |

After:

@us:
[128, 256)        95 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[256, 512)         3 |@                                                   |

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220926220250.157022-1-nathanl@linux.ibm.com

powerpc: Remove CONFIG_PPC_FSL_BOOK3E

2022-09-26T13:00:13+00:00

CONFIG_PPC_FSL_BOOK3E is redundant with CONFIG_PPC_E500.

Remove it.

And rename five files accordingly.

Signed-off-by: Christophe Leroy 
[mpe: Rename include guards to match new file names]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/795cb93b88c9a0279289712e674f39e3b108a1b4.1663606876.git.christophe.leroy@csgroup.eu

Merge tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-08-07T17:03:24+00:00

Pull misc updates from Andrew Morton:
 "Updates to various subsystems which I help look after. lib, ocfs2,
  fatfs, autofs, squashfs, procfs, etc. A relatively small amount of
  material this time"

* tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
  scripts/gdb: ensure the absolute path is generated on initial source
  MAINTAINERS: kunit: add David Gow as a maintainer of KUnit
  mailmap: add linux.dev alias for Brendan Higgins
  mailmap: update Kirill's email
  profile: setup_profiling_timer() is moslty not implemented
  ocfs2: fix a typo in a comment
  ocfs2: use the bitmap API to simplify code
  ocfs2: remove some useless functions
  lib/mpi: fix typo 'the the' in comment
  proc: add some (hopefully) insightful comments
  bdi: remove enum wb_congested_state
  kernel/hung_task: fix address space of proc_dohung_task_timeout_secs
  lib/lzo/lzo1x_compress.c: replace ternary operator with min() and min_t()
  squashfs: support reading fragments in readahead call
  squashfs: implement readahead
  squashfs: always build "file direct" version of page actor
  Revert "squashfs: provide backing_dev_info in order to disable read-ahead"
  fs/ocfs2: Fix spelling typo in comment
  ia64: old_rr4 added under CONFIG_HUGETLB_PAGE
  proc: fix test for "vsyscall=xonly" boot option
  ...

profile: setup_profiling_timer() is moslty not implemented

2022-07-30T01:12:36+00:00

The setup_profiling_timer() is mostly un-implemented by many
architectures.  In many places it isn't guarded by CONFIG_PROFILE which is
needed for it to be used.  Make it a weak symbol in kernel/profile.c and
remove the 'return -EINVAL' implementations from the kenrel.

There are a couple of architectures which do return 0 from the
setup_profiling_timer() function but they don't seem to do anything else
with it.  To keep the /proc compatibility for now, leave these for a
future update or removal.

On ARM, this fixes the following sparse warning:
arch/arm/kernel/smp.c:793:5: warning: symbol 'setup_profiling_timer' was not declared. Should it be static?

Link: https://lkml.kernel.org/r/20220721195509.418205-1-ben-linux@fluff.org
Signed-off-by: Ben Dooks 
Signed-off-by: Andrew Morton

powerpc/crash: save cpu register data in crash_smp_send_stop()

2022-07-28T06:22:13+00:00

During kdump, two set of NMI IPIs are sent to secondary CPUs, if
'crash_kexec_post_notifiers' option is set. The first set of NMI IPIs
to stop the CPUs and the other set to collect register data. Instead,
capture register data for secondary CPUs while stopping them itself.
Also, fallback to smp_send_stop() in case the function gets called
without kdump configured.

Signed-off-by: Hari Bathini 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220630064942.192283-1-hbathini@linux.ibm.com

powerpc: Fix all occurences of "the the"

2022-05-22T05:59:43+00:00

Rather than waiting for the bots to fix these one-by-one, fix all
occurences of "the the" throughout arch/powerpc.

Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220518142629.513007-1-mpe@ellerman.id.au

powerpc/kasan: Don't instrument non-maskable or raw interrupts

2022-05-22T05:58:29+00:00

Disable address sanitization for raw and non-maskable interrupt
handlers, because they can run in real mode, where we cannot access
the shadow memory.  (Note that kasan_arch_is_ready() doesn't test for
real mode, since it is a static branch for speed, and in any case not
all the entry points to the generic KASAN code are protected by
kasan_arch_is_ready guards.)

The changes to interrupt_nmi_enter/exit_prepare() look larger than
they actually are.  The changes are equivalent to adding
!IS_ENABLED(CONFIG_KASAN) to the conditions for calling nmi_enter() or
nmi_exit() in real mode.  That is, the code is equivalent to using the
following condition for calling nmi_enter/exit:

	if (((!IS_ENABLED(CONFIG_PPC_BOOK3S_64) ||
			!firmware_has_feature(FW_FEATURE_LPAR) ||
			radix_enabled()) &&
		    !IS_ENABLED(CONFIG_KASAN) ||
		(mfmsr() & MSR_DR))

That unwieldy condition has been split into several statements with
comments, for easier reading.

The nmi_ipi_lock functions that call atomic functions (i.e.,
nmi_ipi_lock_start(), nmi_ipi_lock() and nmi_ipi_unlock()), besides
being marked noinstr, now call arch_atomic_* functions instead of
atomic_* functions because with KASAN enabled, the atomic_* functions
are wrappers which explicitly do address sanitization on their
arguments.  Since we are trying to avoid address sanitization, we have
to use the lower-level arch_atomic_* versions.

In hv_nmi_check_nonrecoverable(), the regs_set_unrecoverable() call
has been open-coded so as to avoid having to either trust the inlining
or mark regs_set_unrecoverable() as noinstr.

[paulus@ozlabs.org: combined a few work-in-progress commits of
 Daniel's and wrote the commit message.]

Signed-off-by: Daniel Axtens 
Signed-off-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/YoTFGaKM8Pd46PIK@cleo

powerpc: Remove asm/prom.h from all files that don't need it

2022-05-08T12:15:04+00:00

Several files include asm/prom.h for no reason.

Clean it up.

Signed-off-by: Christophe Leroy 
[mpe: Drop change to prom_parse.c as reported by lkp@intel.com]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/7c9b8fda63dcf63e1b28f43e7ebdb95182cbc286.1646767214.git.christophe.leroy@csgroup.eu

powerpc: fix typos in comments

2022-05-05T12:12:44+00:00

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall 
Reviewed-by: Joel Stanley 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220430185654.5855-1-Julia.Lawall@inria.fr