linux.git/arch/s390/kernel/cache.c, branch v4.4.12

s390/cachinfo: add missing facility check to init_cache_level()

2015-07-28T06:54:42+00:00

Stephen Powell reported the following crash on a z890 machine:

Kernel BUG at 00000000001219d0 [verbose debug info unavailable]
illegal operation: 0001 ilc:3 [#1] SMP
Krnl PSW : 0704e00180000000 00000000001219d0 (init_cache_level+0x38/0xe0)
	   R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 EA:3
Krnl Code: 00000000001219c2: a7840056		brc	8,121a6e
	   00000000001219c6: a7190000		lghi	%r1,0
	  #00000000001219ca: eb101000004c	ecag	%r1,%r0,0(%r1)
	  >00000000001219d0: a7390000		lghi	%r3,0
	   00000000001219d4: e310f0a00024	stg	%r1,160(%r15)
	   00000000001219da: a7080000		lhi	%r0,0
	   00000000001219de: a7b9f000		lghi	%r11,-4096
	   00000000001219e2: c0a0002899d9	larl	%r10,634d94
Call Trace:
 [<0000000000478ee2>] detect_cache_attributes+0x2a/0x2b8
 [<000000000097c9b0>] cacheinfo_sysfs_init+0x60/0xc8
 [<00000000001001c0>] do_one_initcall+0x98/0x1c8
 [<000000000094fdc2>] kernel_init_freeable+0x212/0x2d8
 [<000000000062352e>] kernel_init+0x26/0x118
 [<000000000062fd2e>] kernel_thread_starter+0x6/0xc

The illegal operation was executed because of a missing facility check,
which should have made sure that the ECAG execution would only be executed
on machines which have the general-instructions-extension facility
installed.

Reported-and-tested-by: Stephen Powell 
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/cacheinfo: add missing facility check

2015-04-13T08:46:16+00:00

Git commit d97d929f06d0 ("s390: move cacheinfo sysfs to generic cacheinfo
infrastructure") removed the general-instructions-extension availability
check before the ecag instruction is executed.
Without this check this may lead to crashes on machines without this facility.
Therefore add the check again where needed.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/cacheinfo: coding style changes

2015-02-12T08:37:24+00:00

Just some minor coding style changes, while I had to look at the code.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/cacheinfo: fix shared cpu masks

2015-02-12T08:37:24+00:00

When testing Sudeep Holla's cache info rework I didn't realize that the
shared cpu masks are broken (all have the same cpu set).
Let's fix this.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/cacheinfo: don't use smp_processor_id() in preemptible context

2015-02-10T09:15:57+00:00

show_cacheinfo() needs to access the cacheinfo structure of any online
cpu. This was done with using smp_processor_id() as in index while in
preemtible context.
This means the cpu could be offline and the data be gone when it would
be accessed.
Better use any online cpu address and protect the data by get_online_cpus()
and put_online_cpus().

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: move cacheinfo sysfs to generic cacheinfo infrastructure

2015-01-08T09:02:54+00:00

This patch removes the redundant sysfs cacheinfo code by reusing
the newly introduced generic cacheinfo infrastructure through the
commit 246246cbde5e ("drivers: base: support cpu cache information
interface to userspace via sysfs")

Signed-off-by: Sudeep Holla 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390, cacheinfo: Fix CPU hotplug callback registration

2014-03-20T12:43:41+00:00

Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the cacheinfo code in s390 by using this latter form of callback
registration.

Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Ingo Molnar 
Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Rafael J. Wysocki

s390/cache: get rid of compile warning

2013-10-24T15:17:06+00:00

Get rid of this one:

arch/s390/kernel/cache.c: In function 'cache_build_info':
arch/s390/kernel/cache.c:144: warning: 'private' may be used uninitialized
in this function

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: delete __cpuinit usage from all s390 files

2013-07-14T23:36:53+00:00

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/s390 uses of the __cpuinit macros from
all C files.  Currently s390 does not have any __CPUINIT used in
assembly files.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Paul Gortmaker

s390/cache: fix data/instruction cache output

2012-10-18T15:50:11+00:00

The sysfs and procfs output of the instruction and data caches were
wrong: the output of the data cache provided that instruction cache
values and vice versa.
Fix this by using the correct type indication when issueing the
ecag instruction.

Reported-by: Andreas Krebbel 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky