litmus-rt.git/arch/s390/oprofile, branch master

s390: remove 31 bit support

2015-03-25T10:49:33+00:00

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

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

s390: Replace __get_cpu_var uses

2014-08-26T17:45:52+00:00

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	this_cpu_inc(y)

Cc: Martin Schwidefsky 
CC: linux390@de.ibm.com
Acked-by: Heiko Carstens 
Signed-off-by: Christoph Lameter 
Signed-off-by: Tejun Heo

s390/oprofile: make return of 0 explicit

2014-05-27T08:26:00+00:00

Delete unnecessary local variable whose value is always 0 and that hides
the fact that the result is always 0.

A simplified version of the semantic patch that fixes this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@r exists@
local idexpression ret;
expression e;
position p;
@@

-ret = 0;
... when != ret = e
return
- ret
+ 0
  ;
// 

[heiko.carstens: turn prepare_cpu_buffers into a void returning function]
Signed-off-by: Julia Lawall 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/irq: Use defines for external interruption codes

2014-04-03T12:30:52+00:00

Use the new defines for external interruption codes to get rid
of "magic" numbers in the s390 source code. And while we're at it,
also rename the (un-)register_external_interrupt function to
something shorter so that this patch does not exceed the 80
columns all over the place.

Signed-off-by: Thomas Huth 
Signed-off-by: Martin Schwidefsky

s390/cpum_sf: Add raw data sampling to support the diagnostic-sampling function

2013-12-16T13:38:00+00:00

Also support the diagnostic-sampling function in addition to the basic-sampling
function.  Diagnostic-sampling data entries contain hardware model specific
sampling data and additional programs are required to analyze the data.

To deliver diagnostic-sampling, as well, as basis-sampling data entries to user
space, introduce support for sampling "raw data".  If this particular perf
sampling type (PERF_SAMPLE_RAW) is used, sampling data entries are copied
to user space.  External programs can then analyze these data.

Signed-off-by: Hendrik Brueckner 
Signed-off-by: Martin Schwidefsky

s390/perf,oprofile: Share sampling facility

2013-12-16T13:37:52+00:00

Introduce reserve/release functions to share the sampling facility
between perf and oprofile.
Also improve error handling for the sampling facility support in perf.

Signed-off-by: Hendrik Brueckner 
Signed-off-by: Martin Schwidefsky

s390/oprofile: move hwsampler interfaces to cpu_mf.h

2013-12-16T13:37:50+00:00

Extract and move the oprofile hwsampler data structures and interfaces to
the cpu_mf.h header file which contains common interface definitions
for the various CPU-measurement facilities.   This change is necessary for
a new perf PMU.

Few interface names have been revised to fit to the latest CPU-measurement
facilities documentation.  Also declare the data structures as __packed and
correct checkpatch findings.

Signed-off-by: Hendrik Brueckner 
Signed-off-by: Martin Schwidefsky

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2013-09-11T15:36:03+00:00

Pull more s390 updates from Heiko Carstens:
 "This includes one bpf/jit bug fix where the jit compiler could
  sometimes write generated code out of bounds of the allocated memory
  area.

  The rest of the patches are only cleanups and minor improvements"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/irq: reduce size of external interrupt handler hash array
  s390/compat,uid16: use current_cred()
  s390/ap_bus: use and-mask instead of a cast
  s390/ftrace: avoid pointer arithmetics with function pointers
  s390: make various functions static, add declarations to header files
  s390/compat signal: add couple of __force annotations
  s390/mm: add __releases()/__acquires() annotations to gmap_alloc_table()
  s390: keep Kconfig sorted
  s390/irq: rework irq subclass handling
  s390/irq: use hlists for external interrupt handler array
  s390/dumpstack: convert print_symbol to %pSR
  s390/perf: Remove print_hex_dump_bytes() debug output
  s390: update defconfig
  s390/bpf,jit: fix address randomization

s390/irq: rework irq subclass handling

2013-09-04T15:19:13+00:00

Let's not add a function for every external interrupt subclass for
which we need reference counting. Just have two register/unregister
functions which have a subclass parameter:

void irq_subclass_register(enum irq_subclass subclass);
void irq_subclass_unregister(enum irq_subclass subclass);

Signed-off-by: Heiko Carstens

oprofilefs_create_...() do not need superblock argument

2013-09-04T02:52:48+00:00

same story as with oprofilefs_mkdir()

Signed-off-by: Al Viro