linux.git/arch/s390/kernel/sysinfo.c, branch v6.9

s390/sysinfo: allow response buffer in normal memory

2024-03-13T08:23:44+00:00

As provided with commit cd4386a931b63 ("s390/cpcmd,vmcp: avoid GFP_DMA
allocations") the Diagnose Code 8 response buffer does not have to be
below 2GB.

Reviewed-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens

s390/sysinfo: convert bogomips calculation to C

2024-02-16T13:30:17+00:00

Provide several one instruction fpu inline assemebles and use them to
implement the bogomips calculation in C like style. This is more for
illustration purposes on how kernel fpu code can be written in C.

This has the advantage that the author only has to take care of the
floating point instructions, but doesn't need to take care of general
purpose register allocation (if needed), and the semantics of all other
instructions not related to fpu.

Signed-off-by: Heiko Carstens

s390/fpu: decrease stack usage for some cases

2024-02-16T13:30:16+00:00

The kernel_fpu structure has a quite large size of 520 bytes. In order to
reduce stack footprint introduce several kernel fpu structures with
different and also smaller sizes. This way every kernel fpu user must use
the correct variant. A compile time check verifies that the correct variant
is used.

There are several users which use only 16 instead of all 32 vector
registers. For those users the new kernel_fpu_16 structure with a size of
only 266 bytes can be used.

Signed-off-by: Heiko Carstens

s390/fpu: move, rename, and merge header files

2024-02-16T13:30:14+00:00

Move, rename, and merge the fpu and vx header files. This way fpu header
files have a consistent naming scheme (fpu*.h).

Also get rid of the fpu subdirectory and move header files to asm
directory, so that all fpu and vx header files can be found at the same
location.

Merge internal.h header file into other header files, since the internal
helpers are used at many locations. so those helper functions are really
not internal.

Signed-off-by: Heiko Carstens

s390/fpu: make use of __uninitialized macro

2024-02-09T12:58:16+00:00

Code sections in s390 specific kernel code which use floating point or
vector registers all come with a 520 byte stack variable to save already in
use registers, if required.

With INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO enabled this variable
will always be initialized on function entry in addition to saving register
contents, which contradicts the intention (performance improvement) of such
code sections.

Therefore provide a DECLARE_KERNEL_FPU_ONSTACK() macro which provides
struct kernel_fpu variables with an __uninitialized attribute, and convert
all existing code to use this.

This way only this specific type of stack variable will not be initialized,
regardless of config options.

Reviewed-by: Nathan Chancellor 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/20240205154844.3757121-3-hca@linux.ibm.com
Signed-off-by: Heiko Carstens

s390/sysinfo: add variable capacity information

2023-11-22T13:07:28+00:00

If available, add machine variable capacity information to /proc/sysinfo

Acked-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Alexander Gordeev

s390/extable: move EX_TABLE define to asm-extable.h

2022-03-07T23:33:00+00:00

Follow arm64 and riscv and move the EX_TABLE define to asm-extable.h
which is a lot less generic than the current linkage.h.

Also make sure that all files which contain EX_TABLE usages actually
include the new header file. This should make sure that the files
always compile and there won't be any random compile breakage due to
other header file dependencies.

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/sysinfo: get rid of register asm

2021-06-18T14:41:23+00:00

Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: no need to check return value of debugfs_create functions

2019-01-28T14:58:55+00:00

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Kees Cook 
Cc: Christian Borntraeger 
Cc: Hendrik Brueckner 
Cc: linux-s390@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/sysinfo: add missing #ifdef CONFIG_PROC_FS

2018-07-02T10:32:20+00:00

Get rid of this compile warning for !PROC_FS:

  CC      arch/s390/kernel/sysinfo.o
arch/s390/kernel/sysinfo.c:275:12: warning: 'sysinfo_show' defined but not used [-Wunused-function]
 static int sysinfo_show(struct seq_file *m, void *v)

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