linux-toradex.git/kernel/ksysfs.c, branch v4.12

crash: move crashkernel parsing and vmcore related code under CONFIG_CRASH_CORE

2017-05-09T00:15:11+00:00

Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and
reuse crashkernel parameter for fadump", v4.

Traditionally, kdump is used to save vmcore in case of a crash.  Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism.  Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.

This patchset removes dependency with CONFIG_KEXEC for crashkernel
parameter and vmcoreinfo related code as it can be reused without kexec
support.  Also, crashkernel parameter is reused instead of
fadump_reserve_mem to reserve memory for fadump.

The first patch moves crashkernel parameter parsing and vmcoreinfo
related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE.  The
second patch reuses the definitions of append_elf_note() & final_note()
functions under CONFIG_CRASH_CORE in IA64 arch code.  The third patch
removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump)
in powerpc.  The next patch reuses crashkernel parameter for reserving
memory for fadump, instead of the fadump_reserve_mem parameter.  This
has the advantage of using all syntaxes crashkernel parameter supports,
for fadump as well.  The last patch updates fadump kernel documentation
about use of crashkernel parameter.

This patch (of 5):

Traditionally, kdump is used to save vmcore in case of a crash.  Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism.  Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.

But currently, code related to vmcoreinfo and parsing of crashkernel
parameter is built under CONFIG_KEXEC_CORE.  This patch introduces
CONFIG_CRASH_CORE and moves the above mentioned code under this config,
allowing code reuse without dependency on CONFIG_KEXEC.  There is no
functional change with this patch.

Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.com
Signed-off-by: Hari Bathini 
Acked-by: Dave Young 
Cc: Fenghua Yu 
Cc: Tony Luck 
Cc: Eric Biederman 
Cc: Mahesh Salgaonkar 
Cc: Vivek Goyal 
Cc: Michael Ellerman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel/ksysfs.c: add __ro_after_init to bin_attribute structure

2017-02-25T01:46:56+00:00

The object notes_attr of type bin_attribute is not modified after
getting initailized by ksysfs_init.  Apart from initialization in
ksysfs_init it is also passed as an argument to the function
sysfs_create_bin_file but this argument is of type const.  Therefore,
add __ro_after_init to its declaration.

Link: http://lkml.kernel.org/r/1486839969-16891-1-git-send-email-bhumirks@gmail.com
Signed-off-by: Bhumika Goyal 
Acked-by: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kexec: add a kexec_crash_loaded() function

2016-08-02T23:35:30+00:00

Provide a wrapper function to be used by kernel code to check whether a
crash kernel is loaded.  It returns the same value that can be seen in
/sys/kernel/kexec_crash_loaded by userspace programs.

I'm exporting the function, because it will be used by Xen, and it is
possible to compile Xen modules separately to enable the use of PV
drivers with unmodified bare-metal kernels.

Link: http://lkml.kernel.org/r/20160713121955.14969.69080.stgit@hananiah.suse.cz
Signed-off-by: Petr Tesarik 
Cc: Juergen Gross 
Cc: Josh Triplett 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Eric Biederman 
Cc: "H. Peter Anvin" 
Cc: Boris Ostrovsky 
Cc: "Paul E. McKenney" 
Cc: Dave Young 
Cc: David Vrabel 
Cc: Vivek Goyal 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kdump: arrange for paddr_vmcoreinfo_note() to return phys_addr_t

2016-08-02T23:35:27+00:00

On PAE systems (eg, ARM LPAE) the vmcore note may be located above 4GB
physical on 32-bit architectures, so we need a wider type than "unsigned
long" here.  Arrange for paddr_vmcoreinfo_note() to return a
phys_addr_t, thereby allowing it to be located above 4GB.

This makes no difference for kexec-tools, as they already assume a
64-bit type when reading from this file.

Link: http://lkml.kernel.org/r/E1b8koK-0004HS-K9@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King 
Reviewed-by: Pratyush Anand 
Acked-by: Baoquan He 
Cc: Keerthy 
Cc: Vitaly Andrianov 
Cc: Eric Biederman 
Cc: Dave Young 
Cc: Vivek Goyal 
Cc: Simon Horman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rcu: Remove TINY_RCU bloat from pointless boot parameters

2015-12-08T00:59:37+00:00

The rcu_expedited, rcu_normal, and rcu_normal_after_boot kernel boot
parameters are pointless in the case of TINY_RCU because in that case
synchronous grace periods, both expedited and normal, are no-ops.
However, these three symbols contribute several hundred bytes of bloat.
This commit therefore uses CPP directives to avoid compiling this code
in TINY_RCU kernels.

Reported-by: kbuild test robot 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

rcu: Add rcu_normal kernel parameter to suppress expediting

2015-12-04T20:26:53+00:00

Although expedited grace periods can be quite useful, and although their
OS jitter has been greatly reduced, they can still pose problems for
extreme real-time workloads.  This commit therefore adds a rcu_normal
kernel boot parameter (which can also be manipulated via sysfs)
to suppress expedited grace periods, that is, to treat requests for
expedited grace periods as if they were requests for normal grace periods.
If both rcu_expedited and rcu_normal are specified, rcu_normal wins.
This means that if you are relying on expedited grace periods to speed up
boot, you will want to specify rcu_expedited on the kernel command line,
and then specify rcu_normal via sysfs once boot completes.

Signed-off-by: Paul E. McKenney

kexec: split kexec_load syscall from kexec core code

2015-09-10T20:29:01+00:00

There are two kexec load syscalls, kexec_load another and kexec_file_load.
 kexec_file_load has been splited as kernel/kexec_file.c.  In this patch I
split kexec_load syscall code to kernel/kexec.c.

And add a new kconfig option KEXEC_CORE, so we can disable kexec_load and
use kexec_file_load only, or vice verse.

The original requirement is from Ted Ts'o, he want kexec kernel signature
being checked with CONFIG_KEXEC_VERIFY_SIG enabled.  But kexec-tools use
kexec_load syscall can bypass the checking.

Vivek Goyal proposed to create a common kconfig option so user can compile
in only one syscall for loading kexec kernel.  KEXEC/KEXEC_FILE selects
KEXEC_CORE so that old config files still work.

Because there's general code need CONFIG_KEXEC_CORE, so I updated all the
architecture Kconfig with a new option KEXEC_CORE, and let KEXEC selects
KEXEC_CORE in arch Kconfig.  Also updated general kernel code with to
kexec_load syscall.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Dave Young 
Cc: Eric W. Biederman 
Cc: Vivek Goyal 
Cc: Petr Tesarik 
Cc: Theodore Ts'o 
Cc: Josh Boyer 
Cc: David Howells 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kobject: Make support for uevent_helper optional.

2014-04-25T19:00:49+00:00

Support for uevent_helper, aka hotplug, is not required on many systems
these days but it can still be enabled via sysfs or sysctl.

Reported-by: Darren Shepherd 
Signed-off-by: Michael Marineau 
Signed-off-by: Greg Kroah-Hartman

kernel: use macros from compiler.h instead of attribute((...))

2014-04-07T23:36:11+00:00

To increase compiler portability there is  which
provides convenience macros for various gcc constructs.  Eg: __weak for
__attribute__((weak)).  I've replaced all instances of gcc attributes
with the right macro in the kernel subsystem.

Signed-off-by: Gideon Israel Dsouza 
Cc: "Rafael J. Wysocki" 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rcu: Fix sparse warning for rcu_expedited from kernel/ksysfs.c

2014-02-26T14:35:16+00:00

This commit fixes the follwoing warning:

kernel/ksysfs.c:143:5: warning: symbol 'rcu_expedited' was not declared. Should it be static?

Signed-off-by: Paul Gortmaker 
[ paulmck: Moved the declaration to include/linux/rcupdate.h to avoid
	   including the RCU-internal rcu.h file outside of RCU. ]
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett