user/sven/linux.git/kernel/ksysfs.c, branch stable/4.8.y

kexec: add a kexec_crash_loaded() function

2016-08-02T23:35:30Z

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

2016-08-02T23:35:27Z

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

2015-12-08T00:59:37Z

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

2015-12-04T20:26:53Z

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

2015-09-10T20:29:01Z

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.

2014-04-25T19:00:49Z

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((...))

2014-04-07T23:36:11Z

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

2014-02-26T14:35:16Z

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

kdump: fix exported size of vmcoreinfo note

2014-01-24T00:37:03Z

Right now we seem to be exporting the max data size contained inside vmcoreinfo note. But this does not include the size of meta data around vmcore info data. Like name of the note and starting and ending elf_note. I think user space expects total size and that size is put in PT_NOTE elf header. Things seem to be fine so far because we are not using vmcoreinfo note to the maximum capacity. But as it starts filling up, to capacity, at some point of time, problem will be visible. I don't think user space will be broken with this change. So there is no need to introduce vmcoreinfo2. This change is safe and backward compatible. More explanation on why this change is safe is below. vmcoreinfo contains information about kernel which user space needs to know to do things like filtering. For example, various kernel config options or information about size or offset of some data structures etc. All this information is commmunicated to user space with an ELF note present in ELF /proc/vmcore file. Currently vmcoreinfo data size is 4096. With some elf note meta data around it, actual size is 4132 bytes. But we are using barely 25% of that size. Rest is empty. So even if we tell user space that size of ELf note is 4096 and not 4132, nothing will be broken becase after around 1000 bytes, everything is zero anyway. But once we start filling up the note to the capacity, and not report the full size of note, bad things will start happening. Either some data will be lost or tools will be confused that they did not fine the zero note at the end. So I think this change is safe and should not break existing tools. Signed-off-by: Vivek Goyal Cc: Ken'ichi Ohmichi Cc: Dan Aloni Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel: replace strict_strto() with kstrto()

2013-09-12T22:38:03Z

The usage of strict_strto*() is not preferred, because strict_strto*() is obsolete. Thus, kstrto*() should be used. Signed-off-by: Jingoo Han Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds