BMC/Intel-BMC/linux.git/include/linux/compiler.h, branch v4.2-rc1

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-07-01T17:49:25+00:00

Pull module updates from Rusty Russell: "Main excitement here is Peter Zijlstra's lockless rbtree optimization to speed module address lookup. He found some abusers of the module lock doing that too. A little bit of parameter work here too; including Dan Streetman's breaking up the big param mutex so writing a parameter can load another module (yeah, really). Unfortunately that broke the usual suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were appended too" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits) modules: only use mod->param_lock if CONFIG_MODULES param: fix module param locks when !CONFIG_SYSFS. rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE() module: add per-module param_lock module: make perm const params: suppress unused variable error, warn once just in case code changes. modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'. kernel/module.c: avoid ifdefs for sig_enforce declaration kernel/workqueue.c: remove ifdefs over wq_power_efficient kernel/params.c: export param_ops_bool_enable_only kernel/params.c: generalize bool_enable_only kernel/module.c: use generic module param operaters for sig_enforce kernel/params: constify struct kernel_param_ops uses sysfs: tightened sysfs permission checks module: Rework module_addr_{min,max} module: Use __module_address() for module_address_lookup() module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING module: Optimize __module_address() using a latched RB-tree rbtree: Implement generic latch_tree seqlock: Introduce raw_read_seqcount_latch() ...

Merge tag 'libnvdimm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm

2015-06-29T17:34:42+00:00

Pull libnvdimm subsystem from Dan Williams: "The libnvdimm sub-system introduces, in addition to the libnvdimm-core, 4 drivers / enabling modules: NFIT: Instantiates an "nvdimm bus" with the core and registers memory devices (NVDIMMs) enumerated by the ACPI 6.0 NFIT (NVDIMM Firmware Interface table). After registering NVDIMMs the NFIT driver then registers "region" devices. A libnvdimm-region defines an access mode and the boundaries of persistent memory media. A region may span multiple NVDIMMs that are interleaved by the hardware memory controller. In turn, a libnvdimm-region can be carved into a "namespace" device and bound to the PMEM or BLK driver which will attach a Linux block device (disk) interface to the memory. PMEM: Initially merged in v4.1 this driver for contiguous spans of persistent memory address ranges is re-worked to drive PMEM-namespaces emitted by the libnvdimm-core. In this update the PMEM driver, on x86, gains the ability to assert that writes to persistent memory have been flushed all the way through the caches and buffers in the platform to persistent media. See memcpy_to_pmem() and wmb_pmem(). BLK: This new driver enables access to persistent memory media through "Block Data Windows" as defined by the NFIT. The primary difference of this driver to PMEM is that only a small window of persistent memory is mapped into system address space at any given point in time. Per-NVDIMM windows are reprogrammed at run time, per-I/O, to access different portions of the media. BLK-mode, by definition, does not support DAX. BTT: This is a library, optionally consumed by either PMEM or BLK, that converts a byte-accessible namespace into a disk with atomic sector update semantics (prevents sector tearing on crash or power loss). The sinister aspect of sector tearing is that most applications do not know they have a atomic sector dependency. At least today's disk's rarely ever tear sectors and if they do one almost certainly gets a CRC error on access. NVDIMMs will always tear and always silently. Until an application is audited to be robust in the presence of sector-tearing the usage of BTT is recommended. Thanks to: Ross Zwisler, Jeff Moyer, Vishal Verma, Christoph Hellwig, Ingo Molnar, Neil Brown, Boaz Harrosh, Robert Elliott, Matthew Wilcox, Andy Rudoff, Linda Knippers, Toshi Kani, Nicholas Moulin, Rafael Wysocki, and Bob Moore" * tag 'libnvdimm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm: (33 commits) arch, x86: pmem api for ensuring durability of persistent memory updates libnvdimm: Add sysfs numa_node to NVDIMM devices libnvdimm: Set numa_node to NVDIMM devices acpi: Add acpi_map_pxm_to_online_node() libnvdimm, nfit: handle unarmed dimms, mark namespaces read-only pmem: flag pmem block devices as non-rotational libnvdimm: enable iostat pmem: make_request cleanups libnvdimm, pmem: fix up max_hw_sectors libnvdimm, blk: add support for blk integrity libnvdimm, btt: add support for blk integrity fs/block_dev.c: skip rw_page if bdev has integrity libnvdimm: Non-Volatile Devices tools/testing/nvdimm: libnvdimm unit test infrastructure libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memory nd_btt: atomic sector updates libnvdimm: infrastructure for btt devices libnvdimm: write blk label set libnvdimm: write pmem label set libnvdimm: blk labels and namespace instantiation ...

arch, x86: pmem api for ensuring durability of persistent memory updates

2015-06-26T15:23:38+00:00

Based on an original patch by Ross Zwisler [1]. Writes to persistent memory have the potential to be posted to cpu cache, cpu write buffers, and platform write buffers (memory controller) before being committed to persistent media. Provide apis, memcpy_to_pmem(), wmb_pmem(), and memremap_pmem(), to write data to pmem and assert that it is durable in PMEM (a persistent linear address range). A '__pmem' attribute is added so sparse can track proper usage of pointers to pmem. This continues the status quo of pmem being x86 only for 4.2, but reworks to ioremap, and wider implementation of memremap() will enable other archs in 4.3. [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-May/000932.html Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Ross Zwisler [djbw: various reworks] Signed-off-by: Dan Williams

rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()

2015-06-24T00:07:40+00:00

This mirrors the change introduced by 7d0ae8086b8 of same title in Linus' tree; it's not obvious as a merge resolution since we moved the function. Signed-off-by: Stephen Rothwell Signed-off-by: Rusty Russell

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

2015-06-22T21:54:22+00:00

Pull locking updates from Ingo Molnar: "The main changes are: - 'qspinlock' support, enabled on x86: queued spinlocks - these are now the spinlock variant used by x86 as they outperform ticket spinlocks in every category. (Waiman Long) - 'pvqspinlock' support on x86: paravirtualized variant of queued spinlocks. (Waiman Long, Peter Zijlstra) - 'qrwlock' support, enabled on x86: queued rwlocks. Similar to queued spinlocks, they are now the variant used by x86: CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y CONFIG_QUEUED_SPINLOCKS=y CONFIG_ARCH_USE_QUEUED_RWLOCKS=y CONFIG_QUEUED_RWLOCKS=y - various lockdep fixlets - various locking primitives cleanups, further WRITE_ONCE() propagation" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) locking/lockdep: Remove hard coded array size dependency locking/qrwlock: Don't contend with readers when setting _QW_WAITING lockdep: Do not break user-visible string locking/arch: Rename set_mb() to smp_store_mb() locking/arch: Add WRITE_ONCE() to set_mb() rtmutex: Warn if trylock is called from hard/softirq context arch: Remove __ARCH_HAVE_CMPXCHG locking/rtmutex: Drop usage of __HAVE_ARCH_CMPXCHG locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS locking/pvqspinlock: Replace xchg() by the more descriptive set_mb() locking/pvqspinlock, x86: Enable PV qspinlock for Xen locking/pvqspinlock, x86: Enable PV qspinlock for KVM locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching locking/pvqspinlock: Implement simple paravirt support for the qspinlock locking/qspinlock: Revert to test-and-set on hypervisors locking/qspinlock: Use a simple write to grab the lock locking/qspinlock: Optimize for smaller NR_CPUS locking/qspinlock: Extract out code snippets for the next patch locking/qspinlock: Add pending bit ...

rcu: Move lockless_dereference() out of rcupdate.h

2015-05-28T02:02:05+00:00

I want to use lockless_dereference() from seqlock.h, which would mean including rcupdate.h from it, however rcupdate.h already includes seqlock.h. Avoid this by moving lockless_dereference() into compiler.h. This is somewhat tricky since it uses smp_read_barrier_depends() which isn't available there, but its a CPP macro so we can get away with it. The alternative would be moving it into asm/barrier.h, but that would be updating each arch (I can do if people feel that is more appropriate). Cc: Paul McKenney Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Rusty Russell

smp: Make control dependencies work on Alpha, improve documentation

2015-05-27T19:58:02+00:00

The current formulation of control dependencies fails on DEC Alpha, which does not respect dependencies of any kind unless an explicit memory barrier is provided. This means that the current fomulation of control dependencies fails on Alpha. This commit therefore creates a READ_ONCE_CTRL() that has the same overhead on non-Alpha systems, but causes Alpha to produce the needed ordering. This commit also applies READ_ONCE_CTRL() to the one known use of control dependencies. Use of READ_ONCE_CTRL() also has the beneficial effect of adding a bit of self-documentation to control dependencies. Signed-off-by: Paul E. McKenney Acked-by: Peter Zijlstra (Intel)

locking/arch: Add WRITE_ONCE() to set_mb()

2015-05-19T06:31:59+00:00

Since we assume set_mb() to result in a single store followed by a full memory barrier, employ WRITE_ONCE(). Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

kernel: Replace reference to ASSIGN_ONCE() with WRITE_ONCE() in comment

2015-05-08T10:28:53+00:00

Looks like commit : 43239cbe79fc ("kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)") left behind a reference to ASSIGN_ONCE(). Update this to WRITE_ONCE(). Signed-off-by: Preeti U Murthy Signed-off-by: Peter Zijlstra (Intel) Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Thomas Gleixner Cc: borntraeger@de.ibm.com Cc: dave@stgolabs.net Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/20150430115721.22278.94082.stgit@preeti.in.ibm.com Signed-off-by: Ingo Molnar

lib: make memzero_explicit more robust against dead store elimination

2015-05-04T09:49:51+00:00

In commit 0b053c951829 ("lib: memzero_explicit: use barrier instead of OPTIMIZER_HIDE_VAR"), we made memzero_explicit() more robust in case LTO would decide to inline memzero_explicit() and eventually find out it could be elimiated as dead store. While using barrier() works well for the case of gcc, recent efforts from LLVMLinux people suggest to use llvm as an alternative to gcc, and there, Stephan found in a simple stand-alone user space example that llvm could nevertheless optimize and thus elimitate the memset(). A similar issue has been observed in the referenced llvm bug report, which is regarded as not-a-bug. Based on some experiments, icc is a bit special on its own, while it doesn't seem to eliminate the memset(), it could do so with an own implementation, and then result in similar findings as with llvm. The fix in this patch now works for all three compilers (also tested with more aggressive optimization levels). Arguably, in the current kernel tree it's more of a theoretical issue, but imho, it's better to be pedantic about it. It's clearly visible with gcc/llvm though, with the below code: if we would have used barrier() only here, llvm would have omitted clearing, not so with barrier_data() variant: static inline void memzero_explicit(void *s, size_t count) { memset(s, 0, count); barrier_data(s); } int main(void) { char buff[20]; memzero_explicit(buff, sizeof(buff)); return 0; } $ gcc -O2 test.c $ gdb a.out (gdb) disassemble main Dump of assembler code for function main: 0x0000000000400400 <+0>: lea -0x28(%rsp),%rax 0x0000000000400405 <+5>: movq $0x0,-0x28(%rsp) 0x000000000040040e <+14>: movq $0x0,-0x20(%rsp) 0x0000000000400417 <+23>: movl $0x0,-0x18(%rsp) 0x000000000040041f <+31>: xor %eax,%eax 0x0000000000400421 <+33>: retq End of assembler dump. $ clang -O2 test.c $ gdb a.out (gdb) disassemble main Dump of assembler code for function main: 0x00000000004004f0 <+0>: xorps %xmm0,%xmm0 0x00000000004004f3 <+3>: movaps %xmm0,-0x18(%rsp) 0x00000000004004f8 <+8>: movl $0x0,-0x8(%rsp) 0x0000000000400500 <+16>: lea -0x18(%rsp),%rax 0x0000000000400505 <+21>: xor %eax,%eax 0x0000000000400507 <+23>: retq End of assembler dump. As gcc, clang, but also icc defines __GNUC__, it's sufficient to define this in compiler-gcc.h only to be picked up. For a fallback or otherwise unsupported compiler, we define it as a barrier. Similarly, for ecc which does not support gcc inline asm. Reference: https://llvm.org/bugs/show_bug.cgi?id=15495 Reported-by: Stephan Mueller Tested-by: Stephan Mueller Signed-off-by: Daniel Borkmann Cc: Theodore Ts'o Cc: Stephan Mueller Cc: Hannes Frederic Sowa Cc: mancha security Cc: Mark Charlebois Cc: Behan Webster Signed-off-by: Herbert Xu