As using the normal static key API under the hotplug lock is
pretty much impossible, let's provide a variant of some of them
that require the hotplug lock to have already been taken.

These function are only meant to be used in CPU hotplug callbacks.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170801080257.5056-4-marc.zyngier@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

static_key_enable/disable are trying to cap the static key count to
0/1.  However, their use of key->enabled is outside jump_label_lock
so they do not really ensure that.

Rewrite them to do a quick check for an already enabled (respectively,
already disabled), and then recheck under the jump label lock.  Unlike
static_key_slow_inc/dec, a failed check under the jump label lock does
not modify key->enabled.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1501601046-35683-2-git-send-email-pbonzini@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull tracing fixes from Steven Rostedt:
 "There was some breakage with the changes for jump labels in the 4.11
  merge window:

   - powerpc broke as jump labels uses the two LSB bits as flags in
     initialization.

     A check was added to make sure that all jump label entries were 4
     bytes aligned, but powerpc didn't work that way for modules. Adding
     an alignment in the module linker script appeared to be the best
     solution.

   - Jump labels also added an anonymous union to access those LSB bits
     as a normal long. But because this structure had static
     initialization, it broke older compilers that could not statically
     initialize anonymous unions without brackets.

   - The command line parameter for setting function graph filter broke
     the "EMPTY_HASH" descriptor by modifying it instead of creating a
     new hash to hold the entries.

   - The command line parameter ftrace_graph_max_depth was added to
     allow its setting at boot time. It uses existing code and only the
     command line hook was added.

     This is not really a fix, but as it uses existing code without
     affecting anything else, I added it to this release. It was ready
     before the merge window closed, but I wanted to let it sit in
     linux-next for a couple of days first"

* tag 'trace-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace/graph: Add ftrace_graph_max_depth kernel parameter
  tracing: Add #undef to fix compile error
  jump_label: Add comment about initialization order for anonymous unions
  jump_label: Fix anonymous union initialization
  module: set __jump_table alignment to 8
  ftrace/graph: Do not modify the EMPTY_HASH for the function_graph filter
  tracing: Fix code comment for ftrace_ops_get_func()

Commit 3821fd35b58d ("jump_label: Reduce the size of struct static_key")
broke old compilers that could not handle static initialization of anonymous
unions. Boris fixed it with a patch that added brackets around the static
initializer. But this creates a dependency between those initializers and
the structure's order of its fields. Document this dependency in case new
fields are added to struct static_key in the future.

Noted-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Suggested-by: Chris Mason <clm@fb.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pre-4.6 gcc do not allow direct static initialization of members of
anonymous structs/unions. After commit 3821fd35b58d ("jump_label:
Reduce the size of struct static_key") STATIC_KEY_INIT_{TRUE|FALSE}
definitions cannot be compiled with those older compilers.

Placing initializers inside curved brackets works around this problem.

Link: http://lkml.kernel.org/r/1488299542-30765-1-git-send-email-boris.ostrovsky@oracle.com

Fixes: 3821fd35b58d ("jump_label: Reduce the size of struct static_key")
Reviewed-by: Jason Baron <jbaron@akamai.com>
Compiled-by: Chris Mason <clm@fb.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull tracing updates from Steven Rostedt:
 "This release has no new tracing features, just clean ups, minor fixes
  and small optimizations"

* tag 'trace-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (25 commits)
  tracing: Remove outdated ring buffer comment
  tracing/probes: Fix a warning message to show correct maximum length
  tracing: Fix return value check in trace_benchmark_reg()
  tracing: Use modern function declaration
  jump_label: Reduce the size of struct static_key
  tracing/probe: Show subsystem name in messages
  tracing/hwlat: Update old comment about migration
  timers: Make flags output in the timer_start tracepoint useful
  tracing: Have traceprobe_probes_write() not access userspace unnecessarily
  tracing: Have COMM event filter key be treated as a string
  ftrace: Have set_graph_function handle multiple functions in one write
  ftrace: Do not hold references of ftrace_graph_{notrace_}hash out of graph_lock
  tracing: Reset parser->buffer to allow multiple "puts"
  ftrace: Have set_graph_functions handle write with RDWR
  ftrace: Reset fgd->hash in ftrace_graph_write()
  ftrace: Replace (void *)1 with a meaningful macro name FTRACE_GRAPH_EMPTY
  ftrace: Create a slight optimization on searching the ftrace_hash
  tracing: Add ftrace_hash_key() helper function
  ftrace: Convert graph filter to use hash tables
  ftrace: Expose ftrace_hash_empty and ftrace_lookup_ip
  ...

The static_key->next field goes mostly unused. The field is used for
associating module uses with a static key. Most uses of struct static_key
define a static key in the core kernel and make use of it entirely within
the core kernel, or define the static key in a module and make use of it
only from within that module. In fact, of the ~3,000 static keys defined,
I found only about 5 or so that did not fit this pattern.

Thus, we can remove the static_key->next field entirely and overload
the static_key->entries field. That is, when all the static_key uses
are contained within the same module, static_key->entries continues
to point to those uses. However, if the static_key uses are not contained
within the module where the static_key is defined, then we allocate a
struct static_key_mod, store a pointer to the uses within that
struct static_key_mod, and have the static key point at the static_key_mod.
This does incur some extra memory usage when a static_key is used in a
module that does not define it, but since there are only a handful of such
cases there is a net savings.

In order to identify if the static_key->entries pointer contains a
struct static_key_mod or a struct jump_entry pointer, bit 1 of
static_key->entries is set to 1 if it points to a struct static_key_mod and
is 0 if it points to a struct jump_entry. We were already using bit 0 in a
similar way to store the initial value of the static_key. This does mean
that allocations of struct static_key_mod and that the struct jump_entry
tables need to be at least 4-byte aligned in memory. As far as I can tell
all arches meet this criteria.

For my .config, the patch increased the text by 778 bytes, but reduced
the data + bss size by 14912, for a net savings of 14,134 bytes.

   text	   data	    bss	    dec	    hex	filename
8092427	5016512	 790528	13899467	 d416cb	vmlinux.pre
8093205	5001600	 790528	13885333	 d3df95	vmlinux.post

Link: http://lkml.kernel.org/r/1486154544-4321-1-git-send-email-jbaron@akamai.com

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The ending header guard is misplaced. This has no
functional change, this is just an eye-sore.

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: bp@suse.de
Cc: catalin.marinas@arm.com
Cc: jbaron@akamai.com
Cc: pbonzini@redhat.com
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/20170118173804.16281-1-mcgrof@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull RAS updates from Ingo Molnar:
 "The main changes were:

   - Lots of enhancements for AMD SMCA (Scalable MCA
     features/extensions) systems: extract, decode and print more
     hardware error information and add matching support on the
     injection/testing side as well. (Yazn Ghannam)

   - Various MCE handling improvements on modern Intel Xeons. (Tony
     Luck)

   - Plus misc fixes and enhancements"

* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/RAS/mce_amd_inj: Remove debugfs dir recursively on exit
  x86/RAS/mce_amd_inj: Fix signed wrap around when decrementing index 'i'
  x86/RAS/mce_amd_inj: Fix some W= warnings
  x86/MCE/AMD, EDAC: Handle reserved bank 4 on Fam17h properly
  x86/mce/AMD: Extract the error address on SMCA systems
  x86/mce, EDAC/mce_amd: Print MCA_SYND and MCA_IPID during MCE on SMCA systems
  x86/mce/AMD: Save MCA_IPID in MCE struct on SMCA systems
  x86/mce/AMD: Ensure the deferred error interrupt is of type APIC on SMCA systems
  x86/mce/AMD: Update sysfs bank names for SMCA systems
  x86/mce/AMD, EDAC/mce_amd: Define and use tables for known SMCA IP types
  EDAC/mce_amd: Use SMCA prefix for error descriptions arrays
  EDAC/mce_amd: Add missing SMCA error descriptions
  x86/mce/AMD: Read MSRs on the CPU allocating the threshold blocks
  x86/RAS: Add syndrome support to mce_amd_inj
  EDAC/mce_amd: Print syndrome register value on SMCA systems
  x86/mce: Add support for new MCA_SYND register
  x86/mce/AMD: Use msr_ops.misc() in allocate_threshold_blocks()
  x86/mce: Drop X86_FEATURE_MCE_RECOVERY and the related model string test
  x86/mce: Improve memcpy_mcsafe()
  x86/mce: Add PCI quirks to identify Xeons with machine check recovery
  ...

The static key API is currently designed around single variable
definitions. There are cases where an array of static keys is desirable,
so extend the API to allow this rather than using the internal static
key implementation directly.

Cc: Jason Baron <jbaron@akamai.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Suggested-by: Dave P Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>