1. 16 Jan, 2019 1 commit
    • Miroslav Benes's avatar
      livepatch: Send a fake signal periodically · cba82dea
      Miroslav Benes authored
      An administrator may send a fake signal to all remaining blocking tasks
      of a running transition by writing to
      /sys/kernel/livepatch/<patch>/signal attribute. Let's do it
      automatically after 15 seconds. The timeout is chosen deliberately. It
      gives the tasks enough time to transition themselves.
      
      Theoretically, sending it once should be more than enough. However,
      every task must get outside of a patched function to be successfully
      transitioned. It could prove not to be simple and resending could be
      helpful in that case.
      
      A new workqueue job could be a cleaner solution to achieve it, but it
      could also introduce deadlocks and cause more headaches with
      synchronization and cancelling.
      
      [jkosina@suse.cz: removed added newline]
      Signed-off-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      cba82dea
  2. 11 Jan, 2019 11 commits
    • Joe Lawrence's avatar
      selftests/livepatch: introduce tests · a2818ee4
      Joe Lawrence authored
      Add a few livepatch modules and simple target modules that the included
      regression suite can run tests against:
      
        - basic livepatching (multiple patches, atomic replace)
        - pre/post (un)patch callbacks
        - shadow variable API
      Signed-off-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Tested-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Tested-by: default avatarAlice Ferrazzi <alice.ferrazzi@gmail.com>
      Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      a2818ee4
    • Petr Mladek's avatar
      livepatch: Remove ordering (stacking) of the livepatches · d67a5372
      Petr Mladek authored
      The atomic replace and cumulative patches were introduced as a more secure
      way to handle dependent patches. They simplify the logic:
      
        + Any new cumulative patch is supposed to take over shadow variables
          and changes made by callbacks from previous livepatches.
      
        + All replaced patches are discarded and the modules can be unloaded.
          As a result, there is only one scenario when a cumulative livepatch
          gets disabled.
      
      The different handling of "normal" and cumulative patches might cause
      confusion. It would make sense to keep only one mode. On the other hand,
      it would be rude to enforce using the cumulative livepatches even for
      trivial and independent (hot) fixes.
      
      However, the stack of patches is not really necessary any longer.
      The patch ordering was never clearly visible via the sysfs interface.
      Also the "normal" patches need a lot of caution anyway.
      
      Note that the list of enabled patches is still necessary but the ordering
      is not longer enforced.
      
      Otherwise, the code is ready to disable livepatches in an random order.
      Namely, klp_check_stack_func() always looks for the function from
      the livepatch that is being disabled. klp_func structures are just
      removed from the related func_stack. Finally, the ftrace handlers
      is removed only when the func_stack becomes empty.
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      d67a5372
    • Petr Mladek's avatar
      livepatch: Atomic replace and cumulative patches documentation · c4e6874f
      Petr Mladek authored
      User documentation for the atomic replace feature. It makes it easier
      to maintain livepatches using so-called cumulative patches.
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      c4e6874f
    • Petr Mladek's avatar
      livepatch: Remove Nop structures when unused · d697bad5
      Petr Mladek authored
      Replaced patches are removed from the stack when the transition is
      finished. It means that Nop structures will never be needed again
      and can be removed. Why should we care?
      
        + Nop structures give the impression that the function is patched
          even though the ftrace handler has no effect.
      
        + Ftrace handlers do not come for free. They cause slowdown that might
          be visible in some workloads. The ftrace-related slowdown might
          actually be the reason why the function is no longer patched in
          the new cumulative patch. One would expect that cumulative patch
          would help solve these problems as well.
      
        + Cumulative patches are supposed to replace any earlier version of
          the patch. The amount of NOPs depends on which version was replaced.
          This multiplies the amount of scenarios that might happen.
      
          One might say that NOPs are innocent. But there are even optimized
          NOP instructions for different processors, for example, see
          arch/x86/kernel/alternative.c. And klp_ftrace_handler() is much
          more complicated.
      
        + It sounds natural to clean up a mess that is no longer needed.
          It could only be worse if we do not do it.
      
      This patch allows to unpatch and free the dynamic structures independently
      when the transition finishes.
      
      The free part is a bit tricky because kobject free callbacks are called
      asynchronously. We could not wait for them easily. Fortunately, we do
      not have to. Any further access can be avoided by removing them from
      the dynamic lists.
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      d697bad5
    • Jason Baron's avatar
      livepatch: Add atomic replace · e1452b60
      Jason Baron authored
      Sometimes we would like to revert a particular fix. Currently, this
      is not easy because we want to keep all other fixes active and we
      could revert only the last applied patch.
      
      One solution would be to apply new patch that implemented all
      the reverted functions like in the original code. It would work
      as expected but there will be unnecessary redirections. In addition,
      it would also require knowing which functions need to be reverted at
      build time.
      
      Another problem is when there are many patches that touch the same
      functions. There might be dependencies between patches that are
      not enforced on the kernel side. Also it might be pretty hard to
      actually prepare the patch and ensure compatibility with the other
      patches.
      
      Atomic replace && cumulative patches:
      
      A better solution would be to create cumulative patch and say that
      it replaces all older ones.
      
      This patch adds a new "replace" flag to struct klp_patch. When it is
      enabled, a set of 'nop' klp_func will be dynamically created for all
      functions that are already being patched but that will no longer be
      modified by the new patch. They are used as a new target during
      the patch transition.
      
      The idea is to handle Nops' structures like the static ones. When
      the dynamic structures are allocated, we initialize all values that
      are normally statically defined.
      
      The only exception is "new_func" in struct klp_func. It has to point
      to the original function and the address is known only when the object
      (module) is loaded. Note that we really need to set it. The address is
      used, for example, in klp_check_stack_func().
      
      Nevertheless we still need to distinguish the dynamically allocated
      structures in some operations. For this, we add "nop" flag into
      struct klp_func and "dynamic" flag into struct klp_object. They
      need special handling in the following situations:
      
        + The structures are added into the lists of objects and functions
          immediately. In fact, the lists were created for this purpose.
      
        + The address of the original function is known only when the patched
          object (module) is loaded. Therefore it is copied later in
          klp_init_object_loaded().
      
        + The ftrace handler must not set PC to func->new_func. It would cause
          infinite loop because the address points back to the beginning of
          the original function.
      
        + The various free() functions must free the structure itself.
      
      Note that other ways to detect the dynamic structures are not considered
      safe. For example, even the statically defined struct klp_object might
      include empty funcs array. It might be there just to run some callbacks.
      
      Also note that the safe iterator must be used in the free() functions.
      Otherwise already freed structures might get accessed.
      
      Special callbacks handling:
      
      The callbacks from the replaced patches are _not_ called by intention.
      It would be pretty hard to define a reasonable semantic and implement it.
      
      It might even be counter-productive. The new patch is cumulative. It is
      supposed to include most of the changes from older patches. In most cases,
      it will not want to call pre_unpatch() post_unpatch() callbacks from
      the replaced patches. It would disable/break things for no good reasons.
      Also it should be easier to handle various scenarios in a single script
      in the new patch than think about interactions caused by running many
      scripts from older patches. Not to say that the old scripts even would
      not expect to be called in this situation.
      
      Removing replaced patches:
      
      One nice effect of the cumulative patches is that the code from the
      older patches is no longer used. Therefore the replaced patches can
      be removed. It has several advantages:
      
        + Nops' structs will no longer be necessary and might be removed.
          This would save memory, restore performance (no ftrace handler),
          allow clear view on what is really patched.
      
        + Disabling the patch will cause using the original code everywhere.
          Therefore the livepatch callbacks could handle only one scenario.
          Note that the complication is already complex enough when the patch
          gets enabled. It is currently solved by calling callbacks only from
          the new cumulative patch.
      
        + The state is clean in both the sysfs interface and lsmod. The modules
          with the replaced livepatches might even get removed from the system.
      
      Some people actually expected this behavior from the beginning. After all
      a cumulative patch is supposed to "completely" replace an existing one.
      It is like when a new version of an application replaces an older one.
      
      This patch does the first step. It removes the replaced patches from
      the list of patches. It is safe. The consistency model ensures that
      they are no longer used. By other words, each process works only with
      the structures from klp_transition_patch.
      
      The removal is done by a special function. It combines actions done by
      __disable_patch() and klp_complete_transition(). But it is a fast
      track without all the transaction-related stuff.
      Signed-off-by: default avatarJason Baron <jbaron@akamai.com>
      [pmladek@suse.com: Split, reuse existing code, simplified]
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Jiri Kosina <jikos@kernel.org>
      Cc: Miroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      e1452b60
    • Jason Baron's avatar
      livepatch: Use lists to manage patches, objects and functions · 20e55025
      Jason Baron authored
      Currently klp_patch contains a pointer to a statically allocated array of
      struct klp_object and struct klp_objects contains a pointer to a statically
      allocated array of klp_func. In order to allow for the dynamic allocation
      of objects and functions, link klp_patch, klp_object, and klp_func together
      via linked lists. This allows us to more easily allocate new objects and
      functions, while having the iterator be a simple linked list walk.
      
      The static structures are added to the lists early. It allows to add
      the dynamically allocated objects before klp_init_object() and
      klp_init_func() calls. Therefore it reduces the further changes
      to the code.
      
      This patch does not change the existing behavior.
      Signed-off-by: default avatarJason Baron <jbaron@akamai.com>
      [pmladek@suse.com: Initialize lists before init calls]
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Jiri Kosina <jikos@kernel.org>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      20e55025
    • Petr Mladek's avatar
      livepatch: Simplify API by removing registration step · 958ef1e3
      Petr Mladek authored
      The possibility to re-enable a registered patch was useful for immediate
      patches where the livepatch module had to stay until the system reboot.
      The improved consistency model allows to achieve the same result by
      unloading and loading the livepatch module again.
      
      Also we are going to add a feature called atomic replace. It will allow
      to create a patch that would replace all already registered patches.
      The aim is to handle dependent patches more securely. It will obsolete
      the stack of patches that helped to handle the dependencies so far.
      Then it might be unclear when a cumulative patch re-enabling is safe.
      
      It would be complicated to support the many modes. Instead we could
      actually make the API and code easier to understand.
      
      Therefore, remove the two step public API. All the checks and init calls
      are moved from klp_register_patch() to klp_enabled_patch(). Also the patch
      is automatically freed, including the sysfs interface when the transition
      to the disabled state is completed.
      
      As a result, there is never a disabled patch on the top of the stack.
      Therefore we do not need to check the stack in __klp_enable_patch().
      And we could simplify the check in __klp_disable_patch().
      
      Also the API and logic is much easier. It is enough to call
      klp_enable_patch() in module_init() call. The patch can be disabled
      by writing '0' into /sys/kernel/livepatch/<patch>/enabled. Then the module
      can be removed once the transition finishes and sysfs interface is freed.
      
      The only problem is how to free the structures and kobjects safely.
      The operation is triggered from the sysfs interface. We could not put
      the related kobject from there because it would cause lock inversion
      between klp_mutex and kernfs locks, see kn->count lockdep map.
      
      Therefore, offload the free task to a workqueue. It is perfectly fine:
      
        + The patch can no longer be used in the livepatch operations.
      
        + The module could not be removed until the free operation finishes
          and module_put() is called.
      
        + The operation is asynchronous already when the first
          klp_try_complete_transition() fails and another call
          is queued with a delay.
      Suggested-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      958ef1e3
    • Petr Mladek's avatar
      livepatch: Don't block the removal of patches loaded after a forced transition · 68007289
      Petr Mladek authored
      module_put() is currently never called in klp_complete_transition() when
      klp_force is set. As a result, we might keep the reference count even when
      klp_enable_patch() fails and klp_cancel_transition() is called.
      
      This might give the impression that a module might get blocked in some
      strange init state. Fortunately, it is not the case. The reference count
      is ignored when mod->init fails and erroneous modules are always removed.
      
      Anyway, this might be confusing. Instead, this patch moves
      the global klp_forced flag into struct klp_patch. As a result,
      we block only modules that might still be in use after a forced
      transition. Newly loaded livepatches might be eventually completely
      removed later.
      
      It is not a big deal. But the code is at least consistent with
      the reality.
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      68007289
    • Petr Mladek's avatar
      livepatch: Consolidate klp_free functions · 0430f78b
      Petr Mladek authored
      The code for freeing livepatch structures is a bit scattered and tricky:
      
        + direct calls to klp_free_*_limited() and kobject_put() are
          used to release partially initialized objects
      
        + klp_free_patch() removes the patch from the public list
          and releases all objects except for patch->kobj
      
        + object_put(&patch->kobj) and the related wait_for_completion()
          are called directly outside klp_mutex; this code is duplicated;
      
      Now, we are going to remove the registration stage to simplify the API
      and the code. This would require handling more situations in
      klp_enable_patch() error paths.
      
      More importantly, we are going to add a feature called atomic replace.
      It will need to dynamically create func and object structures. We will
      want to reuse the existing init() and free() functions. This would
      create even more error path scenarios.
      
      This patch implements more straightforward free functions:
      
        + checks kobj_added flag instead of @limit[*]
      
        + initializes patch->list early so that the check for empty list
          always works
      
        + The action(s) that has to be done outside klp_mutex are done
          in separate klp_free_patch_finish() function. It waits only
          when patch->kobj was really released via the _start() part.
      
      The patch does not change the existing behavior.
      
      [*] We need our own flag to track that the kobject was successfully
          added to the hierarchy.  Note that kobj.state_initialized only
          indicates that kobject has been initialized, not whether is has
          been added (and needs to be removed on cleanup).
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Miroslav Benes <mbenes@suse.cz>
      Cc: Jessica Yu <jeyu@kernel.org>
      Cc: Jiri Kosina <jikos@kernel.org>
      Cc: Jason Baron <jbaron@akamai.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      0430f78b
    • Petr Mladek's avatar
      livepatch: Shuffle klp_enable_patch()/klp_disable_patch() code · 26c3e98e
      Petr Mladek authored
      We are going to simplify the API and code by removing the registration
      step. This would require calling init/free functions from enable/disable
      ones.
      
      This patch just moves the code to prevent more forward declarations.
      
      This patch does not change the code except for two forward declarations.
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      26c3e98e
    • Petr Mladek's avatar
      livepatch: Change unsigned long old_addr -> void *old_func in struct klp_func · 19514910
      Petr Mladek authored
      The address of the to be patched function and new function is stored
      in struct klp_func as:
      
      	void *new_func;
      	unsigned long old_addr;
      
      The different naming scheme and type are derived from the way
      the addresses are set. @old_addr is assigned at runtime using
      kallsyms-based search. @new_func is statically initialized,
      for example:
      
        static struct klp_func funcs[] = {
      	{
      		.old_name = "cmdline_proc_show",
      		.new_func = livepatch_cmdline_proc_show,
      	}, { }
        };
      
      This patch changes unsigned long old_addr -> void *old_func. It removes
      some confusion when these address are later used in the code. It is
      motivated by a followup patch that adds special NOP struct klp_func
      where we want to assign func->new_func = func->old_addr respectively
      func->new_func = func->old_func.
      
      This patch does not modify the existing behavior.
      Suggested-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
      Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
      Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
      Acked-by: default avatarAlice Ferrazzi <alice.ferrazzi@gmail.com>
      Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      19514910
  3. 06 Jan, 2019 3 commits
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching · 1686cc1a
      Linus Torvalds authored
      Pull livepatch update from Jiri Kosina:
       "Return value checking fixup in livepatching samples, from Nicholas Mc
        Guire"
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
        livepatch: check kzalloc return values
      1686cc1a
    • Linus Torvalds's avatar
      Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux · 5c4a6083
      Linus Torvalds authored
      Pull thermal management updates from Zhang Rui:
      
       - Add locking for cooling device sysfs attribute in case the cooling
         device state is changed by userspace and thermal framework
         simultaneously. (Thara Gopinath)
      
       - Fix a problem that passive cooling is reset improperly after system
         suspend/resume. (Wei Wang)
      
       - Cleanup the driver/thermal/ directory by moving intel and qcom
         platform specific drivers to platform specific sub-directories. (Amit
         Kucheria)
      
       - Some trivial cleanups. (Lukasz Luba, Wolfram Sang)
      
      * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
        thermal/intel: fixup for Kconfig string parsing tightening up
        drivers: thermal: Move QCOM_SPMI_TEMP_ALARM into the qcom subdir
        drivers: thermal: Move various drivers for intel platforms into a subdir
        thermal: Fix locking in cooling device sysfs update cur_state
        Thermal: do not clear passive state during system sleep
        thermal: zx2967_thermal: simplify getting .driver_data
        thermal: st: st_thermal: simplify getting .driver_data
        thermal: spear_thermal: simplify getting .driver_data
        thermal: rockchip_thermal: simplify getting .driver_data
        thermal: int340x_thermal: int3400_thermal: simplify getting .driver_data
        thermal: remove unused function parameter
      5c4a6083
    • Linus Torvalds's avatar
      Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal · c2802302
      Linus Torvalds authored
      Pull thermal SoC updates from Eduardo Valentin:
      
       - Tegra DT binding documentation for Tegra194
      
       - Armada now supports ap806 and cp110
      
       - RCAR thermal now supports R8A774C0 and R8A77990
      
       - Fixes on thermal_hwmon, IMX, generic-ADC, ST, RCAR, Broadcom,
         Uniphier, QCOM, Tegra, PowerClamp, and Armada thermal drivers.
      
      * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal: (22 commits)
        thermal: generic-adc: Fix adc to temp interpolation
        thermal: rcar_thermal: add R8A77990 support
        dt-bindings: thermal: rcar-thermal: add R8A77990 support
        thermal: rcar_thermal: add R8A774C0 support
        dt-bindings: thermal: rcar-thermal: add R8A774C0 support
        dt-bindings: cp110: document the thermal interrupt capabilities
        dt-bindings: ap806: document the thermal interrupt capabilities
        MAINTAINERS: thermal: add entry for Marvell MVEBU thermal driver
        thermal: armada: add overheat interrupt support
        thermal: st: fix Makefile typo
        thermal: uniphier: Convert to SPDX identifier
        thermal/intel_powerclamp: Change to use DEFINE_SHOW_ATTRIBUTE macro
        thermal: tegra: soctherm: Change to use DEFINE_SHOW_ATTRIBUTE macro
        dt-bindings: thermal: tegra-bpmp: Add Tegra194 support
        thermal: imx: save one condition block for normal case of nvmem initialization
        thermal: imx: fix for dependency on cpu-freq
        thermal: tsens: qcom: do not create duplicate regmap debugfs entries
        thermal: armada: Use PTR_ERR_OR_ZERO in armada_thermal_probe_legacy()
        dt-bindings: thermal: rcar-gen3-thermal: All variants use 3 interrupts
        thermal: broadcom: use devm_thermal_zone_of_sensor_register
        ...
      c2802302
  4. 05 Jan, 2019 21 commits
    • Linus Torvalds's avatar
      Merge tag 'trace-v4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · a6701241
      Linus Torvalds authored
      Pull ftrace sh build fix from Steven Rostedt:
       "It appears that the zero-day bot did find a bug in my sh build.
      
        And that I didn't have the bad code in my config file when I cross
        compiled it, although there are a few other errors in sh that makes it
        not build for me, I missed that I added one more"
      
      * tag 'trace-v4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        sh: ftrace: Fix missing parenthesis in WARN_ON()
      a6701241
    • Linus Torvalds's avatar
      Merge tag '4.21-smb3-small-fixes' of git://git.samba.org/sfrench/cifs-2.6 · 7e928df8
      Linus Torvalds authored
      Pull smb3 fixes from Steve French:
       "Three fixes, one for stable, one adds the (most secure) SMB3.1.1
        dialect to default list requested"
      
      * tag '4.21-smb3-small-fixes' of git://git.samba.org/sfrench/cifs-2.6:
        smb3: add smb3.1.1 to default dialect list
        cifs: fix confusing warning message on reconnect
        smb3: fix large reads on encrypted connections
      7e928df8
    • Linus Torvalds's avatar
      Merge tag 'iomap-4.21-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux · 3cd6d495
      Linus Torvalds authored
      Pull iomap maintainer update from Darrick Wong:
       "Christoph Hellwig and I have decided to take responsibility for the fs
        iomap code rather than let it languish further"
      
      * tag 'iomap-4.21-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
        iomap: take responsibility for the filesystem iomap code
      3cd6d495
    • Linus Torvalds's avatar
      Merge tag 'xfs-4.21-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux · acda9efa
      Linus Torvalds authored
      Pull xfs fixlets from Darrick Wong:
       "Remove a couple of unnecessary local variables"
      
      * tag 'xfs-4.21-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
        xfs: xfs_fsops: drop useless LIST_HEAD
        xfs: xfs_buf: drop useless LIST_HEAD
      acda9efa
    • Linus Torvalds's avatar
      Merge tag 'ceph-for-4.21-rc1' of git://github.com/ceph/ceph-client · c7eaf342
      Linus Torvalds authored
      Pull ceph updates from Ilya Dryomov:
       "A fairly quiet round: a couple of messenger performance improvements
        from myself and a few cap handling fixes from Zheng"
      
      * tag 'ceph-for-4.21-rc1' of git://github.com/ceph/ceph-client:
        ceph: don't encode inode pathes into reconnect message
        ceph: update wanted caps after resuming stale session
        ceph: skip updating 'wanted' caps if caps are already issued
        ceph: don't request excl caps when mount is readonly
        ceph: don't update importing cap's mseq when handing cap export
        libceph: switch more to bool in ceph_tcp_sendmsg()
        libceph: use MSG_SENDPAGE_NOTLAST with ceph_tcp_sendpage()
        libceph: use sock_no_sendpage() as a fallback in ceph_tcp_sendpage()
        libceph: drop last_piece logic from write_partial_message_data()
        ceph: remove redundant assignment
        ceph: cleanup splice_dentry()
      c7eaf342
    • Olof Johansson's avatar
      lib/genalloc.c: include vmalloc.h · 35004f2e
      Olof Johansson authored
      Fixes build break on most ARM/ARM64 defconfigs:
      
        lib/genalloc.c: In function 'gen_pool_add_virt':
        lib/genalloc.c:190:10: error: implicit declaration of function 'vzalloc_node'; did you mean 'kzalloc_node'?
        lib/genalloc.c:190:8: warning: assignment to 'struct gen_pool_chunk *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
        lib/genalloc.c: In function 'gen_pool_destroy':
        lib/genalloc.c:254:3: error: implicit declaration of function 'vfree'; did you mean 'kfree'?
      
      Fixes: 6862d2fc ('lib/genalloc.c: use vzalloc_node() to allocate the bitmap')
      Cc: Huang Shijie <sjhuang@iluvatar.ai>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Alexey Skidanov <alexey.skidanov@intel.com>
      Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      35004f2e
    • Linus Torvalds's avatar
      Merge branch 'mount.part1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 505b050f
      Linus Torvalds authored
      Pull vfs mount API prep from Al Viro:
       "Mount API prereqs.
      
        Mostly that's LSM mount options cleanups. There are several minor
        fixes in there, but nothing earth-shattering (leaks on failure exits,
        mostly)"
      
      * 'mount.part1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (27 commits)
        mount_fs: suppress MAC on MS_SUBMOUNT as well as MS_KERNMOUNT
        smack: rewrite smack_sb_eat_lsm_opts()
        smack: get rid of match_token()
        smack: take the guts of smack_parse_opts_str() into a new helper
        LSM: new method: ->sb_add_mnt_opt()
        selinux: rewrite selinux_sb_eat_lsm_opts()
        selinux: regularize Opt_... names a bit
        selinux: switch away from match_token()
        selinux: new helper - selinux_add_opt()
        LSM: bury struct security_mnt_opts
        smack: switch to private smack_mnt_opts
        selinux: switch to private struct selinux_mnt_opts
        LSM: hide struct security_mnt_opts from any generic code
        selinux: kill selinux_sb_get_mnt_opts()
        LSM: turn sb_eat_lsm_opts() into a method
        nfs_remount(): don't leak, don't ignore LSM options quietly
        btrfs: sanitize security_mnt_opts use
        selinux; don't open-code a loop in sb_finish_set_opts()
        LSM: split ->sb_set_mnt_opts() out of ->sb_kern_mount()
        new helper: security_sb_eat_lsm_opts()
        ...
      505b050f
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 9b286efe
      Linus Torvalds authored
      Pull trivial vfs updates from Al Viro:
       "A few cleanups + Neil's namespace_unlock() optimization"
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        exec: make prepare_bprm_creds static
        genheaders: %-<width>s had been there since v6; %-*s - since v7
        VFS: use synchronize_rcu_expedited() in namespace_unlock()
        iov_iter: reduce code duplication
      9b286efe
    • Linus Torvalds's avatar
      Merge tag 'mips_fixes_4.21_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux · 47f3f4eb
      Linus Torvalds authored
      Pull MIPS fixes from Paul Burton:
       "A few early MIPS fixes for 4.21:
      
         - The Broadcom BCM63xx platform sees a fix for resetting the BCM6368
           ethernet switch, and the removal of a platform device we've never
           had a driver for.
      
         - The Alchemy platform sees a few fixes for bitrot that occurred
           within the past few cycles.
      
         - We now enable vectored interrupt support for the MediaTek MT7620
           SoC, which makes sense since they're supported by the SoC but in
           this case also works around a bug relating to the location of
           exception vectors when using a recent version of U-Boot.
      
         - The atomic64_fetch_*_relaxed() family of functions see a fix for a
           regression in MIPS64 kernels since v4.19.
      
         - Cavium Octeon III CN7xxx systems will now disable their RGMII
           interfaces rather than attempt to enable them & warn about the lack
           of support for doing so, as they did since initial CN7xxx ethernet
           support was added in v4.7.
      
         - The Microsemi/Microchip MSCC SoCs gain a MAINTAINERS entry.
      
         - .mailmap now provides consistency for Dengcheng Zhu's name &
           current email address"
      
      * tag 'mips_fixes_4.21_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
        MIPS: OCTEON: mark RGMII interface disabled on OCTEON III
        MIPS: Fix a R10000_LLSC_WAR logic in atomic.h
        MIPS: BCM63XX: drop unused and broken DSP platform device
        mailmap: Update name spelling and email for Dengcheng Zhu
        MIPS: ralink: Select CONFIG_CPU_MIPSR2_IRQ_VI on MT7620/8
        MAINTAINERS: Add a maintainer for MSCC MIPS SoCs
        MIPS: Alchemy: update dma masks for devboard devices
        MIPS: Alchemy: update cpu-feature-overrides
        MIPS: Alchemy: drop DB1000 IrDA support bits
        MIPS: alchemy: cpu_all_mask is forbidden for clock event devices
        MIPS: BCM63XX: fix switch core reset on BCM6368
      47f3f4eb
    • Linus Torvalds's avatar
      Merge tag 'powerpc-4.21-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · f1c2f885
      Linus Torvalds authored
      Pull powerpc fixes from Michael Ellerman:
       "A fix for the recent access_ok() change, which broke the build. We
        recently added a use of type in order to squash a warning elsewhere
        about type being unused.
      
        A handful of other minor build fixes, and one defconfig update.
      
        Thanks to: Christian Lamparter, Christophe Leroy, Diana Craciun,
        Mathieu Malaterre"
      
      * tag 'powerpc-4.21-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc: Drop use of 'type' from access_ok()
        KVM: PPC: Book3S HV: radix: Fix uninitialized var build error
        powerpc/configs: Add PPC4xx_OCM to ppc40x_defconfig
        powerpc/4xx/ocm: Fix phys_addr_t printf warnings
        powerpc/4xx/ocm: Fix compilation error due to PAGE_KERNEL usage
        powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'
      f1c2f885
    • Linus Torvalds's avatar
      Merge branch 'parisc-4.21-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux · cd08f68c
      Linus Torvalds authored
      Pull parisc fix from Helge Deller:
       "Fix boot issues with a series of parisc servers since kernel 4.20.
      
        Remapping kernel text with set_kernel_text_rw() missed to remap from
        lowest up until the highest huge-page aligned kernel text addresss"
      
      * 'parisc-4.21-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
        parisc: Remap hugepage-aligned pages in set_kernel_text_rw()
      cd08f68c
    • Linus Torvalds's avatar
      Merge tag 'for-4.21' of git://git.sourceforge.jp/gitroot/uclinux-h8/linux · 670b321f
      Linus Torvalds authored
      Pull h8300 fix from Yoshinori Sato:
       "Build problem fix"
      
      * tag 'for-4.21' of git://git.sourceforge.jp/gitroot/uclinux-h8/linux:
        h8300: pci: Remove local declaration of pcibios_penalize_isa_irq
      670b321f
    • Linus Torvalds's avatar
      Merge tag 'armsoc-late' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc · b23b0ea3
      Linus Torvalds authored
      Pull more ARM SoC updates from Olof Johansson:
       "A few updates that we merged late but are low risk for regressions for
        other platforms (and a few other straggling patches):
      
         - I mis-tagged the 'drivers' branch, and missed 3 patches. Merged in
           here. They're for a driver for the PL353 SRAM controller and a
           build fix for the qualcomm scm driver.
      
         - A new platform, RDA Micro RDA8810PL (Cortex-A5 w/ integrated
           Vivante GPU, 256MB RAM, Wifi). This includes some acked
           platform-specific drivers (serial, etc). This also include DTs for
           two boards with this SoC, OrangePi 2G and OrangePi i86.
      
         - i.MX8 is another new platform (NXP, 4x Cortex-A53 + Cortex-M4, 4K
           video playback offload). This is the first i.MX 64-bit SoC.
      
         - Some minor updates to Samsung boards (adding a few peripherals in
           DTs).
      
         - Small rework for SMP bootup on STi platforms.
      
         - A couple of TEE driver fixes.
      
         - A couple of new config options (bcm2835 thermal, Uniphier MDMAC)
           enabled in defconfigs"
      
      * tag 'armsoc-late' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (27 commits)
        ARM: multi_v7_defconfig: enable CONFIG_UNIPHIER_MDMAC
        arm64: defconfig: Re-enable bcm2835-thermal driver
        MAINTAINERS: Add entry for RDA Micro SoC architecture
        tty: serial: Add RDA8810PL UART driver
        ARM: dts: rda8810pl: Add interrupt support for UART
        dt-bindings: serial: Document RDA Micro UART
        ARM: dts: rda8810pl: Add timer support
        ARM: dts: Add devicetree for OrangePi i96 board
        ARM: dts: Add devicetree for OrangePi 2G IoT board
        ARM: dts: Add devicetree for RDA8810PL SoC
        ARM: Prepare RDA8810PL SoC
        dt-bindings: arm: Document RDA8810PL and reference boards
        dt-bindings: Add RDA Micro vendor prefix
        ARM: sti: remove pen_release and boot_lock
        arm64: dts: exynos: Add Bluetooth chip to TM2(e) boards
        arm64: dts: imx8mq-evk: enable watchdog
        arm64: dts: imx8mq: add watchdog devices
        MAINTAINERS: add i.MX8 DT path to i.MX architecture
        arm64: add support for i.MX8M EVK board
        arm64: add basic DTS for i.MX8MQ
        ...
      b23b0ea3
    • Linus Torvalds's avatar
      Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux · 078a5a4f
      Linus Torvalds authored
      Pull arm64 fixes from Will Deacon:
       "I'm safely chained back up to my desk, so please pull these arm64
        fixes for -rc1 that address some issues that cropped up during the
        merge window:
      
         - Prevent KASLR from mapping the top page of the virtual address
           space
      
         - Fix device-tree probing of SDEI driver
      
         - Fix incorrect register offset definition in Hisilicon DDRC PMU
           driver
      
         - Fix compilation issue with older binutils not liking unsigned
           immediates
      
         - Fix uapi headers so that libc can provide its own sigcontext
           definition
      
         - Fix handling of private compat syscalls
      
         - Hook up compat io_pgetevents() syscall for 32-bit tasks
      
         - Cleanup to arm64 Makefile (including now to avoid silly conflicts)"
      
      * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
        arm64: compat: Hook up io_pgetevents() for 32-bit tasks
        arm64: compat: Don't pull syscall number from regs in arm_compat_syscall
        arm64: compat: Avoid sending SIGILL for unallocated syscall numbers
        arm64/sve: Disentangle <uapi/asm/ptrace.h> from <uapi/asm/sigcontext.h>
        arm64/sve: ptrace: Fix SVE_PT_REGS_OFFSET definition
        drivers/perf: hisi: Fixup one DDRC PMU register offset
        arm64: replace arm64-obj-* in Makefile with obj-*
        arm64: kaslr: Reserve size of ARM64_MEMSTART_ALIGN in linear region
        firmware: arm_sdei: Fix DT platform device creation
        firmware: arm_sdei: fix wrong of_node_put() in init function
        arm64: entry: remove unused register aliases
        arm64: smp: Fix compilation error
      078a5a4f
    • Linus Torvalds's avatar
      Merge tag 'for-4.21' of git://git.armlinux.org.uk/~rmk/linux-arm · 1205b623
      Linus Torvalds authored
      Pull ARM updates from Russell King:
       "Included in this update:
      
         - Florian Fainelli noticed that userspace segfaults caused by the
           lack of kernel-userspace helpers was hard to diagnose; we now issue
           a warning when userspace tries to use the helpers but the kernel
           has them disabled.
      
         - Ben Dooks wants compatibility for the old ATAG serial number with
           DT systems.
      
         - Some cleanup of assembly by Nicolas Pitre.
      
         - User accessors optimisation from Vincent Whitchurch.
      
         - More robust kdump on SMP systems from Yufen Wang.
      
         - Sebastian Andrzej Siewior noticed problems with the SMP "boot_lock"
           on RT kernels, and so we convert the Versatile series of platforms
           to use a raw spinlock instead, consolidating the Versatile
           implementation. We entirely remove the boot_lock on OMAP systems,
           where it's unnecessary. Further patches for other systems will be
           submitted for the following merge window.
      
         - Start switching old StrongARM-11x0 systems to use gpiolib rather
           than their private GPIO implementation - mostly PCMCIA bits.
      
         - ARM Kconfig cleanups.
      
         - Cleanup a mostly harmless mistake in the recent Spectre patch in
           4.20 (which had the effect that data that can be placed into the
           init sections was incorrectly always placed in the rodata section)"
      
      * tag 'for-4.21' of git://git.armlinux.org.uk/~rmk/linux-arm: (25 commits)
        ARM: omap2: remove unnecessary boot_lock
        ARM: versatile: rename and comment SMP implementation
        ARM: versatile: convert boot_lock to raw
        ARM: vexpress/realview: consolidate immitation CPU hotplug
        ARM: fix the cockup in the previous patch
        ARM: sa1100/cerf: switch to using gpio_led_register_device()
        ARM: sa1100/assabet: switch to using gpio leds
        ARM: sa1100/assabet: add gpio keys support for right-hand two buttons
        ARM: sa1111: remove legacy GPIO interfaces
        pcmcia: sa1100*: remove redundant bvd1/bvd2 setting
        ARM: pxa/lubbock: switch PCMCIA to MAX1600 library
        ARM: pxa/mainstone: switch PCMCIA to MAX1600 library and gpiod APIs
        ARM: sa1100/neponset: switch PCMCIA to MAX1600 library and gpiod APIs
        ARM: sa1100/jornada720: switch PCMCIA to gpiod APIs
        pcmcia: add MAX1600 library
        ARM: sa1100: explicitly register sa11x0-pcmcia devices
        ARM: 8813/1: Make aligned 2-byte getuser()/putuser() atomic on ARMv6+
        ARM: 8812/1: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS
        ARM: 8811/1: always list both ldrd/strd registers explicitly
        ARM: 8808/1: kexec:offline panic_smp_self_stop CPU
        ...
      1205b623
    • Linus Torvalds's avatar
      Merge tag 'csky-for-linus-4.21' of git://github.com/c-sky/csky-linux · 9ee3b3f4
      Linus Torvalds authored
      Pull arch/csky updates from Guo Ren:
       "Here are three main features (cpu_hotplug, basic ftrace, basic perf)
        and some bugfixes:
      
        Features:
         - Add CPU-hotplug support for SMP
         - Add ftrace with function trace and function graph trace
         - Add Perf support
         - Add EM_CSKY_OLD 39
         - optimize kernel panic print.
         - remove syscall_exit_work
      
        Bugfixes:
         - fix abiv2 mmap(... O_SYNC) failure
         - fix gdb coredump error
         - remove vdsp implement for kernel
         - fix qemu failure to bootup sometimes
         - fix ftrace call-graph panic
         - fix device tree node reference leak
         - remove meaningless header-y
         - fix save hi,lo,dspcr regs in switch_stack
         - remove unused members in processor.h"
      
      * tag 'csky-for-linus-4.21' of git://github.com/c-sky/csky-linux:
        csky: Add perf support for C-SKY
        csky: Add EM_CSKY_OLD 39
        clocksource/drivers/c-sky: fixup ftrace call-graph panic
        csky: ftrace call graph supported.
        csky: basic ftrace supported
        csky: remove unused members in processor.h
        csky: optimize kernel panic print.
        csky: stacktrace supported.
        csky: CPU-hotplug supported for SMP
        clocksource/drivers/c-sky: fixup qemu fail to bootup sometimes.
        csky: fixup save hi,lo,dspcr regs in switch_stack.
        csky: remove syscall_exit_work
        csky: fixup remove vdsp implement for kernel.
        csky: bugfix gdb coredump error.
        csky: fixup abiv2 mmap(... O_SYNC) failed.
        csky: define syscall_get_arch()
        elf-em.h: add EM_CSKY
        csky: remove meaningless header-y
        csky: Don't leak device tree node reference
      9ee3b3f4
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · a6598110
      Linus Torvalds authored
      Merge more updates from Andrew Morton:
      
       - procfs updates
      
       - various misc bits
      
       - lib/ updates
      
       - epoll updates
      
       - autofs
      
       - fatfs
      
       - a few more MM bits
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (58 commits)
        mm/page_io.c: fix polled swap page in
        checkpatch: add Co-developed-by to signature tags
        docs: fix Co-Developed-by docs
        drivers/base/platform.c: kmemleak ignore a known leak
        fs: don't open code lru_to_page()
        fs/: remove caller signal_pending branch predictions
        mm/: remove caller signal_pending branch predictions
        arch/arc/mm/fault.c: remove caller signal_pending_branch predictions
        kernel/sched/: remove caller signal_pending branch predictions
        kernel/locking/mutex.c: remove caller signal_pending branch predictions
        mm: select HAVE_MOVE_PMD on x86 for faster mremap
        mm: speed up mremap by 20x on large regions
        mm: treewide: remove unused address argument from pte_alloc functions
        initramfs: cleanup incomplete rootfs
        scripts/gdb: fix lx-version string output
        kernel/kcov.c: mark write_comp_data() as notrace
        kernel/sysctl: add panic_print into sysctl
        panic: add options to print system info when panic happens
        bfs: extra sanity checking and static inode bitmap
        exec: separate MM_ANONPAGES and RLIMIT_STACK accounting
        ...
      a6598110
    • Christoph Hellwig's avatar
      ia64: fix compile without swiotlb · 3fed6ae4
      Christoph Hellwig authored
      Some non-generic ia64 configs don't build swiotlb, and thus should not
      pull in the generic non-coherent DMA infrastructure.
      
      Fixes: 68c60834 ("swiotlb: remove dma_mark_clean")
      Reported-by: default avatarTony Luck <tony.luck@gmail.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3fed6ae4
    • Linus Torvalds's avatar
      x86: re-introduce non-generic memcpy_{to,from}io · 170d13ca
      Linus Torvalds authored
      This has been broken forever, and nobody ever really noticed because
      it's purely a performance issue.
      
      Long long ago, in commit 6175ddf0 ("x86: Clean up mem*io functions")
      Brian Gerst simplified the memory copies to and from iomem, since on
      x86, the instructions to access iomem are exactly the same as the
      regular instructions.
      
      That is technically true, and things worked, and nobody said anything.
      Besides, back then the regular memcpy was pretty simple and worked fine.
      
      Nobody noticed except for David Laight, that is.  David has a testing a
      TLP monitor he was writing for an FPGA, and has been occasionally
      complaining about how memcpy_toio() writes things one byte at a time.
      
      Which is completely unacceptable from a performance standpoint, even if
      it happens to technically work.
      
      The reason it's writing one byte at a time is because while it's
      technically true that accesses to iomem are the same as accesses to
      regular memory on x86, the _granularity_ (and ordering) of accesses
      matter to iomem in ways that they don't matter to regular cached memory.
      
      In particular, when ERMS is set, we default to using "rep movsb" for
      larger memory copies.  That is indeed perfectly fine for real memory,
      since the whole point is that the CPU is going to do cacheline
      optimizations and executes the memory copy efficiently for cached
      memory.
      
      With iomem? Not so much.  With iomem, "rep movsb" will indeed work, but
      it will copy things one byte at a time. Slowly and ponderously.
      
      Now, originally, back in 2010 when commit 6175ddf0 was done, we
      didn't use ERMS, and this was much less noticeable.
      
      Our normal memcpy() was simpler in other ways too.
      
      Because in fact, it's not just about using the string instructions.  Our
      memcpy() these days does things like "read and write overlapping values"
      to handle the last bytes of the copy.  Again, for normal memory,
      overlapping accesses isn't an issue.  For iomem? It can be.
      
      So this re-introduces the specialized memcpy_toio(), memcpy_fromio() and
      memset_io() functions.  It doesn't particularly optimize them, but it
      tries to at least not be horrid, or do overlapping accesses.  In fact,
      this uses the existing __inline_memcpy() function that we still had
      lying around that uses our very traditional "rep movsl" loop followed by
      movsw/movsb for the final bytes.
      
      Somebody may decide to try to improve on it, but if we've gone almost a
      decade with only one person really ever noticing and complaining, maybe
      it's not worth worrying about further, once it's not _completely_ broken?
      Reported-by: default avatarDavid Laight <David.Laight@aculab.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      170d13ca
    • Linus Torvalds's avatar
      Use __put_user_goto in __put_user_size() and unsafe_put_user() · a959dc88
      Linus Torvalds authored
      This actually enables the __put_user_goto() functionality in
      unsafe_put_user().
      
      For an example of the effect of this, this is the code generated for the
      
              unsafe_put_user(signo, &infop->si_signo, Efault);
      
      in the waitid() system call:
      
      	movl %ecx,(%rbx)        # signo, MEM[(struct __large_struct *)_2]
      
      It's just one single store instruction, along with generating an
      exception table entry pointing to the Efault label case in case that
      instruction faults.
      
      Before, we would generate this:
      
      	xorl    %edx, %edx
      	movl %ecx,(%rbx)        # signo, MEM[(struct __large_struct *)_3]
              testl   %edx, %edx
              jne     .L309
      
      with the exception table generated for that 'mov' instruction causing us
      to jump to a stub that set %edx to -EFAULT and then jumped back to the
      'testl' instruction.
      
      So not only do we now get rid of the extra code in the normal sequence,
      we also avoid unnecessarily keeping that extra error register live
      across it all.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a959dc88
    • Linus Torvalds's avatar
      x86 uaccess: Introduce __put_user_goto · 4a789213
      Linus Torvalds authored
      This is finally the actual reason for the odd error handling in the
      "unsafe_get/put_user()" functions, introduced over three years ago.
      
      Using a "jump to error label" interface is somewhat odd, but very
      convenient as a programming interface, and more importantly, it fits
      very well with simply making the target be the exception handler address
      directly from the inline asm.
      
      The reason it took over three years to actually do this? We need "asm
      goto" support for it, which only became the default on x86 last year.
      It's now been a year that we've forced asm goto support (see commit
      e501ce95 "x86: Force asm-goto"), and so let's just do it here too.
      
      [ Side note: this commit was originally done back in 2016. The above
        commentary about timing is obviously about it only now getting merged
        into my real upstream tree     - Linus ]
      
      Sadly, gcc still only supports "asm goto" with asms that do not have any
      outputs, so we are limited to only the put_user case for this.  Maybe in
      several more years we can do the get_user case too.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4a789213
  5. 04 Jan, 2019 4 commits