linux-stable.git/arch/nds32, branch linux-5.4.y

arch, mm: remove stale mentions of DISCONIGMEM

2024-02-23T07:25:13+00:00

[ Upstream commit d3c251ab95b69f3dc189c4657baeac1b4c050789 ]

There are several places that mention DISCONIGMEM in comments or have
stale code guarded by CONFIG_DISCONTIGMEM.

Remove the dead code and update the comments.

Link: https://lkml.kernel.org/r/20210608091316.3622-7-rppt@kernel.org
Signed-off-by: Mike Rapoport 
Acked-by: Arnd Bergmann 
Reviewed-by: David Hildenbrand 
Cc: Geert Uytterhoeven 
Cc: Ivan Kokshaysky 
Cc: Jonathan Corbet 
Cc: Matt Turner 
Cc: Richard Henderson 
Cc: Vineet Gupta 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Stable-dep-of: e1a9ae457369 ("mips: Fix max_mapnr being uninitialized on early stages")
Signed-off-by: Sasha Levin

dma-mapping: drop the dev argument to arch_sync_dma_for_*

2023-04-05T09:16:43+00:00

[ Upstream commit 56e35f9c5b87ec1ae93e483284e189c84388de16 ]

These are pure cache maintainance routines, so drop the unused
struct device argument.

Signed-off-by: Christoph Hellwig 
Suggested-by: Daniel Vetter 
Stable-dep-of: ab327f8acdf8 ("mips: bmips: BCM6358: disable RAC flush for TP1")
Signed-off-by: Sasha Levin

exit: Add and use make_task_dead.

2023-02-06T06:52:49+00:00

commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Eric Biggers 
Signed-off-by: Sasha Levin

nds32: fix access_ok() checks in get/put_user

2022-03-28T06:46:48+00:00

commit 8926d88ced46700bf6117ceaf391480b943ea9f4 upstream.

The get_user()/put_user() functions are meant to check for
access_ok(), while the __get_user()/__put_user() functions
don't.

This broke in 4.19 for nds32, when it gained an extraneous
check in __get_user(), but lost the check it needs in
__put_user().

Fixes: 487913ab18c2 ("nds32: Extract the checking and getting pointer to a macro")
Cc: stable@vger.kernel.org @ v4.19+
Reviewed-by: Christoph Hellwig 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

perf: Protect perf_guest_cbs with RCU

2022-01-20T08:19:18+00:00

commit ff083a2d972f56bebfd82409ca62e5dfce950961 upstream.

Protect perf_guest_cbs with RCU to fix multiple possible errors.  Luckily,
all paths that read perf_guest_cbs already require RCU protection, e.g. to
protect the callback chains, so only the direct perf_guest_cbs touchpoints
need to be modified.

Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure
perf_guest_cbs isn't reloaded between a !NULL check and a dereference.
Fixed via the READ_ONCE() in rcu_dereference().

Bug #2 is that on weakly-ordered architectures, updates to the callbacks
themselves are not guaranteed to be visible before the pointer is made
visible to readers.  Fixed by the smp_store_release() in
rcu_assign_pointer() when the new pointer is non-NULL.

Bug #3 is that, because the callbacks are global, it's possible for
readers to run in parallel with an unregisters, and thus a module
implementing the callbacks can be unloaded while readers are in flight,
resulting in a use-after-free.  Fixed by a synchronize_rcu() call when
unregistering callbacks.

Bug #1 escaped notice because it's extremely unlikely a compiler will
reload perf_guest_cbs in this sequence.  perf_guest_cbs does get reloaded
for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest()
guard all but guarantees the consumer will win the race, e.g. to nullify
perf_guest_cbs, KVM has to completely exit the guest and teardown down
all VMs before KVM start its module unload / unregister sequence.  This
also makes it all but impossible to encounter bug #3.

Bug #2 has not been a problem because all architectures that register
callbacks are strongly ordered and/or have a static set of callbacks.

But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping
perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming
kvm_intel module load/unload leads to:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT SMP
  CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:perf_misc_flags+0x1c/0x70
  Call Trace:
   perf_prepare_sample+0x53/0x6b0
   perf_event_output_forward+0x67/0x160
   __perf_event_overflow+0x52/0xf0
   handle_pmi_common+0x207/0x300
   intel_pmu_handle_irq+0xcf/0x410
   perf_event_nmi_handler+0x28/0x50
   nmi_handle+0xc7/0x260
   default_do_nmi+0x6b/0x170
   exc_nmi+0x103/0x130
   asm_exc_nmi+0x76/0xbf

Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host")
Signed-off-by: Sean Christopherson 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Paolo Bonzini 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman

nds32: fix up stack guard gap

2021-07-28T11:31:01+00:00

commit c453db6cd96418c79702eaf38259002755ab23ff upstream.

Commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas") fixed
up all architectures to deal with the stack guard gap.  But when nds32
was added to the tree, it forgot to do the same thing.

Resolve this by properly fixing up the nsd32's version of
arch_get_unmapped_area()

Cc: Nick Hu 
Cc: Greentime Hu 
Cc: Vincent Chen 
Cc: Michal Hocko 
Cc: Hugh Dickins 
Cc: Qiang Liu 
Cc: stable 
Reported-by: iLifetruth 
Acked-by: Hugh Dickins 
Link: https://lore.kernel.org/r/20210629104024.2293615-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

nds32: flush_dcache_page: use page_mapping_file to avoid races with swapoff

2021-04-14T06:24:10+00:00

commit a3a8833dffb7e7329c2586b8bfc531adb503f123 upstream.

Commit cb9f753a3731 ("mm: fix races between swapoff and flush dcache")
updated flush_dcache_page implementations on several architectures to
use page_mapping_file() in order to avoid races between page_mapping()
and swapoff().

This update missed arch/nds32 and there is a possibility of a race
there.

Replace page_mapping() with page_mapping_file() in nds32 implementation
of flush_dcache_page().

Link: https://lkml.kernel.org/r/20210330175126.26500-1-rppt@kernel.org
Fixes: cb9f753a3731 ("mm: fix races between swapoff and flush dcache")
Signed-off-by: Mike Rapoport 
Reviewed-by: Matthew Wilcox (Oracle) 
Acked-by: Greentime Hu 
Cc: Huang Ying 
Cc: Nick Hu 
Cc: Vincent Chen 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

asm-generic/nds32: don't redefine cacheflush primitives

2020-01-17T18:48:43+00:00

commit 4f0bd808134d73184054ad09173821c84f31dd5d upstream.

The commit c296d4dc13ae ("asm-generic: fix a compilation warning") changed
asm-generic/cachflush.h to use static inlines instead of macros and as a
result the nds32 build with CONFIG_CPU_CACHE_ALIASING=n fails:

  CC      init/main.o
In file included from arch/nds32/include/asm/cacheflush.h:43,
                 from include/linux/highmem.h:12,
                 from include/linux/pagemap.h:11,
                 from include/linux/blkdev.h:16,
                 from include/linux/blk-cgroup.h:23,
                 from include/linux/writeback.h:14,
                 from init/main.c:44:
include/asm-generic/cacheflush.h:50:20: error: static declaration of 'flush_icache_range' follows non-static declaration
 static inline void flush_icache_range(unsigned long start, unsigned long end)
                    ^~~~~~~~~~~~~~~~~~
In file included from include/linux/highmem.h:12,
                 from include/linux/pagemap.h:11,
                 from include/linux/blkdev.h:16,
                 from include/linux/blk-cgroup.h:23,
                 from include/linux/writeback.h:14,
                 from init/main.c:44:
arch/nds32/include/asm/cacheflush.h:11:6: note: previous declaration of 'flush_icache_range' was here
 void flush_icache_range(unsigned long start, unsigned long end);
      ^~~~~~~~~~~~~~~~~~

Surround the inline functions in asm-generic/cacheflush.h by ifdef's so
that architectures could override them and add the required overrides to
nds32.

Fixes: c296d4dc13ae ("asm-generic: fix a compilation warning")
Link: https://lore.kernel.org/lkml/201912212139.yptX8CsV%25lkp@intel.com/
Reported-by: kbuild test robot 
Signed-off-by: Mike Rapoport 
Reviewed-by: Greentime Hu 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

mm: consolidate pgtable_cache_init() and pgd_cache_init()

2019-09-24T22:54:09+00:00

Both pgtable_cache_init() and pgd_cache_init() are used to initialize kmem
cache for page table allocations on several architectures that do not use
PAGE_SIZE tables for one or more levels of the page table hierarchy.

Most architectures do not implement these functions and use __weak default
NOP implementation of pgd_cache_init().  Since there is no such default
for pgtable_cache_init(), its empty stub is duplicated among most
architectures.

Rename the definitions of pgd_cache_init() to pgtable_cache_init() and
drop empty stubs of pgtable_cache_init().

Link: http://lkml.kernel.org/r/1566457046-22637-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport 
Acked-by: Will Deacon 		[arm64]
Acked-by: Thomas Gleixner 	[x86]
Cc: Catalin Marinas 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove quicklist page table caches

2019-09-24T22:54:09+00:00

Patch series "mm: remove quicklist page table caches".

A while ago Nicholas proposed to remove quicklist page table caches [1].

I've rebased his patch on the curren upstream and switched ia64 and sh to
use generic versions of PTE allocation.

[1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com

This patch (of 3):

Remove page table allocator "quicklists".  These have been around for a
long time, but have not got much traction in the last decade and are only
used on ia64 and sh architectures.

The numbers in the initial commit look interesting but probably don't
apply anymore.  If anybody wants to resurrect this it's in the git
history, but it's unhelpful to have this code and divergent allocator
behaviour for minor archs.

Also it might be better to instead make more general improvements to page
allocator if this is still so slow.

Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com
Signed-off-by: Nicholas Piggin 
Signed-off-by: Mike Rapoport 
Cc: Tony Luck 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds