commit e96ebd589debd9a6a793608c4ec7019c38785dea upstream.

This patch implements the __smp_store_release and __smp_load_acquire barriers
using ordered stores and loads.  This avoids the sync instruction present in
the generic implementation.

Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 157e9afcc4fa25068b0e8743bc254a9b56010e13 upstream.

This reverts commit 86d4d068df573a8c2105554624796c086d6bec3d.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 6e9f06ee6c9566f3606d93182ac8f803a148504b upstream.

This reverts commit 9e5c602186a692a7e848c0da17aed40f49d30519.
No need to use the ldcw instruction as SMP spinlock release barrier.
Revert it to gain back speed again.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit b344d6a83d01c52fddbefa6b3b4764da5b1022a0 ]

The kernel test bot reported[1] that using set_mask_bits on a u8 causes
the following issue on parisc:

	hppa-linux-ld: drivers/phy/ti/phy-tusb1210.o: in function `tusb1210_probe':
	>> (.text+0x2f4): undefined reference to `__cmpxchg_called_with_bad_pointer'
	>> hppa-linux-ld: (.text+0x324): undefined reference to `__cmpxchg_called_with_bad_pointer'
	hppa-linux-ld: (.text+0x354): undefined reference to `__cmpxchg_called_with_bad_pointer'

Add support for cmpxchg on u8 pointers.

[1] https://lore.kernel.org/patchwork/patch/1272617/#1468946

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Tested-by: Dave Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit be6577af0cef934ccb036445314072e8cb9217b9 upstream.

Stalls are quite frequent with recent kernels. I enabled
CONFIG_SOFTLOCKUP_DETECTOR and I caught the following stall:

watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [cc1:22803]
CPU: 0 PID: 22803 Comm: cc1 Not tainted 5.6.17+ #3
Hardware name: 9000/800/rp3440
 IAOQ[0]: d_alloc_parallel+0x384/0x688
 IAOQ[1]: d_alloc_parallel+0x388/0x688
 RP(r2): d_alloc_parallel+0x134/0x688
Backtrace:
 [<000000004036974c>] __lookup_slow+0xa4/0x200
 [<0000000040369fc8>] walk_component+0x288/0x458
 [<000000004036a9a0>] path_lookupat+0x88/0x198
 [<000000004036e748>] filename_lookup+0xa0/0x168
 [<000000004036e95c>] user_path_at_empty+0x64/0x80
 [<000000004035d93c>] vfs_statx+0x104/0x158
 [<000000004035dfcc>] __do_sys_lstat64+0x44/0x80
 [<000000004035e5a0>] sys_lstat64+0x20/0x38
 [<0000000040180054>] syscall_exit+0x0/0x14

The code was stuck in this loop in d_alloc_parallel:

    4037d414:   0e 00 10 dc     ldd 0(r16),ret0
    4037d418:   c7 fc 5f ed     bb,< ret0,1f,4037d414 <d_alloc_parallel+0x384>
    4037d41c:   08 00 02 40     nop

This is the inner loop of bit_spin_lock which is called by hlist_bl_unlock in
d_alloc_parallel:

static inline void bit_spin_lock(int bitnum, unsigned long *addr)
{
        /*
         * Assuming the lock is uncontended, this never enters
         * the body of the outer loop. If it is contended, then
         * within the inner loop a non-atomic test is used to
         * busywait with less bus contention for a good time to
         * attempt to acquire the lock bit.
         */
        preempt_disable();
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
        while (unlikely(test_and_set_bit_lock(bitnum, addr))) {
                preempt_enable();
                do {
                        cpu_relax();
                } while (test_bit(bitnum, addr));
                preempt_disable();
        }
#endif
        __acquire(bitlock);
}

After consideration, I realized that we must be losing bit unlocks.
Then, I noticed that we missed defining atomic64_set_release().
Adding this define fixes the stalls in bit operations.

Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 75cf9797006a3a9f29a3a25c1febd6842a4a9eb2 ]

Fix this compiler warning:
kernel/debug/debug_core.c: In function ‘kgdb_cpu_enter’:
arch/parisc/include/asm/cmpxchg.h:48:3: warning: value computed is not used [-Wunused-value]
   48 |  ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
arch/parisc/include/asm/atomic.h:78:30: note: in expansion of macro ‘xchg’
   78 | #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
      |                              ^~~~
kernel/debug/debug_core.c:596:4: note: in expansion of macro ‘atomic_xchg’
  596 |    atomic_xchg(&kgdb_active, cpu);
      |    ^~~~~~~~~~~

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit e16260c21f87b16a33ae8ecac9e8c79f3a8b89bd ]

Fix compilation when the CONFIG_KEXEC_FILE=y and
CONFIG_KEXEC=n.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Helge Deller <deller@gmx.de>

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 <rppt@linux.ibm.com>
Acked-by: Will Deacon <will@kernel.org>		[arm64]
Acked-by: Thomas Gleixner <tglx@linutronix.de>	[x86]
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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 <npiggin@gmail.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>