Update the fscrypt documentation file for inline encryption support.
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Link: https://lore.kernel.org/r/20200724184501.1651378-7-satyat@google.comSigned-off-by: Eric Biggers <ebiggers@google.com>

Normally smp_store_release() or cmpxchg_release() is paired with
smp_load_acquire().  Sometimes smp_load_acquire() can be replaced with
the more lightweight READ_ONCE().  However, for this to be safe, all the
published memory must only be accessed in a way that involves the
pointer itself.  This may not be the case if allocating the object also
involves initializing a static or global variable, for example.

fscrypt_info includes various sub-objects which are internal to and are
allocated by other kernel subsystems such as keyrings and crypto.  So by
using READ_ONCE() for ->i_crypt_info, we're relying on internal
implementation details of these other kernel subsystems.

Remove this fragile assumption by using smp_load_acquire() instead.

(Note: I haven't seen any real-world problems here.  This change is just
fixing the code to be guaranteed correct and less fragile.)

Fixes: e37a784d ("fscrypt: use READ_ONCE() to access ->i_crypt_info")
Link: https://lore.kernel.org/r/20200721225920.114347-5-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

Normally smp_store_release() or cmpxchg_release() is paired with
smp_load_acquire().  Sometimes smp_load_acquire() can be replaced with
the more lightweight READ_ONCE().  However, for this to be safe, all the
published memory must only be accessed in a way that involves the
pointer itself.  This may not be the case if allocating the object also
involves initializing a static or global variable, for example.

super_block::s_master_keys is a keyring, which is internal to and is
allocated by the keyrings subsystem.  By using READ_ONCE() for it, we're
relying on internal implementation details of the keyrings subsystem.

Remove this fragile assumption by using smp_load_acquire() instead.

(Note: I haven't seen any real-world problems here.  This change is just
fixing the code to be guaranteed correct and less fragile.)

Fixes: 22d94f49 ("fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl")
Link: https://lore.kernel.org/r/20200721225920.114347-4-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

Normally smp_store_release() or cmpxchg_release() is paired with
smp_load_acquire().  Sometimes smp_load_acquire() can be replaced with
the more lightweight READ_ONCE().  However, for this to be safe, all the
published memory must only be accessed in a way that involves the
pointer itself.  This may not be the case if allocating the object also
involves initializing a static or global variable, for example.

fscrypt_prepared_key includes a pointer to a crypto_skcipher object,
which is internal to and is allocated by the crypto subsystem.  By using
READ_ONCE() for it, we're relying on internal implementation details of
the crypto subsystem.

Remove this fragile assumption by using smp_load_acquire() instead.

(Note: I haven't seen any real-world problems here.  This change is just
fixing the code to be guaranteed correct and less fragile.)

Fixes: 5fee3609 ("fscrypt: add inline encryption support")
Cc: Satya Tangirala <satyat@google.com>
Link: https://lore.kernel.org/r/20200721225920.114347-3-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

fscrypt_do_sha256() is only used for hashing encrypted filenames to
create no-key tokens, which isn't performance-critical.  Therefore a C
implementation of SHA-256 is sufficient.

Also, the logic to create no-key tokens is always potentially needed.
This differs from fscrypt's other dependencies on crypto API algorithms,
which are conditionally needed depending on what encryption policies
userspace is using.  Therefore, for fscrypt there isn't much benefit to
allowing SHA-256 to be a loadable module.

So, make fscrypt_do_sha256() use the SHA-256 library instead of the
crypto_shash API.  This is much simpler, since it avoids having to
implement one-time-init (which is hard to do correctly, and in fact was
implemented incorrectly) and handle failures to allocate the
crypto_shash object.

Fixes: edc440e3 ("fscrypt: improve format of no-key names")
Cc: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20200721225920.114347-2-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

IV_INO_LBLK_* exist only because of hardware limitations, and currently
the only known use case for them involves AES-256-XTS.  Therefore, for
now only allow them in combination with AES-256-XTS.  This way we don't
have to worry about them being combined with other encryption modes.

(To be clear, combining IV_INO_LBLK_* with other encryption modes
*should* work just fine.  It's just not being tested, so we can't be
100% sure it works.  So with no known use case, it's best to disallow it
for now, just like we don't allow other weird combinations like
AES-256-XTS contents encryption with Adiantum filenames encryption.)

This can be relaxed later if a use case for other combinations arises.

Fixes: b103fb76 ("fscrypt: add support for IV_INO_LBLK_64 policies")
Fixes: e3b1078b ("fscrypt: add support for IV_INO_LBLK_32 policies")
Link: https://lore.kernel.org/r/20200721181012.39308-1-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

The name "FS_KEY_DERIVATION_NONCE_SIZE" is a bit outdated since due to
the addition of FSCRYPT_POLICY_FLAG_DIRECT_KEY, the file nonce may now
be used as a tweak instead of for key derivation.  Also, we're now
prefixing the fscrypt constants with "FSCRYPT_" instead of "FS_".

Therefore, rename this constant to FSCRYPT_FILE_NONCE_SIZE.

Link: https://lore.kernel.org/r/20200708215722.147154-1-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

Each HKDF context byte is associated with a specific format of the
remaining part of the application-specific info string.  Add comments so
that it's easier to keep track of what these all are.

Link: https://lore.kernel.org/r/20200708215529.146890-1-ebiggers@kernel.orgSigned-off-by: Eric Biggers <ebiggers@google.com>

Wire up ext4 to support inline encryption via the helper functions which
fs/crypto/ now provides.  This includes:

- Adding a mount option 'inlinecrypt' which enables inline encryption
  on encrypted files where it can be used.

- Setting the bio_crypt_ctx on bios that will be submitted to an
  inline-encrypted file.

  Note: submit_bh_wbc() in fs/buffer.c also needed to be patched for
  this part, since ext4 sometimes uses ll_rw_block() on file data.

- Not adding logically discontiguous data to bios that will be submitted
  to an inline-encrypted file.

- Not doing filesystem-layer crypto on inline-encrypted files.
Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20200702015607.1215430-5-satyat@google.comSigned-off-by: Eric Biggers <ebiggers@google.com>

Wire up f2fs to support inline encryption via the helper functions which
fs/crypto/ now provides.  This includes:

- Adding a mount option 'inlinecrypt' which enables inline encryption
  on encrypted files where it can be used.

- Setting the bio_crypt_ctx on bios that will be submitted to an
  inline-encrypted file.

- Not adding logically discontiguous data to bios that will be submitted
  to an inline-encrypted file.

- Not doing filesystem-layer crypto on inline-encrypted files.

This patch includes a fix for a race during IPU by
Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Satya Tangirala <satyat@google.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20200702015607.1215430-4-satyat@google.comCo-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>

Add support for inline encryption to fs/crypto/.  With "inline
encryption", the block layer handles the decryption/encryption as part
of the bio, instead of the filesystem doing the crypto itself via
Linux's crypto API. This model is needed in order to take advantage of
the inline encryption hardware present on most modern mobile SoCs.

To use inline encryption, the filesystem needs to be mounted with
'-o inlinecrypt'. Blk-crypto will then be used instead of the traditional
filesystem-layer crypto whenever possible to encrypt the contents
of any encrypted files in that filesystem. Fscrypt still provides the key
and IV to use, and the actual ciphertext on-disk is still the same;
therefore it's testable using the existing fscrypt ciphertext verification
tests.

Note that since blk-crypto has a fallback to Linux's crypto API, and
also supports all the encryption modes currently supported by fscrypt,
this feature is usable and testable even without actual inline
encryption hardware.

Per-filesystem changes will be needed to set encryption contexts when
submitting bios and to implement the 'inlinecrypt' mount option.  This
patch just adds the common code.
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20200702015607.1215430-3-satyat@google.comCo-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>

Introduce SB_INLINECRYPT, which is set by filesystems that wish to use
blk-crypto for file content en/decryption. This flag maps to the
'-o inlinecrypt' mount option which multiple filesystems will implement,
and code in fs/crypto/ needs to be able to check for this mount option
in a filesystem-independent way.
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20200702015607.1215430-2-satyat@google.comSigned-off-by: Eric Biggers <ebiggers@google.com>

Using a mutex for "print this warning only once" is so overdesigned as
to be actively offensive to my sensitive stomach.

Just use "pr_info_once()" that already does this, although in a
(harmlessly) racy manner that can in theory cause the message to be
printed twice if more than one CPU races on that "is this the first
time" test.

[ If somebody really cares about that harmless data race (which sounds
  very unlikely indeed), that person can trivially fix printk_once() by
  using a simple atomic access, preferably with an optimistic non-atomic
  test first before even bothering to treat the pointless "make sure it
  is _really_ just once" case.

  A mutex is most definitely never the right primitive to use for
  something like this. ]

Yes, this is a small and meaningless detail in a code path that hardly
matters.  But let's keep some code quality standards here, and not
accept outrageously bad code.

Link: https://lore.kernel.org/lkml/CAHk-=wgV9toS7GU3KmNpj8hCS9SeF+A0voHS8F275_mgLhL4Lw@mail.gmail.com/
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull x86 fixes from Thomas Gleixner:
 "A series of fixes for x86:

   - Reset MXCSR in kernel_fpu_begin() to prevent using a stale user
     space value.

   - Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly
     whitelisted for split lock detection. Some CPUs which do not
     support it crash even when the MSR is written to 0 which is the
     default value.

   - Fix the XEN PV fallout of the entry code rework

   - Fix the 32bit fallout of the entry code rework

   - Add more selftests to ensure that these entry problems don't come
     back.

   - Disable 16 bit segments on XEN PV. It's not supported because XEN
     PV does not implement ESPFIX64"

* tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ldt: Disable 16-bit segments on Xen PV
  x86/entry/32: Fix #MC and #DB wiring on x86_32
  x86/entry/xen: Route #DB correctly on Xen PV
  x86/entry, selftests: Further improve user entry sanity checks
  x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER
  selftests/x86: Consolidate and fix get/set_eflags() helpers
  selftests/x86/syscall_nt: Clear weird flags after each test
  selftests/x86/syscall_nt: Add more flag combinations
  x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
  x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C
  x86/entry: Assert that syscalls are on the right stack
  x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted
  x86/fpu: Reset MXCSR to default in kernel_fpu_begin()

Pull irq fixes from Thomas Gleixner:
 "A set of interrupt chip driver fixes:

   - Ensure the atomicity of affinity updates in the GIC driver

   - Don't try to sleep in atomic context when waiting for the GICv4.1
     to respond. Use polling instead.

   - Typo fixes in Kconfig and warnings"

* tag 'irq-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic: Atomically update affinity
  irqchip/riscv-intc: Fix a typo in a pr_warn()
  irqchip/gic-v4.1: Use readx_poll_timeout_atomic() to fix sleep in atomic
  irqchip/loongson-pci-msi: Fix a typo in Kconfig

Pull rcu fixlet from Thomas Gleixner:
 "A single fix for a printk format warning in RCU"

* tag 'core-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcuperf: Fix printk format warning

Merge tag 'kbuild-fixes-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes frin Masahiro Yamada:

 - fix various bugs in xconfig

 - fix some issues in cross-compilation using Clang

 - fix documentation

* tag 'kbuild-fixes-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  .gitignore: Do not track `defconfig` from `make savedefconfig`
  kbuild: make Clang build userprogs for target architecture
  kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang
  kconfig: qconf: parse newer types at debug info
  kconfig: qconf: navigate menus on hyperlinks
  kconfig: qconf: don't show goback button on splitMode
  kconfig: qconf: simplify the goBack() logic
  kconfig: qconf: re-implement setSelected()
  kconfig: qconf: make debug links work again
  kconfig: qconf: make search fully work again on split mode
  kconfig: qconf: cleanup includes
  docs: kbuild: fix ReST formatting
  gcc-plugins: fix gcc-plugins directory path in documentation

Pull SCSI fixes from James Bottomley:
 "Four small fixes in three drivers.

  The mptfusion one has actually caused user visible issues in certain
  kernel configurations"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: mptfusion: Don't use GFP_ATOMIC for larger DMA allocations
  scsi: libfc: Skip additional kref updating work event
  scsi: libfc: Handling of extra kref
  scsi: qla2xxx: Fix a condition in qla2x00_find_all_fabric_devs()

Pull block fixes from Jens Axboe:

 - NVMe fixes from Christoph:
    - Fix crash in multi-path disk add (Christoph)
    - Fix ignore of identify error (Sagi)

 - Fix a compiler complaint that a function should be static (Wei)

* tag 'block-5.8-2020-07-05' of git://git.kernel.dk/linux-block:
  block: make function __bio_integrity_free() static
  nvme: fix a crash in nvme_mpath_add_disk
  nvme: fix identify error status silent ignore

Pull io_uring fix from Jens Axboe:
 "Andres reported a regression with the fix that was merged earlier this
  week, where his setup of using signals to interrupt io_uring CQ waits
  no longer worked correctly.

  Fix this, and also limit our use of TWA_SIGNAL to the case where we
  need it, and continue using TWA_RESUME for task_work as before.

  Since the original is marked for 5.7 stable, let's flush this one out
  early"

* tag 'io_uring-5.8-2020-07-05' of git://git.kernel.dk/linux-block:
  io_uring: fix regression with always ignoring signals in io_cqring_wait()

Pull i2c fixes from Wolfram Sang:
 "The usual driver fixes and documentation updates"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: mlxcpld: check correct size of maximum RECV_LEN packet
  i2c: add Kconfig help text for slave mode
  i2c: slave-eeprom: update documentation
  i2c: eg20t: Load module automatically if ID matches
  i2c: designware: platdrv: Set class based on DMI
  i2c: algo-pca: Add 0x78 as SCL stuck low status for PCA9665

Pull MIPS fixes from Thomas Bogendoerfer:

 - fix for missing hazard barrier

 - DT fix for ingenic

 - DT fix of GPHY names for lantiq

 - fix usage of smp_processor_id() while preemption is enabled

* tag 'mips_fixes_5.8_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: Do not use smp_processor_id() in preemptible code
  MIPS: Add missing EHB in mtc0 -> mfc0 sequence for DSPen
  MIPS: ingenic: gcw0: Fix HP detection GPIO.
  MIPS: lantiq: xway: sysctrl: fix the GPHY clock alias names

Use preempt_disable() to fix the following bug under CONFIG_DEBUG_PREEMPT.

[   21.915305] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-mip/1056
[   21.923996] caller is do_ri+0x1d4/0x690
[   21.927921] CPU: 0 PID: 1056 Comm: qemu-system-mip Not tainted 5.8.0-rc2 #3
[   21.934913] Stack : 0000000000000001 ffffffff81370000 ffffffff8071cd60 a80f926d5ac95694
[   21.942984]         a80f926d5ac95694 0000000000000000 98000007f0043c88 ffffffff80f2fe40
[   21.951054]         0000000000000000 0000000000000000 0000000000000001 0000000000000000
[   21.959123]         ffffffff802d60cc 98000007f0043dd8 ffffffff81f4b1e8 ffffffff81f60000
[   21.967192]         ffffffff81f60000 ffffffff80fe0000 ffff000000000000 0000000000000000
[   21.975261]         fffffffff500cce1 0000000000000001 0000000000000002 0000000000000000
[   21.983331]         ffffffff80fe1a40 0000000000000006 ffffffff8077f940 0000000000000000
[   21.991401]         ffffffff81460000 98000007f0040000 98000007f0043c80 000000fffba8cf20
[   21.999471]         ffffffff8071cd60 0000000000000000 0000000000000000 0000000000000000
[   22.007541]         0000000000000000 0000000000000000 ffffffff80212ab4 a80f926d5ac95694
[   22.015610]         ...
[   22.018086] Call Trace:
[   22.020562] [<ffffffff80212ab4>] show_stack+0xa4/0x138
[   22.025732] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
[   22.030903] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
[   22.037375] [<ffffffff80213b84>] do_ri+0x1d4/0x690
[   22.042198] [<ffffffff8020b828>] handle_ri_int+0x44/0x5c
[   24.359386] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-mip/1072
[   24.368204] caller is do_ri+0x1a8/0x690
[   24.372169] CPU: 4 PID: 1072 Comm: qemu-system-mip Not tainted 5.8.0-rc2 #3
[   24.379170] Stack : 0000000000000001 ffffffff81370000 ffffffff8071cd60 a80f926d5ac95694
[   24.387246]         a80f926d5ac95694 0000000000000000 98001007ef06bc88 ffffffff80f2fe40
[   24.395318]         0000000000000000 0000000000000000 0000000000000001 0000000000000000
[   24.403389]         ffffffff802d60cc 98001007ef06bdd8 ffffffff81f4b818 ffffffff81f60000
[   24.411461]         ffffffff81f60000 ffffffff80fe0000 ffff000000000000 0000000000000000
[   24.419533]         fffffffff500cce1 0000000000000001 0000000000000002 0000000000000000
[   24.427603]         ffffffff80fe0000 0000000000000006 ffffffff8077f940 0000000000000020
[   24.435673]         ffffffff81460020 98001007ef068000 98001007ef06bc80 000000fffbbbb370
[   24.443745]         ffffffff8071cd60 0000000000000000 0000000000000000 0000000000000000
[   24.451816]         0000000000000000 0000000000000000 ffffffff80212ab4 a80f926d5ac95694
[   24.459887]         ...
[   24.462367] Call Trace:
[   24.464846] [<ffffffff80212ab4>] show_stack+0xa4/0x138
[   24.470029] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
[   24.475208] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
[   24.481682] [<ffffffff80213b58>] do_ri+0x1a8/0x690
[   24.486509] [<ffffffff8020b828>] handle_ri_int+0x44/0x5c
Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

This resolves the hazard between the mtc0 in the change_c0_status() and
the mfc0 in configure_exception_vector(). Without resolving this hazard
configure_exception_vector() could read an old value and would restore
this old value again. This would revert the changes change_c0_status()
did. I checked this by printing out the read_c0_status() at the end of
per_cpu_trap_init() and the ST0_MX is not set without this patch.

The hazard is documented in the MIPS Architecture Reference Manual Vol.
III: MIPS32/microMIPS32 Privileged Resource Architecture (MD00088), rev
6.03 table 8.1 which includes:

   Producer | Consumer | Hazard
  ----------|----------|----------------------------
   mtc0     | mfc0     | any coprocessor 0 register

I saw this hazard on an Atheros AR9344 rev 2 SoC with a MIPS 74Kc CPU.
There the change_c0_status() function would activate the DSPen by
setting ST0_MX in the c0_status register. This was reverted and then the
system got a DSP exception when the DSP registers were saved in
save_dsp() in the first process switch. The crash looks like this:

[    0.089999] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[    0.097796] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[    0.107070] Kernel panic - not syncing: Unexpected DSP exception
[    0.113470] Rebooting in 1 seconds..

We saw this problem in OpenWrt only on the MIPS 74Kc based Atheros SoCs,
not on the 24Kc based SoCs. We only saw it with kernel 5.4 not with
kernel 4.19, in addition we had to use GCC 8.4 or 9.X, with GCC 8.3 it
did not happen.

In the kernel I bisected this problem to commit 9012d011 ("compiler:
allow all arches to enable CONFIG_OPTIMIZE_INLINING"), but when this was
reverted it also happened after commit 172dcd93 ("MIPS: Always
allocate exception vector for MIPSr2+").

Commit 0b24cae4 ("MIPS: Add missing EHB in mtc0 -> mfc0 sequence.")
does similar changes to a different file. I am not sure if there are
more places affected by this problem.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Running `make savedefconfig` creates by default `defconfig`, which is,
currently, on git’s radar, for example, `git status` lists this file as
untracked.

So, add the file to `.gitignore`, so it’s ignored by git.
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Pull powerpc fixes from Michael Ellerman:
 "One fix for a regression in our pkey handling, which exhibits as
  PROT_EXEC mappings taking continuous page faults.

  Thanks to: Jan Stancek, Aneesh Kumar K.V"

* tag 'powerpc-5.8-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm/pkeys: Make pkey access check work on execute_only_key

Pull arm64 fixes from Will Deacon:
 "Nothing earth-shattering, really - some CPU errata workarounds (one
  day they'll get it right, ha!) and a fix for a boot failure with very
  large kernel images where the alternative patching gets confused when
  patching relative branches using veneers.

   - Fix alternative patching for very large kernel images and modules

   - Hook up existing CPU errata workarounds for Qualcomm Kryo CPUs"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Add KRYO4XX silver CPU cores to erratum list 1530923 and 1024718
  arm64: Add KRYO4XX gold CPU cores to erratum list 1463225 and 1418040
  arm64: Add MIDR value for KRYO4XX gold CPU cores
  arm64/alternatives: use subsections for replacement sequences

When switching to TWA_SIGNAL for task_work notifications, we also made
any signal based condition in io_cqring_wait() return -ERESTARTSYS.
This breaks applications that rely on using signals to abort someone
waiting for events.

Check if we have a signal pending because of queued task_work, and
repeat the signal check once we've run the task_work. This provides a
reliable way of telling the two apart.

Additionally, only use TWA_SIGNAL if we are using an eventfd. If not,
we don't have the dependency situation described in the original commit,
and we can get by with just using TWA_RESUME like we previously did.

Fixes: ce593a6c ("io_uring: use signal based task_work running")
Cc: stable@vger.kernel.org # v5.7
Reported-by: Andres Freund <andres@anarazel.de>
Tested-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Xen PV doesn't implement ESPFIX64, so they don't work right.  Disable
them.  Also print a warning the first time anyone tries to use a
16-bit segment on a Xen PV guest that would otherwise allow it
to help people diagnose this change in behavior.

This gets us closer to having all x86 selftests pass on Xen PV.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/92b2975459dfe5929ecf34c3896ad920bd9e3f2d.1593795633.git.luto@kernel.org

DEFINE_IDTENTRY_MCE and DEFINE_IDTENTRY_DEBUG were wired up as non-RAW
on x86_32, but the code expected them to be RAW.

Get rid of all the macro indirection for them on 32-bit and just use
DECLARE_IDTENTRY_RAW and DEFINE_IDTENTRY_RAW directly.

Also add a warning to make sure that we only hit the _kernel paths
in kernel mode.
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/9e90a7ee8e72fd757db6d92e1e5ff16339c1ecf9.1593795633.git.luto@kernel.org

On Xen PV, #DB doesn't use IST. It still needs to be correctly routed
depending on whether it came from user or kernel mode.

Get rid of DECLARE/DEFINE_IDTENTRY_XEN -- it was too hard to follow the
logic.  Instead, route #DB and NMI through DECLARE/DEFINE_IDTENTRY_RAW on
Xen, and do the right thing for #DB.  Also add more warnings to the
exc_debug* handlers to make this type of failure more obvious.

This fixes various forms of corruption that happen when usermode
triggers #DB on Xen PV.

Fixes: 4c0dcd83 ("x86/entry: Implement user mode C entry points for #DB and #MCE")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/4163e733cce0b41658e252c6c6b3464f33fdff17.1593795633.git.luto@kernel.org

Chasing down a Xen bug caused me to realize that the new entry sanity
checks are still fairly weak.  Add some more checks.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/881de09e786ab93ce56ee4a2437ba2c308afe7a9.1593795633.git.luto@kernel.org

Move the clearing of the high bits of RAX after Xen PV joins the SYSENTER
path so that Xen PV doesn't skip it.

Arguably this code should be deleted instead, but that would belong in the
merge window.

Fixes: ffae641f ("x86/entry/64/compat: Fix Xen PV SYSENTER frame setup")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/9d33b3f3216dcab008070f1c28b6091ae7199969.1593795633.git.luto@kernel.org

Pull xen fixes from Juergen Gross:
 "One small cleanup patch for ARM and two patches for the xenbus driver
  fixing latent problems (large stack allocations and bad return code
  settings)"

* tag 'for-linus-5.8b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/xenbus: let xenbus_map_ring_valloc() return errno values only
  xen/xenbus: avoid large structs and arrays on the stack
  arm/xen: remove the unused macro GRANT_TABLE_PHYSADDR

I2C_SMBUS_BLOCK_MAX defines already the maximum number as defined in the
SMBus 2.0 specs. I don't see a reason to add 1 here. Also, fix the errno
to what is suggested for this error.

Fixes: c9bfdc7c ("i2c: mlxcpld: Add support for smbus block read transaction")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Michael Shych <michaelsh@mellanox.com>
Tested-by: Michael Shych <michaelsh@mellanox.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Pull sysctl fix from Al Viro:
 "Another regression fix for sysctl changes this cycle..."

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  Call sysctl_head_finish on error

I can't recall why there was none, but we surely want to have it.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add more details which have either been missing ever since or describe
recent additions.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The driver can't be loaded automatically because it misses
module alias to be provided. Add corresponding MODULE_DEVICE_TABLE()
call to the driver.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>