Pull RTC fix from Alexandre Belloni:
 "Fix a locking issue in the cmos rtc driver"

* tag 'rtc-5.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
  rtc: cmos: Disable irq around direct invocation of cmos_interrupt()

The qnx4 directory entries are 64-byte blocks that have different
contents depending on the a status byte that is in the last byte of the
block.

In particular, a directory entry can be either a "link info" entry with
a 48-byte name and pointers to the real inode information, or an "inode
entry" with a smaller 16-byte name and the full inode information.

But the code was written to always just treat the directory name as if
it was part of that "inode entry", and just extend the name to the
longer case if the status byte said it was a link entry.

That work just fine and gives the right results, but now that gcc is
tracking data structure accesses much more, the code can trigger a
compiler error about using up to 48 bytes (the long name) in a structure
that only has that shorter name in it:

   fs/qnx4/dir.c: In function ‘qnx4_readdir’:
   fs/qnx4/dir.c:51:32: error: ‘strnlen’ specified bound 48 exceeds source size 16 [-Werror=stringop-overread]
      51 |                         size = strnlen(de->di_fname, size);
         |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from fs/qnx4/qnx4.h:3,
                    from fs/qnx4/dir.c:16:
   include/uapi/linux/qnx4_fs.h:45:25: note: source object declared here
      45 |         char            di_fname[QNX4_SHORT_NAME_MAX];
         |                         ^~~~~~~~

which is because the source code doesn't really make this whole "one of
two different types" explicit.

Fix this by introducing a very explicit union of the two types, and
basically explaining to the compiler what is really going on.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The sparc mdesc code does pointer games with 'struct mdesc_hdr', but
didn't describe to the compiler how that header is then followed by the
data that the header describes.

As a result, gcc is now unhappy since it does stricter pointer range
tracking, and doesn't understand about how these things work.  This
results in various errors like:

    arch/sparc/kernel/mdesc.c: In function ‘mdesc_node_by_name’:
    arch/sparc/kernel/mdesc.c:647:22: error: ‘strcmp’ reading 1 or more bytes from a region of size 0 [-Werror=stringop-overread]
      647 |                 if (!strcmp(names + ep[ret].name_offset, name))
          |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

which are easily avoided by just describing 'struct mdesc_hdr' better,
and making the node_block() helper function look into that unsized
data[] that follows the header.

This makes the sparc64 build happy again at least for my cross-compiler
version (gcc version 11.2.1).

Link: https://lore.kernel.org/lkml/CAHk-=wi4NW3NC0xWykkw=6LnjQD6D_rtRtxY9g8gQAJXtQMi8A@mail.gmail.com/


Cc: Guenter Roeck <linux@roeck-us.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge absolute_pointer macro series from Guenter Roeck:
 "Kernel test builds currently fail for several architectures with error
  messages such as the following.

  drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
  arch/m68k/include/asm/string.h:72:25: error:
        '__builtin_memcpy' reading 6 bytes from a region of size 0
                [-Werror=stringop-overread]

  Such warnings may be reported by gcc 11.x for string and memory
  operations on fixed addresses if gcc's builtin functions are used for
  those operations.

  This series introduces absolute_pointer() to fix the problem.
  absolute_pointer() disassociates a pointer from its originating symbol
  type and context, and thus prevents gcc from making assumptions about
  pointers passed to memory operations"

* emailed patches from Guenter Roeck <linux@roeck-us.net>:
  alpha: Use absolute_pointer to define COMMAND_LINE
  alpha: Move setup.h out of uapi
  net: i825xx: Use absolute_pointer for memcpy from fixed memory location
  compiler.h: Introduce absolute_pointer macro

alpha:allmodconfig fails to build with the following error
when using gcc 11.x.

  arch/alpha/kernel/setup.c: In function 'setup_arch':
  arch/alpha/kernel/setup.c:493:13: error:
	'strcmp' reading 1 or more bytes from a region of size 0

Avoid the problem by declaring COMMAND_LINE as absolute_pointer().

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Most of the contents of setup.h have no value for userspace
applications.  The file was probably moved to uapi accidentally.

Keep the file in uapi to define the alpha-specific COMMAND_LINE_SIZE.
Move all other defines to arch/alpha/include/asm/setup.h.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

gcc 11.x reports the following compiler warning/error.

  drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
  arch/m68k/include/asm/string.h:72:25: error:
	'__builtin_memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread]

Use absolute_pointer() to work around the problem.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

absolute_pointer() disassociates a pointer from its originating symbol
type and context. Use it to prevent compiler warnings/errors such as

  drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
  arch/m68k/include/asm/string.h:72:25: error:
	'__builtin_memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread]

Such warnings may be reported by gcc 11.x for string and memory
operations on fixed addresses.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The lib/bootconfig.c file is shared with the 'bootconfig' tooling, and
as a result, the changes incommit 77e02cf5 ("memblock: introduce
saner 'memblock_free_ptr()' interface") need to also be reflected in the
tooling header file.

So define the new memblock_free_ptr() wrapper, and remove unused __pa()
and memblock_free().

Fixes: 77e02cf5

 ("memblock: introduce saner 'memblock_free_ptr()' interface")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On sparc64, __fls() returns an "int", but the drm TTM code expected it
to be "unsigned long" as on x86.  As a result, on sparc (and arc, and
m68k) you get build errors because 'min()' checks that the types match.

As suggested by Linus, it can use min_t instead of min to force the type
to be "unsigned int".

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The boot-time allocation interface for memblock is a mess, with
'memblock_alloc()' returning a virtual pointer, but then you are
supposed to free it with 'memblock_free()' that takes a _physical_
address.

Not only is that all kinds of strange and illogical, but it actually
causes bugs, when people then use it like a normal allocation function,
and it fails spectacularly on a NULL pointer:

   https://lore.kernel.org/all/20210912140820.GD25450@xsang-OptiPlex-9020/

or just random memory corruption if the debug checks don't catch it:

   https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@suse.cz/



I really don't want to apply patches that treat the symptoms, when the
fundamental cause is this horribly confusing interface.

I started out looking at just automating a sane replacement sequence,
but because of this mix or virtual and physical addresses, and because
people have used the "__pa()" macro that can take either a regular
kernel pointer, or just the raw "unsigned long" address, it's all quite
messy.

So this just introduces a new saner interface for freeing a virtual
address that was allocated using 'memblock_alloc()', and that was kept
as a regular kernel pointer.  And then it converts a couple of users
that are obvious and easy to test, including the 'xbc_nodes' case in
lib/bootconfig.c that caused problems.

Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: 40caa127

 ("init: bootconfig: Remove all bootconfig data when the init memory is removed")
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Linus proposes to revert an accounting for sops objects in
do_semtimedop() because it's really just a temporary buffer
for a single semtimedop() system call.

This object can consume up to 2 pages, syscall is sleeping
one, size and duration can be controlled by user, and this
allocation can be repeated by many thread at the same time.

However Shakeel Butt pointed that there are much more popular
objects with the same life time and similar memory
consumption, the accounting of which was decided to be
rejected for performance reasons.

Considering at least 2 pages for task_struct and 2 pages for
the kernel stack, a back of the envelope calculation gives a
footprint amplification of <1.5 so this temporal buffer can be
safely ignored.

The factor would IMO be interesting if it was >> 2 (from the
PoV of excessive (ab)use, fine-grained accounting seems to be
currently unfeasible due to performance impact).

Link: https://lore.kernel.org/lkml/90e2...

Stephen reported that the build was broken since commit
6d2ef226 ("compiler_attributes.h: drop __has_attribute() support for
gcc4"), with errors such as:

  include/linux/compiler_attributes.h:296:5: warning: "__has_attribute" is not defined, evaluates to 0 [-Wundef]
    296 | #if __has_attribute(__warning__)
        |     ^~~~~~~~~~~~~~~
  make[2]: *** [arch/powerpc/boot/Makefile:225: arch/powerpc/boot/crt0.o] Error 1

But we expect __has_attribute() to always be defined now that we've
stopped using GCC 4.

Linus debugged it to the point of reading the GCC sources, and noticing
that the problem is that __has_attribute() is not defined when
preprocessing assembly files, which is what we're doing here.

Our assembly files don't include, or need, compiler_attributes.h, but
they are getting it unconditionally from the -include in BOOT_CFLAGS,
which is then added in its entirety to BOOT_AFLAGS.

That -include was added in commit 77433830

 ("powerpc: boot: include
compiler_attributes.h") so that we'd have "fallthrough" and other
attributes defined for the C files in arch/powerpc/boot. But it's not
needed for assembly files.

The minimal fix is to move the addition to BOOT_CFLAGS of -include
compiler_attributes.h until after we've copied BOOT_CFLAGS into
BOOT_AFLAGS. That avoids including compiler_attributes.h for asm files,
but makes no other change to BOOT_CFLAGS or BOOT_AFLAGS.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Debugged-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As previously noted in commit 66e4f4a9 ("rtc: cmos: Use
spin_lock_irqsave() in cmos_interrupt()"):

<4>[  254.192378] WARNING: inconsistent lock state
<4>[  254.192384] 5.12.0-rc1-CI-CI_DRM_9834+ #1 Not tainted
<4>[  254.192396] --------------------------------
<4>[  254.192400] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
<4>[  254.192409] rtcwake/5309 [HC0[0]:SC0[0]:HE1:SE1] takes:
<4>[  254.192429] ffffffff8263c5f8 (rtc_lock){?...}-{2:2}, at: cmos_interrupt+0x18/0x100
<4>[  254.192481] {IN-HARDIRQ-W} state was registered at:
<4>[  254.192488]   lock_acquire+0xd1/0x3d0
<4>[  254.192504]   _raw_spin_lock+0x2a/0x40
<4>[  254.192519]   cmos_interrupt+0x18/0x100
<4>[  254.192536]   rtc_handler+0x1f/0xc0
<4>[  254.192553]   acpi_ev_fixed_event_detect+0x109/0x13c
<4>[  254.192574]   acpi_ev_sci_xrupt_handler+0xb/0x28
<4>[  254.192596]   acpi_irq+0x13/0x30
<4>[  254.192620]   __handle_irq_event_percpu+0x43/0x2c0
<4>[  254.192641]   handle_irq_event_percpu+0x2b/0x70
<4>[  254.192661]   handle_irq_event+0x2f/0x50
<4>[  254.192680]   handle_fasteoi_irq+0x9e/0x150
<4>[  254.192693]   __common_interrupt+0x76/0x140
<4>[  254.192715]   common_interrupt+0x96/0xc0
<4>[  254.192732]   asm_common_interrupt+0x1e/0x40
<4>[  254.192750]   _raw_spin_unlock_irqrestore+0x38/0x60
<4>[  254.192767]   resume_irqs+0xba/0xf0
<4>[  254.192786]   dpm_resume_noirq+0x245/0x3d0
<4>[  254.192811]   suspend_devices_and_enter+0x230/0xaa0
<4>[  254.192835]   pm_suspend.cold.8+0x301/0x34a
<4>[  254.192859]   state_store+0x7b/0xe0
<4>[  254.192879]   kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.192899]   new_sync_write+0x11d/0x1b0
<4>[  254.192916]   vfs_write+0x265/0x390
<4>[  254.192933]   ksys_write+0x5a/0xd0
<4>[  254.192949]   do_syscall_64+0x33/0x80
<4>[  254.192965]   entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.192986] irq event stamp: 43775
<4>[  254.192994] hardirqs last  enabled at (43775): [<ffffffff81c00c42>] asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193023] hardirqs last disabled at (43774): [<ffffffff81aa691a>] sysvec_apic_timer_interrupt+0xa/0xb0
<4>[  254.193049] softirqs last  enabled at (42548): [<ffffffff81e00342>] __do_softirq+0x342/0x48e
<4>[  254.193074] softirqs last disabled at (42543): [<ffffffff810b45fd>] irq_exit_rcu+0xad/0xd0
<4>[  254.193101]
                  other info that might help us debug this:
<4>[  254.193107]  Possible unsafe locking scenario:

<4>[  254.193112]        CPU0
<4>[  254.193117]        ----
<4>[  254.193121]   lock(rtc_lock);
<4>[  254.193137]   <Interrupt>
<4>[  254.193142]     lock(rtc_lock);
<4>[  254.193156]
                   *** DEADLOCK ***

<4>[  254.193161] 6 locks held by rtcwake/5309:
<4>[  254.193174]  #0: ffff888104861430 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x5a/0xd0
<4>[  254.193232]  #1: ffff88810f823288 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe7/0x1c0
<4>[  254.193282]  #2: ffff888100cef3c0 (kn->active#285
<7>[  254.192706] i915 0000:00:02.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:51:pipe A] hw state readout: disabled
<4>[  254.193307] ){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1c0
<4>[  254.193333]  #3: ffffffff82649fa8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend.cold.8+0xce/0x34a
<4>[  254.193387]  #4: ffffffff827a2108 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x47/0x70
<4>[  254.193433]  #5: ffff8881019ea178 (&dev->mutex){....}-{3:3}, at: device_resume+0x68/0x1e0
<4>[  254.193485]
                  stack backtrace:
<4>[  254.193492] CPU: 1 PID: 5309 Comm: rtcwake Not tainted 5.12.0-rc1-CI-CI_DRM_9834+ #1
<4>[  254.193514] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019
<4>[  254.193524] Call Trace:
<4>[  254.193536]  dump_stack+0x7f/0xad
<4>[  254.193567]  mark_lock.part.47+0x8ca/0xce0
<4>[  254.193604]  __lock_acquire+0x39b/0x2590
<4>[  254.193626]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
<4>[  254.193660]  lock_acquire+0xd1/0x3d0
<4>[  254.193677]  ? cmos_interrupt+0x18/0x100
<4>[  254.193716]  _raw_spin_lock+0x2a/0x40
<4>[  254.193735]  ? cmos_interrupt+0x18/0x100
<4>[  254.193758]  cmos_interrupt+0x18/0x100
<4>[  254.193785]  cmos_resume+0x2ac/0x2d0
<4>[  254.193813]  ? acpi_pm_set_device_wakeup+0x1f/0x110
<4>[  254.193842]  ? pnp_bus_suspend+0x10/0x10
<4>[  254.193864]  pnp_bus_resume+0x5e/0x90
<4>[  254.193885]  dpm_run_callback+0x5f/0x240
<4>[  254.193914]  device_resume+0xb2/0x1e0
<4>[  254.193942]  ? pm_dev_err+0x25/0x25
<4>[  254.193974]  dpm_resume+0xea/0x3f0
<4>[  254.194005]  dpm_resume_end+0x8/0x10
<4>[  254.194030]  suspend_devices_and_enter+0x29b/0xaa0
<4>[  254.194066]  pm_suspend.cold.8+0x301/0x34a
<4>[  254.194094]  state_store+0x7b/0xe0
<4>[  254.194124]  kernfs_fop_write_iter+0x11d/0x1c0
<4>[  254.194151]  new_sync_write+0x11d/0x1b0
<4>[  254.194183]  vfs_write+0x265/0x390
<4>[  254.194207]  ksys_write+0x5a/0xd0
<4>[  254.194232]  do_syscall_64+0x33/0x80
<4>[  254.194251]  entry_SYSCALL_64_after_hwframe+0x44/0xae
<4>[  254.194274] RIP: 0033:0x7f07d79691e7
<4>[  254.194293] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
<4>[  254.194312] RSP: 002b:00007ffd9cc2c768 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4>[  254.194337] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f07d79691e7
<4>[  254.194352] RDX: 0000000000000004 RSI: 0000556ebfc63590 RDI: 000000000000000b
<4>[  254.194366] RBP: 0000556ebfc63590 R08: 0000000000000000 R09: 0000000000000004
<4>[  254.194379] R10: 0000556ebf0ec2a6 R11: 0000000000000246 R12: 0000000000000004

which breaks S3-resume on fi-kbl-soraka presumably as that's slow enough
to trigger the alarm during the suspend.

Fixes: 6950d046 ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ")
References: 66e4f4a9

 ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"):
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Xiaofei Tan <tanxiaofei@huawei.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210305122140.28774-1-chris@chris-wilson.co.uk

When building objtool with HOSTCC=clang, there are several errors along
the lines of

  orc_dump.c:201:28: error: unknown attribute 'error' ignored [-Werror,-Wunknown-attributes]

This occurs after commit 4e59869a ("compiler-gcc.h: drop checks for
older GCC versions"), which removed the GCC_VERSION gating.  The removed
version check just so happened to prevent __compiletime_error() from
being defined with clang because it pretends to be GCC 4.2.1 for
compatibility but the error attribute was not added to clang until
14.0.0.

Commit 815f0ddb ("include/linux/compiler*.h: make compiler-*.h
mutually exclusive") and commit a3f8a30f ("Compiler Attributes: use
feature checks instead of version checks") refactored the handling of
attributes in the main kernel to avoid situations like this but that
refactoring has never been done for the tools directory.

Refactoring is a rather large undertaking and this has never been an
issue before so instead, just guard the definition of
__compiletime_error() with __has_attribute() so that there are no more
errors.

Fixes: 4e59869a

 ("compiler-gcc.h: drop checks for older GCC versions")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge patch series from Nick Desaulniers to update the minimum gcc
version to 5.1.

This is some of the left-overs from the merge window that I didn't want
to deal with yesterday, so it comes in after -rc1 but was sent before.

Gcc-4.9 support has been an annoyance for some time, and with -Werror I
had the choice of applying a fairly big patch from Kees Cook to remove a
fair number of initializer warnings (still leaving some), or this patch
series from Nick that just removes the source of the problem.

The initializer cleanups might still be worth it regardless, but
honestly, I preferred just tackling the problem with gcc-4.9 head-on.
We've been more aggressiuve about no longer having to care about
compilers that were released a long time ago, and I think it's been a
good thing.

I added a couple of patches on top to sort out a few left-overs now that
we no longer support gcc-4.x.

As noted by Arnd, as a result of this minimum compiler version upgrade
we can probably change our use of '--std=gnu89' to '--std=gnu11', and
finally start using local loop declarations etc.  But this series does
_not_ yet do that.

Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/
Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/
Link: https://github.com/ClangBuiltLinux/linux/issues/1438

* emailed patches from Nick Desaulniers <ndesaulniers@google.com>:
  Drop some straggling mentions of gcc-4.9 as being stale
  compiler_attributes.h: drop __has_attribute() support for gcc4
  vmlinux.lds.h: remove old check for GCC 4.9
  compiler-gcc.h: drop checks for older GCC versions
  Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround
  arm64: remove GCC version check for ARCH_SUPPORTS_INT128
  powerpc: remove GCC version check for UPD_CONSTR
  riscv: remove Kconfig check for GCC version for ARCH_RV64I
  Kconfig.debug: drop GCC 5+ version check for DWARF5
  mm/ksm: remove old GCC 4.9+ check
  compiler.h: drop fallback overflow checkers
  Documentation: raise minimum supported version of GCC to 5.1

Fix up the admin-guide README file to the new gcc-5.1 requirement, and
remove a stale comment about gcc support for the __assume_aligned__
attribute.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that GCC 5.1 is the minimally supported default, the manual
workaround for older gcc versions not having __has_attribute() are no
longer relevant and can be removed.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that GCC 5.1 is the minimally supported version of GCC, we can
effectively revert commit 85c2ce91

 ("sched, vmlinux.lds: Increase
STRUCT_ALIGNMENT to 64 bytes for GCC-4.9")

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that GCC 5.1 is the minimally supported default, drop the values we
don't use.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that GCC 5.1 is the minimally supported version, we can drop this
workaround for older versions of GCC.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that GCC 5.1 is the minimally supported compiler version, this
Kconfig check is no longer necessary.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that GCC 5.1 is the minimum supported version, we can drop this
workaround for older versions of GCC. This adversely affected clang,
too.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The minimum supported version of GCC is now 5.1. The check wasn't
correct as written anyways since GCC_VERSION is 0 when CC=clang.

Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now that the minimum supported version of GCC is 5.1, we no longer need
this Kconfig version check for CONFIG_DEBUG_INFO_DWARF5.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The minimum supported version of GCC has been raised to GCC 5.1.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Once upgrading the minimum supported version of GCC to 5.1, we can drop
the fallback code for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW.

This is effectively a revert of commit f0907827 ("compiler.h: enable
builtin overflow checkers and add fallback code")

Link: https://github.com/ClangBuiltLinux/linux/issues/1438#issuecomment-916745801


Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

commit fad7cd33 ("nbd: add the check to prevent overflow in
__nbd_ioctl()") raised an issue from the fallback helpers added in
commit f0907827 ("compiler.h: enable builtin overflow checkers and
add fallback code")

Specifically, the helpers for checking whether the results of a
multiplication overflowed (__unsigned_mul_overflow,
__signed_add_overflow) use the division operator when
!COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW.  This is problematic for 64b
operands on 32b hosts.

Also, because the macro is type agnostic, it is very difficult to write
a similarly type generic macro that dispatches to one of:
 * div64_s64
 * div64_u64
 * div_s64
 * div_u64

Raising the minimum supported versions allows us to remove all of the
fallback helpers for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW, instead
dispatching the compiler builtins.

arm64 has already raised the minimum supported GCC version to 5.1, do
this for all targets now.  See the link below for the previous
discussion.

Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/
Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/
Link: https://github.com/ClangBuiltLinux/linux/issues/1438


Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 865c50e1 ("x86/uaccess: utilize CONFIG_CC_HAS_ASM_GOTO_OUTPUT")
added an optimised version of __get_user_asm() for x86 using 'asm goto'.

Like the non-optimised code, the 32-bit implementation of 64-bit
get_user() expands to a pair of 32-bit accesses.  Unlike the
non-optimised code, the _original_ pointer is incremented to copy the
high word instead of loading through a new pointer explicitly
constructed to point at a 32-bit type.  Consequently, if the pointer
points at a 64-bit type then we end up loading the wrong data for the
upper 32-bits.

This was observed as a mount() failure in Android targeting i686 after
b0cfcdd9

 ("d_path: make 'prepend()' fill up the buffer exactly on
overflow") because the call to copy_from_kernel_nofault() from
prepend_copy() ends up in __get_kernel_nofault() and casts the source
pointer to a 'u64 __user *'.  An attempt to mount at "/debug_ramdisk"
therefore ends up failing trying to mount "/debumdismdisk".

Use the existing '__gu_ptr' source pointer to unsigned int for 32-bit
__get_user_asm_u64() instead of the original pointer.

Cc: Bill Wendling <morbo@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 865c50e1

 ("x86/uaccess: utilize CONFIG_CC_HAS_ASM_GOTO_OUTPUT")
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'perf-tools-for-v5.15-2021-09-11' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull more perf tools updates from Arnaldo Carvalho de Melo:

 - Add missing fields and remove some duplicate fields when printing a
   perf_event_attr.

 - Fix hybrid config terms list corruption.

 - Update kernel header copies, some resulted in new kernel features
   being automagically added to 'perf trace' syscall/tracepoint argument
   id->string translators.

 - Add a file generated during the documentation build to .gitignore.

 - Add an option to build without libbfd, as some distros, like Debian
   consider its ABI unstable.

 - Add support to print a textual representation of IBS raw sample data
   in 'perf report'.

 - Fix bpf 'perf test' sample mismatch reporting

 - Fix passing arguments to stackcollapse report in a 'perf script'
   python script.

 - Allow build-id with trailing zeros.

 - Look for ImageBase in PE file to compute .text offset.

* tag 'perf-tools-for-v5.15-2021-09-11' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (25 commits)
  tools headers UAPI: Update tools's copy of drm.h headers
  tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
  tools headers UAPI: Sync linux/fs.h with the kernel sources
  tools headers UAPI: Sync linux/in.h copy with the kernel sources
  perf tools: Add an option to build without libbfd
  perf tools: Allow build-id with trailing zeros
  perf tools: Fix hybrid config terms list corruption
  perf tools: Factor out copy_config_terms() and free_config_terms()
  perf tools: Fix perf_event_attr__fprintf() missing/dupl. fields
  perf tools: Ignore Documentation dependency file
  perf bpf: Provide a weak btf__load_from_kernel_by_id() for older libbpf versions
  tools include UAPI: Update linux/mount.h copy
  perf beauty: Cover more flags in the  move_mount syscall argument beautifier
  tools headers UAPI: Sync linux/prctl.h with the kernel sources
  tools include UAPI: Sync sound/asound.h copy with the kernel sources
  tools headers UAPI: Sync linux/kvm.h with the kernel sources
  tools headers UAPI: Sync x86's asm/kvm.h with the kernel sources
  perf report: Add support to print a textual representation of IBS raw sample data
  perf report: Add tools/arch/x86/include/asm/amd-ibs.h
  perf env: Add perf_env__cpuid, perf_env__{nr_}pmu_mappings
  ...

Pull compiler attributes updates from Miguel Ojeda:

 - Fix __has_attribute(__no_sanitize_coverage__) for GCC 4 (Marco Elver)

 - Add Nick as Reviewer for compiler_attributes.h (Nick Desaulniers)

 - Move __compiletime_{error|warning} (Nick Desaulniers)

* tag 'compiler-attributes-for-linus-v5.15-rc1-v2' of git://github.com/ojeda/linux:
  compiler_attributes.h: move __compiletime_{error|warning}
  MAINTAINERS: add Nick as Reviewer for compiler_attributes.h
  Compiler Attributes: fix __has_attribute(__no_sanitize_coverage__) for GCC 4

Pull auxdisplay updates from Miguel Ojeda:
 "An assortment of improvements for auxdisplay:

   - Replace symbolic permissions with octal permissions (Jinchao Wang)

   - ks0108: Switch to use module_parport_driver() (Andy Shevchenko)

   - charlcd: Drop unneeded initializers and switch to C99 style (Andy
     Shevchenko)

   - hd44780: Fix oops on module unloading (Lars Poeschel)

   - Add I2C gpio expander example (Ralf Schlatterbeck)"

* tag 'auxdisplay-for-linus-v5.15-rc1' of git://github.com/ojeda/linux:
  auxdisplay: Replace symbolic permissions with octal permissions
  auxdisplay: ks0108: Switch to use module_parport_driver()
  auxdisplay: charlcd: Drop unneeded initializers and switch to C99 style
  auxdisplay: hd44780: Fix oops on module unloading
  auxdisplay: Add I2C gpio expander example

Pull CPU hotplug updates from Thomas Gleixner:
 "Updates for the SMP and CPU hotplug:

   - Remove DEFINE_SMP_CALL_CACHE_FUNCTION() which is a left over of the
     original hotplug code and now causing trouble with the ARM64 cache
     topology setup due to the pointless SMP function call.

     It's not longer required as the hotplug callbacks are guaranteed to
     be invoked on the upcoming CPU.

   - Remove the deprecated and now unused CPU hotplug functions

   - Rewrite the CPU hotplug API documentation"

* tag 'smp-urgent-2021-09-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation: core-api/cpuhotplug: Rewrite the API section
  cpu/hotplug: Remove deprecated CPU-hotplug functions.
  thermal: Replace deprecated CPU-hotplug functions.
  drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()

Merge tag 'char-misc-5.15-rc1-lkdtm' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull misc driver fix from Greg KH:
 "Here is a single patch for 5.15-rc1, for the lkdtm misc driver.

  It resolves a build issue that many people were hitting with your
  current tree, and Kees and others felt would be good to get merged
  before -rc1 comes out, to prevent them from having to constantly hit
  it as many development trees restart on -rc1, not older -rc releases.

  It has NOT been in linux-next, but has passed 0-day testing and looks
  'obviously correct' when reviewing it locally :)"

* tag 'char-misc-5.15-rc1-lkdtm' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  lkdtm: Use init_uts_ns.name instead of macros

Pull IPMI updates from Corey Minyard:
 "A couple of very minor fixes for style and rate limiting.

  Nothing big, but probably needs to go in"

* tag 'for-linus-5.15-1' of git://github.com/cminyard/linux-ipmi:
  char: ipmi: use DEVICE_ATTR helper macro
  ipmi: rate limit ipmi smi_event failure message

Pull scheduler fixes from Borislav Petkov:

 - Make sure the idle timer expires in hardirq context, on PREEMPT_RT

 - Make sure the run-queue balance callback is invoked only on the
   outgoing CPU

* tag 'sched_urgent_for_v5.15_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Prevent balance_push() on remote runqueues
  sched/idle: Make the idle timer expire in hard interrupt context

Pull locking fixes from Borislav Petkov:

 - Fix the futex PI requeue machinery to not return to userspace in
   inconsistent state

 - Avoid a potential null pointer dereference in the ww_mutex deadlock
   check

 - Other smaller cleanups and optimizations

* tag 'locking_urgent_for_v5.15_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/rtmutex: Fix ww_mutex deadlock check
  futex: Remove unused variable 'vpid' in futex_proxy_trylock_atomic()
  futex: Avoid redundant task lookup
  futex: Clarify comment for requeue_pi_wake_futex()
  futex: Prevent inconsistent state and exit race
  futex: Return error code instead of assigning it without effect
  locking/rwsem: Add missing __init_rwsem() for PREEMPT_RT

Pull timer fix from Borislav Petkov:

 - Handle negative second values properly when converting a timespec64
   to nanoseconds.

* tag 'timers_urgent_for_v5.15_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Handle negative seconds correctly in timespec64_to_ns()

Pull namei updates from Al Viro:
 "Clearing fallout from mkdirat in io_uring series. The fix in the
  kern_path_locked() patch plus associated cleanups"

* 'misc.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  putname(): IS_ERR_OR_NULL() is wrong here
  namei: Standardize callers of filename_create()
  namei: Standardize callers of filename_lookup()
  rename __filename_parentat() to filename_parentat()
  namei: Fix use after free in kern_path_locked