The arm64 ptdump code can race with concurrent modification of the
kernel page tables. At the time this was added, this was sound as:

* Modifications to leaf entries could result in stale information being
  logged, but would not result in a functional problem.

* Boot time modifications to non-leaf entries (e.g. freeing of initmem)
  were performed when the ptdump code cannot be invoked.

* At runtime, modifications to non-leaf entries only occurred in the
  vmalloc region, and these were strictly additive, as intermediate
  entries were never freed.

However, since commit:

  commit 324420bf ("arm64: add support for ioremap() block mappings")

... it has been possible to create huge mappings in the vmalloc area at
runtime, and as part of this existing intermediate levels of table my be
removed and freed.

It's possible for the ptdump code to race with this, and continue to
walk tables which have been freed (and potentially poisoned or
reallocated). As a result of this, the ptdump code may dereference bogus
addresses, which could be fatal.

Since huge-vmap is a TLB and memory optimization, we can disable it when
the runtime ptdump code is in use to avoid this problem.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 324420bf ("arm64: add support for ioremap() block mappings")
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When dumping the page table in response to an unexpected kernel page
fault, we print the virtual (hashed) address of the page table base, but
display physical addresses for everything else.

Make the page table dumping code in show_pte() consistent, by printing
the page table base pointer as a physical address.
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

ARCH_WANT_COMPAT_IPC_PARSE_VERSION is selected unconditionally. It
makes little sense if kernel is compiled without COMPAT support.
Fix it.

This patch makes no functional changes since all existing code which
is guarded with ARCH_WANT_COMPAT_IPC_PARSE_VERSION is also guarded
with COMPAT.
Signed-off-by: Yury Norov <ynorov@marvell.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Since commit 7faa313f ("arm64: preempt: Fix big-endian when checking
preempt count in assembly") both the preempt count and the 'need_resched'
flag are checked as part of a single 64-bit load in cond_yield_neon(),
so update the stale comment to reflect reality.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Since commit 5768402f ("perf/ring_buffer: Use high order allocations
for AUX buffers optimistically"), the perf core tends to back aux buffer
allocations with high-order pages with the order encoded in the
PagePrivate data. The Arm SPE driver explicitly rejects such pages,
causing the perf tool to fail with:

  | failed to mmap with 12 (Cannot allocate memory)

In actual fact, we can simply treat these pages just like any other
since the perf core takes care to populate the page array appropriately.
In theory we could try to map with PMDs where possible, but for now,
let's just get things working again.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 5768402f ("perf/ring_buffer: Use high order allocations for AUX buffers optimistically")
Reported-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

DMA allocations that can't sleep may return non-remapped addresses, but
we do not properly handle them in the mmap and get_sgtable methods.
Resolve non-vmalloc addresses using virt_to_page to handle this corner
case.

Cc: <stable@vger.kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into for-next/core

Merge branch 'for-next/timers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core

Conflicts:
	arch/arm64/Kconfig
	arch/arm64/include/asm/arch_timer.h

Merge branch 'for-next/mitigations' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core

Merge branch 'for-next/futex' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core

Add ARM64 to the legend of architectures.  It's already used in several
places in kernel-parameters.txt.
Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Configure arm64 runtime CPU speculation bug mitigations in accordance
with the 'mitigations=' cmdline option.  This affects Meltdown, Spectre
v2, and Speculative Store Bypass.

The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
[will: reorder checks so KASLR implies KPTI and SSBS is affected by cmdline]
Signed-off-by: Will Deacon <will.deacon@arm.com>

SSBS provides a relatively cheap mitigation for SSB, but it is still a
mitigation and its presence does not indicate that the CPU is unaffected
by the vulnerability.

Tweak the mitigation logic so that we report the correct string in sysfs.
Signed-off-by: Will Deacon <will.deacon@arm.com>

Enable CPU vulnerabilty show functions for spectre_v1, spectre_v2,
meltdown and store-bypass.
Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Return status based on ssbd_state and __ssb_safe. If the
mitigation is disabled, or the firmware isn't responding then
return the expected machine state based on a whitelist of known
good cores.

Given a heterogeneous machine, the overall machine vulnerability
defaults to safe but is reset to unsafe when we miss the whitelist
and the firmware doesn't explicitly tell us the core is safe.
In order to make that work we delay transitioning to vulnerable
until we know the firmware isn't responding to avoid a case
where we miss the whitelist, but the firmware goes ahead and
reports the core is not vulnerable. If all the cores in the
machine have SSBS, then __ssb_safe will remain true.
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

__early_cpu_boot_status is of type long. Use quad
assembler directive to allocate proper size.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Arun KS <arunks@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Instead of always going via arch_counter_get_cntvct_stable to access the
counter workaround, let's have arch_timer_read_counter point to the
right method.

For that, we need to track whether any CPU in the system has a
workaround for the counter. This is done by having an atomic variable
tracking this.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The use of a static key in a hotplug path has proved to be a real
nightmare, and makes it impossible to have scream-free lockdep
kernel.

Let's remove the static key altogether, and focus on something saner.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Let's start with the removal of the arch_timer_read_ool_enabled
static key in arch_timer_reg_read_stable. It is not a fast path,
and we can simplify things a bit.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When a given timer is affected by an erratum and requires an
alternative implementation of set_next_event, we do a rather
complicated dance to detect and call the workaround on each
set_next_event call.

This is clearly idiotic, as we can perfectly detect whether
this CPU requires a workaround while setting up the clock event
device.

This only requires the CPU-specific detection to be done a bit
earlier, and we can then safely override the set_next_event pointer
if we have a workaround associated to that CPU.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by; Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Only arch_timer_read_counter will guarantee that workarounds are
applied. So let's use this one instead of arch_counter_get_cntvct.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Only arch_timer_read_counter will guarantee that workarounds are
applied. So let's use this one instead of arch_counter_get_cntvct.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The VDSO code uses the kernel helper that was originally designed
to abstract the access between 32 and 64bit systems. It worked so
far because this function is declared as 'inline'.

As we're about to revamp that part of the code, the VDSO would
break. Let's fix it by doing what should have been done from
the start, a proper system register access.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Neoverse-N1 is also affected by ARM64_ERRATUM_1188873, so let's
add it to the list of affected CPUs.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[will: Update silicon-errata.txt]
Signed-off-by: Will Deacon <will.deacon@arm.com>

New CPU, new part number. You know the drill.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Since ARM64_ERRATUM_1188873 only affects AArch32 EL0, it makes some
sense that it should depend on COMPAT.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

We currently deal with ARM64_ERRATUM_1188873 by always trapping EL0
accesses for both instruction sets. Although nothing wrong comes out
of that, people trying to squeeze the last drop of performance from
buggy HW find this over the top. Oh well.

Let's change the mitigation by flipping the counter enable bit
on return to userspace. Non-broken HW gets an extra branch on
the fast path, which is hopefully not the end of the world.
The arch timer workaround is also removed.
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

As of commit ece0e2b6 ("mm: remove pte_*map_nested()"),
pte_unmap_nested() is no longer used and can be removed from the arm64
code.
Signed-off-by: Qian Cai <cai@lca.pw>
[will: also remove pte_offset_map_nested()]
Signed-off-by: Will Deacon <will.deacon@arm.com>

When building with -Wunused-but-set-variable, the compiler shouts about
a number of pte_unmap() users, since this expands to an empty macro on
arm64:

  | mm/gup.c: In function 'gup_pte_range':
  | mm/gup.c:1727:16: warning: variable 'ptem' set but not used
  | [-Wunused-but-set-variable]
  | mm/gup.c: At top level:
  | mm/memory.c: In function 'copy_pte_range':
  | mm/memory.c:821:24: warning: variable 'orig_dst_pte' set but not used
  | [-Wunused-but-set-variable]
  | mm/memory.c:821:9: warning: variable 'orig_src_pte' set but not used
  | [-Wunused-but-set-variable]
  | mm/swap_state.c: In function 'swap_ra_info':
  | mm/swap_state.c:641:15: warning: variable 'orig_pte' set but not used
  | [-Wunused-but-set-variable]
  | mm/madvise.c: In function 'madvise_free_pte_range':
  | mm/madvise.c:318:9: warning: variable 'orig_pte' set but not used
  | [-Wunused-but-set-variable]

Rewrite pte_unmap() as a static inline function, which silences the
warnings.
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Will Deacon <will.deacon@arm.com>

With the introduction of the config option that allows to enable kuser
helpers, it is now possible to reduce TASK_SIZE_32 when these are
disabled and 64K pages are enabled. This extends the compliance with
the section 6.5.8 of the C standard (C99).
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When executing clock_gettime(), either in the vDSO or via a system call,
we need to ensure that the read of the counter register occurs within
the seqlock reader critical section. This ensures that updates to the
clocksource parameters (e.g. the multiplier) are consistent with the
counter value and therefore avoids the situation where time appears to
go backwards across multiple reads.

Extend the vDSO logic so that the seqlock critical section covers the
read of the counter register as well as accesses to the data page. Since
reads of the counter system registers are not ordered by memory barrier
instructions, introduce dependency ordering from the counter read to a
subsequent memory access so that the seqlock memory barriers apply to
the counter access in both the vDSO and the system call paths.

Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/linux-arm-kernel/alpine.DEB.2.21.1902081950260.1662@nanos.tec.linutronix.de/Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Functions called in '_sdei_handler' are needed to be marked as
'nokprobe'. Because these functions are called in NMI context and
neither the arch-code's debug infrastructure nor kprobes core supports
this.
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The file offset argument to the arm64 sys_mmap() implementation is
scaled from bytes to pages by shifting right by PAGE_SHIFT.
Unfortunately, the offset is passed in as a signed 'off_t' type and
therefore large offsets (i.e. with the top bit set) are incorrectly
sign-extended by the shift. This has been observed to cause false mmap()
failures when mapping GPU doorbells on an arm64 server part.

Change the type of the file offset argument to sys_mmap() from 'off_t'
to 'unsigned long' so that the shifting scales the value as expected.

Cc: <stable@vger.kernel.org>
Signed-off-by: Boyang Zhou <zhouby_cn@126.com>
[will: rewrote commit message]
Signed-off-by: Will Deacon <will.deacon@arm.com>

The nature of silicon errata means that the Kconfig help text for our
various software workarounds has been written by many different people.
Along the way, we've accumulated typos and inconsistencies which make
the options needlessly difficult to read.

Fix up minor issues with the help text.
Signed-off-by: Will Deacon <will.deacon@arm.com>

Ensure we are always able to detect whether or not the CPU is affected
by SSB, so that we can later advertise this to userspace.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
[will: Use IS_ENABLED instead of #ifdef]
Signed-off-by: Will Deacon <will.deacon@arm.com>

Track whether all the cores in the machine are vulnerable to Spectre-v2,
and whether all the vulnerable cores have been mitigated. We then expose
this information to userspace via sysfs.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Ensure we are always able to detect whether or not the CPU is affected
by Spectre-v2, so that we can later advertise this to userspace.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The SMCCC ARCH_WORKAROUND_1 service can indicate that although the
firmware knows about the Spectre-v2 mitigation, this particular
CPU is not vulnerable, and it is thus not necessary to call
the firmware on this CPU.

Let's use this information to our benefit.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

We currently have a list of CPUs affected by Spectre-v2, for which
we check that the firmware implements ARCH_WORKAROUND_1. It turns
out that not all firmwares do implement the required mitigation,
and that we fail to let the user know about it.

Instead, let's slightly revamp our checks, and rely on a whitelist
of cores that are known to be non-vulnerable, and let the user know
the status of the mitigation in the kernel log.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

We implement page table isolation as a mitigation for meltdown.
Report this to userspace via sysfs.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>