pte_valid should check if the PTE_VALID bit (1 << 0) is set in the pte,
so fix the macro definition to use bitwise & instead of logical &&.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

When unlocking a spinlock, we perform a read-modify-write on the owner
ticket in order to increment it and store it back with release
semantics.

In the LL/SC case, we load the 16-bit ticket using a 32-bit load and
therefore store back the wrong halfword on a big-endian system,
corrupting the lock after the first unlock and killing the system dead.

This patch fixes the unlock code to use 16-bit accessors consistently.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The flush_tlb_page() function is used on user address ranges when PTEs
(or PMDs/PUDs for huge pages) were changed (attributes or clearing). For
such cases, it is more efficient to invalidate only the last level of
the TLB with the "tlbi vale1is" instruction.

In the TLB shoot-down case, the TLB caching of the intermediate page
table levels (pmd, pud, pgd) is handled by __flush_tlb_pgtable() via the
__(pte|pmd|pud)_free_tlb() functions and it is not deferred to
tlb_finish_mmu() (as of commit 285994a6 - "arm64: Invalidate the TLB
corresponding to intermediate page table levels"). The tlb_flush()
function only needs to invalidate the TLB for the last level of page
tables; the __flush_tlb_range() function gains a fourth argument for
last level TLBI.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch moves the MAX_TLB_RANGE check into the
flush_tlb(_kernel)_range functions directly to avoid the
undescore-prefixed definitions (and for consistency with a subsequent
patch).
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Currently create_mapping is marked with __ref, apparently because it
refers to early_alloc. However, create_mapping has no logic to prevent
erroneous use of early_alloc after it has been freed, and is only ever
called by __init functions anyway. Thus the __ref marker is misleading
and unnecessary.

Instead, this patch marks create_mapping as __init, resulting in
warnings if it is used from a a non __init functions, and allowing its
memory to be reclaimed.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

lib/list_sort.c defines a 'struct debug_el', where "el" is assumedly a
a contraction of "element". This conflicts with 'enum debug_el' in our
asm/debug-monitors.h header file, where "el" stands for Exception Level.

The result is build failure when targetting allmodconfig, so rename our
enum to 'dbg_active_el' to be slightly more explicit about what it is.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

It is not needed after booting, this patch moves the
free_initrd_mem() function to the __init section.

This patch also make keep_initrd __initdata, to reduce kernel
size.
Signed-off-by: NWang Long <long.wanglong@huawei.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

cpuid_feature_extract_field takes care of the fiddly ID register
field sign-extension, so use that instead of rolling our own version.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Rework the cpufeature detection to support ISAR0 and use that for
detecting the presence of LSE atomics.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

ARMv8 CPUs do not support any of the v8.1 features, so group them
together in Kconfig to make it clear that they're part of 8.1 and not
relevant to older cores.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Other CPU features follow an 'ARM64_HAS_*' naming scheme, so do the same
for the LSE atomics.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

We implement an optimised cmpxchg_local macro, so let the kernel know.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

If we attempt to atomic64_dec_if_positive on INT_MIN, we will underflow
and incorrectly decide that the original parameter was positive.

This patches fixes the broken condition code so that we handle this
corner case correctly.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

We don't need duplicate cmpxchg implementations, so use cmpxchg to
implement atomic{,64}_cmpxchg, like we do for xchg already.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The cost of changing a cacheline from shared to exclusive state can be
significant, especially when this is triggered by an exclusive store,
since it may result in having to retry the transaction.

This patch makes use of prfm to prefetch cachelines for write prior to
ldxr/stxr loops when using the ll/sc atomic routines.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The common (i.e. identical for ll/sc and lse) atomic macros in atomic.h
are needlessley different for atomic_t and atomic64_t.

This patch tidies up the definitions to make them consistent across the
two atomic types and factors out common code such as the add_unless
implementation based on cmpxchg.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

cmpxchg doesn't require memory barrier semantics when the value
comparison fails, so make the barrier conditional on success.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

We can perform the cmpxchg comparison using eor and cbnz which avoids
the "cc" clobber for the ll/sc case and consequently for the LSE case
where we may have to fall-back on the ll/sc code at runtime.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of our cmpxchg_double primitives
so that the LSE casp instruction is used instead.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of our cmpxchg primitives so that
the LSE cas instruction is used instead.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of our xchg primitives so that
the LSE swp instruction (yes, you read right!) is used instead.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of our bitops functions so that
LSE atomic instructions are used instead.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of our locking functions so that
LSE atomic instructions are used for spinlocks and rwlocks.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.

This patch introduces runtime patching of atomic_t and atomic64_t
routines so that the call-site for the out-of-line ll/sc sequences is
patched with an LSE atomic instruction when we detect that
the CPU supports it.

If binutils is not recent enough to assemble the LSE instructions, then
the ll/sc sequences are inlined as though CONFIG_ARM64_LSE_ATOMICS=n.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

In order to patch in the new atomic instructions at runtime, we need to
generate wrappers around the out-of-line exclusive load/store atomics.

This patch adds a new Kconfig option, CONFIG_ARM64_LSE_ATOMICS. which
causes our atomic functions to branch to the out-of-line ll/sc
implementations. To avoid the register spill overhead of the PCS, the
out-of-line functions are compiled with specific compiler flags to
force out-of-line save/restore of any registers that are usually
caller-saved.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Add a CPU feature for the LSE atomic instructions, so that they can be
patched in at runtime when we detect that they are supported.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The ARM v8.1 architecture introduces new atomic instructions to the A64
instruction set for things like cmpxchg, so advertise their availability
to userspace using a hwcap.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

In preparation for the Large System Extension (LSE) atomic instructions
introduced by ARM v8.1, move the current exclusive load/store (LL/SC)
atomics into their own header file.
Reviewed-by: NSteve Capper <steve.capper@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

cpufeature.h makes use of DECLARE_BITMAP, which in turn relies on the
BITS_TO_LONGS and DIV_ROUND_UP macros.

This patch includes kernel.h in cpufeature.h to prevent all users having
to do the same thing.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

STXR can fail for a number of reasons, so don't fail an rwlock trylock
operation simply because the STXR reported failure.

I'm not aware of any issues with the current code, but this makes it
consistent with spin_trylock and also other architectures (e.g. arch/arm).
Reported-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Implement atomic logic ops -- atomic_{or,xor,and}.

These will replace the atomic_{set,clear}_mask functions that are
available on some archs.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Implement atomic logic ops -- atomic_{or,xor,and}.

These will replace the atomic_{set,clear}_mask functions that are
available on some archs.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Our ticket-based spinlock structures rely on a definition of u16, so
include linux/types.h explicitly to ensure the thing compiles.

Found by a module build failure in -next:

  arch/arm64/include/asm/spinlock_types.h:27:2: error: unknown type name 'u16'
  arch/arm64/include/asm/spinlock_types.h:28:2: error: unknown type name 'u16'
  arch/arm64/include/asm/spinlock_types.h:33:13: error: expected declaration specifiers or '...' before numeric constant
  include/linux/spinlock_types.h:21:2: error: unknown type name 'arch_spinlock_t'
  arch/arm64/include/asm/spinlock.h:34:35: error: unknown type name 'arch_spinlock_t'
  arch/arm64/include/asm/spinlock.h:65:37: error: unknown type name 'arch_spinlock_t'
Reported-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The generic slowpath WARN implementation prints a backtrace, but
the report_bug() based implementation does not, opting to print the
registers instead which is generally not as useful.

Ideally, report_bug() should be fixed to make the behaviour more
consistent, but in the meantime this patch generates a backtrace
directly from the arm64 backend instead so that this functionality
is not lost with the migration to report_bug().

As a side-effect, the backtrace will be outside the oops end
marker, but that's hard to avoid without modifying generic code.

This patch can go away if report_bug() grows the ability in the
future to generate a backtrace directly or call an arch hook at the
appropriate time.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Currently, the minimal default BUG() implementation from asm-
generic is used for arm64.

This patch uses the BRK software breakpoint instruction to generate
a trap instead, similarly to most other arches, with the generic
BUG code generating the dmesg boilerplate.

This allows bug metadata to be moved to a separate table and
reduces the amount of inline code at BUG and WARN sites.  This also
avoids clobbering any registers before they can be dumped.

To mitigate the size of the bug table further, this patch makes
use of the existing infrastructure for encoding addresses within
the bug table as 32-bit offsets instead of absolute pointers.
(Note that this limits the kernel size to 2GB.)

Traps are registered at arch_initcall time for aarch64, but BUG
has minimal real dependencies and it is desirable to be able to
generate bug splats as early as possible.  This patch redirects
all debug exceptions caused by BRK directly to bug_handler() until
the full debug exception support has been initialised.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

<asm/debug-monitors.h> relies on <asm/ptrace.h>, but doesn't
declare this dependency.  This becomes a problem once
debug-monitors.h starts getting included all over the place to get
the BRK immedates.

The missing include of <asm/memory.h> (for UL()) in <asm/esr.h> is
also added.  The series no longer relies on this, but I spotted it
during development and it may as well get fixed.

No functional change.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The way the KGDB_DYN_BRK_INS_BYTEx macros are declared is more
complex than it needs to be.  Also, the macros are only used in one
place, which is arch-specific anyway.

This patch refactors the macros to simplify them, and exposes an
argument so that we can have a single macro instead of 4.

As a side effect, this patch also fixes some anomalous spellings of
"KGDB".

These changes alter the compile types of some integer constants
that are harmless but trigger truncation warnings in gcc when
assigning to 32-bit variables.  This patch adds an explicit cast
for the affected cases.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

It makes sense to keep all the architectural exception syndrome
definitions in the same place.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The naming of DBG_ESR_VAL_BRK is inconsistent with the way other
similar macros are named.

This patch makes the naming more consistent, and appends "64"
as a reminder that this ESR pattern only matches from AArch64
state.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

<asm/esr.h> has perfectly good constants for defining ESR values
already.  Let's use them.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>