Clarify that the memory below the start of the image but inside the
region covered by the linear mapping has no special significance to
the kernel, and may be used by the firmware provided that it is marked
as reserved.

Also, fix up some whitespace errors.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

For some reason, the ll/sc cmpxchg asm is all off to the left and
awkward to read in conjunction with the following (correctly indented)
LSE version.

This patch shifts the ll/sc code back to where it should be.
Signed-off-by: Will Deacon <will.deacon@arm.com>

Commit 4b3dc967 ("arm64: force CONFIG_SMP=y and remove redundant
#ifdefs") forces SMP on arm64. To build the necessary objects for SMP,
they were added to the arm64-obj-y rule in arch/arm64/kernel/Makefile,
without removing the arm64-obj-$(CONFIG_SMP) rule.

Remove redundant object file list depending on always-yes CONFIG_SMP in
arch/arm64/kernel/Makefile.
Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Commit 4b3dc967 ("arm64: force CONFIG_SMP=y and remove redundant
and therfore can not be selected anymore.

Remove dead #ifdef-block depending on UP_LATE_INIT in
arch/arm64/kernel/setup.c
Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
[will: kill do_post_cpus_up_work altogether]
Signed-off-by: Will Deacon <will.deacon@arm.com>

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: Will 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: Will 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: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will 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: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will 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: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will 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: Will 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: Wang Long <long.wanglong@huawei.com>
Signed-off-by: Will 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: Will 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: Will 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: Will 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: Will Deacon <will.deacon@arm.com>

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

Merge branch 'locking/arch-atomic' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into aarch64/for-next/core

Merge in PeterZ's logical atomic ops so that we can implement them in
our subsequent LSE atomics.

Add a few atomic_t tests, gets some compile coverage for the new
operations.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Replace the deprecated atomic_{set,clear}_mask() usage with the now
ubiquous atomic_{or,andnot}() functions.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Move the now generic definitions of atomic_{set,clear}_mask() into
linux/atomic.h to avoid endless and pointless repetition.

Also, provide an atomic_andnot() wrapper for those few archs that can
implement that.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas 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: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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

For tilegx, these are relatively straightforward; the architecture
provides atomic "or" and "and", both 32-bit and 64-bit.  To support
xor we provide a loop using "cmpexch".

For the older 32-bit tilepro architecture, we have to extend
the set of low-level assembly routines to include 32-bit "and",
as well as all three 64-bit routines.  Somewhat confusingly,
some 32-bit versions are already used by the bitops inlines, with
parameter types appropriate for bitops, so we have to do a bit of
casting to match "int" to "unsigned long".
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1436474297-32187-1-git-send-email-cmetcalf@ezchip.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>