History log of /arch/arm/include/asm/mmu.h
Revision Date Author Comments
a1af3474487cc3b8731b990dceac6b6aad7f3ed8 07-Oct-2013 Victor Kamensky <victor.kamensky@linaro.org> ARM: tlb: ASID macro should give 32bit result for BE correct operation

In order for ASID macro to be used as expression passed to
inline asm as 'r' operand it needs to give 32 bit unsigned result,
not unsigned 64bit expression.

Otherwise when 64bit ASID is passed to inline assembler statement
as 'r' operand (32bit) compiler behavior is not well specified.
For example when __flush_tlb_mm function compiled in big endian
case, and ASID is passed to tlb_op macro directly, 0 will be passed
as 'mcr 15, 0, r4, cr8, cr3, {2}' argument in r4, unless ASID
macro changed to produce 32 bit result.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
48be69a026b2c17350a5ef18a1959a919f60be7d 24-Jul-2013 Russell King <rmk+kernel@arm.linux.org.uk> ARM: move signal handlers into a vdso-like page

Move the signal handlers into a VDSO page rather than keeping them in
the vectors page. This allows us to place them randomly within this
page, and also map the page at a random location within userspace
further protecting these code fragments from ROP attacks. The new
VDSO page is also poisoned in the same way as the vector page.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
bdae73cd374e28db544fdd9b77de689a36e3c129 23-Jul-2013 Catalin Marinas <catalin.marinas@arm.com> ARM: 7790/1: Fix deferred mm switch on VIVT processors

As of commit b9d4d42ad9 (ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on
pre-ARMv6 CPUs), the mm switching on VIVT processors is done in the
finish_arch_post_lock_switch() function to avoid whole cache flushing
with interrupts disabled. The need for deferred mm switch is stored as a
thread flag (TIF_SWITCH_MM). However, with preemption enabled, we can
have another thread switch before finish_arch_post_lock_switch(). If the
new thread has the same mm as the previous 'next' thread, the scheduler
will not call switch_mm() and the TIF_SWITCH_MM flag won't be set for
the new thread.

This patch moves the switch pending flag to the mm_context_t structure
since this is specific to the mm rather than thread.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: <stable@vger.kernel.org> # 3.5+
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
8a4e3a9ead7e37ce1505602b564c15da09ac039f 28-Feb-2013 Will Deacon <will.deacon@arm.com> ARM: 7659/1: mm: make mm->context.id an atomic64_t variable

mm->context.id is updated under asid_lock when a new ASID is allocated
to an mm_struct. However, it is also read without the lock when a task
is being scheduled and checking whether or not the current ASID
generation is up-to-date.

If two threads of the same process are being scheduled in parallel and
the bottom bits of the generation in their mm->context.id match the
current generation (that is, the mm_struct has not been used for ~2^24
rollovers) then the non-atomic, lockless access to mm->context.id may
yield the incorrect ASID.

This patch fixes this issue by making mm->context.id and atomic64_t,
ensuring that the generation is always read consistently. For code that
only requires access to the ASID bits (e.g. TLB flushing by mm), then
the value is accessed directly, which GCC converts to an ldrb.

Cc: <stable@vger.kernel.org> # 3.8
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
3e99675af1b25a191c467700499b1cbe5585a778 25-Nov-2012 Nicolas Pitre <nicolas.pitre@linaro.org> ARM: 7582/2: rename kvm_seq to vmalloc_seq so to avoid confusion with KVM

The kvm_seq value has nothing to do what so ever with this other KVM.
Given that KVM support on ARM is imminent, it's best to rename kvm_seq
into something else to clearly identify what it is about i.e. a sequence
number for vmalloc section mappings.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
b5466f8728527a05a493cc4abe9e6f034a1bbaab 15-Jun-2012 Will Deacon <will.deacon@arm.com> ARM: mm: remove IPI broadcasting on ASID rollover

ASIDs are allocated to MMU contexts based on a rolling counter. This
means that after 255 allocations we must invalidate all existing ASIDs
via an expensive IPI mechanism to synchronise all of the online CPUs and
ensure that all tasks execute with an ASID from the new generation.

This patch changes the rollover behaviour so that we rely instead on the
hardware broadcasting of the TLB invalidation to avoid the IPI calls.
This works by keeping track of the active ASID on each core, which is
then reserved in the case of a rollover so that currently scheduled
tasks can continue to run. For cores without hardware TLB broadcasting,
we keep track of pending flushes in a cpumask, so cores can flush their
local TLB before scheduling a new mm.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
b9d4d42ad901cc848ac87f1cb8923fded3645568 28-Nov-2011 Catalin Marinas <catalin.marinas@arm.com> ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on pre-ARMv6 CPUs

This patch removes the __ARCH_WANT_INTERRUPTS_ON_CTXSW definition for
ARMv5 and earlier processors. On such processors, the context switch
requires a full cache flush. To avoid high interrupt latencies, this
patch defers the mm switching to the post-lock switch hook if the
interrupts are disabled.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Tested-by: Marc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
7fec1b57b8a925d83c194f995f83d9f8442fd48e 28-Nov-2011 Catalin Marinas <catalin.marinas@arm.com> ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on ASID-capable CPUs

Since the ASIDs must be unique to an mm across all the CPUs in a system,
the __new_context() function needs to broadcast a context reset event to
all the CPUs during ASID allocation if a roll-over occurred. Such IPIs
cannot be issued with interrupts disabled and ARM had to define
__ARCH_WANT_INTERRUPTS_ON_CTXSW.

This patch changes the check_context() function to
check_and_switch_context() called from switch_mm(). In case of
ASID-capable CPUs (ARMv6 onwards), if a new ASID is needed and the
interrupts are disabled, it defers the __new_context() and
cpu_switch_mm() calls to the post-lock switch hook where the interrupts
are enabled. Setting the reserved TTBR0 was also moved to
check_and_switch_context() from cpu_v7_switch_mm().

Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Tested-by: Marc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
9f97da78bf018206fb623cd351d454af2f105fe0 28-Mar-2012 David Howells <dhowells@redhat.com> Disintegrate asm/system.h for ARM

Disintegrate asm/system.h for ARM.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org
bd31b85960a7fcb2d7ede216460b8da71a88411c 03-Jul-2009 Thomas Gleixner <tglx@linutronix.de> locking, ARM: Annotate low level hw locks as raw

Annotate the low level hardware locks which must not be preempted.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
28c22d7dc99486ef4186dde41d5260e75b3076f7 23-Nov-2010 MyungJoo Ham <myungjoo.ham@gmail.com> ARM: 6490/1: MM: bugfix: initialize spinlock for init_mm.context

init_mm used at kernel/sched.c:idle_task_exit() has spin_lock
(init_mm.context.id_lock) that is not initialized when spin_lock/unlock
is called at an ARM machine. Note that mm_struct.context.id_lock is
usually initialized except for the instance of init_mm at
linux/arch/arm/mm/context.c

Not initializing this spinlock incurs "BUG: pinlock bad magic"
warning when spinlock debug is enabled. We have observed such
instances when testing PM in S5PC210 machines.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
11805bcfa411c816b7c76fc40724be6733c74ffc 26-Jan-2010 Catalin Marinas <catalin.marinas@arm.com> ARM: 5905/1: ARM: Global ASID allocation on SMP

The current ASID allocation algorithm doesn't ensure the notification
of the other CPUs when the ASID rolls over. This may lead to two
processes using the same ASID (but different generation) or multiple
threads of the same process using different ASIDs.

This patch adds the broadcasting of the ASID rollover event to the
other CPUs. To avoid a race on multiple CPUs modifying "cpu_last_asid"
during the handling of the broadcast, the ASID numbering now starts at
"smp_processor_id() + 1". At rollover, the cpu_last_asid will be set
to NR_CPUS.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
8feae13110d60cc6287afabc2887366b0eb226c2 08-Jan-2009 David Howells <dhowells@redhat.com> NOMMU: Make VMAs per MM as for MMU-mode linux

Make VMAs per mm_struct as for MMU-mode linux. This solves two problems:

(1) In SYSV SHM where nattch for a segment does not reflect the number of
shmat's (and forks) done.

(2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an
exec'ing process when VM_EXECUTABLE is specified, regardless of the fact
that a VMA might be shared and already have its vm_mm assigned to another
process or a dead process.

A new struct (vm_region) is introduced to track a mapped region and to remember
the circumstances under which it may be shared and the vm_list_struct structure
is discarded as it's no longer required.

This patch makes the following additional changes:

(1) Regions are now allocated with alloc_pages() rather than kmalloc() and
with no recourse to __GFP_COMP, so the pages are not composite. Instead,
each page has a reference on it held by the region. Anything else that is
interested in such a page will have to get a reference on it to retain it.
When the pages are released due to unmapping, each page is passed to
put_page() and will be freed when the page usage count reaches zero.

(2) Excess pages are trimmed after an allocation as the allocation must be
made as a power-of-2 quantity of pages.

(3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may
end up with overlapping VMAs within the tree, the VMA struct address is
appended to the sort key.

(4) Non-anonymous VMAs are now added to the backing inode's prio list.

(5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of
the backing region. The VMA and region structs will be split if
necessary.

(6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory
segment instead of all the attachments at that addresss. Multiple
shmat()'s return the same address under NOMMU-mode instead of different
virtual addresses as under MMU-mode.

(7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode.

(8) /proc/maps is now the global list of mapped regions, and may list bits
that aren't actually mapped anywhere.

(9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount
of RAM currently allocated by mmap to hold mappable regions that can't be
mapped directly. These are copies of the backing device or file if not
anonymous.

These changes make NOMMU mode more similar to MMU mode. The downside is that
NOMMU mode requires some extra memory to track things over NOMMU without this
patch (VMAs are no longer shared, and there are now region structs).

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Mike Frysinger <vapier.adi@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
4baa9922430662431231ac637adedddbb0cfb2d7 02-Aug-2008 Russell King <rmk@dyn-67.arm.linux.org.uk> [ARM] move include/asm-arm to arch/arm/include/asm

Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>