The mandatory barriers (mb, rmb, wmb) are used even on uniprocessor
systems for things like ordering Normal Non-cacheable memory accesses
with DMA transfer (via Device memory writes). The current implementation
uses dmb() for mb() and friends but this is not sufficient. The DMB only
ensures the relative ordering of the observability of accesses by other
processors or devices acting as masters. In case of DMA transfers
started by writes to device memory, the relative ordering is not ensured
because accesses to slave ports of a device are not considered
observable by the DMB definition.
A DSB is required for the data to reach the main memory (even if mapped
as Normal Non-cacheable) before the device receives the notification to
begin the transfer. Furthermore, some L2 cache controllers (like L2x0 or
PL310) buffer stores to Normal Non-cacheable memory and this would need
to be drained with the outer_sync() function call.
The patch also allows platforms to define their own mandatory barriers
implementation by selecting CONFIG_ARCH_HAS_BARRIERS and providing a
mach/barriers.h file.
Note that the SMP barriers are unchanged (being DMBs as before) since
they are only guaranteed to work with Normal Cacheable memory.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The L2x0 cache controllers need to explicitly drain their write buffer
even for Normal Noncacheable memory accesses.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch introduces the outer_cache_fns.sync function pointer together
with the OUTER_CACHE_SYNC config option that can be used to drain the
write buffer of the outer cache.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add ARM_L1_CACHE_SHIFT_6 to arch/arm/Kconfig to allow CPUs with
L1 cache lines which are 64bytes to indicate this without having to
alter the arch/arm/mm/Kconfig entry each time.
Update the mm Kconfig so that ARM_L1_CACHE_SHIFT default value
uses this and change OMAP3 and S5PC1XX to select ARM_L1_CACHE_SHIFT_6.
Acked-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
update_mmu_cache() is called with the page table for the faulted-in
page still mapped. We need to modify the PTE for this page to ensure
coherency with other shared mappings when multiple shared mappings
exist within a MM.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On VIVT ARM, when we have multiple shared mappings of the same file
in the same MM, we need to ensure that we have coherency across all
copies. We do this via make_coherent() by making the pages
uncacheable.
This used to work fine, until we allowed highmem with highpte - we
now have a page table which is mapped as required, and is not available
for modification via update_mmu_cache().
Ralf Beache suggested getting rid of the PTE value passed to
update_mmu_cache():
On MIPS update_mmu_cache() calls __update_tlb() which walks pagetables
to construct a pointer to the pte again. Passing a pte_t * is much
more elegant. Maybe we might even replace the pte argument with the
pte_t?
Ben Herrenschmidt would also like the pte pointer for PowerPC:
Passing the ptep in there is exactly what I want. I want that
-instead- of the PTE value, because I have issue on some ppc cases,
for I$/D$ coherency, where set_pte_at() may decide to mask out the
_PAGE_EXEC.
So, pass in the mapped page table pointer into update_mmu_cache(), and
remove the PTE value, updating all implementations and call sites to
suit.
Includes a fix from Stephen Rothwell:
sparc: fix fallout from update_mmu_cache API change
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Some glibc versions intentionally create lots of alignment faults in
their gconv code, which if not fixed up, results in segfaults during
boot. This can prevent systems booting properly.
There is no clear hard-configurable default for this; the desired
default depends on the nature of the userspace which is going to be
booted.
So, provide a way for the alignment fault handler to be configured via
the kernel command line.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Makes it consistent with VMALLOC_START
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Adds DMA area to 'virtual memory map' startup message
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Code based on parisc and x86_32.
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch implements the work-around for the errata 588369.The secure
API is used to alter L2 debug register because of trust-zone.
This version updated with comments from Russell and Catalin and
generated against 2.6.33-rc6 mainline kernel. Detail
comments can be found:
http://www.spinics.net/lists/linux-omap/msg23431.html
Signed-off-by: Woodruff Richard <r-woodruff2@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds L2 Cache support for OMAP4. External L2 cache
is used in OMAP4
CC: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds the cache maintainance by line helper functions.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Otherwise the kernel built with both CPU_V6 and CPU_V7 will not
boot on omap2.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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>
The ARM setup code includes its own parser for early params, there's
also one in the generic init code.
This patch removes __early_init (and related code) from
arch/arm/kernel/setup.c, and changes users to the generic early_init
macro instead.
The generic macro takes a char * argument, rather than char **, so we
need to update the parser functions a little.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Always creating this directory avoids other users having to jump
through silly hoops when they want to share this directory.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This allows the procfs vmallocinfo file to show who created the ioremap
regions. Note: __builtin_return_address(0) doesn't do what's expected
if its used in an inline function, so we leave __arm_ioremap callers
in such places alone.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARMv6 and ARMv7 CPUs can perform speculative prefetching, which makes
DMA cache coherency handling slightly more interesting. Rather than
being able to rely upon the CPU not accessing the DMA buffer until DMA
has completed, we now must expect that the cache could be loaded with
possibly stale data from the DMA buffer.
Where DMA involves data being transferred to the device, we clean the
cache before handing it over for DMA, otherwise we invalidate the buffer
to get rid of potential writebacks. On DMA Completion, if data was
transferred from the device, we invalidate the buffer to get rid of
any stale speculative prefetches.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-By: Santosh Shilimkar <santosh.shilimkar@ti.com>
These are now unused, and so can be removed.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-By: Santosh Shilimkar <santosh.shilimkar@ti.com>
dma_cache_maint_contiguous is now simple enough to live inside
dma_cache_maint_page, so move it there.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-By: Santosh Shilimkar <santosh.shilimkar@ti.com>
The DMA API has the notion of buffer ownership; make it explicit in the
ARM implementation of this API. This gives us a set of hooks to allow
us to deal with CPU cache issues arising from non-cache coherent DMA.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-By: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-By: Jamie Iles <jamie@jamieiles.com>
The perf events subsystem allows counting of both hardware and
software events. This patch implements the bare minimum for software
performance events.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We already know the pfn for the page to be modified in make_coherent,
so let's stop recalculating it unnecessarily.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
update_mmu_cache() is called with a page table already mapped. We
call make_coherent(), which then calls adjust_pte() which wants to
map other page tables. This causes kmap_atomic() to BUG() because
the slot its trying to use is already taken.
Since do_adjust_pte() modifies the page tables, we are also missing
any form of locking, so we're risking corrupting the page tables.
Fix this by using pte_offset_map_nested(), and taking the pte page
table lock around do_adjust_pte().
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The comments in cacheflush.h should follow what's in
struct cpu_cache_fns. The comments for V6 and V7 are
unnecessary.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The comments in arm_machine_restart() suggest that cpu_proc_fin()
will clean and disable cache and turn off interrupts. This does
not seem to be implemented for proc-v7.S, implement it the same
way as for proc-v6.S.
This also makes kexec work for v7. Note that a related TLB and
branch traget flush patch is also needed to avoid kexec
"crc error".
Note that there are still some issues that seem to be related
to L2 cache being on and causing occasional uncompress "crc error"
with kexec. Anyways, this gets kexec mostly working on V7 for now.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We need to do that if we tinker with the MMU entries.
This fixes the occasional bug with kexec where the new
fails to uncompress with "crc error". Most likely at
least kexec on v6 and v7 need this fix.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
A kernel with both ARMv6 and ARMv7 selected results in build errors.
Fix this by specifying the proper architectures for these assembly
files.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Makes it consistent with the extern declaration, used when CONFIG_HIGHMEM
is set Removes redundant casts in printout messages
Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Check whether L2 is present or not in XSC3. If it's present, enable L2
immediately.
Disabling L2 after L2 is enabled that would result in unpredicatable behavior
of XSC3 processor.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Outer cache checked whether L2 is enabled or not. If L2 isn't enabled in XSC3,
it would enable L2. This operation is evil that would make system hang.
In XSC3 core document, these words are mentioned in below.
"Following reset, the L2 Unified Cache Enable bit is cleared. To enable the L2
Cache, software may set the bit to a '1' before or at the same time as enabling
the MMU. Enabling the L2 Cache after the MMU has been enabled or disabling the
L2 Cache after the L2 Cache has been enabled, may result in unpredictable
behavior of the processor."
When outer cache is initialized, the MMU is already enabled. We couldn't enable
L2 after MMU enabled.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
PAGE_KERNEL should not be executable; any area marked executable can
be prefetched into the instruction cache. We don't want vmalloc areas
to be read in this way.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
It is unpredictable to have the same memory mapped using different
shared bit settings for ARMv6 and ARMv7 CPUs. Fix this for the CPU
write buffer bug test.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
26-bit ARM support was removed a long time ago, and this symbol has
been defined to be 'y' ever since. As it's never disabled anymore,
we can kill it without any side effects.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit 2c9b9c849 added an argument to __cpuc_flush_dcache_page
and renamed it.
Update a caller of the old function to fix this build error:
CC arch/arm/mm/copypage-v6.o
arch/arm/mm/copypage-v6.c: In function 'v6_copy_user_highpage_nonaliasing':
arch/arm/mm/copypage-v6.c:51: error: implicit declaration of function '__cpuc_flush_dcache_page'
make[1]: *** [arch/arm/mm/copypage-v6.o] Error 1
make: *** [arch/arm/mm] Error 2
Reported-by: Jinsung Yang <jsgood.yang@samsung.com>
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There is not enough users to warrant its existence, and it is actually
an obstacle to progress with the new DMA API which cannot cover this
case properly.
To keep backward compatibility, let's perform the necessary custom
cache maintenance locally in the only driver affected.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There's no point having the hardware support background operations
if we issue a cache operation, and then wait for it to complete
before calculating the address of the next operation. We gain no
advantage in the cache controller stalling the bus until completion.
What we should be doing is using the 'wait' time productively by
calculating the address of the next operation, and only then waiting
for the previous operation to complete. This means that cache
operations can occur in parallel with the CPU calculating the next
address.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Taking the spinlock for every iteration is very expensive; instead,
batch iterations up into 4K blocks, releasing and reacquiring the
spinlock between each block.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Catalin Marinas