On ARMv7 CPUs that cache first level page table entries (like the
Cortex-A15), using a reserved ASID while changing the TTBR or flushing
the TLB is unsafe.
This is because the CPU may cache the first level entry as the result of
a speculative memory access while the reserved ASID is assigned. After
the process owning the page tables dies, the memory will be reallocated
and may be written with junk values which can be interpreted as global,
valid PTEs by the processor. This will result in the TLB being populated
with bogus global entries.
This patch avoids the use of a reserved context ID in the v7 switch_mm
and ASID rollover code by temporarily using the swapper_pg_dir pointed
at by TTBR1, which contains only global entries that are not tagged
with ASIDs.
Acked-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>
This patch makes TTBR1 point to swapper_pg_dir so that global, kernel
mappings can be used exclusively on v6 and v7 cores where they are
needed.
Signed-off-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>
CONFIG_PM is now set whenever we support either runtime PM in addition
to suspend and hibernate. This causes build errors when runtime PM is
enabled on a platform, but the CPU does not have the appropriate support
for suspend.
So, switch this code to use CONFIG_PM_SLEEP rather than CONFIG_PM to
allow runtime PM to be enabled without causing build errors.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On the r2p* and r3p* versions of the Cortex-A9, a speculative memory
access may cause a page table walk which starts prior to an ASID switch
but completes afterwards. This can populate the micro-TLB with a stale
entry which may be hit with the new ASID.
This workaround places two dsb instructions in the mm switching code so
that no page table walks can cross the ASID switch.
Acked-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>
This adds core support for saving and restoring CPU coprocessor
registers for suspend/resume support. This contains support for suspend
with ARM920, ARM926, SA11x0, PXA25x, PXA27x, PXA3xx, V6 and V7 CPUs.
Tested on Assabet and Tegra 2.
Tested-by: Colin Cross <ccross@android.com>
Tested-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On versions of the Cortex-A9 prior to r3p0, an interrupted ICIALLUIS
operation may prevent the completion of a following broadcasted
operation if the second operation is received by a CPU before the
ICIALLUIS has completed, potentially leading to corrupted entries in
the cache or TLB.
This workaround sets a bit in the diagnostic register of the Cortex-A9,
causing CP15 maintenance operations to be uninterruptible.
Acked-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>
Commit d30e45e (ARM: pgtable: switch order of Linux vs hardware page tables)
introduced a pre-increment addressing offset which is out of range for
Thumb-2. Thumb-2 only permits offsets <256. So split the intruction in
two for Thumb-2.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The hardware page tables use an XN bit 'execute never'. Historically,
we've had a Linux 'execute allow' bit, in the positive sense. Get rid
of this artifact as future hardware will continue to have the XN sense.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This switches the ordering of the Linux vs hardware page tables in
each page, thereby eliminating some of the arithmetic in the page
table walks. As we now place the Linux page table at the beginning
of the page, we can deal with the offset in the pgt by simply masking
it away, along with the other control bits.
This also makes the arithmetic all be positive, rather than a mixture.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Directives such as .long and .word do not magically cause the
assembler location counter to become aligned in gas. As a result,
using these directives in code sections can result in misaligned
data words when building a Thumb-2 kernel (CONFIG_THUMB2_KERNEL).
This is a Bad Thing, since the ABI permits the compiler to assume
that fundamental types of word size or above are word- aligned when
accessing them from C. If the data is not really word-aligned,
this can cause impaired performance and stray alignment faults in
some circumstances.
In general, the following rules should be applied when using data
word declaration directives inside code sections:
* .quad and .double:
.align 3
* .long, .word, .single, .float:
.align (or .align 2)
* .short:
No explicit alignment required, since Thumb-2
instructions are always 2 or 4 bytes in size.
immediately after an instruction.
In this specific case, we can achieve the desired alignment by
forcing a 32-bit branch instruction using the W() macro, since the
assembler location counter is already 32-bit aligned in this case.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The SWP instruction was deprecated in the ARMv6 architecture,
superseded by the LDREX/STREX family of instructions for
load-linked/store-conditional operations. The ARMv7 multiprocessing
extensions mandate that SWP/SWPB instructions are treated as undefined
from reset, with the ability to enable them through the System Control
Register SW bit.
This patch adds the alternative solution to emulate the SWP and SWPB
instructions using LDREX/STREX sequences, and log statistics to
/proc/cpu/swp_emulation. To correctly deal with copy-on-write, it also
modifies cpu_v7_set_pte_ext to change the mappings to priviliged RO when
user RO.
Signed-off-by: Leif Lindholm <leif.lindholm@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch removes the domain switching functionality via the set_fs and
__switch_to functions on cores that have a TLS register.
Currently, the ioremap and vmalloc areas share the same level 1 page
tables and therefore have the same domain (DOMAIN_KERNEL). When the
kernel domain is modified from Client to Manager (via the __set_fs or in
the __switch_to function), the XN (eXecute Never) bit is overridden and
newer CPUs can speculatively prefetch the ioremap'ed memory.
Linux performs the kernel domain switching to allow user-specific
functions (copy_to/from_user, get/put_user etc.) to access kernel
memory. In order for these functions to work with the kernel domain set
to Client, the patch modifies the LDRT/STRT and related instructions to
the LDR/STR ones.
The user pages access rights are also modified for kernel read-only
access rather than read/write so that the copy-on-write mechanism still
works. CPU_USE_DOMAINS gets disabled only if the hardware has a TLS register
(CPU_32v6K is defined) since writing the TLS value to the high vectors page
isn't possible.
The user addresses passed to the kernel are checked by the access_ok()
function so that they do not point to the kernel space.
Tested-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When hotplug CPU is enabled, we need to keep the list of supported CPUs,
their setup functions, and __lookup_processor_type in place so that we
can find and initialize secondary CPUs. Move these into the __CPUINIT
section.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit 14eff18126 added proper
detection for ARM11MPCore/Cortex-A9 instead of detecting them
as ARMv7. However, it was missing the HWCAP_TLS flags.
HWCAP_TLS is needed if support for earlier ARMv6 is compiled
into the same kernel. Without HWCAP_TLS flags the userspace
won't work unless nosmp is specified:
Kernel panic - not syncing: Attempted to kill init!
CPU0: stopping
<c005d5e4>] (unwind_backtrace+0x0/0xec) from [<c004c2f8>] (do_IPI+0xfc/0x184)
<c004c2f8>] (do_IPI+0xfc/0x184) from [<c03f25bc>] (__irq_svc+0x9c/0x160)
Exception stack(0xc0565f80 to 0xc0565fc8)
5f80: 00000001 c05772a0 00000000 00003a61 c0564000 c05cf500 c003603c c0578600
5fa0: 80033ef0 410fc091 0000001f 00000000 00000000 c0565fc8 c00b91f8 c0057cb4
5fc0: 20000013 ffffffff
[<c03f25bc>] (__irq_svc+0x9c/0x160) from [<c0057cb4>] (default_idle+0x30/0x38)
[<c0057cb4>] (default_idle+0x30/0x38) from [<c005829c>] (cpu_idle+0x9c/0xf8)
[<c005829c>] (cpu_idle+0x9c/0xf8) from [<c0008d48>] (start_kernel+0x2a4/0x300)
[<c0008d48>] (start_kernel+0x2a4/0x300) from [<80008084>] (0x80008084)
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
UP systems do not implement all the instructions that SMP systems have,
so in order to boot a SMP kernel on a UP system, we need to rewrite
parts of the kernel.
Do this using an 'alternatives' scheme, where the kernel code and data
is modified prior to initialization to replace the SMP instructions,
thereby rendering the problematical code ineffectual. We use the linker
to generate a list of 32-bit word locations and their replacement values,
and run through these replacements when we detect a UP system.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On the r2p0, r2p1 and r2p2 versions of the Cortex-A9, data corruption
can occur under very rare conditions due to a store buffer optimisation.
This workaround sets a bit in the diagnostic register of the Cortex-A9,
disabling the optimisation and preventing the problem from occurring.
Acked-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>
Setting of these bits can cause issues on other SMP SoC's not produced
by ARM.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On the r2p0, r2p1 and r2p2 versions of the Cortex-A9, data corruption
can occur if a shared cache line is replaced on one CPU as another CPU
is accessing it.
This workaround sets two bits in the diagnostic register of the Cortex-A9,
reducing the linefill issuing capabilities of the processor and
avoiding the erroneous behaviour.
Acked-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>
On versions of the Cortex-A9 up to and including r2p2, under rare
circumstances, a DMB instruction between 2 write operations may not
ensure the correct visibility ordering of the 2 writes.
This workaround sets a bit in the diagnostic register of the Cortex-A9,
causing the DMB instruction to behave like a DSB, which functions
correctly on the affected cores.
Acked-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>
Kconfig doesn't have any knowledge of specific v7 cores, so it is possible
to select errata workarounds that may cause inadvertent behaviour when
executed on a core other than those targetted by the fix.
This patch improves the variant and revision checking in proc-v7.S so
that the primary part number is also considered when applying errata
workarounds.
Acked-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>
All implementations of cpu_proc_fin() start by disabling interrupts
and then flush caches. Rather than have every processors proc_fin()
implementation do this, move it out into generic code - and move the
cache flush past setup_mm_for_reboot() (so it can benefit from having
caches still enabled.)
This allows cpu_proc_fin() to become independent of the L1/L2 cache
types, and eventually move the L2 cache flushing into the L2 support
code.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The TLS register is only available on ARM1136 r1p0 and later.
Set HWCAP_TLS flags if hardware TLS is available and test for
it if CONFIG_CPU_32v6K is not set for V6.
Note that we set the TLS instruction in __kuser_get_tls
dynamically as suggested by Jamie Lokier <jamie@shareable.org>.
Also the __switch_to code is optimized out in most cases as
suggested by Nicolas Pitre <nico@fluxnic.net>.
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
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>
If running in non-secure mode, enabling this register will fault.
Signed-off-by: Tony Thompson <Anthony.Thompson@arm.com>
Acked-by: Srinidhi Kasagar <srinidhikasagar@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Mapping the same memory using two different attributes (memory
type, shareability, cacheability) is unpredictable. During boot,
we encounter a situation when we're updating the kernel's page
tables which can lead to dirty cache lines existing in the cache
which are subsequently missed. This causes stack corruption,
and therefore a crash.
Therefore, ensure that the shared and cacheability settings
matches the configuration that will be used later; this together
with the restriction in early_cachepolicy() ensures that we won't
create a mismatch during boot.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Instruction fault status register, IFSR, was introduced on ARMv6 to
provide status information about the last insturction fault. It
needed for proper prefetch abort handling.
Now we have three prefetch abort model:
* legacy - for CPUs before ARMv6. They doesn't provide neither
IFSR nor IFAR. We simulate IFSR with section translation fault
status for them to generalize code;
* ARMv6 - provides IFSR, but not IFAR;
* ARMv7 - provides both IFSR and IFAR.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (417 commits)
MAINTAINERS: EB110ATX is not ebsa110
MAINTAINERS: update Eric Miao's email address and status
fb: add support of LCD display controller on pxa168/910 (base layer)
[ARM] 5552/1: ep93xx get_uart_rate(): use EP93XX_SYSCON_PWRCNT and EP93XX_SYSCON_PWRCN
[ARM] pxa/sharpsl_pm: zaurus needs generic pxa suspend/resume routines
[ARM] 5544/1: Trust PrimeCell resource sizes
[ARM] pxa/sharpsl_pm: cleanup of gpio-related code.
[ARM] pxa/sharpsl_pm: drop set_irq_type calls
[ARM] pxa/sharpsl_pm: merge pxa-specific code into generic one
[ARM] pxa/sharpsl_pm: merge the two sharpsl_pm.c since it's now pxa specific
[ARM] sa1100: remove unused collie_pm.c
[ARM] pxa: fix the conflicting non-static declarations of global_gpios[]
[ARM] 5550/1: Add default configure file for w90p910 platform
[ARM] 5549/1: Add clock api for w90p910 platform.
[ARM] 5548/1: Add gpio api for w90p910 platform
[ARM] 5551/1: Add multi-function pin api for w90p910 platform.
[ARM] Make ARM_VIC_NR depend on ARM_VIC
[ARM] 5546/1: ARM PL022 SSP/SPI driver v3
ARM: OMAP4: SMP: Update defconfig for OMAP4430
ARM: OMAP4: SMP: Enable SMP support for OMAP4430
...
Currently, whenever an erratum workaround is enabled, it will be
applied whether or not the erratum is relevent for the CPU. This
patch changes this - we check the variant and revision fields in the
main ID register to determine which errata to apply.
We also avoid re-applying erratum 460075 if it has already been applied.
Applying this fix in non-secure mode results in the kernel failing to
boot (or even do anything.)
This fixes booting on some ARMv7 based platforms which otherwise
silently fail.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Starting with ARMv6, the CPUs support the BE-8 variant of big-endian
(byte-invariant). This patch adds the core support:
- setting of the BE-8 mode via the CPSR.E register for both kernel and
user threads
- big-endian page table walking
- REV used to rotate instructions read from memory during fault
processing as they are still little-endian format
- Kconfig and Makefile support for BE-8. The --be8 option must be passed
to the final linking stage to convert the instructions to
little-endian
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds a comment to the proc-v7.S file for the setting of the
PRRR and NMRR registers. It also sets the PRRR[13:12] bits to 0
(corresponding to the reserved TEX[0]CB encoding 110) to be consistent
with the documentation.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The SWP instruction has been deprecated starting with the ARMv6
architecture. On ARMv7 processors with the multiprocessor extensions
(like Cortex-A9), this instruction is disabled by default but it can be
enabled by setting bit 10 in the System Control register. Note that
setting this bit is safe even if the ARMv7 processor has the SWP
instruction enabled by default.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
There are additional bits to set for the ARMv7 SMP extensions in the
TTBR registers. The IRGN bits order is counter-intuitive but it allows
software built for the ARMv7 base architecture to run on an
implementation with the MP extensions.
Signed-off-by: Tony Thompson <Anthony.Thompson@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
ARMv7 SMP hardware can handle the TLB maintenance operations
broadcasting in hardware so that the software can avoid the costly IPIs.
This patch adds the necessary checks (the MMFR3 CPUID register) to avoid
the broadcasting if already supported by the hardware.
(this patch is based on the work done by Tony Thompson @ ARM)
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* master.kernel.org:/home/rmk/linux-2.6-arm: (45 commits)
[ARM] 5489/1: ARM errata: Data written to the L2 cache can be overwritten with stale data
[ARM] 5490/1: ARM errata: Processor deadlock when a false hazard is created
[ARM] 5487/1: ARM errata: Stale prediction on replaced interworking branch
[ARM] 5488/1: ARM errata: Invalidation of the Instruction Cache operation can fail
davinci: DM644x: NAND: update partitioning
davinci: update DM644x support in preparation for more SoCs
davinci: DM644x: rename board file
davinci: update pin-multiplexing support
davinci: serial: generalize for more SoCs
davinci: DM355 IRQ Definitions
davinci: DM646x: add interrupt number and priorities
davinci: PSC: Clear bits in MDCTL reg before setting new bits
davinci: gpio bugfixes
davinci: add EDMA driver
davinci: timers: use clk_get_rate()
[ARM] pxa/littleton: add missing da9034 touchscreen support
[ARM] pxa/zylonite: configure GPIO18/19 correctly, used by 2 GPIO expanders
[ARM] pxa/zylonite: fix the issue of unused SDATA_IN_1 pin get AC97 not working
[ARM] pxa: make ads7846 on corgi and spitz to sync on HSYNC
[ARM] pxa: remove unused CPU_FREQ_PXA Kconfig symbol
...
This patch is a workaround for the 460075 Cortex-A8 (r2p0) erratum. It
configures the L2 cache auxiliary control register so that the Write
Allocate mode for the L2 cache is disabled.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds a workaround for the 458693 Cortex-A8 (r2p0)
erratum. It sets the corresponding bits in the auxiliary control
register so that the PLD instruction becomes a NOP.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds the workaround for the 430973 Cortex-A8 (r1p0..r1p2)
erratum. The BTAC/BTB is now flushed at every context switch.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arm is placing some code in the .text.init section, but it does not
reference that section in its linker scripts.
This change moves this code from the .text.init section to the
.init.text section, which is presumably where it belongs.
Signed-off-by: Tim Abbott <tabbott@mit.edu>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
