Currently omap3_cpuidle_update_states makes whole sale decision
on which C states to update based on enable_off_mode variable
Instead, achieve the same functionality by independently providing
mpu and core deepest states the system is allowed to achieve and
update the idle states accordingly.
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
[khilman: fixed additional user of this API in OMAP CPUidle driver]
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
While coming out of MPU OSWR/OFF states, L2 controller is reseted.
The reset behavior is implementation specific as per ARMv7 TRM and
hence $L2 needs to be invalidated before it's use. Since the
AUXCTRL register is also reconfigured, disable L2 cache before
invalidating it and re-enables it afterwards. This is as per
Cortex-A8 ARM documentation.
Currently this is identified as being needed on OMAP3630 as the
disable/enable is done from "public side" while, on OMAP3430, this
is done in the "secure side".
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Tony Lindgren <tony@atomide.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[nm@ti.com: ported to 2.6.37-rc2, added hooks to enable the logic only on 3630]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@nokia.com>
Signed-off-by: Peter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Erratum id: i608
RTA (Retention Till Access) feature is not supported and leads to device
stability issues when enabled. This impacts modules with embedded memories
on OMAP3630
Workaround is to disable RTA on boot and coming out of core off.
For disabling RTA coming out of off mode, we do this by overriding the
restore pointer for 3630 as the first point of entry before caches are
touched and is common for GP and HS devices. To disable earlier than
this could be possible by modifying the PPA for HS devices, but not for
GP devices.
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Tony Lindgren <tony@atomide.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[ambresh@ti.com: co-developer]
Signed-off-by: Ambresh K <ambresh@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Introduce errata handling for OMAP3. This patch introduces
errata variable and stub for initialization which will be
filled up by follow-on patches.
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Erratum i581 impacts OMAP3 platforms.
PRCM DPLL control FSM removes SDRC_IDLEREQ before DPLL3 locks causing
the DPLL not to be locked at times.
IMPORTANT:
*) This is not a complete workaround implementation as recommended
by the silicon erratum. This is a support logic for detecting lockups and
attempting to recover where possible and is known to provide stability
in multiple platforms.
*) This code is mostly important for inactive and retention. The ROM code
waits for the maximum DLL lock time when resuming from off mode. So for
off mode this code isn't really needed.
*) counters are introduced here for eventual export to userspace once the
cleanups are completed.
This should eventually get refactored as part of cleanups to sleep34xx.S
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Analysis in TI kernel with ETM showed that using cache mapped flush
in kernel instead of SO mapped flush cost drops by 65% (3.39mS down
to 1.17mS) for clean_l2 which is used during sleep sequences.
Overall:
- speed up
- unfortunately there isn't a good alternative flush method today
- code reduction and less maintenance and potential bug in
unmaintained code
This also fixes the bug with the clean_l2 function usage.
Reported-by: Tony Lindgren <tony@atomide.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Tony Lindgren <tony@atomide.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
[nm@ti.com: ported rkw's proposal to 2.6.37-rc2]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
omap2_common_pm_init is the API where generic system devices like
mpu, l3 etc get initialized. This has to happen really early on
during the boot and not at a later time. This is especially important
with the new opp changes as these devices need to be built before the
opp tables init happen. Today both are device initcalls and it works
just because of the order of compilation. Making this postcore_initcall
is ideal because the omap device layer init happens as a core_initcall
and typically rest of the driver/device inits are arch_initcall or
something lower.
Signed-off-by: Thara Gopinath <thara@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Some bad interaction between the idle and the suspend paths has been
identified: the idle code is called during the suspend enter and exit
sequences. This could cause corruption or lock-up of resources.
The solution is to move the calls to disable_hlt at the very beginning
of the suspend sequence (ex. in omap3_pm_begin instead of
omap3_pm_prepare), and the call to enable_hlt at the very end of
the suspend sequence (ex. in omap3_pm_end instead of omap3_pm_finish).
Tested with RET and OFF on Beagle and OMAP3EVM.
Signed-off-by: Jean Pihet <j-pihet@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
* 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
ARM: S5PV210: update MAX8998 platform data to get rid of WARN()
ARM S3C24XX: Fix compilation of PM code for S3C2416
ARM: S3C24XX: Fix CONFIG_S3C_DEV_NAND Kconfig entry
As PControl G20 is a carrier board for the Stamp9G20 SoM, some code can
be shared. Therefore board-stamp9g20.c is refactored to allow reusing the
SoM initialization and board-pcontrol-g20.c is modified to use it.
Signed-off-by: Christian Glindkamp <christian.glindkamp@taskit.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
The uhpck clock should be divided from the utmi clock, not its parent
(main). This change is mostly cosmetic as the uhpck rate value is not
used anywhere except for the debugfs clock output.
Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Fix interrupt priority level handling on SH-Mobile ARM.
SH-Mobile ARM platforms using multiple interrupt priority
levels need this patch to fix a potential dead lock that
may occur if multiple interrupts with different levels
are pending simultaneously.
The default INTC configuration is to use the same priority
level for all interrupts, so this issue does not trigger by
default. It is however common for board code to override the
interrupt priority for certain interrupt sources depending
on the application. Without this fix such boards may lock up.
In detail, this patch updates the INTC code in entry-macro.S
to make sure that the INTLVLA register gets set as expected.
To trigger this bug modify the board specific code to adjust
the interrupt priority level for the ethernet chip. After
changing the priority level simply use flood ping to drown
the board with interrupts.
This patch applies to INTCA-based processors such as sh7372,
sh7377 and sh7372. GIC-based processors are not affected.
Suitable for v2.6.37-rc and stable from v2.6.34 to v2.6.36.
Cc: stable@kernel.org
Signed-off-by: Magnus Damm <damm@opensource.se>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Turn down the warning noise from the compiler,
basically a SH-Mobile specific version of the
patch located in the RMK patch tracker:
6484/1: "fix compile warning in mm/init.c",
Without this patch the following warning triggers:
CC arch/arm/kernel/sys_arm.o
arch/arm/mm/init.c: In function 'mem_init':
arch/arm/mm/init.c:606: warning: format '%08lx' expects type 'long unsigned int', but argument 12 has type 'unsigned int'
CC arch/arm/kernel/traps.o
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patch adds new entries required by the new version of MAX8998
driver. Without them, the driver fails to init. See commit 50f19a4596
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
S3C2416 PM code uses low-level sleep routines from S3C2412 code,
but these routines are compiled only for S3C2412 SoC.
Split S3C2412_PM to two parts: S3C2412_PM, S3C2412_PM_SLEEP and
select last in S3C2416's Kconfig.
Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Cache ownership must be acquired by reading/writing data from the
cache line to make cache operation have the desired effect on the
SMP MPCore CPU. However, the ownership is never acquired in the
v6_dma_inv_range function when cleaning the first line and
flushing the last one, in case the address is not aligned
to D_CACHE_LINE_SIZE boundary.
Fix this by reading/writing data if needed, before performing
cache operations.
While at it, fix v6_dma_flush_range to prevent RWFO outside
the buffer.
Cc: stable@kernel.org
Signed-off-by: Valentine Barshak <vbarshak@mvista.com>
Signed-off-by: George G. Davis <gdavis@mvista.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Because the nwfpe support is unlikely to be used on new platforms
and requires CONFIG_OABI_COMPAT, which is not generally used with
ARMv7+, we shouldn't expect to build nwfpe support into a Thumb-2
kernel.
At present, nwfpe contains assembly code which isn't Thumb-2
compatible, and for now it doesn't appear useful to port this
code.
All ARMv7-A/R platforms necessarily have VFPv3 hardware floating-
point natively, making emulation unnecessary.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This makes sense, because Thumb-2 code can't execute on plain
ARMv6 processors.
This will avoid accidentally configuring a broken kernel where the
config otherwise would allow multiple architecture versions to
coexist in the same kernel.
Not adding !CPU_V5 etc., because the chance of anyone trying to
put v5 and v7 in the same kernel is low, and I'm not aware of
any mach which can do this. These could be added later if it
matters.
Note that the rules may need to be refined if support for the
ARM1156J(F)-S processor is later added to the kernel, since this
processor supports the rare ARMv6T2 extensions, which add support
for Thumb-2 and a few other ARMv7 features.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current implementation of the v7_coherent_*_range function assumes
that the D and I cache lines have the same size, which is incorrect
architecturally. This patch adds the icache_line_size macro which reads
the CTR register. The main loop in v7_coherent_*_range is split in two
independent loops or the D and I caches. This also has the performance
advantage that the DSB is moved outside the main loop.
Reported-by: Kevin Sapp <ksapp@quicinc.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current implementation of the dcache_line_size macro reads the L1
cache size from the CCSIDR register. This, however, is not guaranteed to
be the smallest cache line in the cache hierarchy. The patch changes to
the macro to use the more architecturally correct CTR register.
Reported-by: Kevin Sapp <ksapp@quicinc.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
After Charu's GPIO hwmod patches, GPIO initialization on N800 emits
the following messages for all GPIO banks:
omap_hwmod: gpio1: cannot be enabled (3)
This is due to OMAP24XX_ST_GPIOS_SHIFT being defined as a bitmask.
Fix this and also fix two other macros that had the same problem.
Thanks to Tony Lindgren <tony@atomide.com> for originally reporting
this bug.
Signed-off-by: Paul Walmsley <paul@pwsan.com
Cc: Charulatha Varadarajan <charu@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
commit 0d8e2d0dad (OMAP2+: PM/serial:
hold console semaphore while OMAP UARTs are disabled) added use of the
console semaphore to protect UARTs from being accessed after disabled
during idle, but this causes problems in suspend.
During suspend, the console semaphore is acquired by the console
suspend method (console_suspend()) so the try_acquire_console_sem()
will always fail and suspend will be aborted.
To fix, introduce a check so the console semaphore is only attempted
during idle, and not during suspend. Also use the same check so that
the console semaphore is not prematurely released during resume.
Thanks to Paul Walmsley for suggesting adding the same check during
resume.
Cc: Paul Walmsley <paul@pwsan.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Tested-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Kernel was failing to boot on omap1611 based OSK boards due to
mis-configured SRAM size. Existing code was using a hard-coded value
for 250k, which was then rounded down by PAGE_SIZE. Increasing this to
256k allows kernel to boot on omap1611 SoCs.
Problem reported by and initial fix suggested by Tim Bird.
Thanks to Tony Lindgren for helping diagnose the problem to being
specific to OMAP1611 and not affecting OMAP1610/OMAP1623.
Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
clk_get() return value should be checked with IS_ERR().
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Currently the {set,get}_pull callbacks of the s3c24xx_gpiocfg_default structure
are initalized via s3c_gpio_{get,set}pull_1up. This results in a linker
error when only CONFIG_CPU_S3C2442 is selected:
arch/arm/plat-s3c24xx/built-in.o:(.data+0x13f4): undefined reference to
`s3c_gpio_getpull_1up'
arch/arm/plat-s3c24xx/built-in.o:(.data+0x13f8): undefined reference to
`s3c_gpio_setpull_1up'
The s3c2442 has pulldowns instead of pullups compared to the s3c2440.
The method of controlling them is the same though.
So this patch modifies the existing s3c_gpio_{get,set}pull_1up helper functions
to take an additional parameter deciding whether the pin has a pullup or pulldown.
The s3c_gpio_{get,set}pull_1{down,up} functions then wrap that functions passing
either S3C_GPIO_PULL_UP or S3C_GPIO_PULL_DOWN.
Furthermore this patch sets up the s3c24xx_gpiocfg_default.{get,set}_pull fields
in the s3c244{0,2}_map_io function to the new pulldown helper functions.
Based on patch from "Lars-Peter Clausen" <lars@metafoo.de>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Commit 0ea1293009 ("arm: return both physical and virtual addresses
from addruart") took out the test for MMU on/off but didn't switch the
ldr instructions to no longer be conditionals based on said test.
Fix that.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clk_get() returns ERR_PTR() on error, not NULL.
Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
[tony@atomide.com: updated to include err.h to compile on omap1]
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch complements ed919b0 "mmc: sdio: fix runtime PM anomalies by
introducing MMC_CAP_POWER_OFF_CARD" by declaring MMC_CAP_POWER_OFF_CARD
on the ZOOM's wl1271 mmc slot.
This is required in order not to break runtime PM support for the wl1271
sdio driver.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
* master.kernel.org:/home/rmk/linux-2.6-arm:
ARM: 6524/1: GIC irq desciptor bug fix
ARM: 6523/1: iop: ensure sched_clock() is notrace
ARM: 6456/1: Fix for building DEBUG with sa11xx_base.c as a module.
ARM: 6519/1: kuser: Fix incorrect cmpxchg syscall in kuser helpers
ARM: 6505/1: kprobes: Don't HAVE_KPROBES when CONFIG_THUMB2_KERNEL is selected
ARM: 6508/1: vexpress: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
ARM: 6507/1: RealView: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
ARM: 6504/1: Thumb-2: Fix long-distance conditional branches in head.S for Thumb-2.
ARM: 6503/1: Thumb-2: Restore sensible zImage header layout for CONFIG_THUMB2_KERNEL
ARM: 6502/1: Thumb-2: Fix CONFIG_THUMB2_KERNEL breakage in compressed/head.S
ARM: 6501/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in mm/proc-v7.S
ARM: 6500/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in kernel/head.S
ARM: 6499/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in bootp/init.S
ARM: 6498/1: vfp: Correct data alignment for CONFIG_THUMB2_KERNEL
ARM: 6497/1: kexec: Correct data alignment for CONFIG_THUMB2_KERNEL
ARM: 6496/1: GIC: Do not try to register more then NR_IRQS interrupts
ARM: cns3xxx: Fix build with CONFIG_PCI=y
gic_set_cpu will directly use irq_desc[]. If CONFIG_SPARSE_IRQ is
enabled, there is no irq_desc[]. So we need use irq_to_desc(irq) to
get the descriptor for irq.
Signed-off-by: Chao Xie <chao.xie@marvell.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Include sched.h to ensure sched_clock() has the notrace
annotation, and mark any functions it calls as notrace
too.
Include sched.h to ensure sched_clock() has the notrace
annotation, and mark any functions it calls as notrace
too.
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The existing code invokes the syscall with rubbish in r7,
due to what looks like an incorrect literal load idiom.
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 MACH_MINI2440 entry requires the backlight LED driver, but this
subsystem has not been enabled and the select of LEDS_TRIGGER_BACKLIGHT
alone is insufficient to enable the necessary bits of the LED driver.
Add NEW_LEDS, LEDS_CLASS and LEDS_TRIGGER to the select to allow the
kernel to link.
This fixes the following error:
drivers/built-in.o: In function `led_trigger_set':
/home/ben/linux.git/drivers/leds/led-triggers.c:116: undefined reference to `led_brightness_set'
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Wakeup-on-timer code does not have/need debugfs dependency. Move
the function out of debugfs ifdef.
Fixes compile error when CONFIG_DEBUG_FS is disabled but PM debug is
enabled.
Reported-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
for the epson frambuffer support it's CONFIG_FB_S1D13XXX
not CONFIG_FB_S1D135XX
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
as based on http://www.picotux.com/pt200/picotux200.pdf
these board does not have such I/O
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
to be a few more concistant with the other boards
as ek is for evaluation kit and dk for development kit
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
Convert the following AT91RM9200-based boards to the new-style UART
initialization:
- Ajeco 1ARM Single Board Computer
- Sperry-Sun KAFA board
- picotux 200
Remove the deprecated at91_init_serial
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
Currently, the kprobes implementation for ARM only supports the ARM
instruction set, so it only works if CONFIG_THUMB2_KERNEL is not
enabled.
Until kprobes is updated to work with Thumb-2, turning it on will
cause horrible things to happen, so this patch disables it for now.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
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.
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>
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.
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>
Nishanth Menon
Peter 'p2' De Schrijver
Richard Woodruff
Thara Gopinath
Jean Pihet
Linus Torvalds
Christian Glindkamp
Ryan Mallon
Magnus Damm
Marek Szyprowski
Yauhen Kharuzhy
Kukjin Kim
Valentine Barshak
Dave Martin
Russell King
Catalin Marinas
Paul Walmsley
Kevin Hilman
Aaro Koskinen
Vasily Khoruzhick
Olof Johansson
Vasiliy Kulikov
Ohad Ben-Cohen
Chao Xie
Rabin Vincent
Ben Dooks
Jean-Christophe PLAGNIOL-VILLARD