Rather than clipping the number of CPUs using the compile-time NR_CPUS
constant, use the runtime nr_cpu_ids value instead. This allows the
nr_cpus command line option to work as expected.
Cc: <stable@kernel.org>
Reported-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
If an ARM system has multiple cpus in the same socket and the
kernel is booted with maxcpus=1, secondary cpus are possible but
not present due to how platform_smp_prepare_cpus() is called.
Since most typical ARM processors don't actually support physical
hotplug, initialize the present map to be equal to the possible
map in generic ARM SMP code. Also, always call
platform_smp_prepare_cpus() as long as max_cpus is non-zero (0
means no SMP) to allow platform code to do any SMP setup.
After applying this patch it's possible to boot an ARM system
with maxcpus=1 on the command line and then hotplug in secondary
cpus via sysfs. This is more in line with how x86 does things.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: David Brown <davidb@codeaurora.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than having each platform class provide a mach/smp.h header for
smp_cross_call(), arrange for them to register the function with the
core ARM SMP code instead.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Realview and Versatile Express share the same SMP bringup code, so
consolidate the two implementations.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Fix two section mismatch warnings in the platform SMP bringup code for
Realview and Versatile Express:
WARNING: arch/arm/mach-realview/built-in.o(.text+0x8ac): Section mismatch in reference from the function write_pen_release() to the variable .cpuinit.data:pen_release
The function write_pen_release() references
the variable __cpuinitdata pen_release.
This is often because write_pen_release lacks a __cpuinitdata
annotation or the annotation of pen_release is wrong.
WARNING: arch/arm/mach-vexpress/built-in.o(.text+0x7b4): Section mismatch in reference from the function write_pen_release() to the variable .cpuinit.data:pen_release
The function write_pen_release() references
the variable __cpuinitdata pen_release.
This is often because write_pen_release lacks a __cpuinitdata
annotation or the annotation of pen_release is wrong.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There is a subtle race in the CPU hotplug code, where a CPU which has
been offlined can online itself before being requested, which results
in things going astray on the next online/offline cycle.
What happens in the normal online/offline/online cycle is:
CPU0 CPU3
requests boot of CPU3
pen_release = 3
flush cache line
checks pen_release, reads 3
starts boot
pen_release = -1
... requests CPU3 offline ...
... dies ...
checks pen_release, reads -1
requests boot of CPU3
pen_release = 3
flush cache line
checks pen_release, reads 3
starts boot
pen_release = -1
However, as the write of -1 of pen_release is not fully flushed back to
memory, and the checking of pen_release is done with caches disabled,
this allows CPU3 the opportunity to read the old value of pen_release:
CPU0 CPU3
requests boot of CPU3
pen_release = 3
flush cache line
checks pen_release, reads 3
starts boot
pen_release = -1
... requests CPU3 offline ...
... dies ...
checks pen_release, reads 3
starts boot
pen_release = -1
requests boot of CPU3
pen_release = 3
flush cache line
Fix this by grouping the write of pen_release along with its cache line
flushing code to ensure that any update to pen_release is always pushed
out to physical memory.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
All platforms call trace_hardirqs_off() in their secondary startup code,
so move this into the core SMP code - it doesn't need to be in the
per-platform code.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There is a certain amount of smp_prepare_cpus() which doesn't belong
in the platform support code - that is, code which is invariant to the
SMP implementation. Move this code into arch/arm/kernel/smp.c, and
add a platform_ prefix to the original function.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Milo is an old boot loader, which is no longer relevant for these
platforms. References to it are misleading. Move the code out
of poke_milo(), and remove references to milo in comments.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
scu_get_core_count() never returns zero cores, so we don't need to
check and correct if ncores is zero.
Tegra was missing the check against NR_CPUS, leading to a potential
bitfield overflow if this becomes the case.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Ensure that the number of CPUs is sanity checked before setting
the number of possible CPUs. This avoids any chance of overflowing
the cpu_possible bitmap.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We don't need to re-pass the base address for the CPU interfaces to the
GIC for secondary CPUs, as it will never be different from the boot CPU
- and even if it was, we'd overwrite the boot CPU's base address.
Get rid of this argument, and rename to gic_secondary_init().
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This allows us to use smp_cross_call() to trigger a number of different
software generated interrupts, rather than combining them all on one
SGI. Recover the SGI number via do_IPI.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The platsmp.c file defines the REALVIEW_SYS_FLAGS* macros which are
already present in platform.h. Just use the latter.
Signed-off-by: Colin Tuckley <colin.tuckley@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch sets bit 0 in the startup address passed to the secondary
CPUs so that they branch into Thumb-2 mode.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This is a RealView platform supporting core tiles with ARM11MPCore,
Cortex-A8 or Cortex-A9 (multicore) processors. It has support for MMC,
CompactFlash, PCI-E.
Signed-off-by: Colin Tuckley <colin.tuckley@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The SCU can be used by non-realview platforms, so make it visible
for other people to use rather than having them copy the header file.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Having discussed broadcast tick support with Thomas Glexiner, the
broadcast tick devices should be registered with a higher rating
than the global tick device, and it should have the ONESHOT and
PERIODIC feature flags set.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Thomas Glexiner <tglx@linutronix.de>
smp_cross_call_done() is a no-op for MPCore, and since it's only
used by platform code, there's no point in having it unless it's
doing something.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The ARM SMP code wasn't properly updated for the cpumask changes, which
results in smp_timer_broadcast() broadcasting ticks to non-online CPUs.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/mach-realview/platsmp.c:140: error: 'jiffies' undeclared (first use in this function)
drivers/amba/bus.c:246: error: 'NO_IRQ' undeclared (first use in this function)
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Some of the calls weren't necessary and some others were duplicated.
This patch tidies up the platsmp.c file.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
All the cases where the local timer for a CPU is accessed happen on the
corresponding current CPU, hence no need to access the per-CPU local
timer mappings.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds the necessary definitions and Kconfig entries to enable
Cortex-A9 (ARMv7 SMP) tiles on the RealView/EB board.
Signed-off-by: Jon Callan <Jon.Callan@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Remove includes of asm/hardware.h in addition to asm/arch/hardware.h.
Then, since asm/hardware.h only exists to include asm/arch/hardware.h,
update everything to directly include asm/arch/hardware.h and remove
asm/hardware.h.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch annotates the platform_secondary_init function in
arch/arm/mach-realview/platsmp.c with trace_hardirqs_off to avoid a
warning when LOCKDEP and TRACE_IRQFLAGS are enabled.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch moves the SCU initialisation from __v6_setup to the
smp_prepare_cpus() function as it relies on platform-specific
settings. Changes to get_core_count() are mainly for allowing cleaner
code with the upcoming PB11MPCore patches.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds the core-tile detection and only enables devices if the
corresponding tile is present. It currently detects the ARM11MPCore via
the core_tile_eb11mp() macro.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch moves the platform specific definitions from platform.h into
the board-eb.h file. It drops the INT_* definitions as they are no
longer used in irqs.h (moved to board-eb.h). It renames REALVIEW_*
macros to REALVIEW_EB_* or REALVIEW_EB11MP_* to distinguish between
standard EB and EB + the ARM11MPCore tile. The platform.h file contains
common definitions to the RealView platforms and it is only directly
included in board-*.h files.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds dummy local timers for each CPU so that the board clock
device is used to broadcast events to the other CPUs. The patch also
adds the declaration for the dummy_timer_setup function (the equivalent
of local_timer_setup when CONFIG_LOCAL_TIMERS is not set).
Due to the way clockevents work, the dummy timer on the first CPU has to
be registered before the board timer.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
In some situations, the pen_release store in platform_secondary_init()
may stay forever in the write buffer while the CPU is waiting on the
boot_lock to be released in boot_secondary(). The primary CPU could
never see the pen_release update without the barriers.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current implementation only assumes one GIC to be present in the
system. However, there are platforms with more than one cascaded interrupt
controllers (RealView/EB MPCore for example).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
A change to the SMP initialisation caused the following oops:
CPU1: Booted secondary processor
CPU1: D VIPT write-back cache
CPU1: I cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
CPU1: D cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
<7>Calibrating delay loop... 83.14 BogoMIPS (lpj=415744)
<1>Unable to handle kernel NULL pointer dereference at virtual address 0000001c
...
PC is at enqueue_task+0x1c/0x64
LR is at activate_task+0xcc/0xe4
SMP initialisation now requires cpu_possible_map to be initialised in
setup_arch(). Move this from smp_prepare_cpus() to smp_init_cpus()
and call it from our setup_arch() if CONFIG_SMP is enabled.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move __io_address to arch-realview/hardware.h, drop core.h from platsmp.c
and localtimer.c, and include asm/io.h where required.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
