Consolidating the "pen_release" stuff amongst the various SoC
implementations gives credence to having a CPU holding pen for
secondary CPUs. However, this is far from the truth.
Many SoC implementations cargo-cult copied various bits of the pen
release implementation from the initial Realview/Versatile Express
implementation without understanding what it was or why it existed.
The reason it existed is because these are _development_ platforms,
and some board firmware is unable to individually control the
startup of secondary CPUs. Moreover, they do not have a way to
power down or reset secondary CPUs for hot-unplug. Hence, the
pen_release implementation was designed for ARM Ltd's development
platforms to provide a working implementation, even though it is
very far from what is required.
It was decided a while back to reduce the duplication by consolidating
the "pen_release" variable, but this only made the situation worse -
we have ended up with several implementations that read this variable
but do not write it - again, showing the cargo-cult mentality at work,
lack of proper review of new code, and in some cases a lack of testing.
While it would be preferable to remove pen_release entirely from the
kernel, this is not possible without help from the SoC maintainers,
which seems to be lacking. However, I want to remove pen_release from
arch code to remove the credence that having it gives.
This patch removes pen_release from the arch code entirely, adding
private per-SoC definitions for it instead, and explicitly stating
that write_pen_release() is cargo-cult copied and should not be
copied any further. Rename write_pen_release() in a similar fashion
as well.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Now that __cpuinit has been removed, the __ref markings on these
functions are useless. Remove them. This also reduces the size of
the multi_v7_defconfig image:
$ size before after
text data bss dec hex filename
12683578 1470996 348904 14503478 dd4e36 before
12683274 1470996 348904 14503174 dd4d06 after
presumably because now we don't have to jump to code in the
.ref.text section and/or the noinline marking is removed.
Cc: Shiraz Hashim <shiraz.linux.kernel@gmail.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <linux-omap@vger.kernel.org>
Cc: <linux-arm-msm@vger.kernel.org>
Cc: <spear-devel@list.st.com>
Cc: <linux-tegra@vger.kernel.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Barry Song <baohua@kernel.org>
Acked-by: Andy Gross <agross@codeaurora.org>
Acked-by: Viresh Kumar <vireshk@kernel.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
Pull ARM updates from Russell King:
"The major items included in here are:
- MCPM, multi-cluster power management, part of the infrastructure
required for ARMs big.LITTLE support.
- A rework of the ARM KVM code to allow re-use by ARM64.
- Error handling cleanups of the IS_ERR_OR_NULL() madness and fixes
of that stuff for arch/arm
- Preparatory patches for Cortex-M3 support from Uwe Kleine-König.
There is also a set of three patches in here from Hugh/Catalin to
address freeing of inappropriate page tables on LPAE. You already
have these from akpm, but they were already part of my tree at the
time he sent them, so unfortunately they'll end up with duplicate
commits"
* 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (77 commits)
ARM: EXYNOS: remove unnecessary use of IS_ERR_VALUE()
ARM: IMX: remove unnecessary use of IS_ERR_VALUE()
ARM: OMAP: use consistent error checking
ARM: cleanup: OMAP hwmod error checking
ARM: 7709/1: mcpm: Add explicit AFLAGS to support v6/v7 multiplatform kernels
ARM: 7700/2: Make cpu_init() notrace
ARM: 7702/1: Set the page table freeing ceiling to TASK_SIZE
ARM: 7701/1: mm: Allow arch code to control the user page table ceiling
ARM: 7703/1: Disable preemption in broadcast_tlb*_a15_erratum()
ARM: mcpm: provide an interface to set the SMP ops at run time
ARM: mcpm: generic SMP secondary bringup and hotplug support
ARM: mcpm_head.S: vlock-based first man election
ARM: mcpm: Add baremetal voting mutexes
ARM: mcpm: introduce helpers for platform coherency exit/setup
ARM: mcpm: introduce the CPU/cluster power API
ARM: multi-cluster PM: secondary kernel entry code
ARM: cacheflush: add synchronization helpers for mixed cache state accesses
ARM: cpu hotplug: remove majority of cache flushing from platforms
ARM: smp: flush L1 cache in cpu_die()
ARM: tegra: remove tegra specific cpu_disable()
...
There are no conflicting files between the three mach-spear* directories
and plat-spear any more, so we can now move all file to a common
mach-spear directory.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
