Impact: __per_cpu_load available on all SMP capable archs
Percpu now requires three symbols to be defined - __per_cpu_load,
__per_cpu_start and __per_cpu_end. There were three archs which
didn't have it. Update them as follows.
* powerpc: can use generic PERCPU() macro. Compile tested for
powerpc32, compile/boot tested for powerpc64.
* ia64: can use generic PERCPU_VADDR() macro. __phys_per_cpu_start is
identical to __per_cpu_load. Compile tested and symbol table looks
identical after the change except for the additional __per_cpu_load.
* arm: added explicit __per_cpu_load definition. Currently uses
unified .init output section so can't use the generic macro. Dunno
whether the unified .init ouput section is required by arch
peculiarity so I left it alone. Please break it up and use PERCPU()
if possible.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Pat Gefre <pfg@sgi.com>
Cc: Russell King <rmk@arm.linux.org.uk>
arm, arm/mach-integrator and powerpc were missing
.data.percpu.page_aligned in their percpu output section definitions.
Add it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Initial fix for making sure that we can access percpu variables
in all C code (commit: 10617bbe84)
inadvertantly allocated the memory in the "percpu" section of
the vmlinux ELF executable. This confused kexec/dump.
Signed-off-by: Tony Luck <tony.luck@intel.com>
ia64 handles per-cpu variables a litle differently from other architectures
in that it maps the physical memory allocated for each cpu at a constant
virtual address (0xffffffffffff0000). This mapping is not enabled until
the architecture specific cpu_init() function is run, which causes problems
since some generic code is run before this point. In particular when
CONFIG_PRINTK_TIME is enabled, the boot cpu will trap on the access to
per-cpu memory at the first printk() call so the boot will fail without
the kernel printing anything to the console.
Fix this by allocating percpu memory for cpu0 in the kernel data section
and doing all initialization to enable percpu access in head.S before
calling any generic code.
Other cpus must take care not to access per-cpu variables too early, but
their code path from start_secondary() to cpu_init() is all in arch/ia64
Signed-off-by: Tony Luck <tony.luck@intel.com>
Move the LOAD_OFFSET definition from vmlinux.lds.S into system.h.
On paravirtualized environments, it is necessary to detect the
execution environment. One of the solutions is the multi entry point.
The multi entry point allows a boot loader to start the kernel execution
from the entry point which is different from the ELF entry point.
The non standard entry point will defined as the specialized elf note
which contains the LMA of the entry point symbol.
The constant, LOAD_OFFSET, is necessary to calculate the symbol's LMA.
Move the definition into the public header file to make it available
to the multi entry point support.
Cc: "He, Qing" <qing.he@intel.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Problem: An application violating the architectural rules regarding
operation dependencies and having specific Register Stack Engine (RSE)
state at the time of the violation, may result in an illegal operation
fault and invalid RSE state. Such faults may initiate a cascade of
repeated illegal operation faults within OS interruption handlers.
The specific behavior is OS dependent.
Implication: An application causing an illegal operation fault with
specific RSE state may result in a series of illegal operation faults
and an eventual OS stack overflow condition.
Workaround: OS interruption handlers that switch to kernel backing
store implement a check for invalid RSE state to avoid the series
of illegal operation faults.
The core of the workaround is the RSE_WORKAROUND code sequence
inserted into each invocation of the SAVE_MIN_WITH_COVER and
SAVE_MIN_WITH_COVER_R19 macros. This sequence includes hard-coded
constants that depend on the number of stacked physical registers
being 96. The rest of this patch consists of code to disable this
workaround should this not be the case (with the presumption that
if a future Itanium processor increases the number of registers, it
would also remove the need for this patch).
Move the start of the RBS up to a mod32 boundary to avoid some
corner cases.
The dispatch_illegal_op_fault code outgrew the spot it was
squatting in when built with this patch and CONFIG_VIRT_CPU_ACCOUNTING=y
Move it out to the end of the ivt.
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch consolidate all definitions of .init.text, .init.data
and .exit.text, .exit.data section definitions in
the generic vmlinux.lds.h.
This is a preparational patch - alone it does not buy
us much good.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Rename _bss to __bss_start as on other architectures. That makes it
possible to use the <linux/sections.h> instead of own declarations. Also
add __bss_stop because that symbol exists on other architectures.
Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Explicitly put the unwind section into its own program-header. This
used to be unnecessary (probably because binutils did it for us), but
with current binutils (e.g., v2.17.50.20070804) we won't get
the PT_IA_64_UNWIND header without this patch which will break
unwinding in a debugger and simulators such as Ski.
Signed-off-by: David Mosberger-Tang <dmosberger@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Add NOTES to linker script such that the kernel can be built with
recent versions of binutils. Without this patch, final link fails
with this error:
ld: .tmp_vmlinux1: section `.text' can't be allocated in segment 0
ld: final link failed: Bad value
This error is due to the fact that the --build-id option is used
with newer linkers to include a .notes section on the kernel, but
without the NOTES macro, that section won't be included in the kernel
which then leads to the above error message.
Signed-off-by: David Mosberger-Tang <dmosberger@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
In 741f98fe29 Sam added full
checking across the entire vmlinux image. This flushed out
a dozen new section mismatch warnings. Start the whack-a-mole
game again to stomp them out.
Signed-off-by: Tony Luck <tony.luck@intel.com>
per cpu data section contains two types of data. One set which is
exclusively accessed by the local cpu and the other set which is per cpu,
but also shared by remote cpus. In the current kernel, these two sets are
not clearely separated out. This can potentially cause the same data
cacheline shared between the two sets of data, which will result in
unnecessary bouncing of the cacheline between cpus.
One way to fix the problem is to cacheline align the remotely accessed per
cpu data, both at the beginning and at the end. Because of the padding at
both ends, this will likely cause some memory wastage and also the
interface to achieve this is not clean.
This patch:
Moves the remotely accessed per cpu data (which is currently marked
as ____cacheline_aligned_in_smp) into a different section, where all the data
elements are cacheline aligned. And as such, this differentiates the local
only data and remotely accessed data cleanly.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Update all arch/*/kernel/vmlinux.lds.S to not include space for initramfs
when CONFIG_BLK_DEV_INITRAMFS is not selected. This saves another 4 kbytes
on most platfoms (some reserve PAGE_SIZE for initramfs).
Signed-off-by: Jean-Paul Saman <jean-paul.saman@nxp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not efficient to use a per-cpu variable just to store
how many physical stack register a cpu has. Ever since the
incarnation of ia64 up till upcoming Montecito processor, that
variable has "glued" to 96. Having a variable in memory means
that the kernel is burning an extra cacheline access on every
syscall and kernel exit path. Such "static" value is better
served with the instruction patching utility exists today.
Convert ia64_phys_stacked_size_p8 into dynamic insn patching.
This also has a pleasant side effect of eliminating access to
per-cpu area while psr.ic=0 in the kernel exit path. (fixable
for per-cpu DTC work, but why bother?)
There are some concerns with the default value that the instruc-
tion encoded in the kernel image. It shouldn't be concerned.
The reasons are:
(1) cpu_init() is called at CPU initialization. In there, we
find out physical stack register size from PAL and patch
two instructions in kernel exit code. The code in question
can not be executed before the patching is done.
(2) current implementation stores zero in ia64_phys_stacked_size_p8,
and that's what the current kernel exit path loads the value with.
With the new code, it is equivalent that we store reg size 96
in ia64_phys_stacked_size_p8, thus creating a better safety net.
Given (1) above can never fail, having (2) is just a bonus.
All in all, this patch allow one less memory reference in the kernel
exit path, thus reducing syscall and interrupt return latency; and
avoid polluting potential useful data in the CPU cache.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Occasionally the FSYS_RETURN patch list can have an odd length, causing other
data structures to get out of alignment. In OpenVZ it is odd and we get
misaligned kernel image, which does not boot.
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Add a vmlinux.lds.h helper macro for defining the eight-level initcall table,
teach all the architectures to use it.
This is a prerequisite for a patch which performs initcall synchronisation for
multithreaded-probing.
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
[ Added AVR32 as well ]
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Minor reformatting to vmlinux.lds.S to make it 80-column usable,
in accordance with Linux coding style.
Signed-off-by: Al Stone <ahs3@fc.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Memory errors encountered by user applications may surface
when the CPU is running in kernel context. The current code
will not attempt recovery if the MCA surfaces in kernel
context (privilage mode 0). This patch adds a check for cases
where the user initiated the load that surfaces in kernel
interrupt code.
An example is a user process lauching a load from memory
and the data in memory had bad ECC. Before the bad data
gets to the CPU register, and interrupt comes in. The
code jumps to the IVT interrupt entry point and begins
execution in kernel context. The process of saving the
user registers (SAVE_REST) causes the bad data to be loaded
into a CPU register, triggering the MCA. The MCA surfaces in
kernel context, even though the load was initiated from
user context.
As suggested by David and Tony, this patch uses an exception
table like approach, puting the tagged recovery addresses in
a searchable table. One difference from the exception table
is that MCAs do not surface in precise places (such as with
a TLB miss), so instead of tagging specific instructions,
address ranges are registers. A single macro is used to do
the tagging, with the input parameter being the label
of the starting address and the macro being the ending
address. This limits clutter in the code.
This patch only tags one spot, the interrupt ivt entry.
Testing showed that spot to be a "heavy hitter" with
MCAs surfacing while saving user registers. Other spots
can be added as needed by adding a single macro.
Signed-off-by: Russ Anderson (rja@sgi.com)
Signed-off-by: Tony Luck <tony.luck@intel.com>
ia64_mv is initialized based on platform detected or specified.
However, there is one instantiation of each platform type. We
don't expect to switch platform vector during run time. Move
those platform specific type into init section since a copy is
made into global ia64_mv at initialization.
Also move instruction patch list into init section as well.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
sparc64, i386 and x86_64 have support for a special data section dedicated
to rarely updated data that is frequently read. The section was created to
avoid false sharing of those rarely read data with frequently written kernel
data.
This patch creates such a data section for ia64 and will group rarely written
data into this section.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch contains the ia64 architecture specific changes to prevent the
possible race conditions.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Not safe to insert kprobes on IVT code.
This patch checks to see if the address on which Kprobes is being inserted is
in ivt code and if it is in ivt code then refuse to register kprobe.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Acked-by: David Mosberger <davidm@napali.hpl.hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
