Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
Add a platform check to the snsc driver init function, to prevent
loading on non-sn2 systems.
Signed-off-by: Greg Edwards <edwardsg@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Mark the static struct file_operations in drivers/char as const. Making
them const prevents accidental bugs, and moves them to the .rodata section
so that they no longer do any false sharing; in addition with the proper
debug option they are then protected against corruption..
[akpm@osdl.org: build fix]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
from: Greg Howard <ghoward@sgi.com>
Fix Altix system controller (snsc) device names to include the slot number
of the blade whose associated system controller is the target of the device
interface. Including the slot number avoids a problem we're currently
having where slots within the same enclosure are attempting to create
multiple kobjects with identical names.
Signed-off-by: Greg Howard <ghoward@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change driver to use kzalloc rather than kmalloc+memset
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The previous patch adding the ability to nest struct class_device
changed the paramaters to the call class_device_create(). This patch
fixes up all in-kernel users of the function.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some of the SN code & #defines related to compact nodes & IO discovery
have gotten stale over the years. This patch attempts to clean them up.
Some of the various SN MAX_xxx #defines were also unclear & misused.
The primary changes are:
- use MAX_NUMNODES. This is the generic linux #define for the number
of nodes that are known to the generic kernel. Arrays & loops
for constructs that are 1:1 with linux-defined nodes should
use the linux #define - not an SN equivalent.
- use MAX_COMPACT_NODES for MAX_NUMNODES + NUM_TIOS. This is the
number of nodes in the SSI system. Compact nodes are a hack to
get around the IA64 architectural limit of 256 nodes. Large SGI
systems have more than 256 nodes. When we upgrade to ACPI3.0,
I _hope_ that all nodes will be real nodes that are known to
the generic kernel. That will allow us to delete the notion
of "compact nodes".
- add MAX_NUMALINK_NODES for the total number of nodes that
are in the numalink domain - all partitions.
- simplified (understandable) scan_for_ionodes()
- small amount of cleanup related to cnodes
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix a typo in scdrv_init() which was breaking the build for SGI sn2.
Signed-off-by: Jason Uhlenkott <jasonuhl@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The following is an update of the patch I sent yesterday
(3/9/05) incorporating suggestions from Christoph Hellwig and
Andreas Schwab. It allows Altix and Altix-like systems to
handle environmental events generated by the system controllers,
and should apply on top of Jack Steiner's patch of 3/1/05 ("New
chipset support for SN platform") and Mark Goodwin's patch of
3/8/05 ("Altix SN topology support for new chipsets and pci
topology").
Signed-off-by: Greg Howard <ghoward@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
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!
David Howells