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)
Kill warning:
drivers/char/ip2/ip2main.c: In function âip2_loadmainâ:
drivers/char/ip2/ip2main.c:782: warning: label âout_classâ defined but not used
This driver's initialization (and cleanup of errors during init) is
extremely convoluted, and could stand to be transformed into the standard
unwinding-goto style of error cleanup.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Acked-by: Michael H. Warfield <mhw@wittsend.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As part of an SMP cleanliness pass over UML, I consted a bunch of
structures in order to not have to document their locking. One of these
structures was a struct tty_operations. In order to const it in UML
without introducing compiler complaints, the declaration of
tty_set_operations needs to be changed, and then all of its callers need to
be fixed.
This patch declares all struct tty_operations in the tree as const. In all
cases, they are static and used only as input to tty_set_operations. As an
extra check, I ran an i386 allyesconfig build which produced no extra
warnings.
53 drivers are affected. I checked the history of a bunch of them, and in
most cases, there have been only a handful of maintenance changes in the
last six months. serial_core.c was the busiest one that I looked at.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is one of a series of patches I plan to gradually trickle into the
tree which eliminates almost all remaining use of pci_find_* and lets me
build a pci_find_* free kernel for all but some obscure ISDN and SCSI
drivers. This is important as all pci_find_* users are not hotplug safe -
even if they are not the device being plugged.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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>
I've always found this flag confusing. Now that devfs is no longer around, it
has been renamed, and the documentation for when this flag should be used has
been updated.
Also fixes all drivers that use this flag.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Priority: tossup.
In theory some of these (previously) __init functions could be called
after init, but that problem has not been observed AFAIK.
There were 2 cases of cleanup_module() (module_exit) calling __init
functions (clear_requested_irq() & have_requested_irq()).
These are more serious, but still not observed AFAIK.
Fix sections mismatch:
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'cleanup_module' (at offset 0x228b) and 'ip2_loadmain'
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'cleanup_module' (at offset 0x22ae) and 'ip2_loadmain'
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'ip2_loadmain' (at offset 0x2501) and 'set_irq'
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'ip2_loadmain' (at offset 0x25de) and 'set_irq'
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'ip2_loadmain' (at offset 0x2698) and 'set_irq'
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'ip2_loadmain' (at offset 0x2922) and 'set_irq'
WARNING: drivers/char/ip2/ip2main.o - Section mismatch: reference to .init.text: from .text between 'ip2_loadmain' (at offset 0x299e) and 'set_irq'
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With Eric's "i386: Add a temporary to make put_user more type safe" patch we
get a pile of warnings out of ip2m1in.c:
drivers/char/ip2main.c: In function `ip2_ipl_ioctl':
drivers/char/ip2main.c:2910: warning: assignment makes integer from pointer without a cast
drivers/char/ip2main.c:2911: warning: assignment makes integer from pointer without a cast
drivers/char/ip2main.c:2912: warning: assignment makes integer from pointer without a cast
etc.
This ioctl is copying the kernel virtual address of a large number of
functions out to userspace. Heaven knows why.
Rather than fixing the warnings, I think we'll just nuke that code.
The patch also fixes a couple of `defined but not used' warnings.
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
used by this driver reside.
Renamed ip2.c to ip2base.c to allow ip2.o to be built from multiple
objects.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Michael H. Warfield <mhw@WittsEnd.com>
This fixes the pragma packing in the ip2 driver by popping the previous
setting rather than explicitly assuming that the correct setting is 4.
This also gets around a compiler bug in the FRV compiler when building
allmodconfig.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is the drivers/char/ part of the big kfree cleanup patch.
Remove pointless checks for NULL prior to calling kfree() in drivers/char/.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch contains the following cleanups:
- i2cmd.c: #if 0 the unused function i2cmdUnixFlags
- i2cmd.c: make the needlessly global funciton i2cmdBaudDef static
- ip2main.c: remove dead code that wasn't reachable due to an #ifdef
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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!
