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)
We have the info stored in an ata_busy_sleep() variable, so might as
well print it, and provide some additional diagnostic info.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Don't write the same code twice, in two different functions, when they
both call the same initialization function, with the same private_data
pointer info.
Also, note a bug found with a FIXME.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
ata_device_add fails, calls ata_host_remove with pointers to unitialized
memory.
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
We don't currently support pure polled operation so when we meet a BIOS
which forgot to assign an IRQ to a PCI device it all goes a little pear
shaped. Trap this case properly.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Our ATA probe code checks that a device is not reporting a diagnostic
failure during start up. Unfortunately at least one device seems to like
doing this - the Gigabyte iRAM.
This is only done for the master right now (which is fine for the iRAM
as it is SATA), as with PATA some combinations of ATAPI device seem to
fool the check into seeing a drive that isn't there if it is applied to
the slave.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Non-uniform ports handling got broken while updating libata to handle
those in the same host. Only separate irq for the non-uniform
secondary port was implemented while all other fields (host flags,
transfer mode...) of the secondary port simply shared those of the
first.
For ata_piix combined mode, which ATM is the only user of non-uniform
ports, this causes the secondary port assume the wrong type. This can
cause PATA port to use SATA ops, which results in bogus check on PCS
and detection failure.
This patch adds ata_probe_ent->pinfo2 which points to optional
port_info for the secondary port. For the time being, this seems to
be the simplest solution. This workaround will be removed together
with ata_probe_ent itself after init model is updated to allow more
flexibility.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Nelson A. de Oliveira <naoliv@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
The biggest change is that ata_host_set is renamed to ata_host.
* ata_host_set => ata_host
* ata_probe_ent->host_flags => ata_probe_ent->port_flags
* ata_probe_ent->host_set_flags => ata_probe_ent->_host_flags
* ata_host_stats => ata_port_stats
* ata_port->host => ata_port->scsi_host
* ata_port->host_set => ata_port->host
* ata_port_info->host_flags => ata_port_info->flags
* ata_(.*)host_set(.*)\(\) => ata_\1host\2()
The leading underscore in ata_probe_ent->_host_flags is to avoid
reusing ->host_flags for different purpose. Currently, the only user
of the field is libata-bmdma.c and probe_ent itself is scheduled to be
removed.
ata_port->host is reused for different purpose but this field is used
inside libata core proper and of different type.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
The CFA world has some additional rules and drive modes we need to support for
newer expansion cards and on embedded boxes
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Jeff Garzik