7d12e780e0
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)
|
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|---|---|---|
| .. | ||
| 3780i.c | ||
| 3780i.h | ||
| Makefile | ||
| mwavedd.c | ||
| mwavedd.h | ||
| mwavepub.h | ||
| README | ||
| smapi.c | ||
| smapi.h | ||
| tp3780i.c | ||
| tp3780i.h | ||
Module options
--------------
The mwave module takes the following options. Note that these options
are not saved by the BIOS and so do not persist after unload and reload.
mwave_debug=value, where value is bitwise OR of trace flags:
0x0001 mwavedd api tracing
0x0002 smapi api tracing
0x0004 3780i tracing
0x0008 tp3780i tracing
Tracing only occurs if the driver has been compiled with the
MW_TRACE macro #defined (i.e. let EXTRA_CFLAGS += -DMW_TRACE
in the Makefile).
mwave_3780i_irq=5/7/10/11/15
If the dsp irq has not been setup and stored in bios by the
thinkpad configuration utility then this parameter allows the
irq used by the dsp to be configured.
mwave_3780i_io=0x130/0x350/0x0070/0xDB0
If the dsp io range has not been setup and stored in bios by the
thinkpad configuration utility then this parameter allows the
io range used by the dsp to be configured.
mwave_uart_irq=3/4
If the mwave's uart irq has not been setup and stored in bios by the
thinkpad configuration utility then this parameter allows the
irq used by the mwave uart to be configured.
mwave_uart_io=0x3f8/0x2f8/0x3E8/0x2E8
If the uart io range has not been setup and stored in bios by the
thinkpad configuration utility then this parameter allows the
io range used by the mwave uart to be configured.
Example to enable the 3780i DSP using ttyS1 resources:
insmod mwave mwave_3780i_irq=10 mwave_3780i_io=0x0130 mwave_uart_irq=3 mwave_uart_io=0x2f8
Accessing the driver
--------------------
You must also create a node for the driver:
mkdir -p /dev/modems
mknod --mode=660 /dev/modems/mwave c 10 219