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)
The third argument of au1xxx_dbdma_chan_alloc's callback function is not
used anywhere.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Patch from Pavel Pisa
There has been problems that for some paths that clock are not stopped
during new command programming and initiation. Result is issuing
of incorrect command to the card. Some other problems are cleaned too.
Noisy report of known ERRATUM #4 has been suppressed.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than having every driver duplicate the set_ios debugging,
provide a single version in mmc.c which can be expanded as we
add additional functionality.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than each driver test MMC_DEBUG itself, and define DEBUG,
pass it in via the makefile instead.
Fix drivers to use pr_debug() where appropriate, and avoid defining
a DEBUG() macro.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
MODULE_PARM was actually breaking: recent gcc version optimize them out as
unused. It's time to replace the last users, which are generally in the
most unloved drivers anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix a trivial compilation warning:
CC drivers/mmc/au1xmmc.o
drivers/mmc/au1xmmc.c: In function ‘au1xmmc_dma_callback’:
drivers/mmc/au1xmmc.c:743: warning: unused variable ‘status’
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Acked-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
drivers/mmc/au1xmmc.c doesn't compile because commit
e92251762d introduced a typo and passes
the wrong argument to the mmc_resp_type macro.
Error because of the typo:
CC drivers/mmc/au1xmmc.o
drivers/mmc/au1xmmc.c: In function ‘au1xmmc_send_command’:
drivers/mmc/au1xmmc.c:197: warning: implicit declaration of function ‘mmc_rsp_type’
...
LD .tmp_vmlinux1
drivers/built-in.o: In function `au1xmmc_request':au1xmmc.c:(.text+0x89504): undefined reference to `mmc_rsp_type'
:au1xmmc.c:(.text+0x8968c): undefined reference to `mmc_rsp_type'
make: *** [.tmp_vmlinux1] Error 1
Error because of the wrong argument:
CC drivers/mmc/au1xmmc.o
drivers/mmc/au1xmmc.c: In function ‘au1xmmc_send_command’:
drivers/mmc/au1xmmc.c:197: error: invalid type argument of ‘->’
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
drivers/mmc/au1xmmc.c currently doesn't compile; it needs to be
converted to use platform_driver. I cannot test this change because
of lack of hardware but I followed the drivers this one is based on,
and the code is certainly not worse than before.
drivers/mmc/au1xmmc.c: At top level:
drivers/mmc/au1xmmc.c:1002: error: ‘platform_bus_type’ undeclared here (not in a function)
make[2]: *** [drivers/mmc/au1xmmc.o] Error 1
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
