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)
104 lines
2.7 KiB
C
104 lines
2.7 KiB
C
/*
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* Definitions for ADB (Apple Desktop Bus) support.
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*/
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#ifndef __ADB_H
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#define __ADB_H
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/* ADB commands */
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#define ADB_BUSRESET 0
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#define ADB_FLUSH(id) (0x01 | ((id) << 4))
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#define ADB_WRITEREG(id, reg) (0x08 | (reg) | ((id) << 4))
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#define ADB_READREG(id, reg) (0x0C | (reg) | ((id) << 4))
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/* ADB default device IDs (upper 4 bits of ADB command byte) */
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#define ADB_DONGLE 1 /* "software execution control" devices */
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#define ADB_KEYBOARD 2
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#define ADB_MOUSE 3
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#define ADB_TABLET 4
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#define ADB_MODEM 5
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#define ADB_MISC 7 /* maybe a monitor */
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#define ADB_RET_OK 0
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#define ADB_RET_TIMEOUT 3
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/* The kind of ADB request. The controller may emulate some
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or all of those CUDA/PMU packet kinds */
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#define ADB_PACKET 0
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#define CUDA_PACKET 1
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#define ERROR_PACKET 2
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#define TIMER_PACKET 3
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#define POWER_PACKET 4
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#define MACIIC_PACKET 5
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#define PMU_PACKET 6
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#define ADB_QUERY 7
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/* ADB queries */
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/* ADB_QUERY_GETDEVINFO
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* Query ADB slot for device presence
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* data[2] = id, rep[0] = orig addr, rep[1] = handler_id
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*/
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#define ADB_QUERY_GETDEVINFO 1
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#ifdef __KERNEL__
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struct adb_request {
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unsigned char data[32];
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int nbytes;
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unsigned char reply[32];
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int reply_len;
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unsigned char reply_expected;
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unsigned char sent;
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unsigned char complete;
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void (*done)(struct adb_request *);
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void *arg;
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struct adb_request *next;
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};
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struct adb_ids {
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int nids;
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unsigned char id[16];
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};
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/* Structure which encapsulates a low-level ADB driver */
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struct adb_driver {
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char name[16];
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int (*probe)(void);
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int (*init)(void);
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int (*send_request)(struct adb_request *req, int sync);
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int (*autopoll)(int devs);
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void (*poll)(void);
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int (*reset_bus)(void);
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};
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/* Values for adb_request flags */
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#define ADBREQ_REPLY 1 /* expect reply */
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#define ADBREQ_SYNC 2 /* poll until done */
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#define ADBREQ_NOSEND 4 /* build the request, but don't send it */
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/* Messages sent thru the client_list notifier. You should NOT stop
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the operation, at least not with this version */
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enum adb_message {
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ADB_MSG_POWERDOWN, /* Currently called before sleep only */
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ADB_MSG_PRE_RESET, /* Called before resetting the bus */
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ADB_MSG_POST_RESET /* Called after resetting the bus (re-do init & register) */
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};
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extern struct adb_driver *adb_controller;
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extern struct blocking_notifier_head adb_client_list;
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int adb_request(struct adb_request *req, void (*done)(struct adb_request *),
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int flags, int nbytes, ...);
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int adb_register(int default_id,int handler_id,struct adb_ids *ids,
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void (*handler)(unsigned char *, int, int));
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int adb_unregister(int index);
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void adb_poll(void);
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void adb_input(unsigned char *, int, int);
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int adb_reset_bus(void);
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int adb_try_handler_change(int address, int new_id);
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int adb_get_infos(int address, int *original_address, int *handler_id);
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#endif /* __KERNEL__ */
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#endif /* __ADB_H */
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