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authorDavid Howells <dhowells@redhat.com>2006-10-05 14:55:46 +0100
committerDavid Howells <dhowells@warthog.cambridge.redhat.com>2006-10-05 15:10:12 +0100
commit7d12e780e003f93433d49ce78cfedf4b4c52adc5 (patch)
tree6748550400445c11a306b132009f3001e3525df8 /drivers/usb/input/hid-core.c
parentda482792a6d1a3fbaaa25fae867b343fb4db3246 (diff)
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
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)
Diffstat (limited to 'drivers/usb/input/hid-core.c')
-rw-r--r--drivers/usb/input/hid-core.c28
1 files changed, 14 insertions, 14 deletions
diff --git a/drivers/usb/input/hid-core.c b/drivers/usb/input/hid-core.c
index e0fd11605b43..a6738a83ff5b 100644
--- a/drivers/usb/input/hid-core.c
+++ b/drivers/usb/input/hid-core.c
@@ -780,13 +780,13 @@ static __inline__ int search(__s32 *array, __s32 value, unsigned n)
return -1;
}
-static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value, int interrupt, struct pt_regs *regs)
+static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value, int interrupt)
{
hid_dump_input(usage, value);
if (hid->claimed & HID_CLAIMED_INPUT)
- hidinput_hid_event(hid, field, usage, value, regs);
+ hidinput_hid_event(hid, field, usage, value);
if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt)
- hiddev_hid_event(hid, field, usage, value, regs);
+ hiddev_hid_event(hid, field, usage, value);
}
/*
@@ -795,7 +795,7 @@ static void hid_process_event(struct hid_device *hid, struct hid_field *field, s
* reporting to the layer).
*/
-static void hid_input_field(struct hid_device *hid, struct hid_field *field, __u8 *data, int interrupt, struct pt_regs *regs)
+static void hid_input_field(struct hid_device *hid, struct hid_field *field, __u8 *data, int interrupt)
{
unsigned n;
unsigned count = field->report_count;
@@ -822,19 +822,19 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, __u
for (n = 0; n < count; n++) {
if (HID_MAIN_ITEM_VARIABLE & field->flags) {
- hid_process_event(hid, field, &field->usage[n], value[n], interrupt, regs);
+ hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
continue;
}
if (field->value[n] >= min && field->value[n] <= max
&& field->usage[field->value[n] - min].hid
&& search(value, field->value[n], count))
- hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt, regs);
+ hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
if (value[n] >= min && value[n] <= max
&& field->usage[value[n] - min].hid
&& search(field->value, value[n], count))
- hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt, regs);
+ hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
}
memcpy(field->value, value, count * sizeof(__s32));
@@ -842,7 +842,7 @@ exit:
kfree(value);
}
-static int hid_input_report(int type, struct urb *urb, int interrupt, struct pt_regs *regs)
+static int hid_input_report(int type, struct urb *urb, int interrupt)
{
struct hid_device *hid = urb->context;
struct hid_report_enum *report_enum = hid->report_enum + type;
@@ -892,7 +892,7 @@ static int hid_input_report(int type, struct urb *urb, int interrupt, struct pt_
hiddev_report_event(hid, report);
for (n = 0; n < report->maxfield; n++)
- hid_input_field(hid, report->field[n], data, interrupt, regs);
+ hid_input_field(hid, report->field[n], data, interrupt);
if (hid->claimed & HID_CLAIMED_INPUT)
hidinput_report_event(hid, report);
@@ -1004,7 +1004,7 @@ done:
* Input interrupt completion handler.
*/
-static void hid_irq_in(struct urb *urb, struct pt_regs *regs)
+static void hid_irq_in(struct urb *urb)
{
struct hid_device *hid = urb->context;
int status;
@@ -1012,7 +1012,7 @@ static void hid_irq_in(struct urb *urb, struct pt_regs *regs)
switch (urb->status) {
case 0: /* success */
hid->retry_delay = 0;
- hid_input_report(HID_INPUT_REPORT, urb, 1, regs);
+ hid_input_report(HID_INPUT_REPORT, urb, 1);
break;
case -ECONNRESET: /* unlink */
case -ENOENT:
@@ -1193,7 +1193,7 @@ static int hid_submit_ctrl(struct hid_device *hid)
* Output interrupt completion handler.
*/
-static void hid_irq_out(struct urb *urb, struct pt_regs *regs)
+static void hid_irq_out(struct urb *urb)
{
struct hid_device *hid = urb->context;
unsigned long flags;
@@ -1238,7 +1238,7 @@ static void hid_irq_out(struct urb *urb, struct pt_regs *regs)
* Control pipe completion handler.
*/
-static void hid_ctrl(struct urb *urb, struct pt_regs *regs)
+static void hid_ctrl(struct urb *urb)
{
struct hid_device *hid = urb->context;
unsigned long flags;
@@ -1249,7 +1249,7 @@ static void hid_ctrl(struct urb *urb, struct pt_regs *regs)
switch (urb->status) {
case 0: /* success */
if (hid->ctrl[hid->ctrltail].dir == USB_DIR_IN)
- hid_input_report(hid->ctrl[hid->ctrltail].report->type, urb, 0, regs);
+ hid_input_report(hid->ctrl[hid->ctrltail].report->type, urb, 0);
break;
case -ESHUTDOWN: /* unplug */
unplug = 1;