linux/drivers/char/rtc.c, branch v2.6.19

[RTC] Consistently use of tabs for formatting.

2006-10-09T22:20:47Z

IRQ: Maintain regs pointer globally rather than passing to IRQ handlers

2006-10-05T14:10:12Z

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 (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

[PATCH] remove unnecessary barrier in rtc_get_rtc_time

2006-09-29T16:18:05Z

Signed-off-by: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] rtc: lockdep fix/workaround

2006-09-26T00:38:35Z

BUG: warning at kernel/lockdep.c:1816/trace_hardirqs_on() (Not tainted) [] show_trace_log_lvl+0x58/0x171 [] show_trace+0xd/0x10 [] dump_stack+0x19/0x1b [] trace_hardirqs_on+0xa2/0x11e [] _spin_unlock_irq+0x22/0x26 [] rtc_get_rtc_time+0x32/0x176 [] hpet_rtc_interrupt+0x92/0x14d [] handle_IRQ_event+0x20/0x4d [] __do_IRQ+0x94/0xef [] do_IRQ+0x9e/0xbd [] common_interrupt+0x25/0x2c DWARF2 unwinder stuck at common_interrupt+0x25/0x2c Signed-off-by: Peter Zijlstra Acked-by: Ingo Molnar Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] lockdep: HPET/RTC fix

2006-07-12T19:52:55Z

Joseph Fannin reported that hpet_rtc_interrupt() enables hardirqs in irq context: [ 25.628000] [] trace_hardirqs_on+0xce/0x200 [ 25.628000] [] _spin_unlock_irq+0x31/0x70 [ 25.628000] [] rtc_get_rtc_time+0x44/0x1a0 [ 25.628000] [] hpet_rtc_interrupt+0x21b/0x280 [ 25.628000] [] handle_IRQ_event+0x31/0x70 [ 25.628000] [] handle_edge_irq+0xe7/0x210 [ 25.628000] [] do_IRQ+0x92/0x120 [ 25.628000] [] common_interrupt+0x25/0x2c the call of rtc_get_rtc_time() is highly suspect. At a minimum we need the patch below to save/restore hardirq state. Signed-off-by: Ingo Molnar Cc: Joseph Fannin Cc: John Stultz Cc: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] char/rtc: Handle memory-mapped chips properly

2006-07-10T20:24:25Z

Handle memory-mapped chips properly, needed for example on DECstations. This support was in Linux 2.4 but for some reason got lost in 2.6. This patch is taken directly from the linux-mips repository. [akpm@osdl.org: cleanup] Signed-off-by: Maciej W. Rozycki Signed-off-by: Martin Michlmayr Cc: Paul Gortmaker Cc: Ralf Baechle Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] make more file_operation structs static

2006-07-03T22:26:59Z

Mark the static struct file_operations in drivers/char as const. Making them const prevents accidental bugs, and moves them to the .rodata section so that they no longer do any false sharing; in addition with the proper debug option they are then protected against corruption.. [akpm@osdl.org: build fix] Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] irq-flags: drivers/char: Use the new IRQF_ constants

2006-07-02T20:58:49Z

Signed-off-by: Thomas Gleixner Cc: Ingo Molnar Cc: "David S. Miller" Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Remove obsolete #include

2006-06-30T17:25:36Z

Signed-off-by: Jörn Engel Signed-off-by: Adrian Bunk

[SPARC64]: Use in-kernel PROM tree for EBUS and ISA.

2006-06-24T06:15:28Z

Signed-off-by: David S. Miller