linux.git/arch/ia64/kernel/entry.S, branch v2.6.26

[IA64] trivial cleanup for entry.S

2008-05-14T22:56:09+00:00

This patch does:
 - make comment at next to resched check more robust
 - move "re-check" comments to next to where change predicate regs

Signed-off-by: Hidetoshi Seto 
Signed-off-by: Tony Luck

[IA64] fix interrupt masking for pending works on kernel leave

2008-05-14T22:55:35+00:00

[Bug-fix for "[BUG?][2.6.25-mm1] sleeping during IRQ disabled"]

This patch does:
 - enable interrupts before calling schedule() as same as others, ex. x86
 - enable interrupts during ia64_do_signal() and ia64_sync_krbs()
 - do_notify_resume_user() is still called with interrupts disabled, since
   we can take short path of fsys_mode if-statement quickly.
 - pfm_handle_work() is also called with interrupts disabled, since
   it can deal interrupt mask within itself.
 - fix/add some comments/notes

Reported-by: KOSAKI Motohiro 
Signed-off-by: Hidetoshi Seto 
Signed-off-by: Tony Luck

[IA64] disable interrupts on exit of ia64_trace_syscall

2008-04-22T15:55:51+00:00

While testing with CONFIG_VIRT_CPU_ACCOUNTING=y, I found that
I occasionally get very huge system time in some threads.

So I dug the issue and finally noticed that it was caused
because of an interrupt which interrupt in the following window:

> [arch/ia64/kernel/entry.S: (!CONFIG_PREEMPT && CONFIG_VIRT_CPU_ACCOUNTING)]
>
> ENTRY(ia64_leave_syscall)
>    :
> (pUStk) rsm psr.i
>         cmp.eq pLvSys,p0=r0,r0          // pLvSys=1: leave from syscall
> (pUStk) cmp.eq.unc p6,p0=r0,r0          // p6 <- pUStk
> .work_processed_syscall:
>         adds r2=PT(LOADRS)+16,r12
> (pUStk) mov.m r22=ar.itc                        // fetch time at leave
>         adds r18=TI_FLAGS+IA64_TASK_SIZE,r13
>         ;;
> <<< window: from here >>>
> (p6)    ld4 r31=[r18]  // load current_thread_info()->flags
>         ld8 r19=[r2],PT(B6)-PT(LOADRS)
>         adds r3=PT(AR_BSPSTORE)+16,r12
>         ;;
>         mov r16=ar.bsp
>         ld8 r18=[r2],PT(R9)-PT(B6)
> (p6)    and r15=TIF_WORK_MASK,r31  // any work other than TIF_SYSCALL_TRACE?
>         ;;
>         ld8 r23=[r3],PT(R11)-PT(AR_BSPSTORE)
> (p6)    cmp4.ne.unc p6,p0=r15, r0               // any special work pending?
> (p6)    br.cond.spnt .work_pending_syscall
>         ;;
>         ld8 r9=[r2],PT(CR_IPSR)-PT(R9)
>         ld8 r11=[r3],PT(CR_IIP)-PT(R11)
> (pNonSys) break 0 // bug check: we shouldn't be here if pNonSys is TRUE!
>         ;;
>         invala
> <<< window: to here >>>
>         rsm psr.i | psr.ic // turn off interrupts and interruption collection

If pUStk is true, it means we are going to return user mode, hence we fetch
ar.itc to get time at leave from system.
It seems that it is not possible to interrupt the window if pUStk is true,
because interrupts are disabled early.  And also disabling interrupt makes
sense because it is safe for referring current_thread_info()->flags.

However interrupting the window while pUStk is true was possible.
The route was:
ia64_trace_syscall
-> .work_pending_syscall_end
-> .work_processed_syscall
Only in case entering the window from this route, interrupts are enabled
during in the window even if pUStk is true.  I suppose interrupts must be
disabled here anyway if pUStk is true.
I'm not sure but afraid that what kind of bad effect were there, other
than crazy system time which I found.

FYI, there was a commit 6f6d75825dc49b082906b84537b4df28293c2977 that
points out a bug at same point(exit of ia64_trace_syscall) in 2006.
It can be said that there was an another bug.

Signed-off-by: Hidetoshi Seto 
Signed-off-by: Tony Luck

[IA64] VIRT_CPU_ACCOUNTING (accurate cpu time accounting)

2008-02-20T20:55:37+00:00

This patch implements VIRT_CPU_ACCOUNTING for ia64,
which enable us to use more accurate cpu time accounting.

The VIRT_CPU_ACCOUNTING is an item of kernel config, which s390
and powerpc arch have.  By turning this config on, these archs
change the mechanism of cpu time accounting from tick-sampling
based one to state-transition based one.

The state-transition based accounting is done by checking time
(cycle counter in processor) at every state-transition point,
such as entrance/exit of kernel, interrupt, softirq etc.
The difference between point to point is the actual time consumed
during in the state. There is no doubt about that this value is
more accurate than that of tick-sampling based accounting.

Signed-off-by: Hidetoshi Seto 
Signed-off-by: Tony Luck

[IA64] Wire up timerfd_{create,settime,gettime} syscalls

2008-02-08T20:00:32+00:00

Add ia64 hooks for the new syscalls that were added in
commit 4d672e7ac79b5ec5cdc90e450823441e20464691

Signed-off-by: Tony Luck

timerfd: new timerfd API

2008-02-05T17:44:07+00:00

This is the new timerfd API as it is implemented by the following patch:

int timerfd_create(int clockid, int flags);
int timerfd_settime(int ufd, int flags,
		    const struct itimerspec *utmr,
		    struct itimerspec *otmr);
int timerfd_gettime(int ufd, struct itimerspec *otmr);

The timerfd_create() API creates an un-programmed timerfd fd.  The "clockid"
parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME.

The timerfd_settime() API give new settings by the timerfd fd, by optionally
retrieving the previous expiration time (in case the "otmr" parameter is not
NULL).

The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit
is set in the "flags" parameter.  Otherwise it's a relative time.

The timerfd_gettime() API returns the next expiration time of the timer, or
{0, 0} if the timerfd has not been set yet.

Like the previous timerfd API implementation, read(2) and poll(2) are
supported (with the same interface).  Here's a simple test program I used to
exercise the new timerfd APIs:

http://www.xmailserver.org/timerfd-test2.c

[akpm@linux-foundation.org: coding-style cleanups]
[akpm@linux-foundation.org: fix ia64 build]
[akpm@linux-foundation.org: fix m68k build]
[akpm@linux-foundation.org: fix mips build]
[akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds]
[heiko.carstens@de.ibm.com: fix s390]
[akpm@linux-foundation.org: fix powerpc build]
[akpm@linux-foundation.org: fix sparc64 more]
Signed-off-by: Davide Libenzi 
Cc: Michael Kerrisk 
Cc: Thomas Gleixner 
Cc: Davide Libenzi 
Cc: Michael Kerrisk 
Cc: Martin Schwidefsky 
Signed-off-by: Heiko Carstens 
Cc: Michael Kerrisk 
Cc: Davide Libenzi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[IA64] fallocate system call

2007-07-19T20:48:00+00:00

sys_fallocate for ia64. This uses an empty slot #1303 erroneously
marked as reserved for move_pages (which had already been allocated
as syscall #1276)

Signed-Off-By: Dave Chinner 
Signed-off-by: Tony Luck

[IA64] wire up {signal,timer,event}fd syscalls

2007-05-14T22:55:11+00:00

Signed-off-by: Tony Luck

[IA64] Wire up epoll_pwait and utimensat

2007-05-10T16:44:42+00:00

Another day, another pair of new system calls.

Signed-off-by: Tony Luck

[IA64] wire up pselect, ppoll

2007-05-08T22:57:59+00:00

Signed-off-by: Alexey Kuznetsov 
Signed-off-by: Alexey Dobriyan 
Signed-off-by: Tony Luck