Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 884 insertions, 0 deletions

diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S
new file mode 100644
index 00000000000..0d8650f7fce
--- /dev/null
+++ b/arch/ia64/kernel/fsys.S
@@ -0,0 +1,884 @@
+/*
+ * This file contains the light-weight system call handlers (fsyscall-handlers).
+ *
+ * Copyright (C) 2003 Hewlett-Packard Co
+ * 	David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * 25-Sep-03 davidm	Implement fsys_rt_sigprocmask().
+ * 18-Feb-03 louisk	Implement fsys_gettimeofday().
+ * 28-Feb-03 davidm	Fixed several bugs in fsys_gettimeofday().  Tuned it some more,
+ *			probably broke it along the way... ;-)
+ * 13-Jul-04 clameter   Implement fsys_clock_gettime and revise fsys_gettimeofday to make
+ *                      it capable of using memory based clocks without falling back to C code.
+ */
+
+#include <asm/asmmacro.h>
+#include <asm/errno.h>
+#include <asm/offsets.h>
+#include <asm/percpu.h>
+#include <asm/thread_info.h>
+#include <asm/sal.h>
+#include <asm/signal.h>
+#include <asm/system.h>
+#include <asm/unistd.h>
+
+#include "entry.h"
+
+/*
+ * See Documentation/ia64/fsys.txt for details on fsyscalls.
+ *
+ * On entry to an fsyscall handler:
+ *   r10	= 0 (i.e., defaults to "successful syscall return")
+ *   r11	= saved ar.pfs (a user-level value)
+ *   r15	= system call number
+ *   r16	= "current" task pointer (in normal kernel-mode, this is in r13)
+ *   r32-r39	= system call arguments
+ *   b6		= return address (a user-level value)
+ *   ar.pfs	= previous frame-state (a user-level value)
+ *   PSR.be	= cleared to zero (i.e., little-endian byte order is in effect)
+ *   all other registers may contain values passed in from user-mode
+ *
+ * On return from an fsyscall handler:
+ *   r11	= saved ar.pfs (as passed into the fsyscall handler)
+ *   r15	= system call number (as passed into the fsyscall handler)
+ *   r32-r39	= system call arguments (as passed into the fsyscall handler)
+ *   b6		= return address (as passed into the fsyscall handler)
+ *   ar.pfs	= previous frame-state (as passed into the fsyscall handler)
+ */
+
+ENTRY(fsys_ni_syscall)
+	.prologue
+	.altrp b6
+	.body
+	mov r8=ENOSYS
+	mov r10=-1
+	FSYS_RETURN
+END(fsys_ni_syscall)
+
+ENTRY(fsys_getpid)
+	.prologue
+	.altrp b6
+	.body
+	add r9=TI_FLAGS+IA64_TASK_SIZE,r16
+	;;
+	ld4 r9=[r9]
+	add r8=IA64_TASK_TGID_OFFSET,r16
+	;;
+	and r9=TIF_ALLWORK_MASK,r9
+	ld4 r8=[r8]				// r8 = current->tgid
+	;;
+	cmp.ne p8,p0=0,r9
+(p8)	br.spnt.many fsys_fallback_syscall
+	FSYS_RETURN
+END(fsys_getpid)
+
+ENTRY(fsys_getppid)
+	.prologue
+	.altrp b6
+	.body
+	add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16
+	;;
+	ld8 r17=[r17]				// r17 = current->group_leader
+	add r9=TI_FLAGS+IA64_TASK_SIZE,r16
+	;;
+
+	ld4 r9=[r9]
+	add r17=IA64_TASK_REAL_PARENT_OFFSET,r17 // r17 = &current->group_leader->real_parent
+	;;
+	and r9=TIF_ALLWORK_MASK,r9
+
+1:	ld8 r18=[r17]				// r18 = current->group_leader->real_parent
+	;;
+	cmp.ne p8,p0=0,r9
+	add r8=IA64_TASK_TGID_OFFSET,r18	// r8 = &current->group_leader->real_parent->tgid
+	;;
+
+	/*
+	 * The .acq is needed to ensure that the read of tgid has returned its data before
+	 * we re-check "real_parent".
+	 */
+	ld4.acq r8=[r8]				// r8 = current->group_leader->real_parent->tgid
+#ifdef CONFIG_SMP
+	/*
+	 * Re-read current->group_leader->real_parent.
+	 */
+	ld8 r19=[r17]				// r19 = current->group_leader->real_parent
+(p8)	br.spnt.many fsys_fallback_syscall
+	;;
+	cmp.ne p6,p0=r18,r19			// did real_parent change?
+	mov r19=0			// i must not leak kernel bits...
+(p6)	br.cond.spnt.few 1b			// yes -> redo the read of tgid and the check
+	;;
+	mov r17=0			// i must not leak kernel bits...
+	mov r18=0			// i must not leak kernel bits...
+#else
+	mov r17=0			// i must not leak kernel bits...
+	mov r18=0			// i must not leak kernel bits...
+	mov r19=0			// i must not leak kernel bits...
+#endif
+	FSYS_RETURN
+END(fsys_getppid)
+
+ENTRY(fsys_set_tid_address)
+	.prologue
+	.altrp b6
+	.body
+	add r9=TI_FLAGS+IA64_TASK_SIZE,r16
+	;;
+	ld4 r9=[r9]
+	tnat.z p6,p7=r32		// check argument register for being NaT
+	;;
+	and r9=TIF_ALLWORK_MASK,r9
+	add r8=IA64_TASK_PID_OFFSET,r16
+	add r18=IA64_TASK_CLEAR_CHILD_TID_OFFSET,r16
+	;;
+	ld4 r8=[r8]
+	cmp.ne p8,p0=0,r9
+	mov r17=-1
+	;;
+(p6)	st8 [r18]=r32
+(p7)	st8 [r18]=r17
+(p8)	br.spnt.many fsys_fallback_syscall
+	;;
+	mov r17=0			// i must not leak kernel bits...
+	mov r18=0			// i must not leak kernel bits...
+	FSYS_RETURN
+END(fsys_set_tid_address)
+
+/*
+ * Ensure that the time interpolator structure is compatible with the asm code
+ */
+#if IA64_TIME_INTERPOLATOR_SOURCE_OFFSET !=0 || IA64_TIME_INTERPOLATOR_SHIFT_OFFSET != 2 \
+	|| IA64_TIME_INTERPOLATOR_JITTER_OFFSET != 3 || IA64_TIME_INTERPOLATOR_NSEC_OFFSET != 4
+#error fsys_gettimeofday incompatible with changes to struct time_interpolator
+#endif
+#define CLOCK_REALTIME 0
+#define CLOCK_MONOTONIC 1
+#define CLOCK_DIVIDE_BY_1000 0x4000
+#define CLOCK_ADD_MONOTONIC 0x8000
+
+ENTRY(fsys_gettimeofday)
+	.prologue
+	.altrp b6
+	.body
+	mov r31 = r32
+	tnat.nz p6,p0 = r33		// guard against NaT argument
+(p6)    br.cond.spnt.few .fail_einval
+	mov r30 = CLOCK_DIVIDE_BY_1000
+	;;
+.gettime:
+	// Register map
+	// Incoming r31 = pointer to address where to place result
+	//          r30 = flags determining how time is processed
+	// r2,r3 = temp r4-r7 preserved
+	// r8 = result nanoseconds
+	// r9 = result seconds
+	// r10 = temporary storage for clock difference
+	// r11 = preserved: saved ar.pfs
+	// r12 = preserved: memory stack
+	// r13 = preserved: thread pointer
+	// r14 = address of mask / mask
+	// r15 = preserved: system call number
+	// r16 = preserved: current task pointer
+	// r17 = wall to monotonic use
+	// r18 = time_interpolator->offset
+	// r19 = address of wall_to_monotonic
+	// r20 = pointer to struct time_interpolator / pointer to time_interpolator->address
+	// r21 = shift factor
+	// r22 = address of time interpolator->last_counter
+	// r23 = address of time_interpolator->last_cycle
+	// r24 = adress of time_interpolator->offset
+	// r25 = last_cycle value
+	// r26 = last_counter value
+	// r27 = pointer to xtime
+	// r28 = sequence number at the beginning of critcal section
+	// r29 = address of seqlock
+	// r30 = time processing flags / memory address
+	// r31 = pointer to result
+	// Predicates
+	// p6,p7 short term use
+	// p8 = timesource ar.itc
+	// p9 = timesource mmio64
+	// p10 = timesource mmio32
+	// p11 = timesource not to be handled by asm code
+	// p12 = memory time source ( = p9 | p10)
+	// p13 = do cmpxchg with time_interpolator_last_cycle
+	// p14 = Divide by 1000
+	// p15 = Add monotonic
+	//
+	// Note that instructions are optimized for McKinley. McKinley can process two
+	// bundles simultaneously and therefore we continuously try to feed the CPU
+	// two bundles and then a stop.
+	tnat.nz p6,p0 = r31	// branch deferred since it does not fit into bundle structure
+	mov pr = r30,0xc000	// Set predicates according to function
+	add r2 = TI_FLAGS+IA64_TASK_SIZE,r16
+	movl r20 = time_interpolator
+	;;
+	ld8 r20 = [r20]		// get pointer to time_interpolator structure
+	movl r29 = xtime_lock
+	ld4 r2 = [r2]		// process work pending flags
+	movl r27 = xtime
+	;;	// only one bundle here
+	ld8 r21 = [r20]		// first quad with control information
+	and r2 = TIF_ALLWORK_MASK,r2
+(p6)    br.cond.spnt.few .fail_einval	// deferred branch
+	;;
+	add r10 = IA64_TIME_INTERPOLATOR_ADDRESS_OFFSET,r20
+	extr r3 = r21,32,32	// time_interpolator->nsec_per_cyc
+	extr r8 = r21,0,16	// time_interpolator->source
+	cmp.ne p6, p0 = 0, r2	// Fallback if work is scheduled
+(p6)    br.cond.spnt.many fsys_fallback_syscall
+	;;
+	cmp.eq p8,p12 = 0,r8	// Check for cpu timer
+	cmp.eq p9,p0 = 1,r8	// MMIO64 ?
+	extr r2 = r21,24,8	// time_interpolator->jitter
+	cmp.eq p10,p0 = 2,r8	// MMIO32 ?
+	cmp.ltu p11,p0 = 2,r8	// function or other clock
+(p11)	br.cond.spnt.many fsys_fallback_syscall
+	;;
+	setf.sig f7 = r3	// Setup for scaling of counter
+(p15)	movl r19 = wall_to_monotonic
+(p12)	ld8 r30 = [r10]
+	cmp.ne p13,p0 = r2,r0	// need jitter compensation?
+	extr r21 = r21,16,8	// shift factor
+	;;
+.time_redo:
+	.pred.rel.mutex p8,p9,p10
+	ld4.acq r28 = [r29]	// xtime_lock.sequence. Must come first for locking purposes
+(p8)	mov r2 = ar.itc		// CPU_TIMER. 36 clocks latency!!!
+	add r22 = IA64_TIME_INTERPOLATOR_LAST_COUNTER_OFFSET,r20
+(p9)	ld8 r2 = [r30]		// readq(ti->address). Could also have latency issues..
+(p10)	ld4 r2 = [r30]		// readw(ti->address)
+(p13)	add r23 = IA64_TIME_INTERPOLATOR_LAST_CYCLE_OFFSET,r20
+	;;			// could be removed by moving the last add upward
+	ld8 r26 = [r22]		// time_interpolator->last_counter
+(p13)	ld8 r25 = [r23]		// time interpolator->last_cycle
+	add r24 = IA64_TIME_INTERPOLATOR_OFFSET_OFFSET,r20
+(p15)	ld8 r17 = [r19],IA64_TIMESPEC_TV_NSEC_OFFSET
+ 	ld8 r9 = [r27],IA64_TIMESPEC_TV_NSEC_OFFSET
+	add r14 = IA64_TIME_INTERPOLATOR_MASK_OFFSET, r20
+	;;
+	ld8 r18 = [r24]		// time_interpolator->offset
+	ld8 r8 = [r27],-IA64_TIMESPEC_TV_NSEC_OFFSET	// xtime.tv_nsec
+(p13)	sub r3 = r25,r2	// Diff needed before comparison (thanks davidm)
+	;;
+	ld8 r14 = [r14]		// time_interpolator->mask
+(p13)	cmp.gt.unc p6,p7 = r3,r0	// check if it is less than last. p6,p7 cleared
+	sub r10 = r2,r26	// current_counter - last_counter
+	;;
+(p6)	sub r10 = r25,r26	// time we got was less than last_cycle
+(p7)	mov ar.ccv = r25	// more than last_cycle. Prep for cmpxchg
+	;;
+	and r10 = r10,r14	// Apply mask
+	;;
+	setf.sig f8 = r10
+	nop.i 123
+	;;
+(p7)	cmpxchg8.rel r3 = [r23],r2,ar.ccv
+EX(.fail_efault, probe.w.fault r31, 3)	// This takes 5 cycles and we have spare time
+	xmpy.l f8 = f8,f7	// nsec_per_cyc*(counter-last_counter)
+(p15)	add r9 = r9,r17		// Add wall to monotonic.secs to result secs
+	;;
+(p15)	ld8 r17 = [r19],-IA64_TIMESPEC_TV_NSEC_OFFSET
+(p7)	cmp.ne p7,p0 = r25,r3	// if cmpxchg not successful redo
+	// simulate tbit.nz.or p7,p0 = r28,0
+	and r28 = ~1,r28	// Make sequence even to force retry if odd
+	getf.sig r2 = f8
+	mf
+	add r8 = r8,r18		// Add time interpolator offset
+	;;
+	ld4 r10 = [r29]		// xtime_lock.sequence
+(p15)	add r8 = r8, r17	// Add monotonic.nsecs to nsecs
+	shr.u r2 = r2,r21
+	;;		// overloaded 3 bundles!
+	// End critical section.
+	add r8 = r8,r2		// Add xtime.nsecs
+	cmp4.ne.or p7,p0 = r28,r10
+(p7)	br.cond.dpnt.few .time_redo	// sequence number changed ?
+	// Now r8=tv->tv_nsec and r9=tv->tv_sec
+	mov r10 = r0
+	movl r2 = 1000000000
+	add r23 = IA64_TIMESPEC_TV_NSEC_OFFSET, r31
+(p14)	movl r3 = 2361183241434822607	// Prep for / 1000 hack
+	;;
+.time_normalize:
+	mov r21 = r8
+	cmp.ge p6,p0 = r8,r2
+(p14)	shr.u r20 = r8, 3		// We can repeat this if necessary just wasting some time
+	;;
+(p14)	setf.sig f8 = r20
+(p6)	sub r8 = r8,r2
+(p6)	add r9 = 1,r9			// two nops before the branch.
+(p14)	setf.sig f7 = r3		// Chances for repeats are 1 in 10000 for gettod
+(p6)	br.cond.dpnt.few .time_normalize
+	;;
+	// Divided by 8 though shift. Now divide by 125
+	// The compiler was able to do that with a multiply
+	// and a shift and we do the same
+EX(.fail_efault, probe.w.fault r23, 3)		// This also costs 5 cycles
+(p14)	xmpy.hu f8 = f8, f7			// xmpy has 5 cycles latency so use it...
+	;;
+	mov r8 = r0
+(p14)	getf.sig r2 = f8
+	;;
+(p14)	shr.u r21 = r2, 4
+	;;
+EX(.fail_efault, st8 [r31] = r9)
+EX(.fail_efault, st8 [r23] = r21)
+	FSYS_RETURN
+.fail_einval:
+	mov r8 = EINVAL
+	mov r10 = -1
+	FSYS_RETURN
+.fail_efault:
+	mov r8 = EFAULT
+	mov r10 = -1
+	FSYS_RETURN
+END(fsys_gettimeofday)
+
+ENTRY(fsys_clock_gettime)
+	.prologue
+	.altrp b6
+	.body
+	cmp4.ltu p6, p0 = CLOCK_MONOTONIC, r32
+	// Fallback if this is not CLOCK_REALTIME or CLOCK_MONOTONIC
+(p6)	br.spnt.few fsys_fallback_syscall
+	mov r31 = r33
+	shl r30 = r32,15
+	br.many .gettime
+END(fsys_clock_gettime)
+
+/*
+ * long fsys_rt_sigprocmask (int how, sigset_t *set, sigset_t *oset, size_t sigsetsize).
+ */
+#if _NSIG_WORDS != 1
+# error Sorry, fsys_rt_sigprocmask() needs to be updated for _NSIG_WORDS != 1.
+#endif
+ENTRY(fsys_rt_sigprocmask)
+	.prologue
+	.altrp b6
+	.body
+
+	add r2=IA64_TASK_BLOCKED_OFFSET,r16
+	add r9=TI_FLAGS+IA64_TASK_SIZE,r16
+	cmp4.ltu p6,p0=SIG_SETMASK,r32
+
+	cmp.ne p15,p0=r0,r34			// oset != NULL?
+	tnat.nz p8,p0=r34
+	add r31=IA64_TASK_SIGHAND_OFFSET,r16
+	;;
+	ld8 r3=[r2]				// read/prefetch current->blocked
+	ld4 r9=[r9]
+	tnat.nz.or p6,p0=r35
+
+	cmp.ne.or p6,p0=_NSIG_WORDS*8,r35
+	tnat.nz.or p6,p0=r32
+(p6)	br.spnt.few .fail_einval		// fail with EINVAL
+	;;
+#ifdef CONFIG_SMP
+	ld8 r31=[r31]				// r31 <- current->sighand
+#endif
+	and r9=TIF_ALLWORK_MASK,r9
+	tnat.nz.or p8,p0=r33
+	;;
+	cmp.ne p7,p0=0,r9
+	cmp.eq p6,p0=r0,r33			// set == NULL?
+	add r31=IA64_SIGHAND_SIGLOCK_OFFSET,r31	// r31 <- current->sighand->siglock
+(p8)	br.spnt.few .fail_efault		// fail with EFAULT
+(p7)	br.spnt.many fsys_fallback_syscall	// got pending kernel work...
+(p6)	br.dpnt.many .store_mask		// -> short-circuit to just reading the signal mask
+
+	/* Argh, we actually have to do some work and _update_ the signal mask: */
+
+EX(.fail_efault, probe.r.fault r33, 3)		// verify user has read-access to *set
+EX(.fail_efault, ld8 r14=[r33])			// r14 <- *set
+	mov r17=(1 << (SIGKILL - 1)) | (1 << (SIGSTOP - 1))
+	;;
+
+	rsm psr.i				// mask interrupt delivery
+	mov ar.ccv=0
+	andcm r14=r14,r17			// filter out SIGKILL & SIGSTOP
+
+#ifdef CONFIG_SMP
+	mov r17=1
+	;;
+	cmpxchg4.acq r18=[r31],r17,ar.ccv	// try to acquire the lock
+	mov r8=EINVAL			// default to EINVAL
+	;;
+	ld8 r3=[r2]			// re-read current->blocked now that we hold the lock
+	cmp4.ne p6,p0=r18,r0
+(p6)	br.cond.spnt.many .lock_contention
+	;;
+#else
+	ld8 r3=[r2]			// re-read current->blocked now that we hold the lock
+	mov r8=EINVAL			// default to EINVAL
+#endif
+	add r18=IA64_TASK_PENDING_OFFSET+IA64_SIGPENDING_SIGNAL_OFFSET,r16
+	add r19=IA64_TASK_SIGNAL_OFFSET,r16
+	cmp4.eq p6,p0=SIG_BLOCK,r32
+	;;
+	ld8 r19=[r19]			// r19 <- current->signal
+	cmp4.eq p7,p0=SIG_UNBLOCK,r32
+	cmp4.eq p8,p0=SIG_SETMASK,r32
+	;;
+	ld8 r18=[r18]			// r18 <- current->pending.signal
+	.pred.rel.mutex p6,p7,p8
+(p6)	or r14=r3,r14			// SIG_BLOCK
+(p7)	andcm r14=r3,r14		// SIG_UNBLOCK
+
+(p8)	mov r14=r14			// SIG_SETMASK
+(p6)	mov r8=0			// clear error code
+	// recalc_sigpending()
+	add r17=IA64_SIGNAL_GROUP_STOP_COUNT_OFFSET,r19
+
+	add r19=IA64_SIGNAL_SHARED_PENDING_OFFSET+IA64_SIGPENDING_SIGNAL_OFFSET,r19
+	;;
+	ld4 r17=[r17]		// r17 <- current->signal->group_stop_count
+(p7)	mov r8=0		// clear error code
+
+	ld8 r19=[r19]		// r19 <- current->signal->shared_pending
+	;;
+	cmp4.gt p6,p7=r17,r0	// p6/p7 <- (current->signal->group_stop_count > 0)?
+(p8)	mov r8=0		// clear error code
+
+	or r18=r18,r19		// r18 <- current->pending | current->signal->shared_pending
+	;;
+	// r18 <- (current->pending | current->signal->shared_pending) & ~current->blocked:
+	andcm r18=r18,r14
+	add r9=TI_FLAGS+IA64_TASK_SIZE,r16
+	;;
+
+(p7)	cmp.ne.or.andcm p6,p7=r18,r0		// p6/p7 <- signal pending
+	mov r19=0					// i must not leak kernel bits...
+(p6)	br.cond.dpnt.many .sig_pending
+	;;
+
+1:	ld4 r17=[r9]				// r17 <- current->thread_info->flags
+	;;
+	mov ar.ccv=r17
+	and r18=~_TIF_SIGPENDING,r17		// r18 <- r17 & ~(1 << TIF_SIGPENDING)
+	;;
+
+	st8 [r2]=r14				// update current->blocked with new mask
+	cmpxchg4.acq r14=[r9],r18,ar.ccv	// current->thread_info->flags <- r18
+	;;
+	cmp.ne p6,p0=r17,r14			// update failed?
+(p6)	br.cond.spnt.few 1b			// yes -> retry
+
+#ifdef CONFIG_SMP
+	st4.rel [r31]=r0			// release the lock
+#endif
+	ssm psr.i
+	;;
+
+	srlz.d					// ensure psr.i is set again
+	mov r18=0					// i must not leak kernel bits...
+
+.store_mask:
+EX(.fail_efault, (p15) probe.w.fault r34, 3)	// verify user has write-access to *oset
+EX(.fail_efault, (p15) st8 [r34]=r3)
+	mov r2=0					// i must not leak kernel bits...
+	mov r3=0					// i must not leak kernel bits...
+	mov r8=0				// return 0
+	mov r9=0					// i must not leak kernel bits...
+	mov r14=0					// i must not leak kernel bits...
+	mov r17=0					// i must not leak kernel bits...
+	mov r31=0					// i must not leak kernel bits...
+	FSYS_RETURN
+
+.sig_pending:
+#ifdef CONFIG_SMP
+	st4.rel [r31]=r0			// release the lock
+#endif
+	ssm psr.i
+	;;
+	srlz.d
+	br.sptk.many fsys_fallback_syscall	// with signal pending, do the heavy-weight syscall
+
+#ifdef CONFIG_SMP
+.lock_contention:
+	/* Rather than spinning here, fall back on doing a heavy-weight syscall.  */
+	ssm psr.i
+	;;
+	srlz.d
+	br.sptk.many fsys_fallback_syscall
+#endif
+END(fsys_rt_sigprocmask)
+
+ENTRY(fsys_fallback_syscall)
+	.prologue
+	.altrp b6
+	.body
+	/*
+	 * We only get here from light-weight syscall handlers.  Thus, we already
+	 * know that r15 contains a valid syscall number.  No need to re-check.
+	 */
+	adds r17=-1024,r15
+	movl r14=sys_call_table
+	;;
+	rsm psr.i
+	shladd r18=r17,3,r14
+	;;
+	ld8 r18=[r18]				// load normal (heavy-weight) syscall entry-point
+	mov r29=psr				// read psr (12 cyc load latency)
+	mov r27=ar.rsc
+	mov r21=ar.fpsr
+	mov r26=ar.pfs
+END(fsys_fallback_syscall)
+	/* FALL THROUGH */
+GLOBAL_ENTRY(fsys_bubble_down)
+	.prologue
+	.altrp b6
+	.body
+	/*
+	 * We get here for syscalls that don't have a lightweight handler.  For those, we
+	 * need to bubble down into the kernel and that requires setting up a minimal
+	 * pt_regs structure, and initializing the CPU state more or less as if an
+	 * interruption had occurred.  To make syscall-restarts work, we setup pt_regs
+	 * such that cr_iip points to the second instruction in syscall_via_break.
+	 * Decrementing the IP hence will restart the syscall via break and not
+	 * decrementing IP will return us to the caller, as usual.  Note that we preserve
+	 * the value of psr.pp rather than initializing it from dcr.pp.  This makes it
+	 * possible to distinguish fsyscall execution from other privileged execution.
+	 *
+	 * On entry:
+	 *	- normal fsyscall handler register usage, except that we also have:
+	 *	- r18: address of syscall entry point
+	 *	- r21: ar.fpsr
+	 *	- r26: ar.pfs
+	 *	- r27: ar.rsc
+	 *	- r29: psr
+	 */
+#	define PSR_PRESERVED_BITS	(IA64_PSR_UP | IA64_PSR_MFL | IA64_PSR_MFH | IA64_PSR_PK \
+					 | IA64_PSR_DT | IA64_PSR_PP | IA64_PSR_SP | IA64_PSR_RT \
+					 | IA64_PSR_IC)
+	/*
+	 * Reading psr.l gives us only bits 0-31, psr.it, and psr.mc.  The rest we have
+	 * to synthesize.
+	 */
+#	define PSR_ONE_BITS		((3 << IA64_PSR_CPL0_BIT) | (0x1 << IA64_PSR_RI_BIT) \
+					 | IA64_PSR_BN | IA64_PSR_I)
+
+	invala
+	movl r8=PSR_ONE_BITS
+
+	mov r25=ar.unat			// save ar.unat (5 cyc)
+	movl r9=PSR_PRESERVED_BITS
+
+	mov ar.rsc=0			// set enforced lazy mode, pl 0, little-endian, loadrs=0
+	movl r28=__kernel_syscall_via_break
+	;;
+	mov r23=ar.bspstore		// save ar.bspstore (12 cyc)
+	mov r31=pr			// save pr (2 cyc)
+	mov r20=r1			// save caller's gp in r20
+	;;
+	mov r2=r16			// copy current task addr to addl-addressable register
+	and r9=r9,r29
+	mov r19=b6			// save b6 (2 cyc)
+	;;
+	mov psr.l=r9			// slam the door (17 cyc to srlz.i)
+	or r29=r8,r29			// construct cr.ipsr value to save
+	addl r22=IA64_RBS_OFFSET,r2	// compute base of RBS
+	;;
+	// GAS reports a spurious RAW hazard on the read of ar.rnat because it thinks
+	// we may be reading ar.itc after writing to psr.l.  Avoid that message with
+	// this directive:
+	dv_serialize_data
+	mov.m r24=ar.rnat		// read ar.rnat (5 cyc lat)
+	lfetch.fault.excl.nt1 [r22]
+	adds r16=IA64_TASK_THREAD_ON_USTACK_OFFSET,r2
+
+	// ensure previous insn group is issued before we stall for srlz.i:
+	;;
+	srlz.i				// ensure new psr.l has been established
+	/////////////////////////////////////////////////////////////////////////////
+	////////// from this point on, execution is not interruptible anymore
+	/////////////////////////////////////////////////////////////////////////////
+	addl r1=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r2	// compute base of memory stack
+	cmp.ne pKStk,pUStk=r0,r0	// set pKStk <- 0, pUStk <- 1
+	;;
+	st1 [r16]=r0			// clear current->thread.on_ustack flag
+	mov ar.bspstore=r22		// switch to kernel RBS
+	mov b6=r18			// copy syscall entry-point to b6 (7 cyc)
+	add r3=TI_FLAGS+IA64_TASK_SIZE,r2
+	;;
+	ld4 r3=[r3]				// r2 = current_thread_info()->flags
+	mov r18=ar.bsp			// save (kernel) ar.bsp (12 cyc)
+	mov ar.rsc=0x3			// set eager mode, pl 0, little-endian, loadrs=0
+	br.call.sptk.many b7=ia64_syscall_setup
+	;;
+	ssm psr.i
+	movl r2=ia64_ret_from_syscall
+	;;
+	mov rp=r2				// set the real return addr
+	tbit.z p8,p0=r3,TIF_SYSCALL_TRACE
+	;;
+(p10)	br.cond.spnt.many ia64_ret_from_syscall	// p10==true means out registers are more than 8
+(p8)	br.call.sptk.many b6=b6		// ignore this return addr
+	br.cond.sptk ia64_trace_syscall
+END(fsys_bubble_down)
+
+	.rodata
+	.align 8
+	.globl fsyscall_table
+
+	data8 fsys_bubble_down
+fsyscall_table:
+	data8 fsys_ni_syscall
+	data8 0				// exit			// 1025
+	data8 0				// read
+	data8 0				// write
+	data8 0				// open
+	data8 0				// close
+	data8 0				// creat		// 1030
+	data8 0				// link
+	data8 0				// unlink
+	data8 0				// execve
+	data8 0				// chdir
+	data8 0				// fchdir		// 1035
+	data8 0				// utimes
+	data8 0				// mknod
+	data8 0				// chmod
+	data8 0				// chown
+	data8 0				// lseek		// 1040
+	data8 fsys_getpid		// getpid
+	data8 fsys_getppid		// getppid
+	data8 0				// mount
+	data8 0				// umount
+	data8 0				// setuid		// 1045
+	data8 0				// getuid
+	data8 0				// geteuid
+	data8 0				// ptrace
+	data8 0				// access
+	data8 0				// sync			// 1050
+	data8 0				// fsync
+	data8 0				// fdatasync
+	data8 0				// kill
+	data8 0				// rename
+	data8 0				// mkdir		// 1055
+	data8 0				// rmdir
+	data8 0				// dup
+	data8 0				// pipe
+	data8 0				// times
+	data8 0				// brk			// 1060
+	data8 0				// setgid
+	data8 0				// getgid
+	data8 0				// getegid
+	data8 0				// acct
+	data8 0				// ioctl		// 1065
+	data8 0				// fcntl
+	data8 0				// umask
+	data8 0				// chroot
+	data8 0				// ustat
+	data8 0				// dup2			// 1070
+	data8 0				// setreuid
+	data8 0				// setregid
+	data8 0				// getresuid
+	data8 0				// setresuid
+	data8 0				// getresgid		// 1075
+	data8 0				// setresgid
+	data8 0				// getgroups
+	data8 0				// setgroups
+	data8 0				// getpgid
+	data8 0				// setpgid		// 1080
+	data8 0				// setsid
+	data8 0				// getsid
+	data8 0				// sethostname
+	data8 0				// setrlimit
+	data8 0				// getrlimit		// 1085
+	data8 0				// getrusage
+	data8 fsys_gettimeofday		// gettimeofday
+	data8 0				// settimeofday
+	data8 0				// select
+	data8 0				// poll			// 1090
+	data8 0				// symlink
+	data8 0				// readlink
+	data8 0				// uselib
+	data8 0				// swapon
+	data8 0				// swapoff		// 1095
+	data8 0				// reboot
+	data8 0				// truncate
+	data8 0				// ftruncate
+	data8 0				// fchmod
+	data8 0				// fchown		// 1100
+	data8 0				// getpriority
+	data8 0				// setpriority
+	data8 0				// statfs
+	data8 0				// fstatfs
+	data8 0				// gettid		// 1105
+	data8 0				// semget
+	data8 0				// semop
+	data8 0				// semctl
+	data8 0				// msgget
+	data8 0				// msgsnd		// 1110
+	data8 0				// msgrcv
+	data8 0				// msgctl
+	data8 0				// shmget
+	data8 0				// shmat
+	data8 0				// shmdt		// 1115
+	data8 0				// shmctl
+	data8 0				// syslog
+	data8 0				// setitimer
+	data8 0				// getitimer
+	data8 0					 		// 1120
+	data8 0
+	data8 0
+	data8 0				// vhangup
+	data8 0				// lchown
+	data8 0				// remap_file_pages	// 1125
+	data8 0				// wait4
+	data8 0				// sysinfo
+	data8 0				// clone
+	data8 0				// setdomainname
+	data8 0				// newuname		// 1130
+	data8 0				// adjtimex
+	data8 0
+	data8 0				// init_module
+	data8 0				// delete_module
+	data8 0							// 1135
+	data8 0
+	data8 0				// quotactl
+	data8 0				// bdflush
+	data8 0				// sysfs
+	data8 0				// personality		// 1140
+	data8 0				// afs_syscall
+	data8 0				// setfsuid
+	data8 0				// setfsgid
+	data8 0				// getdents
+	data8 0				// flock		// 1145
+	data8 0				// readv
+	data8 0				// writev
+	data8 0				// pread64
+	data8 0				// pwrite64
+	data8 0				// sysctl		// 1150
+	data8 0				// mmap
+	data8 0				// munmap
+	data8 0				// mlock
+	data8 0				// mlockall
+	data8 0				// mprotect		// 1155
+	data8 0				// mremap
+	data8 0				// msync
+	data8 0				// munlock
+	data8 0				// munlockall
+	data8 0				// sched_getparam	// 1160
+	data8 0				// sched_setparam
+	data8 0				// sched_getscheduler
+	data8 0				// sched_setscheduler
+	data8 0				// sched_yield
+	data8 0				// sched_get_priority_max	// 1165
+	data8 0				// sched_get_priority_min
+	data8 0				// sched_rr_get_interval
+	data8 0				// nanosleep
+	data8 0				// nfsservctl
+	data8 0				// prctl		// 1170
+	data8 0				// getpagesize
+	data8 0				// mmap2
+	data8 0				// pciconfig_read
+	data8 0				// pciconfig_write
+	data8 0				// perfmonctl		// 1175
+	data8 0				// sigaltstack
+	data8 0				// rt_sigaction
+	data8 0				// rt_sigpending
+	data8 fsys_rt_sigprocmask	// rt_sigprocmask
+	data8 0				// rt_sigqueueinfo	// 1180
+	data8 0				// rt_sigreturn
+	data8 0				// rt_sigsuspend
+	data8 0				// rt_sigtimedwait
+	data8 0				// getcwd
+	data8 0				// capget		// 1185
+	data8 0				// capset
+	data8 0				// sendfile
+	data8 0
+	data8 0
+	data8 0				// socket		// 1190
+	data8 0				// bind
+	data8 0				// connect
+	data8 0				// listen
+	data8 0				// accept
+	data8 0				// getsockname		// 1195
+	data8 0				// getpeername
+	data8 0				// socketpair
+	data8 0				// send
+	data8 0				// sendto
+	data8 0				// recv			// 1200
+	data8 0				// recvfrom
+	data8 0				// shutdown
+	data8 0				// setsockopt
+	data8 0				// getsockopt
+	data8 0				// sendmsg		// 1205
+	data8 0				// recvmsg
+	data8 0				// pivot_root
+	data8 0				// mincore
+	data8 0				// madvise
+	data8 0				// newstat		// 1210
+	data8 0				// newlstat
+	data8 0				// newfstat
+	data8 0				// clone2
+	data8 0				// getdents64
+	data8 0				// getunwind		// 1215
+	data8 0				// readahead
+	data8 0				// setxattr
+	data8 0				// lsetxattr
+	data8 0				// fsetxattr
+	data8 0				// getxattr		// 1220
+	data8 0				// lgetxattr
+	data8 0				// fgetxattr
+	data8 0				// listxattr
+	data8 0				// llistxattr
+	data8 0				// flistxattr		// 1225
+	data8 0				// removexattr
+	data8 0				// lremovexattr
+	data8 0				// fremovexattr
+	data8 0				// tkill
+	data8 0				// futex		// 1230
+	data8 0				// sched_setaffinity
+	data8 0				// sched_getaffinity
+	data8 fsys_set_tid_address	// set_tid_address
+	data8 0				// fadvise64_64
+	data8 0				// tgkill		// 1235
+	data8 0				// exit_group
+	data8 0				// lookup_dcookie
+	data8 0				// io_setup
+	data8 0				// io_destroy
+	data8 0				// io_getevents		// 1240
+	data8 0				// io_submit
+	data8 0				// io_cancel
+	data8 0				// epoll_create
+	data8 0				// epoll_ctl
+	data8 0				// epoll_wait		// 1245
+	data8 0				// restart_syscall
+	data8 0				// semtimedop
+	data8 0				// timer_create
+	data8 0				// timer_settime
+	data8 0				// timer_gettime 	// 1250
+	data8 0				// timer_getoverrun
+	data8 0				// timer_delete
+	data8 0				// clock_settime
+	data8 fsys_clock_gettime	// clock_gettime
+	data8 0				// clock_getres		// 1255
+	data8 0				// clock_nanosleep
+	data8 0				// fstatfs64
+	data8 0				// statfs64
+	data8 0
+	data8 0							// 1260
+	data8 0
+	data8 0				// mq_open
+	data8 0				// mq_unlink
+	data8 0				// mq_timedsend
+	data8 0				// mq_timedreceive	// 1265
+	data8 0				// mq_notify
+	data8 0				// mq_getsetattr
+	data8 0				// kexec_load
+	data8 0
+	data8 0							// 1270
+	data8 0
+	data8 0
+	data8 0
+	data8 0
+	data8 0							// 1275
+	data8 0
+	data8 0
+	data8 0
+	data8 0
+
+	.org fsyscall_table + 8*NR_syscalls	// guard against failures to increase NR_syscalls