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linux/arch/ia64/kernel/fsys.S
Petr Tesarik 2d2b690164 [IA64] Optimize ticket spinlocks in fsys_rt_sigprocmask 
Tony's fix (f574c84319) has a small bug,
it incorrectly uses "r3" as a scratch register in the first of the two
unlock paths ... it is also inefficient.  Optimize the fast path again.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-09-15 15:35:48 -07:00

1050 lines
30 KiB
ArmAsm
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/*
* 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.
* 08-Feb-07 Fenghua Yu Implement fsys_getcpu.
*
*/
#include <asm/asmmacro.h>
#include <asm/errno.h>
#include <asm/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"
#include "paravirt_inst.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 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_TGIDLINK_OFFSET,r17
;;
and r9=TIF_ALLWORK_MASK,r9
ld8 r17=[r17] // r17 = current->group_leader->pids[PIDTYPE_PID].pid
;;
add r8=IA64_PID_LEVEL_OFFSET,r17
;;
ld4 r8=[r8] // r8 = pid->level
add r17=IA64_PID_UPID_OFFSET,r17 // r17 = &pid->numbers[0]
;;
shl r8=r8,IA64_UPID_SHIFT
;;
add r17=r17,r8 // r17 = &pid->numbers[pid->level]
;;
ld4 r8=[r17] // r8 = pid->numbers[pid->level].nr
;;
mov r17=0
;;
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
add r17=IA64_TASK_TGIDLINK_OFFSET,r16
;;
ld4 r9=[r9]
tnat.z p6,p7=r32 // check argument register for being NaT
ld8 r17=[r17] // r17 = current->pids[PIDTYPE_PID].pid
;;
and r9=TIF_ALLWORK_MASK,r9
add r8=IA64_PID_LEVEL_OFFSET,r17
add r18=IA64_TASK_CLEAR_CHILD_TID_OFFSET,r16
;;
ld4 r8=[r8] // r8 = pid->level
add r17=IA64_PID_UPID_OFFSET,r17 // r17 = &pid->numbers[0]
;;
shl r8=r8,IA64_UPID_SHIFT
;;
add r17=r17,r8 // r17 = &pid->numbers[pid->level]
;;
ld4 r8=[r17] // r8 = pid->numbers[pid->level].nr
;;
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)
#if IA64_GTOD_LOCK_OFFSET !=0
#error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t
#endif
#if IA64_ITC_JITTER_OFFSET !=0
#error fsys_gettimeofday incompatible with changes to struct itc_jitter_data_t
#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 value
// r15 = preserved: system call number
// r16 = preserved: current task pointer
// r17 = (not used)
// r18 = (not used)
// r19 = address of itc_lastcycle
// r20 = struct fsyscall_gtod_data (= address of gtod_lock.sequence)
// r21 = address of mmio_ptr
// r22 = address of wall_time or monotonic_time
// r23 = address of shift / value
// r24 = address mult factor / cycle_last value
// r25 = itc_lastcycle value
// r26 = address clocksource cycle_last
// r27 = (not used)
// r28 = sequence number at the beginning of critcal section
// r29 = address of itc_jitter
// 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 - not used
// p11 = timesource not to be handled by asm code
// p12 = memory time source ( = p9 | p10) - not used
// p13 = do cmpxchg with itc_lastcycle
// 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.
add r2 = TI_FLAGS+IA64_TASK_SIZE,r16
tnat.nz p6,p0 = r31 // guard against Nat argument
(p6) br.cond.spnt.few .fail_einval
movl r20 = fsyscall_gtod_data // load fsyscall gettimeofday data address
;;
ld4 r2 = [r2] // process work pending flags
movl r29 = itc_jitter_data // itc_jitter
add r22 = IA64_GTOD_WALL_TIME_OFFSET,r20 // wall_time
add r21 = IA64_CLKSRC_MMIO_OFFSET,r20
mov pr = r30,0xc000 // Set predicates according to function
;;
and r2 = TIF_ALLWORK_MASK,r2
add r19 = IA64_ITC_LASTCYCLE_OFFSET,r29
(p15) add r22 = IA64_GTOD_MONO_TIME_OFFSET,r20 // monotonic_time
;;
add r26 = IA64_CLKSRC_CYCLE_LAST_OFFSET,r20 // clksrc_cycle_last
cmp.ne p6, p0 = 0, r2 // Fallback if work is scheduled
(p6) br.cond.spnt.many fsys_fallback_syscall
;;
// Begin critical section
.time_redo:
ld4.acq r28 = [r20] // gtod_lock.sequence, Must take first
;;
and r28 = ~1,r28 // And make sequence even to force retry if odd
;;
ld8 r30 = [r21] // clocksource->mmio_ptr
add r24 = IA64_CLKSRC_MULT_OFFSET,r20
ld4 r2 = [r29] // itc_jitter value
add r23 = IA64_CLKSRC_SHIFT_OFFSET,r20
add r14 = IA64_CLKSRC_MASK_OFFSET,r20
;;
ld4 r3 = [r24] // clocksource mult value
ld8 r14 = [r14] // clocksource mask value
cmp.eq p8,p9 = 0,r30 // use cpu timer if no mmio_ptr
;;
setf.sig f7 = r3 // Setup for mult scaling of counter
(p8) cmp.ne p13,p0 = r2,r0 // need itc_jitter compensation, set p13
ld4 r23 = [r23] // clocksource shift value
ld8 r24 = [r26] // get clksrc_cycle_last value
(p9) cmp.eq p13,p0 = 0,r30 // if mmio_ptr, clear p13 jitter control
;;
.pred.rel.mutex p8,p9
MOV_FROM_ITC(p8, p6, r2, r10) // CPU_TIMER. 36 clocks latency!!!
(p9) ld8 r2 = [r30] // MMIO_TIMER. Could also have latency issues..
(p13) ld8 r25 = [r19] // get itc_lastcycle value
ld8 r9 = [r22],IA64_TIMESPEC_TV_NSEC_OFFSET // tv_sec
;;
ld8 r8 = [r22],-IA64_TIMESPEC_TV_NSEC_OFFSET // tv_nsec
(p13) sub r3 = r25,r2 // Diff needed before comparison (thanks davidm)
;;
(p13) cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared
sub r10 = r2,r24 // current_cycle - last_cycle
;;
(p6) sub r10 = r25,r24 // time we got was less than last_cycle
(p7) mov ar.ccv = r25 // more than last_cycle. Prep for cmpxchg
;;
(p7) cmpxchg8.rel r3 = [r19],r2,ar.ccv
;;
(p7) cmp.ne p7,p0 = r25,r3 // if cmpxchg not successful
;;
(p7) sub r10 = r3,r24 // then use new last_cycle instead
;;
and r10 = r10,r14 // Apply mask
;;
setf.sig f8 = r10
nop.i 123
;;
// fault check takes 5 cycles and we have spare time
EX(.fail_efault, probe.w.fault r31, 3)
xmpy.l f8 = f8,f7 // nsec_per_cyc*(counter-last_counter)
;;
getf.sig r2 = f8
mf
;;
ld4 r10 = [r20] // gtod_lock.sequence
shr.u r2 = r2,r23 // shift by factor
;;
add r8 = r8,r2 // Add xtime.nsecs
cmp4.ne p7,p0 = r28,r10
(p7) br.cond.dpnt.few .time_redo // sequence number changed, redo
// End critical section.
// 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 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
;;
(p14) getf.sig r2 = f8
;;
mov r8 = r0
(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(p0, r18, r19) // mask interrupt delivery
andcm r14=r14,r17 // filter out SIGKILL & SIGSTOP
mov r8=EINVAL // default to EINVAL
#ifdef CONFIG_SMP
// __ticket_spin_trylock(r31)
ld4 r17=[r31]
;;
mov.m ar.ccv=r17
extr.u r9=r17,17,15
adds r19=1,r17
extr.u r18=r17,0,15
;;
cmp.eq p6,p7=r9,r18
;;
(p6) cmpxchg4.acq r9=[r31],r19,ar.ccv
(p6) dep.z r20=r19,1,15 // next serving ticket for unlock
(p7) br.cond.spnt.many .lock_contention
;;
cmp4.eq p0,p7=r9,r17
adds r31=2,r31
(p7) br.cond.spnt.many .lock_contention
ld8 r3=[r2] // re-read current->blocked now that we hold the lock
;;
#else
ld8 r3=[r2] // re-read current->blocked now that we hold the lock
#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 r8=[r9],r18,ar.ccv // current->thread_info->flags <- r18
;;
cmp.ne p6,p0=r17,r8 // update failed?
(p6) br.cond.spnt.few 1b // yes -> retry
#ifdef CONFIG_SMP
// __ticket_spin_unlock(r31)
st2.rel [r31]=r20
mov r20=0 // i must not leak kernel bits...
#endif
SSM_PSR_I(p0, p9, r31)
;;
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
// __ticket_spin_unlock(r31)
st2.rel [r31]=r20 // release the lock
#endif
SSM_PSR_I(p0, p9, r17)
;;
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(p0, p9, r17)
;;
srlz.d
br.sptk.many fsys_fallback_syscall
#endif
END(fsys_rt_sigprocmask)
/*
* fsys_getcpu doesn't use the third parameter in this implementation. It reads
* current_thread_info()->cpu and corresponding node in cpu_to_node_map.
*/
ENTRY(fsys_getcpu)
.prologue
.altrp b6
.body
;;
add r2=TI_FLAGS+IA64_TASK_SIZE,r16
tnat.nz p6,p0 = r32 // guard against NaT argument
add r3=TI_CPU+IA64_TASK_SIZE,r16
;;
ld4 r3=[r3] // M r3 = thread_info->cpu
ld4 r2=[r2] // M r2 = thread_info->flags
(p6) br.cond.spnt.few .fail_einval // B
;;
tnat.nz p7,p0 = r33 // I guard against NaT argument
(p7) br.cond.spnt.few .fail_einval // B
#ifdef CONFIG_NUMA
movl r17=cpu_to_node_map
;;
EX(.fail_efault, probe.w.fault r32, 3) // M This takes 5 cycles
EX(.fail_efault, probe.w.fault r33, 3) // M This takes 5 cycles
shladd r18=r3,1,r17
;;
ld2 r20=[r18] // r20 = cpu_to_node_map[cpu]
and r2 = TIF_ALLWORK_MASK,r2
;;
cmp.ne p8,p0=0,r2
(p8) br.spnt.many fsys_fallback_syscall
;;
;;
EX(.fail_efault, st4 [r32] = r3)
EX(.fail_efault, st2 [r33] = r20)
mov r8=0
;;
#else
EX(.fail_efault, probe.w.fault r32, 3) // M This takes 5 cycles
EX(.fail_efault, probe.w.fault r33, 3) // M This takes 5 cycles
and r2 = TIF_ALLWORK_MASK,r2
;;
cmp.ne p8,p0=0,r2
(p8) br.spnt.many fsys_fallback_syscall
;;
EX(.fail_efault, st4 [r32] = r3)
EX(.fail_efault, st2 [r33] = r0)
mov r8=0
;;
#endif
FSYS_RETURN
END(fsys_getcpu)
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(p0, r26, r27)
shladd r18=r17,3,r14
;;
ld8 r18=[r18] // load normal (heavy-weight) syscall entry-point
MOV_FROM_PSR(p0, r29, r26) // 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(paravirt_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
*
* We used to clear some PSR bits here but that requires slow
* serialization. Fortuntely, that isn't really necessary.
* The rationale is as follows: we used to clear bits
* ~PSR_PRESERVED_BITS in PSR.L. Since
* PSR_PRESERVED_BITS==PSR.{UP,MFL,MFH,PK,DT,PP,SP,RT,IC}, we
* ended up clearing PSR.{BE,AC,I,DFL,DFH,DI,DB,SI,TB}.
* However,
*
* PSR.BE : already is turned off in __kernel_syscall_via_epc()
* PSR.AC : don't care (kernel normally turns PSR.AC on)
* PSR.I : already turned off by the time paravirt_fsys_bubble_down gets
* invoked
* PSR.DFL: always 0 (kernel never turns it on)
* PSR.DFH: don't care --- kernel never touches f32-f127 on its own
* initiative
* PSR.DI : always 0 (kernel never turns it on)
* PSR.SI : always 0 (kernel never turns it on)
* PSR.DB : don't care --- kernel never enables kernel-level
* breakpoints
* PSR.TB : must be 0 already; if it wasn't zero on entry to
* __kernel_syscall_via_epc, the branch to paravirt_fsys_bubble_down
* will trigger a taken branch; the taken-trap-handler then
* converts the syscall into a break-based system-call.
*/
/*
* 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 // M0|1
movl r14=ia64_ret_from_syscall // X
nop.m 0
movl r28=__kernel_syscall_via_break // X create cr.iip
;;
mov r2=r16 // A get task addr to addl-addressable register
adds r16=IA64_TASK_THREAD_ON_USTACK_OFFSET,r16 // A
mov r31=pr // I0 save pr (2 cyc)
;;
st1 [r16]=r0 // M2|3 clear current->thread.on_ustack flag
addl r22=IA64_RBS_OFFSET,r2 // A compute base of RBS
add r3=TI_FLAGS+IA64_TASK_SIZE,r2 // A
;;
ld4 r3=[r3] // M0|1 r3 = current_thread_info()->flags
lfetch.fault.excl.nt1 [r22] // M0|1 prefetch register backing-store
nop.i 0
;;
mov ar.rsc=0 // M2 set enforced lazy mode, pl 0, LE, loadrs=0
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
MOV_FROM_ITC(p0, p6, r30, r23) // M get cycle for accounting
#else
nop.m 0
#endif
nop.i 0
;;
mov r23=ar.bspstore // M2 (12 cyc) save ar.bspstore
mov.m r24=ar.rnat // M2 (5 cyc) read ar.rnat (dual-issues!)
nop.i 0
;;
mov ar.bspstore=r22 // M2 (6 cyc) switch to kernel RBS
movl r8=PSR_ONE_BITS // X
;;
mov r25=ar.unat // M2 (5 cyc) save ar.unat
mov r19=b6 // I0 save b6 (2 cyc)
mov r20=r1 // A save caller's gp in r20
;;
or r29=r8,r29 // A construct cr.ipsr value to save
mov b6=r18 // I0 copy syscall entry-point to b6 (7 cyc)
addl r1=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r2 // A compute base of memory stack
mov r18=ar.bsp // M2 save (kernel) ar.bsp (12 cyc)
cmp.ne pKStk,pUStk=r0,r0 // A set pKStk <- 0, pUStk <- 1
br.call.sptk.many b7=ia64_syscall_setup // B
;;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
// mov.m r30=ar.itc is called in advance
add r16=TI_AC_STAMP+IA64_TASK_SIZE,r2
add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r2
;;
ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP // time at last check in kernel
ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE // time at leave kernel
;;
ld8 r20=[r16],TI_AC_STAMP-TI_AC_STIME // cumulated stime
ld8 r21=[r17] // cumulated utime
sub r22=r19,r18 // stime before leave kernel
;;
st8 [r16]=r30,TI_AC_STIME-TI_AC_STAMP // update stamp
sub r18=r30,r19 // elapsed time in user mode
;;
add r20=r20,r22 // sum stime
add r21=r21,r18 // sum utime
;;
st8 [r16]=r20 // update stime
st8 [r17]=r21 // update utime
;;
#endif
mov ar.rsc=0x3 // M2 set eager mode, pl 0, LE, loadrs=0
mov rp=r14 // I0 set the real return addr
and r3=_TIF_SYSCALL_TRACEAUDIT,r3 // A
;;
SSM_PSR_I(p0, p6, r22) // M2 we're on kernel stacks now, reenable irqs
cmp.eq p8,p0=r3,r0 // A
(p10) br.cond.spnt.many ia64_ret_from_syscall // B return if bad call-frame or r15 is a NaT
nop.m 0
(p8) br.call.sptk.many b6=b6 // B (ignore return address)
br.cond.spnt ia64_trace_syscall // B
END(paravirt_fsys_bubble_down)
.rodata
.align 8
.globl paravirt_fsyscall_table
data8 paravirt_fsys_bubble_down
paravirt_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 // mbind
data8 0 // get_mempolicy // 1260
data8 0 // set_mempolicy
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 // vserver
data8 0 // waitid // 1270
data8 0 // add_key
data8 0 // request_key
data8 0 // keyctl
data8 0 // ioprio_set
data8 0 // ioprio_get // 1275
data8 0 // move_pages
data8 0 // inotify_init
data8 0 // inotify_add_watch
data8 0 // inotify_rm_watch
data8 0 // migrate_pages // 1280
data8 0 // openat
data8 0 // mkdirat
data8 0 // mknodat
data8 0 // fchownat
data8 0 // futimesat // 1285
data8 0 // newfstatat
data8 0 // unlinkat
data8 0 // renameat
data8 0 // linkat
data8 0 // symlinkat // 1290
data8 0 // readlinkat
data8 0 // fchmodat
data8 0 // faccessat
data8 0
data8 0 // 1295
data8 0 // unshare
data8 0 // splice
data8 0 // set_robust_list
data8 0 // get_robust_list
data8 0 // sync_file_range // 1300
data8 0 // tee
data8 0 // vmsplice
data8 0
data8 fsys_getcpu // getcpu // 1304
// fill in zeros for the remaining entries
.zero:
.space paravirt_fsyscall_table + 8*NR_syscalls - .zero, 0
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