/*
 * arch/ia64/kernel/entry.S
 *
 * Kernel entry points.
 *
 * Copyright (C) 1998-2003, 2005 Hewlett-Packard Co
 *      David Mosberger-Tang <davidm@hpl.hp.com>
 * Copyright (C) 1999, 2002-2003
 *      Asit Mallick <Asit.K.Mallick@intel.com>
 *      Don Dugger <Don.Dugger@intel.com>
 *      Suresh Siddha <suresh.b.siddha@intel.com>
 *      Fenghua Yu <fenghua.yu@intel.com>
 * Copyright (C) 1999 VA Linux Systems
 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
 */
/*
 * ia64_switch_to now places correct virtual mapping in in TR2 for
 * kernel stack. This allows us to handle interrupts without changing
 * to physical mode.
 *
 * Jonathan Nicklin     <nicklin@missioncriticallinux.com>
 * Patrick O'Rourke     <orourke@missioncriticallinux.com>
 * 11/07/2000
 */
/*
 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
 *                    VA Linux Systems Japan K.K.
 *                    pv_ops.
 */
/*
 * Global (preserved) predicate usage on syscall entry/exit path:
 *
 *      pKStk:          See entry.h.
 *      pUStk:          See entry.h.
 *      pSys:           See entry.h.
 *      pNonSys:        !pSys
 */


#include <asm/asmmacro.h>
#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/kregs.h>
#include <asm/asm-offsets.h>
#include <asm/pgtable.h>
#include <asm/percpu.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
#include <asm/ftrace.h>

#include "minstate.h"

#ifdef __IA64_ASM_PARAVIRTUALIZED_NATIVE
        /*
         * execve() is special because in case of success, we need to
         * setup a null register window frame.
         */
ENTRY(ia64_execve)
        /*
         * Allocate 8 input registers since ptrace() may clobber them
         */
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
        alloc loc1=ar.pfs,8,2,3,0
        mov loc0=rp
        .body
        mov out0=in0                    // filename
        ;;                              // stop bit between alloc and call
        mov out1=in1                    // argv
        mov out2=in2                    // envp
        br.call.sptk.many rp=sys_execve
.ret0:
        cmp4.ge p6,p7=r8,r0
        mov ar.pfs=loc1                 // restore ar.pfs
        sxt4 r8=r8                      // return 64-bit result
        ;;
        stf.spill [sp]=f0
        mov rp=loc0
(p6)    mov ar.pfs=r0                   // clear ar.pfs on success
(p7)    br.ret.sptk.many rp

        /*
         * In theory, we'd have to zap this state only to prevent leaking of
         * security sensitive state (e.g., if current->mm->dumpable is zero).  However,
         * this executes in less than 20 cycles even on Itanium, so it's not worth
         * optimizing for...).
         */
        mov ar.unat=0;          mov ar.lc=0
        mov r4=0;               mov f2=f0;              mov b1=r0
        mov r5=0;               mov f3=f0;              mov b2=r0
        mov r6=0;               mov f4=f0;              mov b3=r0
        mov r7=0;               mov f5=f0;              mov b4=r0
        ldf.fill f12=[sp];      mov f13=f0;             mov b5=r0
        ldf.fill f14=[sp];      ldf.fill f15=[sp];      mov f16=f0
        ldf.fill f17=[sp];      ldf.fill f18=[sp];      mov f19=f0
        ldf.fill f20=[sp];      ldf.fill f21=[sp];      mov f22=f0
        ldf.fill f23=[sp];      ldf.fill f24=[sp];      mov f25=f0
        ldf.fill f26=[sp];      ldf.fill f27=[sp];      mov f28=f0
        ldf.fill f29=[sp];      ldf.fill f30=[sp];      mov f31=f0
        br.ret.sptk.many rp
END(ia64_execve)

/*
 * sys_clone2(u64 flags, u64 ustack_base, u64 ustack_size, u64 parent_tidptr, u64 child_tidptr,
 *            u64 tls)
 */
GLOBAL_ENTRY(sys_clone2)
        /*
         * Allocate 8 input registers since ptrace() may clobber them
         */
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
        alloc r16=ar.pfs,8,2,6,0
        DO_SAVE_SWITCH_STACK
        adds r2=PT(R16)+IA64_SWITCH_STACK_SIZE+16,sp
        mov loc0=rp
        mov loc1=r16                            // save ar.pfs across do_fork
        .body
        mov out1=in1
        mov out2=in2
        tbit.nz p6,p0=in0,CLONE_SETTLS_BIT
        mov out3=in3    // parent_tidptr: valid only w/CLONE_PARENT_SETTID
        ;;
(p6)    st8 [r2]=in5                            // store TLS in r16 for copy_thread()
        mov out4=in4    // child_tidptr:  valid only w/CLONE_CHILD_SETTID or CLONE_CHILD_CLEARTID
        mov out0=in0                            // out0 = clone_flags
        br.call.sptk.many rp=do_fork
.ret1:  .restore sp
        adds sp=IA64_SWITCH_STACK_SIZE,sp       // pop the switch stack
        mov ar.pfs=loc1
        mov rp=loc0
        br.ret.sptk.many rp
END(sys_clone2)

/*
 * sys_clone(u64 flags, u64 ustack_base, u64 parent_tidptr, u64 child_tidptr, u64 tls)
 *      Deprecated.  Use sys_clone2() instead.
 */
GLOBAL_ENTRY(sys_clone)
        /*
         * Allocate 8 input registers since ptrace() may clobber them
         */
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
        alloc r16=ar.pfs,8,2,6,0
        DO_SAVE_SWITCH_STACK
        adds r2=PT(R16)+IA64_SWITCH_STACK_SIZE+16,sp
        mov loc0=rp
        mov loc1=r16                            // save ar.pfs across do_fork
        .body
        mov out1=in1
        mov out2=16                             // stacksize (compensates for 16-byte scratch area)
        tbit.nz p6,p0=in0,CLONE_SETTLS_BIT
        mov out3=in2    // parent_tidptr: valid only w/CLONE_PARENT_SETTID
        ;;
(p6)    st8 [r2]=in4                            // store TLS in r13 (tp)
        mov out4=in3    // child_tidptr:  valid only w/CLONE_CHILD_SETTID or CLONE_CHILD_CLEARTID
        mov out0=in0                            // out0 = clone_flags
        br.call.sptk.many rp=do_fork
.ret2:  .restore sp
        adds sp=IA64_SWITCH_STACK_SIZE,sp       // pop the switch stack
        mov ar.pfs=loc1
        mov rp=loc0
        br.ret.sptk.many rp
END(sys_clone)
#endif /* __IA64_ASM_PARAVIRTUALIZED_NATIVE */

/*
 * prev_task <- ia64_switch_to(struct task_struct *next)
 *      With Ingo's new scheduler, interrupts are disabled when this routine gets
 *      called.  The code starting at .map relies on this.  The rest of the code
 *      doesn't care about the interrupt masking status.
 */
GLOBAL_ENTRY(__paravirt_switch_to)
        .prologue
        alloc r16=ar.pfs,1,0,0,0
        DO_SAVE_SWITCH_STACK
        .body

        adds r22=IA64_TASK_THREAD_KSP_OFFSET,r13
        movl r25=init_task
        mov r27=IA64_KR(CURRENT_STACK)
        adds r21=IA64_TASK_THREAD_KSP_OFFSET,in0
        dep r20=0,in0,61,3              // physical address of "next"
        ;;
        st8 [r22]=sp                    // save kernel stack pointer of old task
        shr.u r26=r20,IA64_GRANULE_SHIFT
        cmp.eq p7,p6=r25,in0
        ;;
        /*
         * If we've already mapped this task's page, we can skip doing it again.
         */
(p6)    cmp.eq p7,p6=r26,r27
(p6)    br.cond.dpnt .map
        ;;
.done:
        ld8 sp=[r21]                    // load kernel stack pointer of new task
        MOV_TO_KR(CURRENT, in0, r8, r9)         // update "current" application register
        mov r8=r13                      // return pointer to previously running task
        mov r13=in0                     // set "current" pointer
        ;;
        DO_LOAD_SWITCH_STACK

#ifdef CONFIG_SMP
        sync.i                          // ensure "fc"s done by this CPU are visible on other CPUs
#endif
        br.ret.sptk.many rp             // boogie on out in new context

.map:
        RSM_PSR_IC(r25)                 // interrupts (psr.i) are already disabled here
        movl r25=PAGE_KERNEL
        ;;
        srlz.d
        or r23=r25,r20                  // construct PA | page properties
        mov r25=IA64_GRANULE_SHIFT<<2
        ;;
        MOV_TO_ITIR(p0, r25, r8)
        MOV_TO_IFA(in0, r8)             // VA of next task...
        ;;
        mov r25=IA64_TR_CURRENT_STACK
        MOV_TO_KR(CURRENT_STACK, r26, r8, r9)   // remember last page we mapped...
        ;;
        itr.d dtr[r25]=r23              // wire in new mapping...
        SSM_PSR_IC_AND_SRLZ_D(r8, r9)   // reenable the psr.ic bit
        br.cond.sptk .done
END(__paravirt_switch_to)

#ifdef __IA64_ASM_PARAVIRTUALIZED_NATIVE
/*
 * Note that interrupts are enabled during save_switch_stack and load_switch_stack.  This
 * means that we may get an interrupt with "sp" pointing to the new kernel stack while
 * ar.bspstore is still pointing to the old kernel backing store area.  Since ar.rsc,
 * ar.rnat, ar.bsp, and ar.bspstore are all preserved by interrupts, this is not a
 * problem.  Also, we don't need to specify unwind information for preserved registers
 * that are not modified in save_switch_stack as the right unwind information is already
 * specified at the call-site of save_switch_stack.
 */

/*
 * save_switch_stack:
 *      - r16 holds ar.pfs
 *      - b7 holds address to return to
 *      - rp (b0) holds return address to save
 */
GLOBAL_ENTRY(save_switch_stack)
        .prologue
        .altrp b7
        flushrs                 // flush dirty regs to backing store (must be first in insn group)
        .save @priunat,r17
        mov r17=ar.unat         // preserve caller's
        .body
#ifdef CONFIG_ITANIUM
        adds r2=16+128,sp
        adds r3=16+64,sp
        adds r14=SW(R4)+16,sp
        ;;
        st8.spill [r14]=r4,16           // spill r4
        lfetch.fault.excl.nt1 [r3],128
        ;;
        lfetch.fault.excl.nt1 [r2],128
        lfetch.fault.excl.nt1 [r3],128
        ;;
        lfetch.fault.excl [r2]
        lfetch.fault.excl [r3]
        adds r15=SW(R5)+16,sp
#else
        add r2=16+3*128,sp
        add r3=16,sp
        add r14=SW(R4)+16,sp
        ;;
        st8.spill [r14]=r4,SW(R6)-SW(R4)        // spill r4 and prefetch offset 0x1c0
        lfetch.fault.excl.nt1 [r3],128  //              prefetch offset 0x010
        ;;
        lfetch.fault.excl.nt1 [r3],128  //              prefetch offset 0x090
        lfetch.fault.excl.nt1 [r2],128  //              prefetch offset 0x190
        ;;
        lfetch.fault.excl.nt1 [r3]      //              prefetch offset 0x110
        lfetch.fault.excl.nt1 [r2]      //              prefetch offset 0x210
        adds r15=SW(R5)+16,sp
#endif
        ;;
        st8.spill [r15]=r5,SW(R7)-SW(R5)        // spill r5
        mov.m ar.rsc=0                  // put RSE in mode: enforced lazy, little endian, pl 0
        add r2=SW(F2)+16,sp             // r2 = &sw->f2
        ;;
        st8.spill [r14]=r6,SW(B0)-SW(R6)        // spill r6
        mov.m r18=ar.fpsr               // preserve fpsr
        add r3=SW(F3)+16,sp             // r3 = &sw->f3
        ;;
        stf.spill [r2]=f2,32
        mov.m r19=ar.rnat
        mov r21=b0

        stf.spill [r3]=f3,32
        st8.spill [r15]=r7,SW(B2)-SW(R7)        // spill r7
        mov r22=b1
        ;;
        // since we're done with the spills, read and save ar.unat:
        mov.m r29=ar.unat
        mov.m r20=ar.bspstore
        mov r23=b2
        stf.spill [r2]=f4,32
        stf.spill [r3]=f5,32
        mov r24=b3
        ;;
        st8 [r14]=r21,SW(B1)-SW(B0)             // save b0
        st8 [r15]=r23,SW(B3)-SW(B2)             // save b2
        mov r25=b4
        mov r26=b5
        ;;
        st8 [r14]=r22,SW(B4)-SW(B1)             // save b1
        st8 [r15]=r24,SW(AR_PFS)-SW(B3)         // save b3
        mov r21=ar.lc           // I-unit
        stf.spill [r2]=f12,32
        stf.spill [r3]=f13,32
        ;;
        st8 [r14]=r25,SW(B5)-SW(B4)             // save b4
        st8 [r15]=r16,SW(AR_LC)-SW(AR_PFS)      // save ar.pfs
        stf.spill [r2]=f14,32
        stf.spill [r3]=f15,32
        ;;
        st8 [r14]=r26                           // save b5
        st8 [r15]=r21                           // save ar.lc
        stf.spill [r2]=f16,32
        stf.spill [r3]=f17,32
        ;;
        stf.spill [r2]=f18,32
        stf.spill [r3]=f19,32
        ;;
        stf.spill [r2]=f20,32
        stf.spill [r3]=f21,32
        ;;
        stf.spill [r2]=f22,32
        stf.spill [r3]=f23,32
        ;;
        stf.spill [r2]=f24,32
        stf.spill [r3]=f25,32
        ;;
        stf.spill [r2]=f26,32
        stf.spill [r3]=f27,32
        ;;
        stf.spill [r2]=f28,32
        stf.spill [r3]=f29,32
        ;;
        stf.spill [r2]=f30,SW(AR_UNAT)-SW(F30)
        stf.spill [r3]=f31,SW(PR)-SW(F31)
        add r14=SW(CALLER_UNAT)+16,sp
        ;;
        st8 [r2]=r29,SW(AR_RNAT)-SW(AR_UNAT)    // save ar.unat
        st8 [r14]=r17,SW(AR_FPSR)-SW(CALLER_UNAT) // save caller_unat
        mov r21=pr
        ;;
        st8 [r2]=r19,SW(AR_BSPSTORE)-SW(AR_RNAT) // save ar.rnat
        st8 [r3]=r21                            // save predicate registers
        ;;
        st8 [r2]=r20                            // save ar.bspstore
        st8 [r14]=r18                           // save fpsr
        mov ar.rsc=3            // put RSE back into eager mode, pl 0
        br.cond.sptk.many b7
END(save_switch_stack)

/*
 * load_switch_stack:
 *      - "invala" MUST be done at call site (normally in DO_LOAD_SWITCH_STACK)
 *      - b7 holds address to return to
 *      - must not touch r8-r11
 */
GLOBAL_ENTRY(load_switch_stack)
        .prologue
        .altrp b7

        .body
        lfetch.fault.nt1 [sp]
        adds r2=SW(AR_BSPSTORE)+16,sp
        adds r3=SW(AR_UNAT)+16,sp
        mov ar.rsc=0                                            // put RSE into enforced lazy mode
        adds r14=SW(CALLER_UNAT)+16,sp
        adds r15=SW(AR_FPSR)+16,sp
        ;;
        ld8 r27=[r2],(SW(B0)-SW(AR_BSPSTORE))   // bspstore
        ld8 r29=[r3],(SW(B1)-SW(AR_UNAT))       // unat
        ;;
        ld8 r21=[r2],16         // restore b0
        ld8 r22=[r3],16         // restore b1
        ;;
        ld8 r23=[r2],16         // restore b2
        ld8 r24=[r3],16         // restore b3
        ;;
        ld8 r25=[r2],16         // restore b4
        ld8 r26=[r3],16         // restore b5
        ;;
        ld8 r16=[r2],(SW(PR)-SW(AR_PFS))        // ar.pfs
        ld8 r17=[r3],(SW(AR_RNAT)-SW(AR_LC))    // ar.lc
        ;;
        ld8 r28=[r2]            // restore pr
        ld8 r30=[r3]            // restore rnat
        ;;
        ld8 r18=[r14],16        // restore caller's unat
        ld8 r19=[r15],24        // restore fpsr
        ;;
        ldf.fill f2=[r14],32
        ldf.fill f3=[r15],32
        ;;
        ldf.fill f4=[r14],32
        ldf.fill f5=[r15],32
        ;;
        ldf.fill f12=[r14],32
        ldf.fill f13=[r15],32
        ;;
        ldf.fill f14=[r14],32
        ldf.fill f15=[r15],32
        ;;
        ldf.fill f16=[r14],32
        ldf.fill f17=[r15],32
        ;;
        ldf.fill f18=[r14],32
        ldf.fill f19=[r15],32
        mov b0=r21
        ;;
        ldf.fill f20=[r14],32
        ldf.fill f21=[r15],32
        mov b1=r22
        ;;
        ldf.fill f22=[r14],32
        ldf.fill f23=[r15],32
        mov b2=r23
        ;;
        mov ar.bspstore=r27
        mov ar.unat=r29         // establish unat holding the NaT bits for r4-r7
        mov b3=r24
        ;;
        ldf.fill f24=[r14],32
        ldf.fill f25=[r15],32
        mov b4=r25
        ;;
        ldf.fill f26=[r14],32
        ldf.fill f27=[r15],32
        mov b5=r26
        ;;
        ldf.fill f28=[r14],32
        ldf.fill f29=[r15],32
        mov ar.pfs=r16
        ;;
        ldf.fill f30=[r14],32
        ldf.fill f31=[r15],24
        mov ar.lc=r17
        ;;
        ld8.fill r4=[r14],16
        ld8.fill r5=[r15],16
        mov pr=r28,-1
        ;;
        ld8.fill r6=[r14],16
        ld8.fill r7=[r15],16

        mov ar.unat=r18                         // restore caller's unat
        mov ar.rnat=r30                         // must restore after bspstore but before rsc!
        mov ar.fpsr=r19                         // restore fpsr
        mov ar.rsc=3                            // put RSE back into eager mode, pl 0
        br.cond.sptk.many b7
END(load_switch_stack)

GLOBAL_ENTRY(prefetch_stack)
        add r14 = -IA64_SWITCH_STACK_SIZE, sp
        add r15 = IA64_TASK_THREAD_KSP_OFFSET, in0
        ;;
        ld8 r16 = [r15]                         // load next's stack pointer
        lfetch.fault.excl [r14], 128
        ;;
        lfetch.fault.excl [r14], 128
        lfetch.fault [r16], 128
        ;;
        lfetch.fault.excl [r14], 128
        lfetch.fault [r16], 128
        ;;
        lfetch.fault.excl [r14], 128
        lfetch.fault [r16], 128
        ;;
        lfetch.fault.excl [r14], 128
        lfetch.fault [r16], 128
        ;;
        lfetch.fault [r16], 128
        br.ret.sptk.many rp
END(prefetch_stack)

        /*
         * Invoke a system call, but do some tracing before and after the call.
         * We MUST preserve the current register frame throughout this routine
         * because some system calls (such as ia64_execve) directly
         * manipulate ar.pfs.
         */
GLOBAL_ENTRY(ia64_trace_syscall)
        PT_REGS_UNWIND_INFO(0)
        /*
         * We need to preserve the scratch registers f6-f11 in case the system
         * call is sigreturn.
         */
        adds r16=PT(F6)+16,sp
        adds r17=PT(F7)+16,sp
        ;;
        stf.spill [r16]=f6,32
        stf.spill [r17]=f7,32
        ;;
        stf.spill [r16]=f8,32
        stf.spill [r17]=f9,32
        ;;
        stf.spill [r16]=f10
        stf.spill [r17]=f11
        br.call.sptk.many rp=syscall_trace_enter // give parent a chance to catch syscall args
        cmp.lt p6,p0=r8,r0                      // check tracehook
        adds r2=PT(R8)+16,sp                    // r2 = &pt_regs.r8
        adds r3=PT(R10)+16,sp                   // r3 = &pt_regs.r10
        mov r10=0
(p6)    br.cond.sptk strace_error               // syscall failed ->
        adds r16=PT(F6)+16,sp
        adds r17=PT(F7)+16,sp
        ;;
        ldf.fill f6=[r16],32
        ldf.fill f7=[r17],32
        ;;
        ldf.fill f8=[r16],32
        ldf.fill f9=[r17],32
        ;;
        ldf.fill f10=[r16]
        ldf.fill f11=[r17]
        // the syscall number may have changed, so re-load it and re-calculate the
        // syscall entry-point:
        adds r15=PT(R15)+16,sp                  // r15 = &pt_regs.r15 (syscall #)
        ;;
        ld8 r15=[r15]
        mov r3=NR_syscalls - 1
        ;;
        adds r15=-1024,r15
        movl r16=sys_call_table
        ;;
        shladd r20=r15,3,r16                    // r20 = sys_call_table + 8*(syscall-1024)
        cmp.leu p6,p7=r15,r3
        ;;
(p6)    ld8 r20=[r20]                           // load address of syscall entry point
(p7)    movl r20=sys_ni_syscall
        ;;
        mov b6=r20
        br.call.sptk.many rp=b6                 // do the syscall
.strace_check_retval:
        cmp.lt p6,p0=r8,r0                      // syscall failed?
        adds r2=PT(R8)+16,sp                    // r2 = &pt_regs.r8
        adds r3=PT(R10)+16,sp                   // r3 = &pt_regs.r10
        mov r10=0
(p6)    br.cond.sptk strace_error               // syscall failed ->
        ;;                                      // avoid RAW on r10
.strace_save_retval:
.mem.offset 0,0; st8.spill [r2]=r8              // store return value in slot for r8
.mem.offset 8,0; st8.spill [r3]=r10             // clear error indication in slot for r10
        br.call.sptk.many rp=syscall_trace_leave // give parent a chance to catch return value
.ret3:
(pUStk) cmp.eq.unc p6,p0=r0,r0                  // p6 <- pUStk
(pUStk) rsm psr.i                               // disable interrupts
        br.cond.sptk ia64_work_pending_syscall_end

strace_error:
        ld8 r3=[r2]                             // load pt_regs.r8
        sub r9=0,r8                             // negate return value to get errno value
        ;;
        cmp.ne p6,p0=r3,r0                      // is pt_regs.r8!=0?
        adds r3=16,r2                           // r3=&pt_regs.r10
        ;;
(p6)    mov r10=-1
(p6)    mov r8=r9
        br.cond.sptk .strace_save_retval
END(ia64_trace_syscall)

        /*
         * When traced and returning from sigreturn, we invoke syscall_trace but then
         * go straight to ia64_leave_kernel rather than ia64_leave_syscall.
         */
GLOBAL_ENTRY(ia64_strace_leave_kernel)
        PT_REGS_UNWIND_INFO(0)
{       /*
         * Some versions of gas generate bad unwind info if the first instruction of a
         * procedure doesn't go into the first slot of a bundle.  This is a workaround.
         */
        nop.m 0
        nop.i 0
        br.call.sptk.many rp=syscall_trace_leave // give parent a chance to catch return value
}
.ret4:  br.cond.sptk ia64_leave_kernel
END(ia64_strace_leave_kernel)

ENTRY(call_payload)
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(0)
        /* call the kernel_thread payload; fn is in r4, arg - in r5 */
        alloc loc1=ar.pfs,0,3,1,0
        mov loc0=rp
        mov loc2=gp
        mov out0=r5             // arg
        ld8 r14 = [r4], 8       // fn.address
        ;;
        mov b6 = r14
        ld8 gp = [r4]           // fn.gp
        ;;
        br.call.sptk.many rp=b6 // fn(arg)
.ret12: mov gp=loc2
        mov rp=loc0
        mov ar.pfs=loc1
        /* ... and if it has returned, we are going to userland */
        cmp.ne pKStk,pUStk=r0,r0
        br.ret.sptk.many rp
END(call_payload)

GLOBAL_ENTRY(ia64_ret_from_clone)
        PT_REGS_UNWIND_INFO(0)
{       /*
         * Some versions of gas generate bad unwind info if the first instruction of a
         * procedure doesn't go into the first slot of a bundle.  This is a workaround.
         */
        nop.m 0
        nop.i 0
        /*
         * We need to call schedule_tail() to complete the scheduling process.
         * Called by ia64_switch_to() after do_fork()->copy_thread().  r8 contains the
         * address of the previously executing task.
         */
        br.call.sptk.many rp=ia64_invoke_schedule_tail
}
.ret8:
(pKStk) br.call.sptk.many rp=call_payload
        adds r2=TI_FLAGS+IA64_TASK_SIZE,r13
        ;;
        ld4 r2=[r2]
        ;;
        mov r8=0
        and r2=_TIF_SYSCALL_TRACEAUDIT,r2
        ;;
        cmp.ne p6,p0=r2,r0
(p6)    br.cond.spnt .strace_check_retval
        ;;                                      // added stop bits to prevent r8 dependency
END(ia64_ret_from_clone)
        // fall through
GLOBAL_ENTRY(ia64_ret_from_syscall)
        PT_REGS_UNWIND_INFO(0)
        cmp.ge p6,p7=r8,r0                      // syscall executed successfully?
        adds r2=PT(R8)+16,sp                    // r2 = &pt_regs.r8
        mov r10=r0                              // clear error indication in r10
(p7)    br.cond.spnt handle_syscall_error       // handle potential syscall failure
#ifdef CONFIG_PARAVIRT
        ;;
        br.cond.sptk.few ia64_leave_syscall
        ;;
#endif /* CONFIG_PARAVIRT */
END(ia64_ret_from_syscall)
#ifndef CONFIG_PARAVIRT
        // fall through
#endif
#endif /* __IA64_ASM_PARAVIRTUALIZED_NATIVE */

/*
 * ia64_leave_syscall(): Same as ia64_leave_kernel, except that it doesn't
 *      need to switch to bank 0 and doesn't restore the scratch registers.
 *      To avoid leaking kernel bits, the scratch registers are set to
 *      the following known-to-be-safe values:
 *
 *                r1: restored (global pointer)
 *                r2: cleared
 *                r3: 1 (when returning to user-level)
 *            r8-r11: restored (syscall return value(s))
 *               r12: restored (user-level stack pointer)
 *               r13: restored (user-level thread pointer)
 *               r14: set to __kernel_syscall_via_epc
 *               r15: restored (syscall #)
 *           r16-r17: cleared
 *               r18: user-level b6
 *               r19: cleared
 *               r20: user-level ar.fpsr
 *               r21: user-level b0
 *               r22: cleared
 *               r23: user-level ar.bspstore
 *               r24: user-level ar.rnat
 *               r25: user-level ar.unat
 *               r26: user-level ar.pfs
 *               r27: user-level ar.rsc
 *               r28: user-level ip
 *               r29: user-level psr
 *               r30: user-level cfm
 *               r31: user-level pr
 *            f6-f11: cleared
 *                pr: restored (user-level pr)
 *                b0: restored (user-level rp)
 *                b6: restored
 *                b7: set to __kernel_syscall_via_epc
 *           ar.unat: restored (user-level ar.unat)
 *            ar.pfs: restored (user-level ar.pfs)
 *            ar.rsc: restored (user-level ar.rsc)
 *           ar.rnat: restored (user-level ar.rnat)
 *       ar.bspstore: restored (user-level ar.bspstore)
 *           ar.fpsr: restored (user-level ar.fpsr)
 *            ar.ccv: cleared
 *            ar.csd: cleared
 *            ar.ssd: cleared
 */
GLOBAL_ENTRY(__paravirt_leave_syscall)
        PT_REGS_UNWIND_INFO(0)
        /*
         * work.need_resched etc. mustn't get changed by this CPU before it returns to
         * user- or fsys-mode, hence we disable interrupts early on.
         *
         * p6 controls whether current_thread_info()->flags needs to be check for
         * extra work.  We always check for extra work when returning to user-level.
         * With CONFIG_PREEMPT, we also check for extra work when the preempt_count
         * is 0.  After extra work processing has been completed, execution
         * resumes at ia64_work_processed_syscall with p6 set to 1 if the extra-work-check
         * needs to be redone.
         */
#ifdef CONFIG_PREEMPT
        RSM_PSR_I(p0, r2, r18)                  // disable interrupts
        cmp.eq pLvSys,p0=r0,r0                  // pLvSys=1: leave from syscall
(pKStk) adds r20=TI_PRE_COUNT+IA64_TASK_SIZE,r13
        ;;
        .pred.rel.mutex pUStk,pKStk
(pKStk) ld4 r21=[r20]                   // r21 <- preempt_count
(pUStk) mov r21=0                       // r21 <- 0
        ;;
        cmp.eq p6,p0=r21,r0             // p6 <- pUStk || (preempt_count == 0)
#else /* !CONFIG_PREEMPT */
        RSM_PSR_I(pUStk, r2, r18)
        cmp.eq pLvSys,p0=r0,r0          // pLvSys=1: leave from syscall
(pUStk) cmp.eq.unc p6,p0=r0,r0          // p6 <- pUStk
#endif
.global __paravirt_work_processed_syscall;
__paravirt_work_processed_syscall:
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
        adds r2=PT(LOADRS)+16,r12
        MOV_FROM_ITC(pUStk, p9, r22, r19)       // fetch time at leave
        adds r18=TI_FLAGS+IA64_TASK_SIZE,r13
        ;;
(p6)    ld4 r31=[r18]                           // load current_thread_info()->flags
        ld8 r19=[r2],PT(B6)-PT(LOADRS)          // load ar.rsc value for "loadrs"
        adds r3=PT(AR_BSPSTORE)+16,r12          // deferred
        ;;
#else
        adds r2=PT(LOADRS)+16,r12
        adds r3=PT(AR_BSPSTORE)+16,r12
        adds r18=TI_FLAGS+IA64_TASK_SIZE,r13
        ;;
(p6)    ld4 r31=[r18]                           // load current_thread_info()->flags
        ld8 r19=[r2],PT(B6)-PT(LOADRS)          // load ar.rsc value for "loadrs"
        nop.i 0
        ;;
#endif
        mov r16=ar.bsp                          // M2  get existing backing store pointer
        ld8 r18=[r2],PT(R9)-PT(B6)              // load b6
(p6)    and r15=TIF_WORK_MASK,r31               // any work other than TIF_SYSCALL_TRACE?
        ;;
        ld8 r23=[r3],PT(R11)-PT(AR_BSPSTORE)    // load ar.bspstore (may be garbage)
(p6)    cmp4.ne.unc p6,p0=r15, r0               // any special work pending?
(p6)    br.cond.spnt .work_pending_syscall
        ;;
        // start restoring the state saved on the kernel stack (struct pt_regs):
        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                  // M0|1 invalidate ALAT
        RSM_PSR_I_IC(r28, r29, r30)     // M2   turn off interrupts and interruption collection
        cmp.eq p9,p0=r0,r0      // A    set p9 to indicate that we should restore cr.ifs

        ld8 r29=[r2],16         // M0|1 load cr.ipsr
        ld8 r28=[r3],16         // M0|1 load cr.iip
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
(pUStk) add r14=TI_AC_LEAVE+IA64_TASK_SIZE,r13
        ;;
        ld8 r30=[r2],16         // M0|1 load cr.ifs
        ld8 r25=[r3],16         // M0|1 load ar.unat
(pUStk) add r15=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13
        ;;
#else
        mov r22=r0              // A    clear r22
        ;;
        ld8 r30=[r2],16         // M0|1 load cr.ifs
        ld8 r25=[r3],16         // M0|1 load ar.unat
(pUStk) add r14=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13
        ;;
#endif
        ld8 r26=[r2],PT(B0)-PT(AR_PFS)  // M0|1 load ar.pfs
        MOV_FROM_PSR(pKStk, r22, r21)   // M2   read PSR now that interrupts are disabled
        nop 0
        ;;
        ld8 r21=[r2],PT(AR_RNAT)-PT(B0) // M0|1 load b0
        ld8 r27=[r3],PT(PR)-PT(AR_RSC)  // M0|1 load ar.rsc
        mov f6=f0                       // F    clear f6
        ;;
        ld8 r24=[r2],PT(AR_FPSR)-PT(AR_RNAT)    // M0|1 load ar.rnat (may be garbage)
        ld8 r31=[r3],PT(R1)-PT(PR)              // M0|1 load predicates
        mov f7=f0                               // F    clear f7
        ;;
        ld8 r20=[r2],PT(R12)-PT(AR_FPSR)        // M0|1 load ar.fpsr
        ld8.fill r1=[r3],16                     // M0|1 load r1
(pUStk) mov r17=1                               // A
        ;;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
(pUStk) st1 [r15]=r17                           // M2|3
#else
(pUStk) st1 [r14]=r17                           // M2|3
#endif
        ld8.fill r13=[r3],16                    // M0|1
        mov f8=f0                               // F    clear f8
        ;;
        ld8.fill r12=[r2]                       // M0|1 restore r12 (sp)
        ld8.fill r15=[r3]                       // M0|1 restore r15
        mov b6=r18                              // I0   restore b6

        LOAD_PHYS_STACK_REG_SIZE(r17)
        mov f9=f0                                       // F    clear f9
(pKStk) br.cond.dpnt.many skip_rbs_switch               // B

        srlz.d                          // M0   ensure interruption collection is off (for cover)
        shr.u r18=r19,16                // I0|1 get byte size of existing "dirty" partition
        COVER                           // B    add current frame into dirty partition & set cr.ifs
        ;;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
        mov r19=ar.bsp                  // M2   get new backing store pointer
        st8 [r14]=r22                   // M    save time at leave
        mov f10=f0                      // F    clear f10

        mov r22=r0                      // A    clear r22
        movl r14=__kernel_syscall_via_epc // X
        ;;
#else
        mov r19=ar.bsp                  // M2   get new backing store pointer
        mov f10=f0                      // F    clear f10

        nop.m 0
        movl r14=__kernel_syscall_via_epc // X
        ;;
#endif
        mov.m ar.csd=r0                 // M2   clear ar.csd
        mov.m ar.ccv=r0                 // M2   clear ar.ccv
        mov b7=r14                      // I0   clear b7 (hint with __kernel_syscall_via_epc)

        mov.m ar.ssd=r0                 // M2   clear ar.ssd
        mov f11=f0                      // F    clear f11
        br.cond.sptk.many rbs_switch    // B
END(__paravirt_leave_syscall)

GLOBAL_ENTRY(__paravirt_leave_kernel)
        PT_REGS_UNWIND_INFO(0)
        /*
         * work.need_resched etc. mustn't get changed by this CPU before it returns to
         * user- or fsys-mode, hence we disable interrupts early on.
         *
         * p6 controls whether current_thread_info()->flags needs to be check for
         * extra work.  We always check for extra work when returning to user-level.
         * With CONFIG_PREEMPT, we also check for extra work when the preempt_count
         * is 0.  After extra work processing has been completed, execution
         * resumes at .work_processed_syscall with p6 set to 1 if the extra-work-check
         * needs to be redone.
         */
#ifdef CONFIG_PREEMPT
        RSM_PSR_I(p0, r17, r31)                 // disable interrupts
        cmp.eq p0,pLvSys=r0,r0                  // pLvSys=0: leave from kernel
(pKStk) adds r20=TI_PRE_COUNT+IA64_TASK_SIZE,r13
        ;;
        .pred.rel.mutex pUStk,pKStk
(pKStk) ld4 r21=[r20]                   // r21 <- preempt_count
(pUStk) mov r21=0                       // r21 <- 0
        ;;
        cmp.eq p6,p0=r21,r0             // p6 <- pUStk || (preempt_count == 0)
#else
        RSM_PSR_I(pUStk, r17, r31)
        cmp.eq p0,pLvSys=r0,r0          // pLvSys=0: leave from kernel
(pUStk) cmp.eq.unc p6,p0=r0,r0          // p6 <- pUStk
#endif
.work_processed_kernel:
        adds r17=TI_FLAGS+IA64_TASK_SIZE,r13
        ;;
(p6)    ld4 r31=[r17]                           // load current_thread_info()->flags
        adds r21=PT(PR)+16,r12
        ;;

        lfetch [r21],PT(CR_IPSR)-PT(PR)
        adds r2=PT(B6)+16,r12
        adds r3=PT(R16)+16,r12
        ;;
        lfetch [r21]
        ld8 r28=[r2],8          // load b6
        adds r29=PT(R24)+16,r12

        ld8.fill r16=[r3],PT(AR_CSD)-PT(R16)
        adds r30=PT(AR_CCV)+16,r12
(p6)    and r19=TIF_WORK_MASK,r31               // any work other than TIF_SYSCALL_TRACE?
        ;;
        ld8.fill r24=[r29]
        ld8 r15=[r30]           // load ar.ccv
(p6)    cmp4.ne.unc p6,p0=r19, r0               // any special work pending?
        ;;
        ld8 r29=[r2],16         // load b7
        ld8 r30=[r3],16         // load ar.csd
(p6)    br.cond.spnt .work_pending
        ;;
        ld8 r31=[r2],16         // load ar.ssd
        ld8.fill r8=[r3],16
        ;;
        ld8.fill r9=[r2],16
        ld8.fill r10=[r3],PT(R17)-PT(R10)
        ;;
        ld8.fill r11=[r2],PT(R18)-PT(R11)
        ld8.fill r17=[r3],16
        ;;
        ld8.fill r18=[r2],16
        ld8.fill r19=[r3],16
        ;;
        ld8.fill r20=[r2],16
        ld8.fill r21=[r3],16
        mov ar.csd=r30
        mov ar.ssd=r31
        ;;
        RSM_PSR_I_IC(r23, r22, r25)     // initiate turning off of interrupt and interruption collection
        invala                  // invalidate ALAT
        ;;
        ld8.fill r22=[r2],24
        ld8.fill r23=[r3],24
        mov b6=r28
        ;;
        ld8.fill r25=[r2],16
        ld8.fill r26=[r3],16
        mov b7=r29
        ;;
        ld8.fill r27=[r2],16
        ld8.fill r28=[r3],16
        ;;
        ld8.fill r29=[r2],16
        ld8.fill r30=[r3],24
        ;;
        ld8.fill r31=[r2],PT(F9)-PT(R31)
        adds r3=PT(F10)-PT(F6),r3
        ;;
        ldf.fill f9=[r2],PT(F6)-PT(F9)
        ldf.fill f10=[r3],PT(F8)-PT(F10)
        ;;
        ldf.fill f6=[r2],PT(F7)-PT(F6)
        ;;
        ldf.fill f7=[r2],PT(F11)-PT(F7)
        ldf.fill f8=[r3],32
        ;;
        srlz.d  // ensure that inter. collection is off (VHPT is don't care, since text is pinned)
        mov ar.ccv=r15
        ;;
        ldf.fill f11=[r2]
        BSW_0(r2, r3, r15)      // switch back to bank 0 (no stop bit required beforehand...)
        ;;
(pUStk) mov r18=IA64_KR(CURRENT)// M2 (12 cycle read latency)
        adds r16=PT(CR_IPSR)+16,r12
        adds r17=PT(CR_IIP)+16,r12

#ifdef CONFIG_VIRT_CPU_ACCOUNTING
        .pred.rel.mutex pUStk,pKStk
        MOV_FROM_PSR(pKStk, r22, r29)   // M2 read PSR now that interrupts are disabled
        MOV_FROM_ITC(pUStk, p9, r22, r29)       // M  fetch time at leave
        nop.i 0
        ;;
#else
        MOV_FROM_PSR(pKStk, r22, r29)   // M2 read PSR now that interrupts are disabled
        nop.i 0
        nop.i 0
        ;;
#endif
        ld8 r29=[r16],16        // load cr.ipsr
        ld8 r28=[r17],16        // load cr.iip
        ;;
        ld8 r30=[r16],16        // load cr.ifs
        ld8 r25=[r17],16        // load ar.unat
        ;;
        ld8 r26=[r16],16        // load ar.pfs
        ld8 r27=[r17],16        // load ar.rsc
        cmp.eq p9,p0=r0,r0      // set p9 to indicate that we should restore cr.ifs
        ;;
        ld8 r24=[r16],16        // load ar.rnat (may be garbage)
        ld8 r23=[r17],16        // load ar.bspstore (may be garbage)
        ;;
        ld8 r31=[r16],16        // load predicates
        ld8 r21=[r17],16        // load b0
        ;;
        ld8 r19=[r16],16        // load ar.rsc value for "loadrs"
        ld8.fill r1=[r17],16    // load r1
        ;;
        ld8.fill r12=[r16],16
        ld8.fill r13=[r17],16
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
(pUStk) adds r3=TI_AC_LEAVE+IA64_TASK_SIZE,r18
#else
(pUStk) adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18
#endif
        ;;
        ld8 r20=[r16],16        // ar.fpsr
        ld8.fill r15=[r17],16
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
(pUStk) adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18  // deferred
#endif
        ;;
        ld8.fill r14=[r16],16
        ld8.fill r2=[r17]
(pUStk) mov r17=1
        ;;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING

        //  mmi_ :  ld8 st1 shr;;         mmi_ : st8 st1 shr;;
        //  mib  :  mov add br        ->  mib  : ld8 add br
        //  bbb_ :  br  nop cover;;       mbb_ : mov br  cover;;
        //
        //  no one require bsp in r16 if (pKStk) branch is selected.
(pUStk) st8 [r3]=r22            // save time at leave
(pUStk) st1 [r18]=r17           // restore current->thread.on_ustack
        shr.u r18=r19,16        // get byte size of existing "dirty" partition
        ;;
        ld8.fill r3=[r16]       // deferred
        LOAD_PHYS_STACK_REG_SIZE(r17)
(pKStk) br.cond.dpnt skip_rbs_switch
        mov r16=ar.bsp          // get existing backing store pointer
#else
        ld8.fill r3=[r16]
(pUStk) st1 [r18]=r17           // restore current->thread.on_ustack
        shr.u r18=r19,16        // get byte size of existing "dirty" partition
        ;;
        mov r16=ar.bsp          // get existing backing store pointer
        LOAD_PHYS_STACK_REG_SIZE(r17)
(pKStk) br.cond.dpnt skip_rbs_switch
#endif

        /*
         * Restore user backing store.
         *
         * NOTE: alloc, loadrs, and cover can't be predicated.
         */
(pNonSys) br.cond.dpnt dont_preserve_current_frame
        COVER                           // add current frame into dirty partition and set cr.ifs
        ;;
        mov r19=ar.bsp                  // get new backing store pointer
rbs_switch:
        sub r16=r16,r18                 // krbs = old bsp - size of dirty partition
        cmp.ne p9,p0=r0,r0              // clear p9 to skip restore of cr.ifs
        ;;
        sub r19=r19,r16                 // calculate total byte size of dirty partition
        add r18=64,r18                  // don't force in0-in7 into memory...
        ;;
        shl r19=r19,16                  // shift size of dirty partition into loadrs position
        ;;
dont_preserve_current_frame:
        /*
         * To prevent leaking bits between the kernel and user-space,
         * we must clear the stacked registers in the "invalid" partition here.
         * Not pretty, but at least it's fast (3.34 registers/cycle on Itanium,
         * 5 registers/cycle on McKinley).
         */
#       define pRecurse p6
#       define pReturn  p7
#ifdef CONFIG_ITANIUM
#       define Nregs    10
#else
#       define Nregs    14
#endif
        alloc loc0=ar.pfs,2,Nregs-2,2,0
        shr.u loc1=r18,9                // RNaTslots <= floor(dirtySize / (64*8))
        sub r17=r17,r18                 // r17 = (physStackedSize + 8) - dirtySize
        ;;
        mov ar.rsc=r19                  // load ar.rsc to be used for "loadrs"
        shladd in0=loc1,3,r17
        mov in1=0
        ;;
        TEXT_ALIGN(32)
rse_clear_invalid:
#ifdef CONFIG_ITANIUM
        // cycle 0
 { .mii
        alloc loc0=ar.pfs,2,Nregs-2,2,0
        cmp.lt pRecurse,p0=Nregs*8,in0  // if more than Nregs regs left to clear, (re)curse
        add out0=-Nregs*8,in0
}{ .mfb
        add out1=1,in1                  // increment recursion count
        nop.f 0
        nop.b 0                         // can't do br.call here because of alloc (WAW on CFM)
        ;;
}{ .mfi // cycle 1
        mov loc1=0
        nop.f 0
        mov loc2=0
}{ .mib
        mov loc3=0
        mov loc4=0
(pRecurse) br.call.sptk.many b0=rse_clear_invalid

}{ .mfi // cycle 2
        mov loc5=0
        nop.f 0
        cmp.ne pReturn,p0=r0,in1        // if recursion count != 0, we need to do a br.ret
}{ .mib
        mov loc6=0
        mov loc7=0
(pReturn) br.ret.sptk.many b0
}
#else /* !CONFIG_ITANIUM */
        alloc loc0=ar.pfs,2,Nregs-2,2,0
        cmp.lt pRecurse,p0=Nregs*8,in0  // if more than Nregs regs left to clear, (re)curse
        add out0=-Nregs*8,in0
        add out1=1,in1                  // increment recursion count
        mov loc1=0
        mov loc2=0
        ;;
        mov loc3=0
        mov loc4=0
        mov loc5=0
        mov loc6=0
        mov loc7=0
(pRecurse) br.call.dptk.few b0=rse_clear_invalid
        ;;
        mov loc8=0
        mov loc9=0
        cmp.ne pReturn,p0=r0,in1        // if recursion count != 0, we need to do a br.ret
        mov loc10=0
        mov loc11=0
(pReturn) br.ret.dptk.many b0
#endif /* !CONFIG_ITANIUM */
#       undef pRecurse
#       undef pReturn
        ;;
        alloc r17=ar.pfs,0,0,0,0        // drop current register frame
        ;;
        loadrs
        ;;
skip_rbs_switch:
        mov ar.unat=r25         // M2
(pKStk) extr.u r22=r22,21,1     // I0 extract current value of psr.pp from r22
(pLvSys)mov r19=r0              // A  clear r19 for leave_syscall, no-op otherwise
        ;;
(pUStk) mov ar.bspstore=r23     // M2
(pKStk) dep r29=r22,r29,21,1    // I0 update ipsr.pp with psr.pp
(pLvSys)mov r16=r0              // A  clear r16 for leave_syscall, no-op otherwise
        ;;
        MOV_TO_IPSR(p0, r29, r25)       // M2
        mov ar.pfs=r26          // I0
(pLvSys)mov r17=r0              // A  clear r17 for leave_syscall, no-op otherwise

        MOV_TO_IFS(p9, r30, r25)// M2
        mov b0=r21              // I0
(pLvSys)mov r18=r0              // A  clear r18 for leave_syscall, no-op otherwise

        mov ar.fpsr=r20         // M2
        MOV_TO_IIP(r28, r25)    // M2
        nop 0
        ;;
(pUStk) mov ar.rnat=r24         // M2 must happen with RSE in lazy mode
        nop 0
(pLvSys)mov r2=r0

        mov ar.rsc=r27          // M2
        mov pr=r31,-1           // I0
        RFI                     // B

        /*
         * On entry:
         *      r20 = &current->thread_info->pre_count (if CONFIG_PREEMPT)
         *      r31 = current->thread_info->flags
         * On exit:
         *      p6 = TRUE if work-pending-check needs to be redone
         *
         * Interrupts are disabled on entry, reenabled depend on work, and
         * disabled on exit.
         */
.work_pending_syscall:
        add r2=-8,r2
        add r3=-8,r3
        ;;
        st8 [r2]=r8
        st8 [r3]=r10
.work_pending:
        tbit.z p6,p0=r31,TIF_NEED_RESCHED       // is resched not needed?
(p6)    br.cond.sptk.few .notify
#ifdef CONFIG_PREEMPT
(pKStk) dep r21=-1,r0,PREEMPT_ACTIVE_BIT,1
        ;;
(pKStk) st4 [r20]=r21
#endif
        SSM_PSR_I(p0, p6, r2)   // enable interrupts
        br.call.spnt.many rp=schedule
.ret9:  cmp.eq p6,p0=r0,r0      // p6 <- 1 (re-check)
        RSM_PSR_I(p0, r2, r20)  // disable interrupts
        ;;
#ifdef CONFIG_PREEMPT
(pKStk) adds r20=TI_PRE_COUNT+IA64_TASK_SIZE,r13
        ;;
(pKStk) st4 [r20]=r0            // preempt_count() <- 0
#endif
(pLvSys)br.cond.sptk.few  __paravirt_pending_syscall_end
        br.cond.sptk.many .work_processed_kernel

.notify:
(pUStk) br.call.spnt.many rp=notify_resume_user
.ret10: cmp.ne p6,p0=r0,r0      // p6 <- 0 (don't re-check)
(pLvSys)br.cond.sptk.few  __paravirt_pending_syscall_end
        br.cond.sptk.many .work_processed_kernel

.global __paravirt_pending_syscall_end;
__paravirt_pending_syscall_end:
        adds r2=PT(R8)+16,r12
        adds r3=PT(R10)+16,r12
        ;;
        ld8 r8=[r2]
        ld8 r10=[r3]
        br.cond.sptk.many __paravirt_work_processed_syscall_target
END(__paravirt_leave_kernel)

#ifdef __IA64_ASM_PARAVIRTUALIZED_NATIVE
ENTRY(handle_syscall_error)
        /*
         * Some system calls (e.g., ptrace, mmap) can return arbitrary values which could
         * lead us to mistake a negative return value as a failed syscall.  Those syscall
         * must deposit a non-zero value in pt_regs.r8 to indicate an error.  If
         * pt_regs.r8 is zero, we assume that the call completed successfully.
         */
        PT_REGS_UNWIND_INFO(0)
        ld8 r3=[r2]             // load pt_regs.r8
        ;;
        cmp.eq p6,p7=r3,r0      // is pt_regs.r8==0?
        ;;
(p7)    mov r10=-1
(p7)    sub r8=0,r8             // negate return value to get errno
        br.cond.sptk ia64_leave_syscall
END(handle_syscall_error)

        /*
         * Invoke schedule_tail(task) while preserving in0-in7, which may be needed
         * in case a system call gets restarted.
         */
GLOBAL_ENTRY(ia64_invoke_schedule_tail)
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
        alloc loc1=ar.pfs,8,2,1,0
        mov loc0=rp
        mov out0=r8                             // Address of previous task
        ;;
        br.call.sptk.many rp=schedule_tail
.ret11: mov ar.pfs=loc1
        mov rp=loc0
        br.ret.sptk.many rp
END(ia64_invoke_schedule_tail)

        /*
         * Setup stack and call do_notify_resume_user(), keeping interrupts
         * disabled.
         *
         * Note that pSys and pNonSys need to be set up by the caller.
         * We declare 8 input registers so the system call args get preserved,
         * in case we need to restart a system call.
         */
GLOBAL_ENTRY(notify_resume_user)
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
        alloc loc1=ar.pfs,8,2,3,0 // preserve all eight input regs in case of syscall restart!
        mov r9=ar.unat
        mov loc0=rp                             // save return address
        mov out0=0                              // there is no "oldset"
        adds out1=8,sp                          // out1=&sigscratch->ar_pfs
(pSys)  mov out2=1                              // out2==1 => we're in a syscall
        ;;
(pNonSys) mov out2=0                            // out2==0 => not a syscall
        .fframe 16
        .spillsp ar.unat, 16
        st8 [sp]=r9,-16                         // allocate space for ar.unat and save it
        st8 [out1]=loc1,-8                      // save ar.pfs, out1=&sigscratch
        .body
        br.call.sptk.many rp=do_notify_resume_user
.ret15: .restore sp
        adds sp=16,sp                           // pop scratch stack space
        ;;
        ld8 r9=[sp]                             // load new unat from sigscratch->scratch_unat
        mov rp=loc0
        ;;
        mov ar.unat=r9
        mov ar.pfs=loc1
        br.ret.sptk.many rp
END(notify_resume_user)

ENTRY(sys_rt_sigreturn)
        PT_REGS_UNWIND_INFO(0)
        /*
         * Allocate 8 input registers since ptrace() may clobber them
         */
        alloc r2=ar.pfs,8,0,1,0
        .prologue
        PT_REGS_SAVES(16)
        adds sp=-16,sp
        .body
        cmp.eq pNonSys,pSys=r0,r0               // sigreturn isn't a normal syscall...
        ;;
        /*
         * leave_kernel() restores f6-f11 from pt_regs, but since the streamlined
         * syscall-entry path does not save them we save them here instead.  Note: we
         * don't need to save any other registers that are not saved by the stream-lined
         * syscall path, because restore_sigcontext() restores them.
         */
        adds r16=PT(F6)+32,sp
        adds r17=PT(F7)+32,sp
        ;;
        stf.spill [r16]=f6,32
        stf.spill [r17]=f7,32
        ;;
        stf.spill [r16]=f8,32
        stf.spill [r17]=f9,32
        ;;
        stf.spill [r16]=f10
        stf.spill [r17]=f11
        adds out0=16,sp                         // out0 = &sigscratch
        br.call.sptk.many rp=ia64_rt_sigreturn
.ret19: .restore sp,0
        adds sp=16,sp
        ;;
        ld8 r9=[sp]                             // load new ar.unat
        mov.sptk b7=r8,ia64_native_leave_kernel
        ;;
        mov ar.unat=r9
        br.many b7
END(sys_rt_sigreturn)

GLOBAL_ENTRY(ia64_prepare_handle_unaligned)
        .prologue
        /*
         * r16 = fake ar.pfs, we simply need to make sure privilege is still 0
         */
        mov r16=r0
        DO_SAVE_SWITCH_STACK
        br.call.sptk.many rp=ia64_handle_unaligned      // stack frame setup in ivt
.ret21: .body
        DO_LOAD_SWITCH_STACK
        br.cond.sptk.many rp                            // goes to ia64_leave_kernel
END(ia64_prepare_handle_unaligned)

        //
        // unw_init_running(void (*callback)(info, arg), void *arg)
        //
#       define EXTRA_FRAME_SIZE ((UNW_FRAME_INFO_SIZE+15)&~15)

GLOBAL_ENTRY(unw_init_running)
        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(2)
        alloc loc1=ar.pfs,2,3,3,0
        ;;
        ld8 loc2=[in0],8
        mov loc0=rp
        mov r16=loc1
        DO_SAVE_SWITCH_STACK
        .body

        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(2)
        .fframe IA64_SWITCH_STACK_SIZE+EXTRA_FRAME_SIZE
        SWITCH_STACK_SAVES(EXTRA_FRAME_SIZE)
        adds sp=-EXTRA_FRAME_SIZE,sp
        .body
        ;;
        adds out0=16,sp                         // &info
        mov out1=r13                            // current
        adds out2=16+EXTRA_FRAME_SIZE,sp        // &switch_stack
        br.call.sptk.many rp=unw_init_frame_info
1:      adds out0=16,sp                         // &info
        mov b6=loc2
        mov loc2=gp                             // save gp across indirect function call
        ;;
        ld8 gp=[in0]
        mov out1=in1                            // arg
        br.call.sptk.many rp=b6                 // invoke the callback function
1:      mov gp=loc2                             // restore gp

        // For now, we don't allow changing registers from within
        // unw_init_running; if we ever want to allow that, we'd
        // have to do a load_switch_stack here:
        .restore sp
        adds sp=IA64_SWITCH_STACK_SIZE+EXTRA_FRAME_SIZE,sp

        mov ar.pfs=loc1
        mov rp=loc0
        br.ret.sptk.many rp
END(unw_init_running)

#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
GLOBAL_ENTRY(_mcount)
        br ftrace_stub
END(_mcount)

.here:
        br.ret.sptk.many b0

GLOBAL_ENTRY(ftrace_caller)
        alloc out0 = ar.pfs, 8, 0, 4, 0
        mov out3 = r0
        ;;
        mov out2 = b0
        add r3 = 0x20, r3
        mov out1 = r1;
        br.call.sptk.many b0 = ftrace_patch_gp
        //this might be called from module, so we must patch gp
ftrace_patch_gp:
        movl gp=__gp
        mov b0 = r3
        ;;
.global ftrace_call;
ftrace_call:
{
        .mlx
        nop.m 0x0
        movl r3 = .here;;
}
        alloc loc0 = ar.pfs, 4, 4, 2, 0
        ;;
        mov loc1 = b0
        mov out0 = b0
        mov loc2 = r8
        mov loc3 = r15
        ;;
        adds out0 = -MCOUNT_INSN_SIZE, out0
        mov out1 = in2
        mov b6 = r3

        br.call.sptk.many b0 = b6
        ;;
        mov ar.pfs = loc0
        mov b0 = loc1
        mov r8 = loc2
        mov r15 = loc3
        br ftrace_stub
        ;;
END(ftrace_caller)

#else
GLOBAL_ENTRY(_mcount)
        movl r2 = ftrace_stub
        movl r3 = ftrace_trace_function;;
        ld8 r3 = [r3];;
        ld8 r3 = [r3];;
        cmp.eq p7,p0 = r2, r3
(p7)    br.sptk.many ftrace_stub
        ;;

        alloc loc0 = ar.pfs, 4, 4, 2, 0
        ;;
        mov loc1 = b0
        mov out0 = b0
        mov loc2 = r8
        mov loc3 = r15
        ;;
        adds out0 = -MCOUNT_INSN_SIZE, out0
        mov out1 = in2
        mov b6 = r3

        br.call.sptk.many b0 = b6
        ;;
        mov ar.pfs = loc0
        mov b0 = loc1
        mov r8 = loc2
        mov r15 = loc3
        br ftrace_stub
        ;;
END(_mcount)
#endif

GLOBAL_ENTRY(ftrace_stub)
        mov r3 = b0
        movl r2 = _mcount_ret_helper
        ;;
        mov b6 = r2
        mov b7 = r3
        br.ret.sptk.many b6

_mcount_ret_helper:
        mov b0 = r42
        mov r1 = r41
        mov ar.pfs = r40
        br b7
END(ftrace_stub)

#endif /* CONFIG_FUNCTION_TRACER */

        .rodata
        .align 8
        .globl sys_call_table
sys_call_table:
        data8 sys_ni_syscall            //  This must be sys_ni_syscall!  See ivt.S.
        data8 sys_exit                          // 1025
        data8 sys_read
        data8 sys_write
        data8 sys_open
        data8 sys_close
        data8 sys_creat                         // 1030
        data8 sys_link
        data8 sys_unlink
        data8 ia64_execve
        data8 sys_chdir
        data8 sys_fchdir                        // 1035
        data8 sys_utimes
        data8 sys_mknod
        data8 sys_chmod
        data8 sys_chown
        data8 sys_lseek                         // 1040
        data8 sys_getpid
        data8 sys_getppid
        data8 sys_mount
        data8 sys_umount
        data8 sys_setuid                        // 1045
        data8 sys_getuid
        data8 sys_geteuid
        data8 sys_ptrace
        data8 sys_access
        data8 sys_sync                          // 1050
        data8 sys_fsync
        data8 sys_fdatasync
        data8 sys_kill
        data8 sys_rename
        data8 sys_mkdir                         // 1055
        data8 sys_rmdir
        data8 sys_dup
        data8 sys_ia64_pipe
        data8 sys_times
        data8 ia64_brk                          // 1060
        data8 sys_setgid
        data8 sys_getgid
        data8 sys_getegid
        data8 sys_acct
        data8 sys_ioctl                         // 1065
        data8 sys_fcntl
        data8 sys_umask
        data8 sys_chroot
        data8 sys_ustat
        data8 sys_dup2                          // 1070
        data8 sys_setreuid
        data8 sys_setregid
        data8 sys_getresuid
        data8 sys_setresuid
        data8 sys_getresgid                     // 1075
        data8 sys_setresgid
        data8 sys_getgroups
        data8 sys_setgroups
        data8 sys_getpgid
        data8 sys_setpgid                       // 1080
        data8 sys_setsid
        data8 sys_getsid
        data8 sys_sethostname
        data8 sys_setrlimit
        data8 sys_getrlimit                     // 1085
        data8 sys_getrusage
        data8 sys_gettimeofday
        data8 sys_settimeofday
        data8 sys_select
        data8 sys_poll                          // 1090
        data8 sys_symlink
        data8 sys_readlink
        data8 sys_uselib
        data8 sys_swapon
        data8 sys_swapoff                       // 1095
        data8 sys_reboot
        data8 sys_truncate
        data8 sys_ftruncate
        data8 sys_fchmod
        data8 sys_fchown                        // 1100
        data8 ia64_getpriority
        data8 sys_setpriority
        data8 sys_statfs
        data8 sys_fstatfs
        data8 sys_gettid                        // 1105
        data8 sys_semget
        data8 sys_semop
        data8 sys_semctl
        data8 sys_msgget
        data8 sys_msgsnd                        // 1110
        data8 sys_msgrcv
        data8 sys_msgctl
        data8 sys_shmget
        data8 sys_shmat
        data8 sys_shmdt                         // 1115
        data8 sys_shmctl
        data8 sys_syslog
        data8 sys_setitimer
        data8 sys_getitimer
        data8 sys_ni_syscall                    // 1120         /* was: ia64_oldstat */
        data8 sys_ni_syscall                                    /* was: ia64_oldlstat */
        data8 sys_ni_syscall                                    /* was: ia64_oldfstat */
        data8 sys_vhangup
        data8 sys_lchown
        data8 sys_remap_file_pages              // 1125
        data8 sys_wait4
        data8 sys_sysinfo
        data8 sys_clone
        data8 sys_setdomainname
        data8 sys_newuname                      // 1130
        data8 sys_adjtimex
        data8 sys_ni_syscall                                    /* was: ia64_create_module */
        data8 sys_init_module
        data8 sys_delete_module
        data8 sys_ni_syscall                    // 1135         /* was: sys_get_kernel_syms */
        data8 sys_ni_syscall                                    /* was: sys_query_module */
        data8 sys_quotactl
        data8 sys_bdflush
        data8 sys_sysfs
        data8 sys_personality                   // 1140
        data8 sys_ni_syscall            // sys_afs_syscall
        data8 sys_setfsuid
        data8 sys_setfsgid
        data8 sys_getdents
        data8 sys_flock                         // 1145
        data8 sys_readv
        data8 sys_writev
        data8 sys_pread64
        data8 sys_pwrite64
        data8 sys_sysctl                        // 1150
        data8 sys_mmap
        data8 sys_munmap
        data8 sys_mlock
        data8 sys_mlockall
        data8 sys_mprotect                      // 1155
        data8 ia64_mremap
        data8 sys_msync
        data8 sys_munlock
        data8 sys_munlockall
        data8 sys_sched_getparam                // 1160
        data8 sys_sched_setparam
        data8 sys_sched_getscheduler
        data8 sys_sched_setscheduler
        data8 sys_sched_yield
        data8 sys_sched_get_priority_max        // 1165
        data8 sys_sched_get_priority_min
        data8 sys_sched_rr_get_interval
        data8 sys_nanosleep
        data8 sys_ni_syscall                    // old nfsservctl
        data8 sys_prctl                         // 1170
        data8 sys_getpagesize
        data8 sys_mmap2
        data8 sys_pciconfig_read
        data8 sys_pciconfig_write
        data8 sys_perfmonctl                    // 1175
        data8 sys_sigaltstack
        data8 sys_rt_sigaction
        data8 sys_rt_sigpending
        data8 sys_rt_sigprocmask
        data8 sys_rt_sigqueueinfo               // 1180
        data8 sys_rt_sigreturn
        data8 sys_rt_sigsuspend
        data8 sys_rt_sigtimedwait
        data8 sys_getcwd
        data8 sys_capget                        // 1185
        data8 sys_capset
        data8 sys_sendfile64
        data8 sys_ni_syscall            // sys_getpmsg (STREAMS)
        data8 sys_ni_syscall            // sys_putpmsg (STREAMS)
        data8 sys_socket                        // 1190
        data8 sys_bind
        data8 sys_connect
        data8 sys_listen
        data8 sys_accept
        data8 sys_getsockname                   // 1195
        data8 sys_getpeername
        data8 sys_socketpair
        data8 sys_send
        data8 sys_sendto
        data8 sys_recv                          // 1200
        data8 sys_recvfrom
        data8 sys_shutdown
        data8 sys_setsockopt
        data8 sys_getsockopt
        data8 sys_sendmsg                       // 1205
        data8 sys_recvmsg
        data8 sys_pivot_root
        data8 sys_mincore
        data8 sys_madvise
        data8 sys_newstat                       // 1210
        data8 sys_newlstat
        data8 sys_newfstat
        data8 sys_clone2
        data8 sys_getdents64
        data8 sys_getunwind                     // 1215
        data8 sys_readahead
        data8 sys_setxattr
        data8 sys_lsetxattr
        data8 sys_fsetxattr
        data8 sys_getxattr                      // 1220
        data8 sys_lgetxattr
        data8 sys_fgetxattr
        data8 sys_listxattr
        data8 sys_llistxattr
        data8 sys_flistxattr                    // 1225
        data8 sys_removexattr
        data8 sys_lremovexattr
        data8 sys_fremovexattr
        data8 sys_tkill
        data8 sys_futex                         // 1230
        data8 sys_sched_setaffinity
        data8 sys_sched_getaffinity
        data8 sys_set_tid_address
        data8 sys_fadvise64_64
        data8 sys_tgkill                        // 1235
        data8 sys_exit_group
        data8 sys_lookup_dcookie
        data8 sys_io_setup
        data8 sys_io_destroy
        data8 sys_io_getevents                  // 1240
        data8 sys_io_submit
        data8 sys_io_cancel
        data8 sys_epoll_create
        data8 sys_epoll_ctl
        data8 sys_epoll_wait                    // 1245
        data8 sys_restart_syscall
        data8 sys_semtimedop
        data8 sys_timer_create
        data8 sys_timer_settime
        data8 sys_timer_gettime                 // 1250
        data8 sys_timer_getoverrun
        data8 sys_timer_delete
        data8 sys_clock_settime
        data8 sys_clock_gettime
        data8 sys_clock_getres                  // 1255
        data8 sys_clock_nanosleep
        data8 sys_fstatfs64
        data8 sys_statfs64
        data8 sys_mbind
        data8 sys_get_mempolicy                 // 1260
        data8 sys_set_mempolicy
        data8 sys_mq_open
        data8 sys_mq_unlink
        data8 sys_mq_timedsend
        data8 sys_mq_timedreceive               // 1265
        data8 sys_mq_notify
        data8 sys_mq_getsetattr
        data8 sys_kexec_load
        data8 sys_ni_syscall                    // reserved for vserver
        data8 sys_waitid                        // 1270
        data8 sys_add_key
        data8 sys_request_key
        data8 sys_keyctl
        data8 sys_ioprio_set
        data8 sys_ioprio_get                    // 1275
        data8 sys_move_pages
        data8 sys_inotify_init
        data8 sys_inotify_add_watch
        data8 sys_inotify_rm_watch
        data8 sys_migrate_pages                 // 1280
        data8 sys_openat
        data8 sys_mkdirat
        data8 sys_mknodat
        data8 sys_fchownat
        data8 sys_futimesat                     // 1285
        data8 sys_newfstatat
        data8 sys_unlinkat
        data8 sys_renameat
        data8 sys_linkat
        data8 sys_symlinkat                     // 1290
        data8 sys_readlinkat
        data8 sys_fchmodat
        data8 sys_faccessat
        data8 sys_pselect6
        data8 sys_ppoll                         // 1295
        data8 sys_unshare
        data8 sys_splice
        data8 sys_set_robust_list
        data8 sys_get_robust_list
        data8 sys_sync_file_range               // 1300
        data8 sys_tee
        data8 sys_vmsplice
        data8 sys_fallocate
        data8 sys_getcpu
        data8 sys_epoll_pwait                   // 1305
        data8 sys_utimensat
        data8 sys_signalfd
        data8 sys_ni_syscall
        data8 sys_eventfd
        data8 sys_timerfd_create                // 1310
        data8 sys_timerfd_settime
        data8 sys_timerfd_gettime
        data8 sys_signalfd4
        data8 sys_eventfd2
        data8 sys_epoll_create1                 // 1315
        data8 sys_dup3
        data8 sys_pipe2
        data8 sys_inotify_init1
        data8 sys_preadv
        data8 sys_pwritev                       // 1320
        data8 sys_rt_tgsigqueueinfo
        data8 sys_recvmmsg
        data8 sys_fanotify_init
        data8 sys_fanotify_mark
        data8 sys_prlimit64                     // 1325
        data8 sys_name_to_handle_at
        data8 sys_open_by_handle_at
        data8 sys_clock_adjtime
        data8 sys_syncfs
        data8 sys_setns                         // 1330
        data8 sys_sendmmsg
        data8 sys_process_vm_readv
        data8 sys_process_vm_writev
        data8 sys_accept4
        data8 sys_finit_module                  // 1335

        .org sys_call_table + 8*NR_syscalls     // guard against failures to increase NR_syscalls
#endif /* __IA64_ASM_PARAVIRTUALIZED_NATIVE */