entry.s

linux 内核源代码

(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 cr.ipsr=r29		// M2
	mov ar.pfs=r26		// I0
(pLvSys)mov r17=r0		// A  clear r17 for leave_syscall, no-op otherwise

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

	mov ar.fpsr=r20		// M2
	mov cr.iip=r28		// 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
	 */
.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		// current_thread_info()->need_resched==0?
(p6)	br.cond.sptk.few .notify
#ifdef CONFIG_PREEMPT
(pKStk) dep r21=-1,r0,PREEMPT_ACTIVE_BIT,1
	;;
(pKStk) st4 [r20]=r21
	ssm psr.i		// enable interrupts
#endif
	br.call.spnt.many rp=schedule
.ret9:	cmp.eq p6,p0=r0,r0				// p6 <- 1
	rsm psr.i		// 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  .work_pending_syscall_end
	br.cond.sptk.many .work_processed_kernel	// re-check

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

.work_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 .work_processed_syscall	// re-check

END(ia64_leave_kernel)

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().  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.
	 */
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_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)

	.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_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_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
	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_timerfd
	data8 sys_eventfd

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