entry.s

LINUX 2.6.17.4的源码

 * this allows them to save the stack-pointer and use that register to do an
 * indirect jump).
 */
G_ENTRY(nmi):
	SAVE_STATE (NMI, r0, NMI_ENTRY_SP); /* Save registers.  */

	stsr	SR_ECR, r6;		/* Find out which nmi it was.  */
	shr	20, r6;			/* Extract NMI code in bits 20-24. */
	movea	PTO, sp, r7;		/* User regs are arg2.  */

	/* Non-maskable interrupts always lie right after maskable interrupts.
	   Call the generic IRQ handler, with two arguments, the IRQ number,
	   and a pointer to the user registers, to handle the specifics.
	   (we subtract one because the first NMI has code 1).  */
	addi	FIRST_NMI - 1, r6, r6
	jarl	CSYM(handle_irq), lp

	RETURN(NMI)
END(nmi)


/*
 * Trap with no handler
 */
L_ENTRY(bad_trap_wrapper):
	mov	r19, r6			// Arg 0: trap number
	movea	PTO, sp, r7		// Arg 1: user regs
	jr	CSYM(bad_trap)		// tail call handler
END(bad_trap_wrapper)


/*
 * Invoke the scheduler, called from the trap/irq kernel exit path.
 *
 * This basically just calls `schedule', but also arranges for extra
 * registers to be saved for ptrace'd processes, so ptrace can modify them.
 */
L_ENTRY(call_scheduler):
	ld.w	TASK_PTRACE[CURRENT_TASK], r19	// See if task is ptrace'd
	cmp	r19, r0
	bnz	1f			// ... yes, do special stuff
	jr	CSYM(schedule)		// ... no, just tail-call scheduler

	// Save extra regs for ptrace'd task.  We want to save anything
	// that would otherwise only be `implicitly' saved by the normal
	// compiler calling-convention.
1:	mov	sp, ep			// Setup EP for SAVE_CALL_SAVED_REGS
	SAVE_CALL_SAVED_REGS		// Save call-saved registers to stack
	mov	lp, r20			// Save LP in a callee-saved register

	jarl	CSYM(schedule), lp	// Call scheduler

	mov	r20, lp
	mov	sp, ep			// We can't rely on EP after return
	RESTORE_CALL_SAVED_REGS		// Restore (possibly modified) regs
	jmp	[lp]			// Return to the return path
END(call_scheduler)


/*
 * This is an out-of-line handler for two special cases during the kernel
 * trap/irq exit sequence:
 *
 *  (1) If r18 is non-zero then a signal needs to be handled, which is
 *	done, and then the caller returned to.
 *
 *  (2) If r18 is non-zero then we're returning to a ptraced process, which
 *	has several special cases -- single-stepping and trap tracing, both
 *	of which require using the `dbret' instruction to exit the kernel
 *	instead of the normal `reti' (this is because the CPU not correctly
 *	single-step after a reti).  In this case, of course, this handler
 *	never returns to the caller.
 *
 * In either case, all registers should have been saved to the current
 * state-save-frame on the stack, except for callee-saved registers.
 *
 * [These two different cases are combined merely to avoid bloating the
 * macro-inlined code, not because they really make much sense together!]
 */
L_ENTRY(handle_signal_or_ptrace_return):
	cmp	r18, r0			// See if handling a signal
	bz	1f			// ... nope, go do ptrace return

	// Handle a signal
	mov	lp, r20			// Save link-pointer
	mov	r10, r21		// Save return-values (for trap)
	mov	r11, r22

	movea	PTO, sp, r6		// Arg 1: struct pt_regs *regs
	mov	r0, r7			// Arg 2: sigset_t *oldset
	jarl	CSYM(do_signal), lp	// Handle the signal
	di				// sig handling enables interrupts

	mov	r20, lp			// Restore link-pointer
	mov	r21, r10		// Restore return-values (for trap)
	mov	r22, r11
	ld.w	TASK_PTRACE[CURRENT_TASK], r19  // check ptrace flags too
	cmp	r19, r0
	bnz	1f			// ... some set, so look more
2:	jmp	[lp]			// ... none set, so return normally

	// ptrace return
1:	ld.w	PTO+PT_PSW[sp], r19	// Look at user-processes's flags
	andi	0x0800, r19, r19	// See if single-step flag is set
	bz	2b			// ... nope, return normally

	// Return as if from a dbtrap insn
	st.b	r0, KM			// Now officially in user state.
	POP_STATE(DBTRAP)		// Restore regs
	st.w	sp, KSP			// Save the kernel stack pointer.
	ld.w	PT_GPR(GPR_SP)-PT_SIZE[sp], sp // Restore user stack pointer.
	DBTRAP_RET			// Return from the trap/interrupt.
END(handle_signal_or_ptrace_return)


/*
 * This is where we switch between two threads.  The arguments are:
 *   r6 -- pointer to the struct thread for the `current' process
 *   r7 -- pointer to the struct thread for the `new' process.
 * when this function returns, it will return to the new thread.
 */
C_ENTRY(switch_thread):
	// Return the previous task (r10 is not clobbered by restore below)
	mov	CURRENT_TASK, r10
	// First, push the current processor state on the stack
	PUSH_STATE(SWITCH)
	// Now save the location of the kernel stack pointer for this thread;
	// since we've pushed all other state on the stack, this is enough to
	// restore it all later.
	st.w	sp, THREAD_KSP[r6]
	// Now restore the stack pointer from the new process
	ld.w	THREAD_KSP[r7], sp
	// ... and restore all state from that
	POP_STATE(SWITCH)
	// Update the current task pointer
	GET_CURRENT_TASK(CURRENT_TASK)
	// Now return into the new thread
	jmp	[lp]
C_END(switch_thread)


	.data

	.align 4
C_DATA(trap_table):
	.long bad_trap_wrapper		// trap 0, doesn't use trap table.
	.long syscall_long		// trap 1, `long' syscall.
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
	.long bad_trap_wrapper
C_END(trap_table)


	.section .rodata

	.align 4
C_DATA(sys_call_table):
	.long CSYM(sys_restart_syscall)	// 0
	.long CSYM(sys_exit)
	.long sys_fork_wrapper
	.long CSYM(sys_read)
	.long CSYM(sys_write)
	.long CSYM(sys_open)		// 5
	.long CSYM(sys_close)
	.long CSYM(sys_waitpid)
	.long CSYM(sys_creat)
	.long CSYM(sys_link)
	.long CSYM(sys_unlink)		// 10
	.long sys_execve_wrapper
	.long CSYM(sys_chdir)
	.long CSYM(sys_time)
	.long CSYM(sys_mknod)
	.long CSYM(sys_chmod)		// 15
	.long CSYM(sys_chown)
	.long CSYM(sys_ni_syscall)	// was: break
	.long CSYM(sys_ni_syscall)	// was: oldstat (aka stat)
	.long CSYM(sys_lseek)
	.long CSYM(sys_getpid)		// 20
	.long CSYM(sys_mount)
	.long CSYM(sys_oldumount)
	.long CSYM(sys_setuid)
	.long CSYM(sys_getuid)
	.long CSYM(sys_stime)		// 25
	.long CSYM(sys_ptrace)
	.long CSYM(sys_alarm)
	.long CSYM(sys_ni_syscall)	// was: oldfstat (aka fstat)
	.long CSYM(sys_pause)
	.long CSYM(sys_utime)		// 30
	.long CSYM(sys_ni_syscall)	// was: stty
	.long CSYM(sys_ni_syscall)	// was: gtty
	.long CSYM(sys_access)
	.long CSYM(sys_nice)
	.long CSYM(sys_ni_syscall)	// 35, was: ftime
	.long CSYM(sys_sync)
	.long CSYM(sys_kill)
	.long CSYM(sys_rename)
	.long CSYM(sys_mkdir)
	.long CSYM(sys_rmdir)		// 40
	.long CSYM(sys_dup)
	.long CSYM(sys_pipe)
	.long CSYM(sys_times)
	.long CSYM(sys_ni_syscall)	// was: prof
	.long CSYM(sys_brk)		// 45
	.long CSYM(sys_setgid)
	.long CSYM(sys_getgid)
	.long CSYM(sys_signal)
	.long CSYM(sys_geteuid)
	.long CSYM(sys_getegid)		// 50
	.long CSYM(sys_acct)
	.long CSYM(sys_umount)		// recycled never used phys()
	.long CSYM(sys_ni_syscall)	// was: lock
	.long CSYM(sys_ioctl)
	.long CSYM(sys_fcntl)		// 55
	.long CSYM(sys_ni_syscall)	// was: mpx
	.long CSYM(sys_setpgid)
	.long CSYM(sys_ni_syscall)	// was: ulimit
	.long CSYM(sys_ni_syscall)
	.long CSYM(sys_umask)		// 60
	.long CSYM(sys_chroot)
	.long CSYM(sys_ustat)
	.long CSYM(sys_dup2)
	.long CSYM(sys_getppid)
	.long CSYM(sys_getpgrp)		// 65
	.long CSYM(sys_setsid)
	.long CSYM(sys_sigaction)
	.long CSYM(sys_sgetmask)
	.long CSYM(sys_ssetmask)
	.long CSYM(sys_setreuid)	// 70
	.long CSYM(sys_setregid)
	.long sys_sigsuspend_wrapper
	.long CSYM(sys_sigpending)
	.long CSYM(sys_sethostname)
	.long CSYM(sys_setrlimit)	// 75
	.long CSYM(sys_getrlimit)
	.long CSYM(sys_getrusage)
	.long CSYM(sys_gettimeofday)
	.long CSYM(sys_settimeofday)
	.long CSYM(sys_getgroups)	// 80
	.long CSYM(sys_setgroups)
	.long CSYM(sys_select)
	.long CSYM(sys_symlink)
	.long CSYM(sys_ni_syscall)	// was: oldlstat (aka lstat)
	.long CSYM(sys_readlink)	// 85
	.long CSYM(sys_uselib)
	.long CSYM(sys_swapon)
	.long CSYM(sys_reboot)
	.long CSYM(old_readdir)
	.long CSYM(sys_mmap)		// 90
	.long CSYM(sys_munmap)
	.long CSYM(sys_truncate)
	.long CSYM(sys_ftruncate)
	.long CSYM(sys_fchmod)
	.long CSYM(sys_fchown)		// 95
	.long CSYM(sys_getpriority)
	.long CSYM(sys_setpriority)
	.long CSYM(sys_ni_syscall)	// was: profil
	.long CSYM(sys_statfs)
	.long CSYM(sys_fstatfs)		// 100
	.long CSYM(sys_ni_syscall)	// i386: ioperm
	.long CSYM(sys_socketcall)
	.long CSYM(sys_syslog)
	.long CSYM(sys_setitimer)
	.long CSYM(sys_getitimer)	// 105
	.long CSYM(sys_newstat)
	.long CSYM(sys_newlstat)
	.long CSYM(sys_newfstat)
	.long CSYM(sys_ni_syscall)	// was: olduname (aka uname)
	.long CSYM(sys_ni_syscall)	// 110, i386: iopl
	.long CSYM(sys_vhangup)
	.long CSYM(sys_ni_syscall)	// was: idle
	.long CSYM(sys_ni_syscall)	// i386: vm86old
	.long CSYM(sys_wait4)
	.long CSYM(sys_swapoff)		// 115
	.long CSYM(sys_sysinfo)
	.long CSYM(sys_ipc)
	.long CSYM(sys_fsync)
	.long sys_sigreturn_wrapper
	.long sys_clone_wrapper		// 120
	.long CSYM(sys_setdomainname)
	.long CSYM(sys_newuname)
	.long CSYM(sys_ni_syscall)	// i386: modify_ldt, m68k: cacheflush
	.long CSYM(sys_adjtimex)
	.long CSYM(sys_ni_syscall)	// 125 - sys_mprotect
	.long CSYM(sys_sigprocmask)
	.long CSYM(sys_ni_syscall)	// sys_create_module
	.long CSYM(sys_init_module)
	.long CSYM(sys_delete_module)
	.long CSYM(sys_ni_syscall)	// 130 - sys_get_kernel_syms
	.long CSYM(sys_quotactl)
	.long CSYM(sys_getpgid)
	.long CSYM(sys_fchdir)
	.long CSYM(sys_bdflush)
	.long CSYM(sys_sysfs)		// 135
	.long CSYM(sys_personality)
	.long CSYM(sys_ni_syscall)	// for afs_syscall
	.long CSYM(sys_setfsuid)
	.long CSYM(sys_setfsgid)
	.long CSYM(sys_llseek)		// 140
	.long CSYM(sys_getdents)
	.long CSYM(sys_select)		// for backward compat; remove someday
	.long CSYM(sys_flock)
	.long CSYM(sys_ni_syscall)	// sys_msync
	.long CSYM(sys_readv)		// 145
	.long CSYM(sys_writev)
	.long CSYM(sys_getsid)
	.long CSYM(sys_fdatasync)
	.long CSYM(sys_sysctl)
	.long CSYM(sys_ni_syscall)	// 150 - sys_mlock
	.long CSYM(sys_ni_syscall)	// sys_munlock
	.long CSYM(sys_ni_syscall)	// sys_mlockall
	.long CSYM(sys_ni_syscall)	// sys_munlockall
	.long CSYM(sys_sched_setparam)
	.long CSYM(sys_sched_getparam)	// 155
	.long CSYM(sys_sched_setscheduler)
	.long CSYM(sys_sched_getscheduler)
	.long CSYM(sys_sched_yield)
	.long CSYM(sys_sched_get_priority_max)
	.long CSYM(sys_sched_get_priority_min)	// 160
	.long CSYM(sys_sched_rr_get_interval)
	.long CSYM(sys_nanosleep)
	.long CSYM(sys_ni_syscall)	// sys_mremap
	.long CSYM(sys_setresuid)
	.long CSYM(sys_getresuid)	// 165
	.long CSYM(sys_ni_syscall)	// for vm86
	.long CSYM(sys_ni_syscall)	// sys_query_module
	.long CSYM(sys_poll)
	.long CSYM(sys_nfsservctl)
	.long CSYM(sys_setresgid)	// 170
	.long CSYM(sys_getresgid)
	.long CSYM(sys_prctl)
	.long sys_rt_sigreturn_wrapper
	.long CSYM(sys_rt_sigaction)
	.long CSYM(sys_rt_sigprocmask)	// 175
	.long CSYM(sys_rt_sigpending)
	.long CSYM(sys_rt_sigtimedwait)
	.long CSYM(sys_rt_sigqueueinfo)
	.long sys_rt_sigsuspend_wrapper
	.long CSYM(sys_pread64)		// 180
	.long CSYM(sys_pwrite64)
	.long CSYM(sys_lchown)
	.long CSYM(sys_getcwd)
	.long CSYM(sys_capget)
	.long CSYM(sys_capset)		// 185
	.long CSYM(sys_sigaltstack)
	.long CSYM(sys_sendfile)
	.long CSYM(sys_ni_syscall)	// streams1
	.long CSYM(sys_ni_syscall)	// streams2
	.long sys_vfork_wrapper		// 190
	.long CSYM(sys_ni_syscall)
	.long CSYM(sys_mmap2)
	.long CSYM(sys_truncate64)
	.long CSYM(sys_ftruncate64)
	.long CSYM(sys_stat64)		// 195
	.long CSYM(sys_lstat64)
	.long CSYM(sys_fstat64)
	.long CSYM(sys_fcntl64)
	.long CSYM(sys_getdents64)
	.long CSYM(sys_pivot_root)	// 200
	.long CSYM(sys_gettid)
	.long CSYM(sys_tkill)
sys_call_table_end:
C_END(sys_call_table)