/* SPDX-License-Identifier: GPL-2.0 * *  Copyright (C) 1999, 2000, 2002  Niibe Yutaka *  Copyright (C) 2003 - 2008  Paul Mundt */ ! NOTE:! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address! to be jumped is too far, but it causes illegal slot exception. /*	 * entry.S contains the system-call and fault low-level handling routines. * This also contains the timer-interrupt handler, as well as all interrupts * and faults that can result in a task-switch. * * NOTE: This code handles signal-recognition, which happens every time * after a timer-interrupt and after each system call. * * NOTE: This code uses a convention that instructions in the delay slot * of a transfer-control instruction are indented by an extra space, thus: * *    jmp	@k0	    ! control-transfer instruction *     ldc	k1, ssr     ! delay slot * * Stack layout in 'ret_from_syscall': * 	ptrace needs to have all regs on the stack. *	if the order here is changed, it needs to be *	updated in ptrace.c and ptrace.h * *	r0 *      ... *	r15 = stack pointer *	spc *	pr *	ssr *	gbr *	mach *	macl *	syscall # * */#include <asm/dwarf.h> #if defined(CONFIG_PREEMPTION)#  define preempt_stop()	cli ; TRACE_IRQS_OFF#else#  define preempt_stop()#  define resume_kernel		__restore_all#endif  	.align	2ENTRY(exception_error)	!	TRACE_IRQS_ON	sti	mov.l	1f, r0	jmp	@r0	 nop 	.align	21:	.long	do_exception_error 	.align	2ret_from_exception:	CFI_STARTPROC simple	CFI_DEF_CFA r14, 0	CFI_REL_OFFSET 17, 64	CFI_REL_OFFSET 15, 60	CFI_REL_OFFSET 14, 56	CFI_REL_OFFSET 13, 52	CFI_REL_OFFSET 12, 48	CFI_REL_OFFSET 11, 44	CFI_REL_OFFSET 10, 40	CFI_REL_OFFSET 9, 36	CFI_REL_OFFSET 8, 32	preempt_stop()ENTRY(ret_from_irq)	!	mov	#OFF_SR, r0	mov.l	@(r0,r15), r0	! get status register	shll	r0	shll	r0		! kernel space?	get_current_thread_info r8, r0	bt	resume_kernel	! Yes, it's from kernel, go back soon #ifdef CONFIG_PREEMPTION	bra	resume_userspace	 nopENTRY(resume_kernel)	cli	TRACE_IRQS_OFF	mov.l	@(TI_PRE_COUNT,r8), r0	! current_thread_info->preempt_count	tst	r0, r0	bf	noreschedneed_resched:	mov.l	@(TI_FLAGS,r8), r0	! current_thread_info->flags	tst	#_TIF_NEED_RESCHED, r0	! need_resched set?	bt	noresched 	mov	#OFF_SR, r0	mov.l	@(r0,r15), r0		! get status register	shlr	r0	and	#(0xf0>>1), r0		! interrupts off (exception path)?	cmp/eq	#(0xf0>>1), r0	bt	noresched	mov.l	1f, r0	jsr	@r0			! call preempt_schedule_irq	 nop	bra	need_resched	 nop noresched:	bra	__restore_all	 nop 	.align 21:	.long	preempt_schedule_irq#endif ENTRY(resume_userspace)	! r8: current_thread_info	cli	TRACE_IRQS_OFF	mov.l	@(TI_FLAGS,r8), r0		! current_thread_info->flags	tst	#(_TIF_WORK_MASK & 0xff), r0	bt/s	__restore_all	 tst	#_TIF_NEED_RESCHED, r0 	.align	2work_pending:	! r0: current_thread_info->flags	! r8: current_thread_info	! t:  result of "tst	#_TIF_NEED_RESCHED, r0"	bf/s	work_resched	 tst	#(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME), r0work_notifysig:	bt/s	__restore_all	 mov	r15, r4	mov	r12, r5		! set arg1(save_r0)	mov	r0, r6	sti	mov.l	2f, r1	mov.l	3f, r0	jmp	@r1	 lds	r0, prwork_resched:	mov.l	1f, r1	jsr	@r1				! schedule	 nop	cli	TRACE_IRQS_OFF	!	mov.l	@(TI_FLAGS,r8), r0		! current_thread_info->flags	tst	#(_TIF_WORK_MASK & 0xff), r0	bt	__restore_all	bra	work_pending	 tst	#_TIF_NEED_RESCHED, r0 	.align	21:	.long	schedule2:	.long	do_notify_resume3:	.long	resume_userspace 	.align	2syscall_exit_work:	! r0: current_thread_info->flags	! r8: current_thread_info	tst	#(_TIF_WORK_SYSCALL_MASK & 0xff), r0	bt/s	work_pending	 tst	#_TIF_NEED_RESCHED, r0	TRACE_IRQS_ON	sti	mov	r15, r4	mov.l	8f, r0			! do_syscall_trace_leave	jsr	@r0	 nop	bra	resume_userspace	 nop __restore_all:	mov	#OFF_SR, r0	mov.l	@(r0,r15), r0	! get status register 	shlr2	r0	and	#0x3c, r0	cmp/eq	#0x3c, r0	bt	1f	TRACE_IRQS_ON	bra	2f	 nop1:	TRACE_IRQS_OFF2:	mov.l	3f, r0	jmp	@r0	 nop 	.align	23:	.long	restore_all 	.align	2syscall_badsys:			! Bad syscall number	get_current_thread_info r8, r0	mov	#-ENOSYS, r0	bra	resume_userspace	 mov.l	r0, @(OFF_R0,r15)	! Return value /* * The main debug trap handler. * * r8=TRA (not the trap number!) * * Note: This assumes that the trapa value is left in its original * form (without the shlr2 shift) so the calculation for the jump * call table offset remains a simple in place mask. */debug_trap:	mov	r8, r0	and	#(0xf << 2), r0	mov.l	1f, r8	add	r0, r8	mov.l	@r8, r8	jsr	@r8	 nop	bra	ret_from_exception	 nop	CFI_ENDPROC 	.align	21:	.long	debug_trap_table /* * Syscall interface: * *	Syscall #: R3 *	Arguments #0 to #3: R4--R7 *	Arguments #4 to #6: R0, R1, R2 *	TRA: See following table. * * (TRA>>2)	Purpose * --------	------- * 0x00-0x0f	original SH-3/4 syscall ABI (not in general use). * 0x10-0x1f	general SH-3/4 syscall ABI. *      0x1f	unified SH-2/3/4 syscall ABI (preferred). * 0x20-0x2f	original SH-2 syscall ABI. * 0x30-0x3f	debug traps used by the kernel. * 0x40-0xff	Not supported by all parts, so left unhandled. * * For making system calls, any trap number in the range for the * given cpu model may be used, but the unified trap number 0x1f is * preferred for compatibility with all models. * * The low bits of the trap number were once documented as matching * the number of arguments, but they were never actually used as such * by the kernel. SH-2 originally used its own separate trap range * because several hardware exceptions fell in the range used for the * SH-3/4 syscall ABI. * * This code also handles delegating other traps to the BIOS/gdb stub. * * Note: When we're first called, the TRA value must be shifted * right 2 bits in order to get the value that was used as the "trapa" * argument. */ 	.align	2	.globl	ret_from_forkret_from_fork:	mov.l	1f, r8	jsr	@r8	 mov	r0, r4	bra	syscall_exit	 nop 	.align	2	.globl	ret_from_kernel_threadret_from_kernel_thread:	mov.l	1f, r8	jsr	@r8	 mov	r0, r4	mov.l	@(OFF_R5,r15), r5   ! fn	jsr	@r5	 mov.l	@(OFF_R4,r15), r4   ! arg	bra	syscall_exit	 nop 	.align	21:	.long	schedule_tail /* * The poorly named main trapa decode and dispatch routine, for * system calls and debug traps through their respective jump tables. */ENTRY(system_call)	setup_frame_reg#if !defined(CONFIG_CPU_SH2)	mov.l	1f, r9	mov.l	@r9, r8		! Read from TRA (Trap Address) Register#endif 	mov	#OFF_TRA, r10	add	r15, r10	mov.l	r8, @r10		! set TRA value to tra 	/*	 * Check the trap type	 */	mov	#((0x20 << 2) - 1), r9	cmp/hi	r9, r8	bt/s	debug_trap		! it's a debug trap..	 nop 	TRACE_IRQS_ON	sti 	!	get_current_thread_info r8, r10	mov.l	@(TI_FLAGS,r8), r8	mov	#(_TIF_WORK_SYSCALL_MASK & 0xff), r10	mov	#(_TIF_WORK_SYSCALL_MASK >> 8), r9	tst	r10, r8	shll8	r9	bf	syscall_trace_entry	tst	r9, r8	bf	syscall_trace_entry	!	mov.l	6f, r8			! Number of syscalls	cmp/hs	r8, r3	bt	syscall_badsys	!syscall_call:	shll2	r3		! x4	mov.l	3f, r8		! Load the address of sys_call_table	add	r8, r3	mov.l	@r3, r8	mov.l	@(OFF_R2,r15), r2	mov.l	@(OFF_R1,r15), r1	mov.l	@(OFF_R0,r15), r0	mov.l	r2, @-r15	mov.l	r1, @-r15	mov.l	r0, @-r15	jsr	@r8	    	! jump to specific syscall handler	 nop	add	#12, r15	mov.l	@(OFF_R0,r15), r12		! save r0	mov.l	r0, @(OFF_R0,r15)		! save the return value	!syscall_exit:	cli	TRACE_IRQS_OFF	!	get_current_thread_info r8, r0	mov.l	@(TI_FLAGS,r8), r0		! current_thread_info->flags	tst	#(_TIF_ALLWORK_MASK & 0xff), r0	mov	#(_TIF_ALLWORK_MASK >> 8), r1	bf	syscall_exit_work	shlr8	r0	tst	r0, r1	bf	syscall_exit_work	bra	__restore_all	 nop 	.align	2syscall_trace_entry:	!                     	Yes it is traced.	mov     r15, r4	mov.l	7f, r11		! Call do_syscall_trace_enter which notifies	jsr	@r11	    	! superior (will chomp R[0-7])	 nop	cmp/eq	#-1, r0	bt	syscall_exit	!			Reload R0-R4 from kernel stack, where the	!   	    	    	parent may have modified them using	!   	    	    	ptrace(POKEUSR).  (Note that R0-R2 are	!   	    	    	reloaded from the kernel stack by syscall_call	!   	    	    	below, so don't need to be reloaded here.)	!   	    	    	This allows the parent to rewrite system calls	!   	    	    	and args on the fly.	mov.l	@(OFF_R4,r15), r4   ! arg0	mov.l	@(OFF_R5,r15), r5	mov.l	@(OFF_R6,r15), r6	mov.l	@(OFF_R7,r15), r7   ! arg3	mov.l	@(OFF_R3,r15), r3   ! syscall_nr	!	mov.l	6f, r10			! Number of syscalls	cmp/hs	r10, r3	bf	syscall_call	mov	#-ENOSYS, r0	bra	syscall_exit	 mov.l	r0, @(OFF_R0,r15)	! Return value 	.align	2#if !defined(CONFIG_CPU_SH2)1:	.long	TRA#endif6:	.long	NR_syscalls3:	.long	sys_call_table7:	.long	do_syscall_trace_enter8:	.long	do_syscall_trace_leave