1 /* $Id: entry.S,v 1.37 2004/06/11 13:02:46 doyu Exp $
3 * linux/arch/sh/entry.S
5 * Copyright (C) 1999, 2000, 2002 Niibe Yutaka
6 * Copyright (C) 2003 Paul Mundt
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
15 ! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
16 ! to be jumped is too far, but it causes illegal slot exception.
19 * entry.S contains the system-call and fault low-level handling routines.
20 * This also contains the timer-interrupt handler, as well as all interrupts
21 * and faults that can result in a task-switch.
23 * NOTE: This code handles signal-recognition, which happens every time
24 * after a timer-interrupt and after each system call.
26 * NOTE: This code uses a convention that instructions in the delay slot
27 * of a transfer-control instruction are indented by an extra space, thus:
29 * jmp @k0 ! control-transfer instruction
30 * ldc k1, ssr ! delay slot
32 * Stack layout in 'ret_from_syscall':
33 * ptrace needs to have all regs on the stack.
34 * if the order here is changed, it needs to be
35 * updated in ptrace.c and ptrace.h
50 #if defined(CONFIG_PREEMPT)
51 # define preempt_stop() cli
53 # define preempt_stop()
54 # define resume_kernel __restore_all
57 #if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
58 ! Handle kernel debug if either kgdb (SW) or gdb-stub (FW) is present.
59 ! If both are configured, handle the debug traps (breakpoints) in SW,
60 ! but still allow BIOS traps to FW.
64 #if defined(CONFIG_SH_STANDARD_BIOS) && defined(CONFIG_SH_KGDB)
65 /* Force BIOS call to FW (debug_trap put TRA in r8) */
70 #endif /* CONFIG_SH_STANDARD_BIOS && CONFIG_SH_KGDB */
73 #if defined(CONFIG_SH_KGDB)
74 /* Jump to kgdb, pass stacked regs as arg */
80 3: .long kgdb_handle_exception
81 #endif /* CONFIG_SH_KGDB */
82 #ifdef CONFIG_SH_STANDARD_BIOS
86 #endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */
90 #if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
93 cmp/eq #0x3f, r0 ! sh_bios() trap
96 cmp/eq #0xff, r0 ! XXX: KGDB trap, fix for SH-2.
100 mov.l @(r0,r15), r0 ! get status register
102 shll r0 ! kernel space?
106 mov.l @r15, r0 ! Restore R0 value
112 ENTRY(exception_error)
114 #ifdef CONFIG_TRACE_IRQFLAGS
126 1: .long break_point_trap_software
127 2: .long do_exception_error
128 #ifdef CONFIG_TRACE_IRQFLAGS
129 3: .long trace_hardirqs_on
135 #ifdef CONFIG_TRACE_IRQFLAGS
143 mov.l @(r0,r15), r0 ! get status register
145 shll r0 ! kernel space?
146 get_current_thread_info r8, r0
147 bt resume_kernel ! Yes, it's from kernel, go back soon
149 #ifdef CONFIG_PREEMPT
153 mov.l @(TI_PRE_COUNT,r8), r0 ! current_thread_info->preempt_count
157 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
158 tst #_TIF_NEED_RESCHED, r0 ! need_resched set?
162 mov.l @(r0,r15), r0 ! get status register
163 and #0xf0, r0 ! interrupts off (exception path)?
168 mov.l r0, @(TI_PRE_COUNT,r8)
170 #ifdef CONFIG_TRACE_IRQFLAGS
180 mov.l r0, @(TI_PRE_COUNT,r8)
182 #ifdef CONFIG_TRACE_IRQFLAGS
196 1: .long PREEMPT_ACTIVE
198 #ifdef CONFIG_TRACE_IRQFLAGS
199 3: .long trace_hardirqs_on
200 4: .long trace_hardirqs_off
204 ENTRY(resume_userspace)
205 ! r8: current_thread_info
207 #ifdef CONFIG_TRACE_IRQFLAGS
212 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
213 tst #_TIF_WORK_MASK, r0
215 tst #_TIF_NEED_RESCHED, r0
219 ! r0: current_thread_info->flags
220 ! r8: current_thread_info
221 ! t: result of "tst #_TIF_NEED_RESCHED, r0"
223 tst #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0
227 mov r12, r5 ! set arg1(save_r0)
234 #ifndef CONFIG_PREEMPT
236 mov.l @(OFF_SP,r15), r0 ! get user space stack pointer
243 ! SP >= 0xc0000000 : gUSA mark
244 mov.l @(r0,r15), r2 ! get user space PC (program counter)
245 mov.l @(OFF_R0,r15), r3 ! end point
246 cmp/hs r3, r2 ! r2 >= r3?
248 add r3, r1 ! rewind point #2
249 mov.l r1, @(r0,r15) ! reset PC to rewind point #2
257 #ifdef CONFIG_TRACE_IRQFLAGS
263 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
264 tst #_TIF_WORK_MASK, r0
267 tst #_TIF_NEED_RESCHED, r0
271 2: .long do_notify_resume
273 #ifdef CONFIG_TRACE_IRQFLAGS
274 4: .long trace_hardirqs_on
275 5: .long trace_hardirqs_off
280 ! r0: current_thread_info->flags
281 ! r8: current_thread_info
282 tst #_TIF_SYSCALL_TRACE, r0
284 tst #_TIF_NEED_RESCHED, r0
285 #ifdef CONFIG_TRACE_IRQFLAGS
291 ! XXX setup arguments...
292 mov.l 4f, r0 ! do_syscall_trace
301 ! XXX setup arguments...
302 mov.l 4f, r11 ! Call do_syscall_trace which notifies
303 jsr @r11 ! superior (will chomp R[0-7])
305 ! Reload R0-R4 from kernel stack, where the
306 ! parent may have modified them using
307 ! ptrace(POKEUSR). (Note that R0-R2 are
308 ! used by the system call handler directly
309 ! from the kernel stack anyway, so don't need
310 ! to be reloaded here.) This allows the parent
311 ! to rewrite system calls and args on the fly.
312 mov.l @(OFF_R4,r15), r4 ! arg0
313 mov.l @(OFF_R5,r15), r5
314 mov.l @(OFF_R6,r15), r6
315 mov.l @(OFF_R7,r15), r7 ! arg3
316 mov.l @(OFF_R3,r15), r3 ! syscall_nr
318 mov.l 2f, r10 ! Number of syscalls
323 mov.l r0, @(OFF_R0,r15) ! Return value
339 syscall_badsys: ! Bad syscall number
342 mov.l r0, @(OFF_R0,r15) ! Return value
349 * Arguments #0 to #3: R4--R7
350 * Arguments #4 to #6: R0, R1, R2
351 * TRA: (number of arguments + 0x10) x 4
353 * This code also handles delegating other traps to the BIOS/gdb stub
359 * 0x0-0xf old syscall ABI
360 * 0x10-0x1f new syscall ABI
361 * 0x20-0xff delegated through debug_trap to BIOS/gdb stub.
363 * Note: When we're first called, the TRA value must be shifted
364 * right 2 bits in order to get the value that was used as the "trapa"
377 1: .long schedule_tail
380 #if !defined(CONFIG_CPU_SH2)
382 mov.l @r9, r8 ! Read from TRA (Trap Address) Register
385 ! Is the trap argument >= 0x20? (TRA will be >= 0x80)
391 mov.l r8, @r9 ! set TRA value to tra
392 #ifdef CONFIG_TRACE_IRQFLAGS
400 get_current_thread_info r8, r10
401 mov.l @(TI_FLAGS,r8), r8
402 mov #_TIF_SYSCALL_TRACE, r10
404 bf syscall_trace_entry
406 mov.l 2f, r8 ! Number of syscalls
412 mov.l 3f, r8 ! Load the address of sys_call_table
415 jsr @r8 ! jump to specific syscall handler
417 mov.l @(OFF_R0,r15), r12 ! save r0
418 mov.l r0, @(OFF_R0,r15) ! save the return value
422 #ifdef CONFIG_TRACE_IRQFLAGS
428 get_current_thread_info r8, r0
429 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
430 tst #_TIF_ALLWORK_MASK, r0
435 #if !defined(CONFIG_CPU_SH2)
439 3: .long sys_call_table
440 4: .long do_syscall_trace
441 #ifdef CONFIG_TRACE_IRQFLAGS
442 5: .long trace_hardirqs_on
443 6: .long trace_hardirqs_off