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 */
83 #endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */
88 #if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
90 mov.l @(r0,r15), r0 ! get status register
92 shll r0 ! kernel space?
95 mov.l @r15, r0 ! Restore R0 value
101 ENTRY(exception_error)
103 #ifdef CONFIG_TRACE_IRQFLAGS
115 1: .long break_point_trap_software
116 2: .long do_exception_error
117 #ifdef CONFIG_TRACE_IRQFLAGS
118 3: .long trace_hardirqs_on
124 #ifdef CONFIG_TRACE_IRQFLAGS
132 mov.l @(r0,r15), r0 ! get status register
134 shll r0 ! kernel space?
135 get_current_thread_info r8, r0
136 bt resume_kernel ! Yes, it's from kernel, go back soon
138 #ifdef CONFIG_PREEMPT
142 mov.l @(TI_PRE_COUNT,r8), r0 ! current_thread_info->preempt_count
146 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
147 tst #_TIF_NEED_RESCHED, r0 ! need_resched set?
151 mov.l @(r0,r15), r0 ! get status register
152 and #0xf0, r0 ! interrupts off (exception path)?
157 mov.l r0, @(TI_PRE_COUNT,r8)
159 #ifdef CONFIG_TRACE_IRQFLAGS
169 mov.l r0, @(TI_PRE_COUNT,r8)
171 #ifdef CONFIG_TRACE_IRQFLAGS
185 1: .long PREEMPT_ACTIVE
187 #ifdef CONFIG_TRACE_IRQFLAGS
188 3: .long trace_hardirqs_on
189 4: .long trace_hardirqs_off
193 ENTRY(resume_userspace)
194 ! r8: current_thread_info
196 #ifdef CONFIG_TRACE_IRQFLAGS
201 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
202 tst #_TIF_WORK_MASK, r0
204 tst #_TIF_NEED_RESCHED, r0
208 ! r0: current_thread_info->flags
209 ! r8: current_thread_info
210 ! t: result of "tst #_TIF_NEED_RESCHED, r0"
212 tst #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0
216 mov r12, r5 ! set arg1(save_r0)
223 #ifndef CONFIG_PREEMPT
225 mov.l @(OFF_SP,r15), r0 ! get user space stack pointer
232 ! SP >= 0xc0000000 : gUSA mark
233 mov.l @(r0,r15), r2 ! get user space PC (program counter)
234 mov.l @(OFF_R0,r15), r3 ! end point
235 cmp/hs r3, r2 ! r2 >= r3?
237 add r3, r1 ! rewind point #2
238 mov.l r1, @(r0,r15) ! reset PC to rewind point #2
246 #ifdef CONFIG_TRACE_IRQFLAGS
252 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
253 tst #_TIF_WORK_MASK, r0
256 tst #_TIF_NEED_RESCHED, r0
260 2: .long do_notify_resume
262 #ifdef CONFIG_TRACE_IRQFLAGS
263 4: .long trace_hardirqs_on
264 5: .long trace_hardirqs_off
269 ! r0: current_thread_info->flags
270 ! r8: current_thread_info
271 tst #_TIF_SYSCALL_TRACE, r0
273 tst #_TIF_NEED_RESCHED, r0
274 #ifdef CONFIG_TRACE_IRQFLAGS
280 ! XXX setup arguments...
281 mov.l 4f, r0 ! do_syscall_trace
290 ! XXX setup arguments...
291 mov.l 4f, r11 ! Call do_syscall_trace which notifies
292 jsr @r11 ! superior (will chomp R[0-7])
294 ! Reload R0-R4 from kernel stack, where the
295 ! parent may have modified them using
296 ! ptrace(POKEUSR). (Note that R0-R2 are
297 ! used by the system call handler directly
298 ! from the kernel stack anyway, so don't need
299 ! to be reloaded here.) This allows the parent
300 ! to rewrite system calls and args on the fly.
301 mov.l @(OFF_R4,r15), r4 ! arg0
302 mov.l @(OFF_R5,r15), r5
303 mov.l @(OFF_R6,r15), r6
304 mov.l @(OFF_R7,r15), r7 ! arg3
305 mov.l @(OFF_R3,r15), r3 ! syscall_nr
307 mov.l 2f, r10 ! Number of syscalls
312 mov.l r0, @(OFF_R0,r15) ! Return value
328 syscall_badsys: ! Bad syscall number
331 mov.l r0, @(OFF_R0,r15) ! Return value
338 * Arguments #0 to #3: R4--R7
339 * Arguments #4 to #6: R0, R1, R2
340 * TRA: (number of arguments + 0x10) x 4
342 * This code also handles delegating other traps to the BIOS/gdb stub
348 * 0x0-0xf old syscall ABI
349 * 0x10-0x1f new syscall ABI
350 * 0x20-0xff delegated through debug_trap to BIOS/gdb stub.
352 * Note: When we're first called, the TRA value must be shifted
353 * right 2 bits in order to get the value that was used as the "trapa"
366 1: .long schedule_tail
369 #if !defined(CONFIG_CPU_SH2)
371 mov.l @r9, r8 ! Read from TRA (Trap Address) Register
374 ! Is the trap argument >= 0x20? (TRA will be >= 0x80)
380 mov.l r8, @r9 ! set TRA value to tra
381 #ifdef CONFIG_TRACE_IRQFLAGS
389 get_current_thread_info r8, r10
390 mov.l @(TI_FLAGS,r8), r8
391 mov #_TIF_SYSCALL_TRACE, r10
393 bf syscall_trace_entry
395 mov.l 2f, r8 ! Number of syscalls
401 mov.l 3f, r8 ! Load the address of sys_call_table
404 jsr @r8 ! jump to specific syscall handler
406 mov.l @(OFF_R0,r15), r12 ! save r0
407 mov.l r0, @(OFF_R0,r15) ! save the return value
411 #ifdef CONFIG_TRACE_IRQFLAGS
417 get_current_thread_info r8, r0
418 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
419 tst #_TIF_ALLWORK_MASK, r0
424 #if !defined(CONFIG_CPU_SH2)
428 3: .long sys_call_table
429 4: .long do_syscall_trace
430 #ifdef CONFIG_TRACE_IRQFLAGS
431 5: .long trace_hardirqs_on
432 6: .long trace_hardirqs_off