2 * Copyright (C) 1999, 2000, 2002 Niibe Yutaka
3 * Copyright (C) 2003 - 2008 Paul Mundt
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License. See the file "COPYING" in the main directory of this archive
12 ! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
13 ! to be jumped is too far, but it causes illegal slot exception.
16 * entry.S contains the system-call and fault low-level handling routines.
17 * This also contains the timer-interrupt handler, as well as all interrupts
18 * and faults that can result in a task-switch.
20 * NOTE: This code handles signal-recognition, which happens every time
21 * after a timer-interrupt and after each system call.
23 * NOTE: This code uses a convention that instructions in the delay slot
24 * of a transfer-control instruction are indented by an extra space, thus:
26 * jmp @k0 ! control-transfer instruction
27 * ldc k1, ssr ! delay slot
29 * Stack layout in 'ret_from_syscall':
30 * ptrace needs to have all regs on the stack.
31 * if the order here is changed, it needs to be
32 * updated in ptrace.c and ptrace.h
47 #if defined(CONFIG_PREEMPT)
48 # define preempt_stop() cli
50 # define preempt_stop()
51 # define resume_kernel __restore_all
56 ENTRY(exception_error)
58 #ifdef CONFIG_TRACE_IRQFLAGS
69 1: .long do_exception_error
70 #ifdef CONFIG_TRACE_IRQFLAGS
71 2: .long trace_hardirqs_on
77 #ifdef CONFIG_TRACE_IRQFLAGS
85 mov.l @(r0,r15), r0 ! get status register
87 shll r0 ! kernel space?
88 get_current_thread_info r8, r0
89 bt resume_kernel ! Yes, it's from kernel, go back soon
96 mov.l @(TI_PRE_COUNT,r8), r0 ! current_thread_info->preempt_count
100 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
101 tst #_TIF_NEED_RESCHED, r0 ! need_resched set?
105 mov.l @(r0,r15), r0 ! get status register
106 and #0xf0, r0 ! interrupts off (exception path)?
110 jsr @r0 ! call preempt_schedule_irq
120 1: .long PREEMPT_ACTIVE
122 3: .long preempt_schedule_irq
125 ENTRY(resume_userspace)
126 ! r8: current_thread_info
128 #ifdef CONFIG_TRACE_IRQFLAGS
133 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
134 tst #_TIF_WORK_MASK, r0
136 tst #_TIF_NEED_RESCHED, r0
140 ! r0: current_thread_info->flags
141 ! r8: current_thread_info
142 ! t: result of "tst #_TIF_NEED_RESCHED, r0"
144 tst #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0
148 mov r12, r5 ! set arg1(save_r0)
159 #ifdef CONFIG_TRACE_IRQFLAGS
165 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
166 tst #_TIF_WORK_MASK, r0
169 tst #_TIF_NEED_RESCHED, r0
173 2: .long do_notify_resume
174 3: .long resume_userspace
175 #ifdef CONFIG_TRACE_IRQFLAGS
176 4: .long trace_hardirqs_on
177 5: .long trace_hardirqs_off
182 ! r0: current_thread_info->flags
183 ! r8: current_thread_info
184 tst #_TIF_WORK_SYSCALL_MASK, r0
186 tst #_TIF_NEED_RESCHED, r0
187 #ifdef CONFIG_TRACE_IRQFLAGS
194 mov.l 8f, r0 ! do_syscall_trace_leave
204 mov.l 7f, r11 ! Call do_syscall_trace_enter which notifies
205 jsr @r11 ! superior (will chomp R[0-7])
207 mov.l r0, @(OFF_R0,r15) ! Save return value
208 ! Reload R0-R4 from kernel stack, where the
209 ! parent may have modified them using
210 ! ptrace(POKEUSR). (Note that R0-R2 are
211 ! used by the system call handler directly
212 ! from the kernel stack anyway, so don't need
213 ! to be reloaded here.) This allows the parent
214 ! to rewrite system calls and args on the fly.
215 mov.l @(OFF_R4,r15), r4 ! arg0
216 mov.l @(OFF_R5,r15), r5
217 mov.l @(OFF_R6,r15), r6
218 mov.l @(OFF_R7,r15), r7 ! arg3
219 mov.l @(OFF_R3,r15), r3 ! syscall_nr
221 mov.l 2f, r10 ! Number of syscalls
226 mov.l r0, @(OFF_R0,r15) ! Return value
237 syscall_badsys: ! Bad syscall number
238 get_current_thread_info r8, r0
241 mov.l r0, @(OFF_R0,r15) ! Return value
244 * The main debug trap handler.
246 * r8=TRA (not the trap number!)
248 * Note: This assumes that the trapa value is left in its original
249 * form (without the shlr2 shift) so the calculation for the jump
250 * call table offset remains a simple in place mask.
264 1: .long debug_trap_table
270 * Arguments #0 to #3: R4--R7
271 * Arguments #4 to #6: R0, R1, R2
272 * TRA: (number of arguments + ABI revision) x 4
274 * This code also handles delegating other traps to the BIOS/gdb stub
280 * 0x00-0x0f original SH-3/4 syscall ABI (not in general use).
281 * 0x10-0x1f general SH-3/4 syscall ABI.
282 * 0x20-0x2f syscall ABI for SH-2 parts.
283 * 0x30-0x3f debug traps used by the kernel.
284 * 0x40-0xff Not supported by all parts, so left unhandled.
286 * Note: When we're first called, the TRA value must be shifted
287 * right 2 bits in order to get the value that was used as the "trapa"
300 1: .long schedule_tail
303 * The poorly named main trapa decode and dispatch routine, for
304 * system calls and debug traps through their respective jump tables.
307 #if !defined(CONFIG_CPU_SH2)
309 mov.l @r9, r8 ! Read from TRA (Trap Address) Register
314 mov.l r8, @r10 ! set TRA value to tra
317 * Check the trap type
319 mov #((0x20 << 2) - 1), r9
321 bt/s debug_trap ! it's a debug trap..
324 #ifdef CONFIG_TRACE_IRQFLAGS
332 get_current_thread_info r8, r10
333 mov.l @(TI_FLAGS,r8), r8
334 mov #_TIF_WORK_SYSCALL_MASK, r10
336 bf syscall_trace_entry
338 mov.l 2f, r8 ! Number of syscalls
344 mov.l 3f, r8 ! Load the address of sys_call_table
347 jsr @r8 ! jump to specific syscall handler
349 mov.l @(OFF_R0,r15), r12 ! save r0
350 mov.l r0, @(OFF_R0,r15) ! save the return value
354 #ifdef CONFIG_TRACE_IRQFLAGS
360 get_current_thread_info r8, r0
361 mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
362 tst #_TIF_ALLWORK_MASK, r0
367 #if !defined(CONFIG_CPU_SH2)
371 3: .long sys_call_table
372 #ifdef CONFIG_TRACE_IRQFLAGS
373 5: .long trace_hardirqs_on
374 6: .long trace_hardirqs_off
376 7: .long do_syscall_trace_enter
377 8: .long do_syscall_trace_leave