1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Common Low Level Interrupts/Traps/Exception !! 2 * PowerPC version
4 * (included from entry-<isa>.S !! 3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
>> 4 * Rewritten by Cort Dougan (cort@fsmlabs.com) for PReP
>> 5 * Copyright (C) 1996 Cort Dougan <cort@fsmlabs.com>
>> 6 * Adapted for Power Macintosh by Paul Mackerras.
>> 7 * Low-level exception handlers and MMU support
>> 8 * rewritten by Paul Mackerras.
>> 9 * Copyright (C) 1996 Paul Mackerras.
>> 10 * MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
5 * 11 *
6 * Copyright (C) 2014-15 Synopsys, Inc. (www.s !! 12 * This file contains the system call entry code, context switch
7 * Copyright (C) 2004, 2007-2010, 2011-2012 Sy !! 13 * code, and exception/interrupt return code for PowerPC.
8 */ <<
9 <<
10 /*-------------------------------------------- <<
11 * Function ABI <<
12 *-------------------------------------------- <<
13 * 14 *
14 * Arguments r0 - r !! 15 * This program is free software; you can redistribute it and/or
15 * Caller Saved Registers r0 - r !! 16 * modify it under the terms of the GNU General Public License
16 * Callee Saved Registers r13- r !! 17 * as published by the Free Software Foundation; either version
17 * Global Pointer (gp) r26 !! 18 * 2 of the License, or (at your option) any later version.
18 * Frame Pointer (fp) r27 !! 19 *
19 * Stack Pointer (sp) r28 !! 20 */
20 * Branch link register (blink) r31 <<
21 *-------------------------------------------- <<
22 */ <<
23 <<
24 ;################### Special Sys Call Wrappers <<
25 <<
26 ENTRY(sys_clone_wrapper) <<
27 SAVE_CALLEE_SAVED_USER <<
28 bl @sys_clone <<
29 DISCARD_CALLEE_SAVED_USER <<
30 <<
31 GET_CURR_THR_INFO_FLAGS r10 <<
32 and.f 0, r10, _TIF_SYSCALL_WORK <<
33 bnz tracesys_exit <<
34 <<
35 b .Lret_from_system_call <<
36 END(sys_clone_wrapper) <<
37 <<
38 ENTRY(sys_clone3_wrapper) <<
39 SAVE_CALLEE_SAVED_USER <<
40 bl @sys_clone3 <<
41 DISCARD_CALLEE_SAVED_USER <<
42 <<
43 GET_CURR_THR_INFO_FLAGS r10 <<
44 and.f 0, r10, _TIF_SYSCALL_WORK <<
45 bnz tracesys_exit <<
46 <<
47 b .Lret_from_system_call <<
48 END(sys_clone3_wrapper) <<
49 <<
50 ENTRY(ret_from_fork) <<
51 ; when the forked child comes here fro <<
52 ; r0 has the last task pointer. <<
53 ; put last task in scheduler queue <<
54 jl @schedule_tail <<
55 <<
56 ld r9, [sp, PT_status32] <<
57 brne r9, 0, 1f <<
58 <<
59 jl.d [r14] ; kernel threa <<
60 mov r0, r13 ; (see PF_KTHR <<
61 <<
62 1: <<
63 ; Return to user space <<
64 ; 1. Any forked task (Reach here via B <<
65 ; 2. First ever init task (Reach here <<
66 ; This is the historic "kernel_exec <<
67 ; user mode, in a round about way s <<
68 ; a kernel thread which is executed <<
69 ; out whenever kernel_execve (now i <<
70 b ret_from_exception <<
71 END(ret_from_fork) <<
72 <<
73 ;################### Non TLB Exception Handlin <<
74 <<
75 ; -------------------------------------------- <<
76 ; Instruction Error Exception Handler <<
77 ; -------------------------------------------- <<
78 <<
79 ENTRY(instr_service) <<
80 <<
81 EXCEPTION_PROLOGUE <<
82 <<
83 bl do_insterror_or_kprobe <<
84 b ret_from_exception <<
85 END(instr_service) <<
86 <<
87 ; -------------------------------------------- <<
88 ; Machine Check Exception Handler <<
89 ; -------------------------------------------- <<
90 21
91 ENTRY(EV_MachineCheck) !! 22 #include <linux/config.h>
>> 23 #include <linux/errno.h>
>> 24 #include <linux/sys.h>
>> 25 #include <linux/threads.h>
>> 26 #include <asm/processor.h>
>> 27 #include <asm/page.h>
>> 28 #include <asm/mmu.h>
>> 29 #include <asm/cputable.h>
>> 30 #include <asm/thread_info.h>
>> 31 #include <asm/ppc_asm.h>
>> 32 #include <asm/offsets.h>
>> 33 #include <asm/unistd.h>
92 34
93 EXCEPTION_PROLOGUE_KEEP_AE ; ECR !! 35 #undef SHOW_SYSCALLS
>> 36 #undef SHOW_SYSCALLS_TASK
94 37
95 lr r0, [efa] !! 38 /*
96 mov r1, sp !! 39 * MSR_KERNEL is > 0x10000 on 4xx since it include MSR_CE.
>> 40 */
>> 41 #if MSR_KERNEL >= 0x10000
>> 42 #define LOAD_MSR_KERNEL(r, x) lis r,(x)@h; ori r,r,(x)@l
>> 43 #else
>> 44 #define LOAD_MSR_KERNEL(r, x) li r,(x)
>> 45 #endif
97 46
98 ; MC exceptions disable MMU !! 47 #ifdef CONFIG_4xx
99 ARC_MMU_REENABLE r3 !! 48 .globl crit_transfer_to_handler
>> 49 crit_transfer_to_handler:
>> 50 lwz r0,crit_r10@l(0)
>> 51 stw r0,GPR10(r11)
>> 52 lwz r0,crit_r11@l(0)
>> 53 stw r0,GPR11(r11)
>> 54 /* fall through */
>> 55 #endif
100 56
101 lsr r3, r10, 8 !! 57 /*
102 bmsk r3, r3, 7 !! 58 * This code finishes saving the registers to the exception frame
103 brne r3, ECR_C_MCHK_DUP_TLB, 1f !! 59 * and jumps to the appropriate handler for the exception, turning
>> 60 * on address translation.
>> 61 * Note that we rely on the caller having set cr0.eq iff the exception
>> 62 * occurred in kernel mode (i.e. MSR:PR = 0).
>> 63 */
>> 64 .globl transfer_to_handler_full
>> 65 transfer_to_handler_full:
>> 66 SAVE_NVGPRS(r11)
>> 67 /* fall through */
>> 68
>> 69 .globl transfer_to_handler
>> 70 transfer_to_handler:
>> 71 stw r2,GPR2(r11)
>> 72 stw r12,_NIP(r11)
>> 73 stw r9,_MSR(r11)
>> 74 andi. r2,r9,MSR_PR
>> 75 mfctr r12
>> 76 mfspr r2,XER
>> 77 stw r12,_CTR(r11)
>> 78 stw r2,_XER(r11)
>> 79 mfspr r12,SPRG3
>> 80 addi r2,r12,-THREAD
>> 81 tovirt(r2,r2) /* set r2 to current */
>> 82 beq 2f /* if from user, fix up THREAD.regs */
>> 83 addi r11,r1,STACK_FRAME_OVERHEAD
>> 84 stw r11,PT_REGS(r12)
>> 85 #ifdef CONFIG_4xx
>> 86 lwz r12,PTRACE-THREAD(r12)
>> 87 andi. r12,r12,PT_PTRACED
>> 88 beq+ 3f
>> 89 /* From user and task is ptraced - load up global dbcr0 */
>> 90 li r12,-1 /* clear all pending debug events */
>> 91 mtspr SPRN_DBSR,r12
>> 92 lis r11,global_dbcr0@ha
>> 93 tophys(r11,r11)
>> 94 addi r11,r11,global_dbcr0@l
>> 95 lwz r12,0(r11)
>> 96 mtspr SPRN_DBCR0,r12
>> 97 lwz r12,4(r11)
>> 98 addi r12,r12,-1
>> 99 stw r12,4(r11)
>> 100 #endif
>> 101 b 3f
>> 102 2: /* if from kernel, check interrupted DOZE/NAP mode and
>> 103 * check for stack overflow
>> 104 */
>> 105 #ifdef CONFIG_6xx
>> 106 mfspr r11,SPRN_HID0
>> 107 mtcr r11
>> 108 BEGIN_FTR_SECTION
>> 109 bt- 8,power_save_6xx_restore /* Check DOZE */
>> 110 END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
>> 111 BEGIN_FTR_SECTION
>> 112 bt- 9,power_save_6xx_restore /* Check NAP */
>> 113 END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
>> 114 #endif /* CONFIG_6xx */
>> 115 .globl transfer_to_handler_cont
>> 116 transfer_to_handler_cont:
>> 117 lwz r11,THREAD_INFO-THREAD(r12)
>> 118 cmplw r1,r11 /* if r1 <= current->thread_info */
>> 119 ble- stack_ovf /* then the kernel stack overflowed */
>> 120 3:
>> 121 mflr r9
>> 122 lwz r11,0(r9) /* virtual address of handler */
>> 123 lwz r9,4(r9) /* where to go when done */
>> 124 FIX_SRR1(r10,r12)
>> 125 mtspr SRR0,r11
>> 126 mtspr SRR1,r10
>> 127 mtlr r9
>> 128 SYNC
>> 129 RFI /* jump to handler, enable MMU */
104 130
105 bl do_tlb_overlap_fault !! 131 /*
106 b ret_from_exception !! 132 * On kernel stack overflow, load up an initial stack pointer
>> 133 * and call StackOverflow(regs), which should not return.
>> 134 */
>> 135 stack_ovf:
>> 136 /* sometimes we use a statically-allocated stack, which is OK. */
>> 137 lis r11,_end@h
>> 138 ori r11,r11,_end@l
>> 139 cmplw r1,r11
>> 140 ble 3b /* r1 <= &_end is OK */
>> 141 SAVE_NVGPRS(r11)
>> 142 addi r3,r1,STACK_FRAME_OVERHEAD
>> 143 lis r1,init_thread_union@ha
>> 144 addi r1,r1,init_thread_union@l
>> 145 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
>> 146 lis r9,StackOverflow@ha
>> 147 addi r9,r9,StackOverflow@l
>> 148 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
>> 149 FIX_SRR1(r10,r12)
>> 150 mtspr SRR0,r9
>> 151 mtspr SRR1,r10
>> 152 SYNC
>> 153 RFI
107 154
>> 155 /*
>> 156 * Handle a system call.
>> 157 */
>> 158 .stabs "arch/ppc/kernel/",N_SO,0,0,0f
>> 159 .stabs "entry.S",N_SO,0,0,0f
>> 160 0:
>> 161
>> 162 _GLOBAL(DoSyscall)
>> 163 stw r0,THREAD+LAST_SYSCALL(r2)
>> 164 stw r3,ORIG_GPR3(r1)
>> 165 li r12,0
>> 166 stw r12,RESULT(r1)
>> 167 lwz r11,_CCR(r1) /* Clear SO bit in CR */
>> 168 rlwinm r11,r11,0,4,2
>> 169 stw r11,_CCR(r1)
>> 170 #ifdef SHOW_SYSCALLS
>> 171 bl do_show_syscall
>> 172 #endif /* SHOW_SYSCALLS */
>> 173 rlwinm r10,r1,0,0,18 /* current_thread_info() */
>> 174 lwz r11,TI_FLAGS(r10)
>> 175 rlwinm r11,r11,0,~_TIF_FORCE_NOERROR
>> 176 stw r11,TI_FLAGS(r10)
>> 177 andi. r11,r11,_TIF_SYSCALL_TRACE
>> 178 bne- syscall_dotrace
>> 179 syscall_dotrace_cont:
>> 180 cmpli 0,r0,NR_syscalls
>> 181 lis r10,sys_call_table@h
>> 182 ori r10,r10,sys_call_table@l
>> 183 slwi r0,r0,2
>> 184 bge- 66f
>> 185 lwzx r10,r10,r0 /* Fetch system call handler [ptr] */
>> 186 mtlr r10
>> 187 addi r9,r1,STACK_FRAME_OVERHEAD
>> 188 blrl /* Call handler */
>> 189 .globl ret_from_syscall
>> 190 ret_from_syscall:
>> 191 #ifdef SHOW_SYSCALLS
>> 192 bl do_show_syscall_exit
>> 193 #endif
>> 194 mr r6,r3
>> 195 li r11,-_LAST_ERRNO
>> 196 cmpl 0,r3,r11
>> 197 rlwinm r12,r1,0,0,18 /* current_thread_info() */
>> 198 blt+ 30f
>> 199 lwz r11,TI_FLAGS(r12)
>> 200 andi. r11,r11,_TIF_FORCE_NOERROR
>> 201 bne 30f
>> 202 neg r3,r3
>> 203 lwz r10,_CCR(r1) /* Set SO bit in CR */
>> 204 oris r10,r10,0x1000
>> 205 stw r10,_CCR(r1)
>> 206
>> 207 /* disable interrupts so current_thread_info()->flags can't change */
>> 208 30: LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
>> 209 SYNC
>> 210 MTMSRD(r10)
>> 211 lwz r9,TI_FLAGS(r12)
>> 212 andi. r0,r9,(_TIF_SYSCALL_TRACE|_TIF_SIGPENDING|_TIF_NEED_RESCHED)
>> 213 bne- syscall_exit_work
>> 214 syscall_exit_cont:
>> 215 #ifdef CONFIG_4xx
>> 216 /* If the process has its own DBCR0 value, load it up */
>> 217 lwz r0,PTRACE(r2)
>> 218 andi. r0,r0,PT_PTRACED
>> 219 bnel- load_4xx_dbcr0
>> 220 #endif
>> 221 stwcx. r0,0,r1 /* to clear the reservation */
>> 222 lwz r4,_LINK(r1)
>> 223 lwz r5,_CCR(r1)
>> 224 mtlr r4
>> 225 mtcr r5
>> 226 lwz r7,_NIP(r1)
>> 227 lwz r8,_MSR(r1)
>> 228 FIX_SRR1(r8, r0)
>> 229 lwz r2,GPR2(r1)
>> 230 lwz r1,GPR1(r1)
>> 231 mtspr SRR0,r7
>> 232 mtspr SRR1,r8
>> 233 SYNC
>> 234 RFI
>> 235
>> 236 66: li r3,-ENOSYS
>> 237 b ret_from_syscall
>> 238
>> 239 .globl ret_from_fork
>> 240 ret_from_fork:
>> 241 REST_NVGPRS(r1)
>> 242 bl schedule_tail
>> 243 li r3,0
>> 244 b ret_from_syscall
>> 245
>> 246 /* Traced system call support */
>> 247 syscall_dotrace:
>> 248 SAVE_NVGPRS(r1)
>> 249 li r0,0xc00
>> 250 stw r0,TRAP(r1)
>> 251 bl do_syscall_trace
>> 252 lwz r0,GPR0(r1) /* Restore original registers */
>> 253 lwz r3,GPR3(r1)
>> 254 lwz r4,GPR4(r1)
>> 255 lwz r5,GPR5(r1)
>> 256 lwz r6,GPR6(r1)
>> 257 lwz r7,GPR7(r1)
>> 258 lwz r8,GPR8(r1)
>> 259 REST_NVGPRS(r1)
>> 260 b syscall_dotrace_cont
>> 261
>> 262 syscall_exit_work:
>> 263 stw r6,RESULT(r1) /* Save result */
>> 264 stw r3,GPR3(r1) /* Update return value */
>> 265 andi. r0,r9,_TIF_SYSCALL_TRACE
>> 266 beq 5f
>> 267 ori r10,r10,MSR_EE
>> 268 SYNC
>> 269 MTMSRD(r10) /* re-enable interrupts */
>> 270 lwz r4,TRAP(r1)
>> 271 andi. r4,r4,1
>> 272 beq 4f
>> 273 SAVE_NVGPRS(r1)
>> 274 li r4,0xc00
>> 275 stw r4,TRAP(r1)
>> 276 4:
>> 277 bl do_syscall_trace
>> 278 REST_NVGPRS(r1)
>> 279 2:
>> 280 lwz r3,GPR3(r1)
>> 281 LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
>> 282 SYNC
>> 283 MTMSRD(r10) /* disable interrupts again */
>> 284 rlwinm r12,r1,0,0,18 /* current_thread_info() */
>> 285 lwz r9,TI_FLAGS(r12)
>> 286 5:
>> 287 andi. r0,r9,_TIF_NEED_RESCHED
>> 288 bne 1f
>> 289 lwz r5,_MSR(r1)
>> 290 andi. r5,r5,MSR_PR
>> 291 beq syscall_exit_cont
>> 292 andi. r0,r9,_TIF_SIGPENDING
>> 293 beq syscall_exit_cont
>> 294 b do_user_signal
108 1: 295 1:
109 ; DEAD END: can't do much, display Reg !! 296 ori r10,r10,MSR_EE
110 SAVE_CALLEE_SAVED_USER !! 297 SYNC
111 !! 298 MTMSRD(r10) /* re-enable interrupts */
112 GET_CURR_TASK_FIELD_PTR TASK_THREAD, !! 299 bl schedule
113 st sp, [r10, THREAD_CALLEE_REG] !! 300 b 2b
114 !! 301
115 j do_machine_check_fault !! 302 #ifdef SHOW_SYSCALLS
116 !! 303 do_show_syscall:
117 END(EV_MachineCheck) !! 304 #ifdef SHOW_SYSCALLS_TASK
118 !! 305 lis r11,show_syscalls_task@ha
119 ; -------------------------------------------- !! 306 lwz r11,show_syscalls_task@l(r11)
120 ; Privilege Violation Exception Handler !! 307 cmp 0,r2,r11
121 ; -------------------------------------------- !! 308 bnelr
122 ENTRY(EV_PrivilegeV) !! 309 #endif
123 !! 310 stw r31,GPR31(r1)
124 EXCEPTION_PROLOGUE !! 311 mflr r31
125 !! 312 lis r3,7f@ha
126 bl do_privilege_fault !! 313 addi r3,r3,7f@l
127 b ret_from_exception !! 314 lwz r4,GPR0(r1)
128 END(EV_PrivilegeV) !! 315 lwz r5,GPR3(r1)
129 !! 316 lwz r6,GPR4(r1)
130 ; -------------------------------------------- !! 317 lwz r7,GPR5(r1)
131 ; Extension Instruction Exception Handler !! 318 lwz r8,GPR6(r1)
132 ; -------------------------------------------- !! 319 lwz r9,GPR7(r1)
133 ENTRY(EV_Extension) !! 320 bl printk
134 !! 321 lis r3,77f@ha
135 EXCEPTION_PROLOGUE !! 322 addi r3,r3,77f@l
136 !! 323 lwz r4,GPR8(r1)
137 bl do_extension_fault !! 324 mr r5,r2
138 b ret_from_exception !! 325 bl printk
139 END(EV_Extension) !! 326 lwz r0,GPR0(r1)
140 !! 327 lwz r3,GPR3(r1)
141 ;################ Trap Handling (Syscall, Brea !! 328 lwz r4,GPR4(r1)
142 !! 329 lwz r5,GPR5(r1)
143 ; -------------------------------------------- !! 330 lwz r6,GPR6(r1)
144 ; syscall Tracing !! 331 lwz r7,GPR7(r1)
145 ; -------------------------------------------- !! 332 lwz r8,GPR8(r1)
146 tracesys: !! 333 mtlr r31
147 ; safekeep EFA (r12) if syscall tracer !! 334 lwz r31,GPR31(r1)
148 ; for traps, ERET is pre-commit so poi !! 335 blr
149 GET_CURR_TASK_FIELD_PTR TASK_THREAD, !! 336
150 st r12, [r11, THREAD_FAULT_ADDR] !! 337 do_show_syscall_exit:
151 !! 338 #ifdef SHOW_SYSCALLS_TASK
152 ; PRE syscall trace hook !! 339 lis r11,show_syscalls_task@ha
153 mov r0, sp !! 340 lwz r11,show_syscalls_task@l(r11)
154 bl @syscall_trace_enter !! 341 cmp 0,r2,r11
155 !! 342 bnelr
156 ; Tracing code now returns the syscall !! 343 #endif
157 mov r8, r0 !! 344 stw r31,GPR31(r1)
158 !! 345 mflr r31
159 ; Do the Sys Call as we normally would !! 346 stw r3,RESULT(r1) /* Save result */
160 cmp r8, NR_syscalls - 1 !! 347 mr r4,r3
161 mov.hi r0, -ENOSYS !! 348 lis r3,79f@ha
162 bhi tracesys_exit !! 349 addi r3,r3,79f@l
163 !! 350 bl printk
164 ; Restore the sys-call args. Mere invo !! 351 lwz r3,RESULT(r1)
165 ; clobbered them (since they are in sc !! 352 mtlr r31
166 ; have deliberately changed the syscal !! 353 lwz r31,GPR31(r1)
167 ld r0, [sp, PT_r0] !! 354 blr
168 ld r1, [sp, PT_r1] !! 355
169 ld r2, [sp, PT_r2] !! 356 7: .string "syscall %d(%x, %x, %x, %x, %x, "
170 ld r3, [sp, PT_r3] !! 357 77: .string "%x), current=%p\n"
171 ld r4, [sp, PT_r4] !! 358 79: .string " -> %x\n"
172 ld r5, [sp, PT_r5] !! 359 .align 2,0
173 ld r6, [sp, PT_r6] !! 360
174 ld r7, [sp, PT_r7] !! 361 #ifdef SHOW_SYSCALLS_TASK
175 ld.as r9, [sys_call_table, r8] !! 362 .data
176 jl [r9] !! 363 .globl show_syscalls_task
177 !! 364 show_syscalls_task:
178 tracesys_exit: !! 365 .long -1
179 st r0, [sp, PT_r0] !! 366 .text
180 !! 367 #endif
181 ; POST syscall trace hook !! 368 #endif /* SHOW_SYSCALLS */
182 mov r0, sp ; pt_regs need <<
183 bl @syscall_trace_exit <<
184 <<
185 ; don't call ret_from_system_call as i <<
186 b ret_from_exception <<
187 <<
188 ; -------------------------------------------- <<
189 ; Breakpoint TRAP <<
190 ; -------------------------------------------- <<
191 trap_with_param: <<
192 mov r0, r12 ; EFA in case ptracer/ <<
193 mov r1, sp ; pt_regs <<
194 <<
195 ; save callee regs in case tracer/gdb <<
196 SAVE_CALLEE_SAVED_USER <<
197 <<
198 ; safekeep ref to callee regs <<
199 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
200 st sp, [r10, THREAD_CALLEE_REG] <<
201 <<
202 ; call the non syscall trap handler <<
203 bl do_non_swi_trap <<
204 <<
205 ; unwind stack to discard callee regs <<
206 DISCARD_CALLEE_SAVED_USER <<
207 <<
208 b ret_from_exception <<
209 <<
210 ; -------------------------------------------- <<
211 ; syscall TRAP <<
212 ; ABI: (r0-r7) up to 8 args, (r8) syscall numb <<
213 ; -------------------------------------------- <<
214 <<
215 ENTRY(EV_Trap) <<
216 <<
217 EXCEPTION_PROLOGUE_KEEP_AE <<
218 <<
219 lr r12, [efa] <<
220 <<
221 FAKE_RET_FROM_EXCPN <<
222 <<
223 ;============ TRAP N : breakpoints, kp <<
224 bmsk.f 0, r10, 7 <<
225 bnz trap_with_param <<
226 <<
227 ;============ TRAP 0 (no param): sysca <<
228 <<
229 ; syscall tracing ongoing, invoke pre- <<
230 GET_CURR_THR_INFO_FLAGS r10 <<
231 and.f 0, r10, _TIF_SYSCALL_WORK <<
232 bnz tracesys ; this never comes bac <<
233 <<
234 ;============ Normal syscall case <<
235 <<
236 cmp r8, NR_syscalls - 1 <<
237 mov.hi r0, -ENOSYS <<
238 bhi .Lret_from_system_call <<
239 <<
240 ld.as r9,[sys_call_table, r8] <<
241 jl [r9] <<
242 <<
243 .Lret_from_system_call: <<
244 st r0, [sp, PT_r0] ; sys call ret <<
245 <<
246 ; fall through to ret_from_exception <<
247 END(EV_Trap) <<
248 <<
249 ;############# Return from Intr/Excp/Trap (Lin <<
250 ; <<
251 ; If ret to user mode do we need to handle sig <<
252 <<
253 ENTRY(ret_from_exception) <<
254 <<
255 ; Pre-{IRQ,Trap,Exception} K/U mode fr <<
256 ld r8, [sp, PT_status32] ; returnin <<
257 <<
258 bbit0 r8, STATUS_U_BIT, resume_kernel <<
259 <<
260 ; Before returning to User mode check- <<
261 ; such as rescheduling/signal-delivery <<
262 resume_user_mode_begin: <<
263 <<
264 ; Disable IRQs to ensures that chk for <<
265 ; (and we don't end up missing a NEED_ <<
266 ; interim IRQ). <<
267 IRQ_DISABLE r10 <<
268 <<
269 ; Fast Path return to user mode if no <<
270 GET_CURR_THR_INFO_FLAGS r9 <<
271 and.f 0, r9, _TIF_WORK_MASK <<
272 bz .Lrestore_regs <<
273 <<
274 ; --- (Slow Path #1) task preemption - <<
275 bbit0 r9, TIF_NEED_RESCHED, .Lchk_pen <<
276 mov blink, resume_user_mode_begin <<
277 j @schedule ; BTST+Bnz cau <<
278 <<
279 .Lchk_pend_signals: <<
280 IRQ_ENABLE r10 <<
281 <<
282 ; --- (Slow Path #2) pending signal - <<
283 mov r0, sp ; pt_regs for arg to d <<
284 <<
285 GET_CURR_THR_INFO_FLAGS r9 <<
286 and.f 0, r9, _TIF_SIGPENDING|_TIF_NO <<
287 bz .Lchk_notify_resume <<
288 <<
289 ; Normal Trap/IRQ entry only saves Scr <<
290 ; in pt_reg since the "C" ABI (kernel <<
291 ; save/restore callee-saved regs. <<
292 ; <<
293 ; However, here we need to explicitly <<
294 ; (i) If this signal causes coredump <<
295 ; (ii) If signal is SIGTRAP/SIGSTOP, t <<
296 ; tracer might call PEEKUSR(CALLE <<
297 ; <<
298 ; NOTE: SP will grow up by size of CAL <<
299 SAVE_CALLEE_SAVED_USER <<
300 <<
301 ; save location of saved Callee Regs @ <<
302 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
303 st sp, [r10, THREAD_CALLEE_REG] <<
304 <<
305 bl @do_signal <<
306 <<
307 ; Ideally we want to discard the Calle <<
308 ; a tracing signal, tracer could have <<
309 RESTORE_CALLEE_SAVED_USER <<
310 <<
311 b resume_user_mode_begin ; loop <<
312 <<
313 ; --- (Slow Path #3) notify_resume --- <<
314 .Lchk_notify_resume: <<
315 btst r9, TIF_NOTIFY_RESUME <<
316 blnz @do_notify_resume <<
317 b resume_user_mode_begin ; unco <<
318 ; for <<
319 369
320 resume_kernel_mode: !! 370 /*
>> 371 * The sigsuspend and rt_sigsuspend system calls can call do_signal
>> 372 * and thus put the process into the stopped state where we might
>> 373 * want to examine its user state with ptrace. Therefore we need
>> 374 * to save all the nonvolatile registers (r13 - r31) before calling
>> 375 * the C code.
>> 376 */
>> 377 .globl ppc_sigsuspend
>> 378 ppc_sigsuspend:
>> 379 SAVE_NVGPRS(r1)
>> 380 lwz r0,TRAP(r1)
>> 381 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
>> 382 stw r0,TRAP(r1) /* register set saved */
>> 383 b sys_sigsuspend
>> 384
>> 385 .globl ppc_rt_sigsuspend
>> 386 ppc_rt_sigsuspend:
>> 387 SAVE_NVGPRS(r1)
>> 388 lwz r0,TRAP(r1)
>> 389 rlwinm r0,r0,0,0,30
>> 390 stw r0,TRAP(r1)
>> 391 b sys_rt_sigsuspend
>> 392
>> 393 .globl ppc_fork
>> 394 ppc_fork:
>> 395 SAVE_NVGPRS(r1)
>> 396 lwz r0,TRAP(r1)
>> 397 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
>> 398 stw r0,TRAP(r1) /* register set saved */
>> 399 b sys_fork
>> 400
>> 401 .globl ppc_vfork
>> 402 ppc_vfork:
>> 403 SAVE_NVGPRS(r1)
>> 404 lwz r0,TRAP(r1)
>> 405 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
>> 406 stw r0,TRAP(r1) /* register set saved */
>> 407 b sys_vfork
>> 408
>> 409 .globl ppc_clone
>> 410 ppc_clone:
>> 411 SAVE_NVGPRS(r1)
>> 412 lwz r0,TRAP(r1)
>> 413 rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
>> 414 stw r0,TRAP(r1) /* register set saved */
>> 415 b sys_clone
321 416
322 ; Disable Interrupts from this point o !! 417 /*
323 ; CONFIG_PREEMPTION: This is a must fo !! 418 * This routine switches between two different tasks. The process
324 ; !CONFIG_PREEMPTION: To ensure restor !! 419 * state of one is saved on its kernel stack. Then the state
325 IRQ_DISABLE r9 !! 420 * of the other is restored from its kernel stack. The memory
>> 421 * management hardware is updated to the second process's state.
>> 422 * Finally, we can return to the second process.
>> 423 * On entry, r3 points to the THREAD for the current task, r4
>> 424 * points to the THREAD for the new task.
>> 425 *
>> 426 * This routine is always called with interrupts disabled.
>> 427 *
>> 428 * Note: there are two ways to get to the "going out" portion
>> 429 * of this code; either by coming in via the entry (_switch)
>> 430 * or via "fork" which must set up an environment equivalent
>> 431 * to the "_switch" path. If you change this , you'll have to
>> 432 * change the fork code also.
>> 433 *
>> 434 * The code which creates the new task context is in 'copy_thread'
>> 435 * in arch/ppc/kernel/process.c
>> 436 */
>> 437 _GLOBAL(_switch)
>> 438 stwu r1,-INT_FRAME_SIZE(r1)
>> 439 mflr r0
>> 440 stw r0,INT_FRAME_SIZE+4(r1)
>> 441 /* r3-r12 are caller saved -- Cort */
>> 442 SAVE_NVGPRS(r1)
>> 443 stw r0,_NIP(r1) /* Return to switch caller */
>> 444 mfmsr r11
>> 445 li r0,MSR_FP /* Disable floating-point */
>> 446 #ifdef CONFIG_ALTIVEC
>> 447 BEGIN_FTR_SECTION
>> 448 oris r0,r0,MSR_VEC@h /* Disable altivec */
>> 449 mfspr r12,SPRN_VRSAVE /* save vrsave register value */
>> 450 stw r12,THREAD+THREAD_VRSAVE(r2)
>> 451 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
>> 452 #endif /* CONFIG_ALTIVEC */
>> 453 and. r0,r0,r11 /* FP or altivec enabled? */
>> 454 beq+ 1f
>> 455 andc r11,r11,r0
>> 456 MTMSRD(r11)
>> 457 isync
>> 458 1: stw r11,_MSR(r1)
>> 459 mfcr r10
>> 460 stw r10,_CCR(r1)
>> 461 stw r1,KSP(r3) /* Set old stack pointer */
>> 462
>> 463 tophys(r0,r4)
>> 464 CLR_TOP32(r0)
>> 465 mtspr SPRG3,r0 /* Update current THREAD phys addr */
>> 466 lwz r1,KSP(r4) /* Load new stack pointer */
>> 467 /* save the old current 'last' for return value */
>> 468 mr r3,r2
>> 469 addi r2,r4,-THREAD /* Update current */
>> 470
>> 471 #ifdef CONFIG_ALTIVEC
>> 472 BEGIN_FTR_SECTION
>> 473 lwz r0,THREAD+THREAD_VRSAVE(r2)
>> 474 mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */
>> 475 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
>> 476 #endif /* CONFIG_ALTIVEC */
>> 477
>> 478 lwz r0,_CCR(r1)
>> 479 mtcrf 0xFF,r0
>> 480 /* r3-r12 are destroyed -- Cort */
>> 481 REST_NVGPRS(r1)
>> 482
>> 483 lwz r4,_NIP(r1) /* Return to _switch caller in new task */
>> 484 mtlr r4
>> 485 addi r1,r1,INT_FRAME_SIZE
>> 486 blr
>> 487
>> 488 .globl sigreturn_exit
>> 489 sigreturn_exit:
>> 490 subi r1,r3,STACK_FRAME_OVERHEAD
>> 491 rlwinm r12,r1,0,0,18 /* current_thread_info() */
>> 492 lwz r9,TI_FLAGS(r12)
>> 493 andi. r0,r9,_TIF_SYSCALL_TRACE
>> 494 bnel- do_syscall_trace
>> 495 /* fall through */
>> 496
>> 497 .globl ret_from_except_full
>> 498 ret_from_except_full:
>> 499 REST_NVGPRS(r1)
>> 500 /* fall through */
>> 501
>> 502 .globl ret_from_except
>> 503 ret_from_except:
>> 504 /* Hard-disable interrupts so that current_thread_info()->flags
>> 505 * can't change between when we test it and when we return
>> 506 * from the interrupt. */
>> 507 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
>> 508 SYNC /* Some chip revs have problems here... */
>> 509 MTMSRD(r10) /* disable interrupts */
>> 510
>> 511 lwz r3,_MSR(r1) /* Returning to user mode? */
>> 512 andi. r0,r3,MSR_PR
>> 513 beq resume_kernel
>> 514
>> 515 user_exc_return: /* r10 contains MSR_KERNEL here */
>> 516 /* Check current_thread_info()->flags */
>> 517 rlwinm r9,r1,0,0,18
>> 518 lwz r9,TI_FLAGS(r9)
>> 519 andi. r0,r9,(_TIF_SIGPENDING|_TIF_NEED_RESCHED)
>> 520 bne do_work
>> 521
>> 522 restore_user:
>> 523 #ifdef CONFIG_4xx
>> 524 /* Check whether this process has its own DBCR0 value */
>> 525 lwz r0,PTRACE(r2)
>> 526 andi. r0,r0,PT_PTRACED
>> 527 bnel- load_4xx_dbcr0
>> 528 #endif
326 529
327 #ifdef CONFIG_PREEMPTION !! 530 #ifdef CONFIG_PREEMPT
>> 531 b restore
328 532
329 ; Can't preempt if preemption disabled !! 533 /* N.B. the only way to get here is from the beq following ret_from_except. */
330 GET_CURR_THR_INFO_FROM_SP r10 !! 534 resume_kernel:
331 ld r8, [r10, THREAD_INFO_PREEMPT_COUN !! 535 /* check current_thread_info->preempt_count */
332 brne r8, 0, .Lrestore_regs !! 536 rlwinm r9,r1,0,0,18
>> 537 lwz r0,TI_PREEMPT(r9)
>> 538 cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
>> 539 bne restore
>> 540 lwz r0,TI_FLAGS(r9)
>> 541 andi. r0,r0,_TIF_NEED_RESCHED
>> 542 beq+ restore
>> 543 andi. r0,r3,MSR_EE /* interrupts off? */
>> 544 beq restore /* don't schedule if so */
>> 545 1: lis r0,PREEMPT_ACTIVE@h
>> 546 stw r0,TI_PREEMPT(r9)
>> 547 ori r10,r10,MSR_EE
>> 548 SYNC
>> 549 MTMSRD(r10) /* hard-enable interrupts */
>> 550 bl schedule
>> 551 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
>> 552 SYNC
>> 553 MTMSRD(r10) /* disable interrupts */
>> 554 rlwinm r9,r1,0,0,18
>> 555 li r0,0
>> 556 stw r0,TI_PREEMPT(r9)
>> 557 lwz r3,TI_FLAGS(r9)
>> 558 andi. r0,r3,_TIF_NEED_RESCHED
>> 559 bne- 1b
>> 560 #else
>> 561 resume_kernel:
>> 562 #endif /* CONFIG_PREEMPT */
>> 563
>> 564 /* interrupts are hard-disabled at this point */
>> 565 restore:
>> 566 lwz r0,GPR0(r1)
>> 567 lwz r2,GPR2(r1)
>> 568 REST_4GPRS(3, r1)
>> 569 REST_2GPRS(7, r1)
>> 570
>> 571 lwz r10,_XER(r1)
>> 572 lwz r11,_CTR(r1)
>> 573 mtspr XER,r10
>> 574 mtctr r11
>> 575
>> 576 PPC405_ERR77(0,r1)
>> 577 stwcx. r0,0,r1 /* to clear the reservation */
>> 578
>> 579 #ifndef CONFIG_4xx
>> 580 lwz r9,_MSR(r1)
>> 581 andi. r10,r9,MSR_RI /* check if this exception occurred */
>> 582 beql nonrecoverable /* at a bad place (MSR:RI = 0) */
>> 583
>> 584 lwz r10,_CCR(r1)
>> 585 lwz r11,_LINK(r1)
>> 586 mtcrf 0xFF,r10
>> 587 mtlr r11
>> 588
>> 589 /*
>> 590 * Once we put values in SRR0 and SRR1, we are in a state
>> 591 * where exceptions are not recoverable, since taking an
>> 592 * exception will trash SRR0 and SRR1. Therefore we clear the
>> 593 * MSR:RI bit to indicate this. If we do take an exception,
>> 594 * we can't return to the point of the exception but we
>> 595 * can restart the exception exit path at the label
>> 596 * exc_exit_restart below. -- paulus
>> 597 */
>> 598 LOAD_MSR_KERNEL(r10,MSR_KERNEL & ~MSR_RI)
>> 599 SYNC
>> 600 MTMSRD(r10) /* clear the RI bit */
>> 601 .globl exc_exit_restart
>> 602 exc_exit_restart:
>> 603 lwz r9,_MSR(r1)
>> 604 lwz r12,_NIP(r1)
>> 605 FIX_SRR1(r9,r10)
>> 606 mtspr SRR0,r12
>> 607 mtspr SRR1,r9
>> 608 REST_4GPRS(9, r1)
>> 609 lwz r1,GPR1(r1)
>> 610 .globl exc_exit_restart_end
>> 611 exc_exit_restart_end:
>> 612 SYNC
>> 613 RFI
>> 614
>> 615 #else /* CONFIG_4xx */
>> 616 /*
>> 617 * This is a bit different on 4xx because 4xx doesn't have
>> 618 * the RI bit in the MSR.
>> 619 * The TLB miss handler checks if we have interrupted
>> 620 * the exception exit path and restarts it if so
>> 621 * (well maybe one day it will... :).
>> 622 */
>> 623 lwz r11,_LINK(r1)
>> 624 mtlr r11
>> 625 lwz r10,_CCR(r1)
>> 626 mtcrf 0xff,r10
>> 627 REST_2GPRS(9, r1)
>> 628 .globl exc_exit_restart
>> 629 exc_exit_restart:
>> 630 lwz r11,_NIP(r1)
>> 631 lwz r12,_MSR(r1)
>> 632 exc_exit_start:
>> 633 mtspr SRR0,r11
>> 634 mtspr SRR1,r12
>> 635 REST_2GPRS(11, r1)
>> 636 lwz r1,GPR1(r1)
>> 637 .globl exc_exit_restart_end
>> 638 exc_exit_restart_end:
>> 639 PPC405_ERR77_SYNC
>> 640 rfi
>> 641 b . /* prevent prefetch past rfi */
333 642
334 ; check if this task's NEED_RESCHED fl !! 643 /*
335 ld r9, [r10, THREAD_INFO_FLAGS] !! 644 * Returning from a critical interrupt in user mode doesn't need
336 bbit0 r9, TIF_NEED_RESCHED, .Lrestore !! 645 * to be any different from a normal exception. For a critical
>> 646 * interrupt in the kernel, we just return (without checking for
>> 647 * preemption) since the interrupt may have happened at some crucial
>> 648 * place (e.g. inside the TLB miss handler), and because we will be
>> 649 * running with r1 pointing into critical_stack, not the current
>> 650 * process's kernel stack (and therefore current_thread_info() will
>> 651 * give the wrong answer).
>> 652 * We have to restore various SPRs that may have been in use at the
>> 653 * time of the critical interrupt.
>> 654 */
>> 655 .globl ret_from_crit_exc
>> 656 ret_from_crit_exc:
>> 657 REST_NVGPRS(r1)
>> 658 lwz r3,_MSR(r1)
>> 659 andi. r3,r3,MSR_PR
>> 660 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
>> 661 bne user_exc_return
>> 662
>> 663 lwz r0,GPR0(r1)
>> 664 lwz r2,GPR2(r1)
>> 665 REST_4GPRS(3, r1)
>> 666 REST_2GPRS(7, r1)
>> 667
>> 668 lwz r10,_XER(r1)
>> 669 lwz r11,_CTR(r1)
>> 670 mtspr XER,r10
>> 671 mtctr r11
>> 672
>> 673 PPC405_ERR77(0,r1)
>> 674 stwcx. r0,0,r1 /* to clear the reservation */
>> 675
>> 676 lwz r11,_LINK(r1)
>> 677 mtlr r11
>> 678 lwz r10,_CCR(r1)
>> 679 mtcrf 0xff,r10
>> 680 /* avoid any possible TLB misses here by turning off MSR.DR, we
>> 681 * assume the instructions here are mapped by a pinned TLB entry */
>> 682 li r10,MSR_IR
>> 683 mtmsr r10
>> 684 isync
>> 685 tophys(r1, r1)
>> 686 lwz r9,_DEAR(r1)
>> 687 lwz r10,_ESR(r1)
>> 688 mtspr SPRN_DEAR,r9
>> 689 mtspr SPRN_ESR,r10
>> 690 lwz r11,_NIP(r1)
>> 691 lwz r12,_MSR(r1)
>> 692 mtspr SRR2,r11
>> 693 mtspr SRR3,r12
>> 694 lwz r9,GPR9(r1)
>> 695 lwz r12,GPR12(r1)
>> 696 lwz r10,crit_sprg0@l(0)
>> 697 mtspr SPRN_SPRG0,r10
>> 698 lwz r10,crit_sprg1@l(0)
>> 699 mtspr SPRN_SPRG1,r10
>> 700 lwz r10,crit_sprg4@l(0)
>> 701 mtspr SPRN_SPRG4,r10
>> 702 lwz r10,crit_sprg5@l(0)
>> 703 mtspr SPRN_SPRG5,r10
>> 704 lwz r10,crit_sprg6@l(0)
>> 705 mtspr SPRN_SPRG6,r10
>> 706 lwz r10,crit_sprg7@l(0)
>> 707 mtspr SPRN_SPRG7,r10
>> 708 lwz r10,crit_srr0@l(0)
>> 709 mtspr SRR0,r10
>> 710 lwz r10,crit_srr1@l(0)
>> 711 mtspr SRR1,r10
>> 712 lwz r10,crit_pid@l(0)
>> 713 mtspr SPRN_PID,r10
>> 714 lwz r10,GPR10(r1)
>> 715 lwz r11,GPR11(r1)
>> 716 lwz r1,GPR1(r1)
>> 717 PPC405_ERR77_SYNC
>> 718 rfci
>> 719 b . /* prevent prefetch past rfci */
337 720
338 ; Invoke PREEMPTION !! 721 /*
339 jl preempt_schedule_irq !! 722 * Load the DBCR0 value for a task that is being ptraced,
>> 723 * having first saved away the global DBCR0.
>> 724 */
>> 725 load_4xx_dbcr0:
>> 726 mfmsr r0 /* first disable debug exceptions */
>> 727 rlwinm r0,r0,0,~MSR_DE
>> 728 mtmsr r0
>> 729 isync
>> 730 mfspr r10,SPRN_DBCR0
>> 731 lis r11,global_dbcr0@ha
>> 732 addi r11,r11,global_dbcr0@l
>> 733 lwz r0,THREAD+THREAD_DBCR0(r2)
>> 734 stw r10,0(r11)
>> 735 mtspr SPRN_DBCR0,r0
>> 736 lwz r10,4(r11)
>> 737 addi r10,r10,1
>> 738 stw r10,4(r11)
>> 739 li r11,-1
>> 740 mtspr SPRN_DBSR,r11 /* clear all pending debug events */
>> 741 blr
>> 742
>> 743 .comm global_dbcr0,8
>> 744 #endif /* CONFIG_4xx */
>> 745
>> 746 do_work: /* r10 contains MSR_KERNEL here */
>> 747 andi. r0,r9,_TIF_NEED_RESCHED
>> 748 beq do_user_signal
>> 749
>> 750 do_resched: /* r10 contains MSR_KERNEL here */
>> 751 ori r10,r10,MSR_EE
>> 752 SYNC
>> 753 MTMSRD(r10) /* hard-enable interrupts */
>> 754 bl schedule
>> 755 recheck:
>> 756 LOAD_MSR_KERNEL(r10,MSR_KERNEL)
>> 757 SYNC
>> 758 MTMSRD(r10) /* disable interrupts */
>> 759 rlwinm r9,r1,0,0,18
>> 760 lwz r9,TI_FLAGS(r9)
>> 761 andi. r0,r9,_TIF_NEED_RESCHED
>> 762 bne- do_resched
>> 763 andi. r0,r9,_TIF_SIGPENDING
>> 764 beq restore_user
>> 765 do_user_signal: /* r10 contains MSR_KERNEL here */
>> 766 ori r10,r10,MSR_EE
>> 767 SYNC
>> 768 MTMSRD(r10) /* hard-enable interrupts */
>> 769 /* save r13-r31 in the exception frame, if not already done */
>> 770 lwz r3,TRAP(r1)
>> 771 andi. r0,r3,1
>> 772 beq 2f
>> 773 SAVE_NVGPRS(r1)
>> 774 rlwinm r3,r3,0,0,30
>> 775 stw r3,TRAP(r1)
>> 776 2: li r3,0
>> 777 addi r4,r1,STACK_FRAME_OVERHEAD
>> 778 bl do_signal
>> 779 REST_NVGPRS(r1)
>> 780 b recheck
340 781
341 ; preempt_schedule_irq() always return !! 782 /*
342 #endif !! 783 * We come here when we are at the end of handling an exception
>> 784 * that occurred at a place where taking an exception will lose
>> 785 * state information, such as the contents of SRR0 and SRR1.
>> 786 */
>> 787 nonrecoverable:
>> 788 lis r10,exc_exit_restart_end@ha
>> 789 addi r10,r10,exc_exit_restart_end@l
>> 790 cmplw r12,r10
>> 791 bge 3f
>> 792 lis r11,exc_exit_restart@ha
>> 793 addi r11,r11,exc_exit_restart@l
>> 794 cmplw r12,r11
>> 795 blt 3f
>> 796 lis r10,ee_restarts@ha
>> 797 lwz r12,ee_restarts@l(r10)
>> 798 addi r12,r12,1
>> 799 stw r12,ee_restarts@l(r10)
>> 800 mr r12,r11 /* restart at exc_exit_restart */
>> 801 blr
>> 802 3: /* OK, we can't recover, kill this process */
>> 803 /* but the 601 doesn't implement the RI bit, so assume it's OK */
>> 804 BEGIN_FTR_SECTION
>> 805 blr
>> 806 END_FTR_SECTION_IFSET(CPU_FTR_601)
>> 807 lwz r3,TRAP(r1)
>> 808 andi. r0,r3,1
>> 809 beq 4f
>> 810 SAVE_NVGPRS(r1)
>> 811 rlwinm r3,r3,0,0,30
>> 812 stw r3,TRAP(r1)
>> 813 4: addi r3,r1,STACK_FRAME_OVERHEAD
>> 814 bl nonrecoverable_exception
>> 815 /* shouldn't return */
>> 816 b 4b
343 817
344 b .Lrestore_regs !! 818 .comm ee_restarts,4
345 819
346 ##### DONT ADD CODE HERE - .Lrestore_regs actu !! 820 /*
>> 821 * PROM code for specific machines follows. Put it
>> 822 * here so it's easy to add arch-specific sections later.
>> 823 * -- Cort
>> 824 */
>> 825 #ifdef CONFIG_PPC_OF
>> 826 /*
>> 827 * On CHRP, the Run-Time Abstraction Services (RTAS) have to be
>> 828 * called with the MMU off.
>> 829 */
>> 830 _GLOBAL(enter_rtas)
>> 831 stwu r1,-INT_FRAME_SIZE(r1)
>> 832 mflr r0
>> 833 stw r0,INT_FRAME_SIZE+4(r1)
>> 834 lis r4,rtas_data@ha
>> 835 lwz r4,rtas_data@l(r4)
>> 836 lis r6,1f@ha /* physical return address for rtas */
>> 837 addi r6,r6,1f@l
>> 838 tophys(r6,r6)
>> 839 tophys(r7,r1)
>> 840 lis r8,rtas_entry@ha
>> 841 lwz r8,rtas_entry@l(r8)
>> 842 mfmsr r9
>> 843 stw r9,8(r1)
>> 844 LOAD_MSR_KERNEL(r0,MSR_KERNEL)
>> 845 SYNC /* disable interrupts so SRR0/1 */
>> 846 MTMSRD(r0) /* don't get trashed */
>> 847 li r9,MSR_KERNEL & ~(MSR_IR|MSR_DR)
>> 848 mtlr r6
>> 849 CLR_TOP32(r7)
>> 850 mtspr SPRG2,r7
>> 851 mtspr SRR0,r8
>> 852 mtspr SRR1,r9
>> 853 RFI
>> 854 1: tophys(r9,r1)
>> 855 lwz r8,INT_FRAME_SIZE+4(r9) /* get return address */
>> 856 lwz r9,8(r9) /* original msr value */
>> 857 FIX_SRR1(r9,r0)
>> 858 addi r1,r1,INT_FRAME_SIZE
>> 859 li r0,0
>> 860 mtspr SPRG2,r0
>> 861 mtspr SRR0,r8
>> 862 mtspr SRR1,r9
>> 863 RFI /* return to caller */
>> 864
>> 865 .globl machine_check_in_rtas
>> 866 machine_check_in_rtas:
>> 867 twi 31,0,0
>> 868 /* XXX load up BATs and panic */
347 869
>> 870 #endif /* CONFIG_PPC_OF */
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