xref: /linux/arch/powerpc/kernel/exceptions-64e.S (revision ec208491936d6adb8a70c3dd4a517cdfe54e823d)
1/*
2 *  Boot code and exception vectors for Book3E processors
3 *
4 *  Copyright (C) 2007 Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp.
5 *
6 *  This program is free software; you can redistribute it and/or
7 *  modify it under the terms of the GNU General Public License
8 *  as published by the Free Software Foundation; either version
9 *  2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/threads.h>
13#include <asm/reg.h>
14#include <asm/page.h>
15#include <asm/ppc_asm.h>
16#include <asm/asm-offsets.h>
17#include <asm/cputable.h>
18#include <asm/setup.h>
19#include <asm/thread_info.h>
20#include <asm/exception-64e.h>
21#include <asm/bug.h>
22#include <asm/irqflags.h>
23#include <asm/ptrace.h>
24#include <asm/ppc-opcode.h>
25#include <asm/mmu.h>
26
27/* XXX This will ultimately add space for a special exception save
28 *     structure used to save things like SRR0/SRR1, SPRGs, MAS, etc...
29 *     when taking special interrupts. For now we don't support that,
30 *     special interrupts from within a non-standard level will probably
31 *     blow you up
32 */
33#define	SPECIAL_EXC_FRAME_SIZE	INT_FRAME_SIZE
34
35/* Exception prolog code for all exceptions */
36#define EXCEPTION_PROLOG(n, type, addition)				    \
37	mtspr	SPRN_SPRG_##type##_SCRATCH,r13;	/* get spare registers */   \
38	mfspr	r13,SPRN_SPRG_PACA;	/* get PACA */			    \
39	std	r10,PACA_EX##type+EX_R10(r13);				    \
40	std	r11,PACA_EX##type+EX_R11(r13);				    \
41	mfcr	r10;			/* save CR */			    \
42	addition;			/* additional code for that exc. */ \
43	std	r1,PACA_EX##type+EX_R1(r13); /* save old r1 in the PACA */  \
44	stw	r10,PACA_EX##type+EX_CR(r13); /* save old CR in the PACA */ \
45	mfspr	r11,SPRN_##type##_SRR1;/* what are we coming from */	    \
46	type##_SET_KSTACK;		/* get special stack if necessary */\
47	andi.	r10,r11,MSR_PR;		/* save stack pointer */	    \
48	beq	1f;			/* branch around if supervisor */   \
49	ld	r1,PACAKSAVE(r13);	/* get kernel stack coming from usr */\
501:	cmpdi	cr1,r1,0;		/* check if SP makes sense */	    \
51	bge-	cr1,exc_##n##_bad_stack;/* bad stack (TODO: out of line) */ \
52	mfspr	r10,SPRN_##type##_SRR0;	/* read SRR0 before touching stack */
53
54/* Exception type-specific macros */
55#define	GEN_SET_KSTACK							    \
56	subi	r1,r1,INT_FRAME_SIZE;	/* alloc frame on kernel stack */
57#define SPRN_GEN_SRR0	SPRN_SRR0
58#define SPRN_GEN_SRR1	SPRN_SRR1
59
60#define CRIT_SET_KSTACK						            \
61	ld	r1,PACA_CRIT_STACK(r13);				    \
62	subi	r1,r1,SPECIAL_EXC_FRAME_SIZE;
63#define SPRN_CRIT_SRR0	SPRN_CSRR0
64#define SPRN_CRIT_SRR1	SPRN_CSRR1
65
66#define DBG_SET_KSTACK						            \
67	ld	r1,PACA_DBG_STACK(r13);					    \
68	subi	r1,r1,SPECIAL_EXC_FRAME_SIZE;
69#define SPRN_DBG_SRR0	SPRN_DSRR0
70#define SPRN_DBG_SRR1	SPRN_DSRR1
71
72#define MC_SET_KSTACK						            \
73	ld	r1,PACA_MC_STACK(r13);					    \
74	subi	r1,r1,SPECIAL_EXC_FRAME_SIZE;
75#define SPRN_MC_SRR0	SPRN_MCSRR0
76#define SPRN_MC_SRR1	SPRN_MCSRR1
77
78#define NORMAL_EXCEPTION_PROLOG(n, addition)				    \
79	EXCEPTION_PROLOG(n, GEN, addition##_GEN)
80
81#define CRIT_EXCEPTION_PROLOG(n, addition)				    \
82	EXCEPTION_PROLOG(n, CRIT, addition##_CRIT)
83
84#define DBG_EXCEPTION_PROLOG(n, addition)				    \
85	EXCEPTION_PROLOG(n, DBG, addition##_DBG)
86
87#define MC_EXCEPTION_PROLOG(n, addition)				    \
88	EXCEPTION_PROLOG(n, MC, addition##_MC)
89
90
91/* Variants of the "addition" argument for the prolog
92 */
93#define PROLOG_ADDITION_NONE_GEN
94#define PROLOG_ADDITION_NONE_CRIT
95#define PROLOG_ADDITION_NONE_DBG
96#define PROLOG_ADDITION_NONE_MC
97
98#define PROLOG_ADDITION_MASKABLE_GEN					    \
99	lbz	r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */	    \
100	cmpwi	cr0,r11,0;		/* yes -> go out of line */	    \
101	beq	masked_interrupt_book3e;
102
103#define PROLOG_ADDITION_2REGS_GEN					    \
104	std	r14,PACA_EXGEN+EX_R14(r13);				    \
105	std	r15,PACA_EXGEN+EX_R15(r13)
106
107#define PROLOG_ADDITION_1REG_GEN					    \
108	std	r14,PACA_EXGEN+EX_R14(r13);
109
110#define PROLOG_ADDITION_2REGS_CRIT					    \
111	std	r14,PACA_EXCRIT+EX_R14(r13);				    \
112	std	r15,PACA_EXCRIT+EX_R15(r13)
113
114#define PROLOG_ADDITION_2REGS_DBG					    \
115	std	r14,PACA_EXDBG+EX_R14(r13);				    \
116	std	r15,PACA_EXDBG+EX_R15(r13)
117
118#define PROLOG_ADDITION_2REGS_MC					    \
119	std	r14,PACA_EXMC+EX_R14(r13);				    \
120	std	r15,PACA_EXMC+EX_R15(r13)
121
122/* Core exception code for all exceptions except TLB misses.
123 * XXX: Needs to make SPRN_SPRG_GEN depend on exception type
124 */
125#define EXCEPTION_COMMON(n, excf, ints)					    \
126	std	r0,GPR0(r1);		/* save r0 in stackframe */	    \
127	std	r2,GPR2(r1);		/* save r2 in stackframe */	    \
128	SAVE_4GPRS(3, r1);		/* save r3 - r6 in stackframe */    \
129	SAVE_2GPRS(7, r1);		/* save r7, r8 in stackframe */	    \
130	std	r9,GPR9(r1);		/* save r9 in stackframe */	    \
131	std	r10,_NIP(r1);		/* save SRR0 to stackframe */	    \
132	std	r11,_MSR(r1);		/* save SRR1 to stackframe */	    \
133	ACCOUNT_CPU_USER_ENTRY(r10,r11);/* accounting (uses cr0+eq) */	    \
134	ld	r3,excf+EX_R10(r13);	/* get back r10 */		    \
135	ld	r4,excf+EX_R11(r13);	/* get back r11 */		    \
136	mfspr	r5,SPRN_SPRG_GEN_SCRATCH;/* get back r13 */		    \
137	std	r12,GPR12(r1);		/* save r12 in stackframe */	    \
138	ld	r2,PACATOC(r13);	/* get kernel TOC into r2 */	    \
139	mflr	r6;			/* save LR in stackframe */	    \
140	mfctr	r7;			/* save CTR in stackframe */	    \
141	mfspr	r8,SPRN_XER;		/* save XER in stackframe */	    \
142	ld	r9,excf+EX_R1(r13);	/* load orig r1 back from PACA */   \
143	lwz	r10,excf+EX_CR(r13);	/* load orig CR back from PACA	*/  \
144	lbz	r11,PACASOFTIRQEN(r13);	/* get current IRQ softe */	    \
145	ld	r12,exception_marker@toc(r2);				    \
146	li	r0,0;							    \
147	std	r3,GPR10(r1);		/* save r10 to stackframe */	    \
148	std	r4,GPR11(r1);		/* save r11 to stackframe */	    \
149	std	r5,GPR13(r1);		/* save it to stackframe */	    \
150	std	r6,_LINK(r1);						    \
151	std	r7,_CTR(r1);						    \
152	std	r8,_XER(r1);						    \
153	li	r3,(n)+1;		/* indicate partial regs in trap */ \
154	std	r9,0(r1);		/* store stack frame back link */   \
155	std	r10,_CCR(r1);		/* store orig CR in stackframe */   \
156	std	r9,GPR1(r1);		/* store stack frame back link */   \
157	std	r11,SOFTE(r1);		/* and save it to stackframe */     \
158	std	r12,STACK_FRAME_OVERHEAD-16(r1); /* mark the frame */	    \
159	std	r3,_TRAP(r1);		/* set trap number		*/  \
160	std	r0,RESULT(r1);		/* clear regs->result */	    \
161	ints;
162
163/* Variants for the "ints" argument */
164#define INTS_KEEP
165#define INTS_DISABLE_SOFT						    \
166	stb	r0,PACASOFTIRQEN(r13);	/* mark interrupts soft-disabled */ \
167	TRACE_DISABLE_INTS;
168#define INTS_DISABLE_HARD						    \
169	stb	r0,PACAHARDIRQEN(r13); /* and hard disabled */
170#define INTS_DISABLE_ALL						    \
171	INTS_DISABLE_SOFT						    \
172	INTS_DISABLE_HARD
173
174/* This is called by exceptions that used INTS_KEEP (that is did not clear
175 * neither soft nor hard IRQ indicators in the PACA. This will restore MSR:EE
176 * to it's previous value
177 *
178 * XXX In the long run, we may want to open-code it in order to separate the
179 *     load from the wrtee, thus limiting the latency caused by the dependency
180 *     but at this point, I'll favor code clarity until we have a near to final
181 *     implementation
182 */
183#define INTS_RESTORE_HARD						    \
184	ld	r11,_MSR(r1);						    \
185	wrtee	r11;
186
187/* XXX FIXME: Restore r14/r15 when necessary */
188#define BAD_STACK_TRAMPOLINE(n)						    \
189exc_##n##_bad_stack:							    \
190	li	r1,(n);			/* get exception number */	    \
191	sth	r1,PACA_TRAP_SAVE(r13);	/* store trap */		    \
192	b	bad_stack_book3e;	/* bad stack error */
193
194#define	EXCEPTION_STUB(loc, label)					\
195	. = interrupt_base_book3e + loc;				\
196	nop;	/* To make debug interrupts happy */			\
197	b	exc_##label##_book3e;
198
199#define ACK_NONE(r)
200#define ACK_DEC(r)							\
201	lis	r,TSR_DIS@h;						\
202	mtspr	SPRN_TSR,r
203#define ACK_FIT(r)							\
204	lis	r,TSR_FIS@h;						\
205	mtspr	SPRN_TSR,r
206
207#define MASKABLE_EXCEPTION(trapnum, label, hdlr, ack)			\
208	START_EXCEPTION(label);						\
209	NORMAL_EXCEPTION_PROLOG(trapnum, PROLOG_ADDITION_MASKABLE)	\
210	EXCEPTION_COMMON(trapnum, PACA_EXGEN, INTS_DISABLE_ALL)		\
211	ack(r8);							\
212	addi	r3,r1,STACK_FRAME_OVERHEAD;				\
213	bl	hdlr;							\
214	b	.ret_from_except_lite;
215
216/* This value is used to mark exception frames on the stack. */
217	.section	".toc","aw"
218exception_marker:
219	.tc	ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
220
221
222/*
223 * And here we have the exception vectors !
224 */
225
226	.text
227	.balign	0x1000
228	.globl interrupt_base_book3e
229interrupt_base_book3e:					/* fake trap */
230	/* Note: If real debug exceptions are supported by the HW, the vector
231	 * below will have to be patched up to point to an appropriate handler
232	 */
233	EXCEPTION_STUB(0x000, machine_check)		/* 0x0200 */
234	EXCEPTION_STUB(0x020, critical_input)		/* 0x0580 */
235	EXCEPTION_STUB(0x040, debug_crit)		/* 0x0d00 */
236	EXCEPTION_STUB(0x060, data_storage)		/* 0x0300 */
237	EXCEPTION_STUB(0x080, instruction_storage)	/* 0x0400 */
238	EXCEPTION_STUB(0x0a0, external_input)		/* 0x0500 */
239	EXCEPTION_STUB(0x0c0, alignment)		/* 0x0600 */
240	EXCEPTION_STUB(0x0e0, program)			/* 0x0700 */
241	EXCEPTION_STUB(0x100, fp_unavailable)		/* 0x0800 */
242	EXCEPTION_STUB(0x120, system_call)		/* 0x0c00 */
243	EXCEPTION_STUB(0x140, ap_unavailable)		/* 0x0f20 */
244	EXCEPTION_STUB(0x160, decrementer)		/* 0x0900 */
245	EXCEPTION_STUB(0x180, fixed_interval)		/* 0x0980 */
246	EXCEPTION_STUB(0x1a0, watchdog)			/* 0x09f0 */
247	EXCEPTION_STUB(0x1c0, data_tlb_miss)
248	EXCEPTION_STUB(0x1e0, instruction_tlb_miss)
249
250#if 0
251	EXCEPTION_STUB(0x280, processor_doorbell)
252	EXCEPTION_STUB(0x220, processor_doorbell_crit)
253#endif
254	.globl interrupt_end_book3e
255interrupt_end_book3e:
256
257/* Critical Input Interrupt */
258	START_EXCEPTION(critical_input);
259	CRIT_EXCEPTION_PROLOG(0x100, PROLOG_ADDITION_NONE)
260//	EXCEPTION_COMMON(0x100, PACA_EXCRIT, INTS_DISABLE_ALL)
261//	bl	special_reg_save_crit
262//	addi	r3,r1,STACK_FRAME_OVERHEAD
263//	bl	.critical_exception
264//	b	ret_from_crit_except
265	b	.
266
267/* Machine Check Interrupt */
268	START_EXCEPTION(machine_check);
269	CRIT_EXCEPTION_PROLOG(0x200, PROLOG_ADDITION_NONE)
270//	EXCEPTION_COMMON(0x200, PACA_EXMC, INTS_DISABLE_ALL)
271//	bl	special_reg_save_mc
272//	addi	r3,r1,STACK_FRAME_OVERHEAD
273//	bl	.machine_check_exception
274//	b	ret_from_mc_except
275	b	.
276
277/* Data Storage Interrupt */
278	START_EXCEPTION(data_storage)
279	NORMAL_EXCEPTION_PROLOG(0x300, PROLOG_ADDITION_2REGS)
280	mfspr	r14,SPRN_DEAR
281	mfspr	r15,SPRN_ESR
282	EXCEPTION_COMMON(0x300, PACA_EXGEN, INTS_KEEP)
283	b	storage_fault_common
284
285/* Instruction Storage Interrupt */
286	START_EXCEPTION(instruction_storage);
287	NORMAL_EXCEPTION_PROLOG(0x400, PROLOG_ADDITION_2REGS)
288	li	r15,0
289	mr	r14,r10
290	EXCEPTION_COMMON(0x400, PACA_EXGEN, INTS_KEEP)
291	b	storage_fault_common
292
293/* External Input Interrupt */
294	MASKABLE_EXCEPTION(0x500, external_input, .do_IRQ, ACK_NONE)
295
296/* Alignment */
297	START_EXCEPTION(alignment);
298	NORMAL_EXCEPTION_PROLOG(0x600, PROLOG_ADDITION_2REGS)
299	mfspr	r14,SPRN_DEAR
300	mfspr	r15,SPRN_ESR
301	EXCEPTION_COMMON(0x600, PACA_EXGEN, INTS_KEEP)
302	b	alignment_more	/* no room, go out of line */
303
304/* Program Interrupt */
305	START_EXCEPTION(program);
306	NORMAL_EXCEPTION_PROLOG(0x700, PROLOG_ADDITION_1REG)
307	mfspr	r14,SPRN_ESR
308	EXCEPTION_COMMON(0x700, PACA_EXGEN, INTS_DISABLE_SOFT)
309	std	r14,_DSISR(r1)
310	addi	r3,r1,STACK_FRAME_OVERHEAD
311	ld	r14,PACA_EXGEN+EX_R14(r13)
312	bl	.save_nvgprs
313	INTS_RESTORE_HARD
314	bl	.program_check_exception
315	b	.ret_from_except
316
317/* Floating Point Unavailable Interrupt */
318	START_EXCEPTION(fp_unavailable);
319	NORMAL_EXCEPTION_PROLOG(0x800, PROLOG_ADDITION_NONE)
320	/* we can probably do a shorter exception entry for that one... */
321	EXCEPTION_COMMON(0x800, PACA_EXGEN, INTS_KEEP)
322	bne	1f			/* if from user, just load it up */
323	bl	.save_nvgprs
324	addi	r3,r1,STACK_FRAME_OVERHEAD
325	INTS_RESTORE_HARD
326	bl	.kernel_fp_unavailable_exception
327	BUG_OPCODE
3281:	ld	r12,_MSR(r1)
329	bl	.load_up_fpu
330	b	fast_exception_return
331
332/* Decrementer Interrupt */
333	MASKABLE_EXCEPTION(0x900, decrementer, .timer_interrupt, ACK_DEC)
334
335/* Fixed Interval Timer Interrupt */
336	MASKABLE_EXCEPTION(0x980, fixed_interval, .unknown_exception, ACK_FIT)
337
338/* Watchdog Timer Interrupt */
339	START_EXCEPTION(watchdog);
340	CRIT_EXCEPTION_PROLOG(0x9f0, PROLOG_ADDITION_NONE)
341//	EXCEPTION_COMMON(0x9f0, PACA_EXCRIT, INTS_DISABLE_ALL)
342//	bl	special_reg_save_crit
343//	addi	r3,r1,STACK_FRAME_OVERHEAD
344//	bl	.unknown_exception
345//	b	ret_from_crit_except
346	b	.
347
348/* System Call Interrupt */
349	START_EXCEPTION(system_call)
350	mr	r9,r13			/* keep a copy of userland r13 */
351	mfspr	r11,SPRN_SRR0		/* get return address */
352	mfspr	r12,SPRN_SRR1		/* get previous MSR */
353	mfspr	r13,SPRN_SPRG_PACA	/* get our PACA */
354	b	system_call_common
355
356/* Auxillary Processor Unavailable Interrupt */
357	START_EXCEPTION(ap_unavailable);
358	NORMAL_EXCEPTION_PROLOG(0xf20, PROLOG_ADDITION_NONE)
359	EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_KEEP)
360	addi	r3,r1,STACK_FRAME_OVERHEAD
361	bl	.save_nvgprs
362	INTS_RESTORE_HARD
363	bl	.unknown_exception
364	b	.ret_from_except
365
366/* Debug exception as a critical interrupt*/
367	START_EXCEPTION(debug_crit);
368	CRIT_EXCEPTION_PROLOG(0xd00, PROLOG_ADDITION_2REGS)
369
370	/*
371	 * If there is a single step or branch-taken exception in an
372	 * exception entry sequence, it was probably meant to apply to
373	 * the code where the exception occurred (since exception entry
374	 * doesn't turn off DE automatically).  We simulate the effect
375	 * of turning off DE on entry to an exception handler by turning
376	 * off DE in the CSRR1 value and clearing the debug status.
377	 */
378
379	mfspr	r14,SPRN_DBSR		/* check single-step/branch taken */
380	andis.	r15,r14,DBSR_IC@h
381	beq+	1f
382
383	LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e)
384	LOAD_REG_IMMEDIATE(r15,interrupt_end_book3e)
385	cmpld	cr0,r10,r14
386	cmpld	cr1,r10,r15
387	blt+	cr0,1f
388	bge+	cr1,1f
389
390	/* here it looks like we got an inappropriate debug exception. */
391	lis	r14,DBSR_IC@h		/* clear the IC event */
392	rlwinm	r11,r11,0,~MSR_DE	/* clear DE in the CSRR1 value */
393	mtspr	SPRN_DBSR,r14
394	mtspr	SPRN_CSRR1,r11
395	lwz	r10,PACA_EXCRIT+EX_CR(r13)	/* restore registers */
396	ld	r1,PACA_EXCRIT+EX_R1(r13)
397	ld	r14,PACA_EXCRIT+EX_R14(r13)
398	ld	r15,PACA_EXCRIT+EX_R15(r13)
399	mtcr	r10
400	ld	r10,PACA_EXCRIT+EX_R10(r13)	/* restore registers */
401	ld	r11,PACA_EXCRIT+EX_R11(r13)
402	mfspr	r13,SPRN_SPRG_CRIT_SCRATCH
403	rfci
404
405	/* Normal debug exception */
406	/* XXX We only handle coming from userspace for now since we can't
407	 *     quite save properly an interrupted kernel state yet
408	 */
4091:	andi.	r14,r11,MSR_PR;		/* check for userspace again */
410	beq	kernel_dbg_exc;		/* if from kernel mode */
411
412	/* Now we mash up things to make it look like we are coming on a
413	 * normal exception
414	 */
415	mfspr	r15,SPRN_SPRG_CRIT_SCRATCH
416	mtspr	SPRN_SPRG_GEN_SCRATCH,r15
417	mfspr	r14,SPRN_DBSR
418	EXCEPTION_COMMON(0xd00, PACA_EXCRIT, INTS_DISABLE_ALL)
419	std	r14,_DSISR(r1)
420	addi	r3,r1,STACK_FRAME_OVERHEAD
421	mr	r4,r14
422	ld	r14,PACA_EXCRIT+EX_R14(r13)
423	ld	r15,PACA_EXCRIT+EX_R15(r13)
424	bl	.save_nvgprs
425	bl	.DebugException
426	b	.ret_from_except
427
428kernel_dbg_exc:
429	b	.	/* NYI */
430
431
432/*
433 * An interrupt came in while soft-disabled; clear EE in SRR1,
434 * clear paca->hard_enabled and return.
435 */
436masked_interrupt_book3e:
437	mtcr	r10
438	stb	r11,PACAHARDIRQEN(r13)
439	mfspr	r10,SPRN_SRR1
440	rldicl	r11,r10,48,1		/* clear MSR_EE */
441	rotldi	r10,r11,16
442	mtspr	SPRN_SRR1,r10
443	ld	r10,PACA_EXGEN+EX_R10(r13);	/* restore registers */
444	ld	r11,PACA_EXGEN+EX_R11(r13);
445	mfspr	r13,SPRN_SPRG_GEN_SCRATCH;
446	rfi
447	b	.
448
449/*
450 * This is called from 0x300 and 0x400 handlers after the prologs with
451 * r14 and r15 containing the fault address and error code, with the
452 * original values stashed away in the PACA
453 */
454storage_fault_common:
455	std	r14,_DAR(r1)
456	std	r15,_DSISR(r1)
457	addi	r3,r1,STACK_FRAME_OVERHEAD
458	mr	r4,r14
459	mr	r5,r15
460	ld	r14,PACA_EXGEN+EX_R14(r13)
461	ld	r15,PACA_EXGEN+EX_R15(r13)
462	INTS_RESTORE_HARD
463	bl	.do_page_fault
464	cmpdi	r3,0
465	bne-	1f
466	b	.ret_from_except_lite
4671:	bl	.save_nvgprs
468	mr	r5,r3
469	addi	r3,r1,STACK_FRAME_OVERHEAD
470	ld	r4,_DAR(r1)
471	bl	.bad_page_fault
472	b	.ret_from_except
473
474/*
475 * Alignment exception doesn't fit entirely in the 0x100 bytes so it
476 * continues here.
477 */
478alignment_more:
479	std	r14,_DAR(r1)
480	std	r15,_DSISR(r1)
481	addi	r3,r1,STACK_FRAME_OVERHEAD
482	ld	r14,PACA_EXGEN+EX_R14(r13)
483	ld	r15,PACA_EXGEN+EX_R15(r13)
484	bl	.save_nvgprs
485	INTS_RESTORE_HARD
486	bl	.alignment_exception
487	b	.ret_from_except
488
489/*
490 * We branch here from entry_64.S for the last stage of the exception
491 * return code path. MSR:EE is expected to be off at that point
492 */
493_GLOBAL(exception_return_book3e)
494	b	1f
495
496/* This is the return from load_up_fpu fast path which could do with
497 * less GPR restores in fact, but for now we have a single return path
498 */
499	.globl fast_exception_return
500fast_exception_return:
501	wrteei	0
5021:	mr	r0,r13
503	ld	r10,_MSR(r1)
504	REST_4GPRS(2, r1)
505	andi.	r6,r10,MSR_PR
506	REST_2GPRS(6, r1)
507	beq	1f
508	ACCOUNT_CPU_USER_EXIT(r10, r11)
509	ld	r0,GPR13(r1)
510
5111:	stdcx.	r0,0,r1		/* to clear the reservation */
512
513	ld	r8,_CCR(r1)
514	ld	r9,_LINK(r1)
515	ld	r10,_CTR(r1)
516	ld	r11,_XER(r1)
517	mtcr	r8
518	mtlr	r9
519	mtctr	r10
520	mtxer	r11
521	REST_2GPRS(8, r1)
522	ld	r10,GPR10(r1)
523	ld	r11,GPR11(r1)
524	ld	r12,GPR12(r1)
525	mtspr	SPRN_SPRG_GEN_SCRATCH,r0
526
527	std	r10,PACA_EXGEN+EX_R10(r13);
528	std	r11,PACA_EXGEN+EX_R11(r13);
529	ld	r10,_NIP(r1)
530	ld	r11,_MSR(r1)
531	ld	r0,GPR0(r1)
532	ld	r1,GPR1(r1)
533	mtspr	SPRN_SRR0,r10
534	mtspr	SPRN_SRR1,r11
535	ld	r10,PACA_EXGEN+EX_R10(r13)
536	ld	r11,PACA_EXGEN+EX_R11(r13)
537	mfspr	r13,SPRN_SPRG_GEN_SCRATCH
538	rfi
539
540/*
541 * Trampolines used when spotting a bad kernel stack pointer in
542 * the exception entry code.
543 *
544 * TODO: move some bits like SRR0 read to trampoline, pass PACA
545 * index around, etc... to handle crit & mcheck
546 */
547BAD_STACK_TRAMPOLINE(0x000)
548BAD_STACK_TRAMPOLINE(0x100)
549BAD_STACK_TRAMPOLINE(0x200)
550BAD_STACK_TRAMPOLINE(0x300)
551BAD_STACK_TRAMPOLINE(0x400)
552BAD_STACK_TRAMPOLINE(0x500)
553BAD_STACK_TRAMPOLINE(0x600)
554BAD_STACK_TRAMPOLINE(0x700)
555BAD_STACK_TRAMPOLINE(0x800)
556BAD_STACK_TRAMPOLINE(0x900)
557BAD_STACK_TRAMPOLINE(0x980)
558BAD_STACK_TRAMPOLINE(0x9f0)
559BAD_STACK_TRAMPOLINE(0xa00)
560BAD_STACK_TRAMPOLINE(0xb00)
561BAD_STACK_TRAMPOLINE(0xc00)
562BAD_STACK_TRAMPOLINE(0xd00)
563BAD_STACK_TRAMPOLINE(0xe00)
564BAD_STACK_TRAMPOLINE(0xf00)
565BAD_STACK_TRAMPOLINE(0xf20)
566
567	.globl	bad_stack_book3e
568bad_stack_book3e:
569	/* XXX: Needs to make SPRN_SPRG_GEN depend on exception type */
570	mfspr	r10,SPRN_SRR0;		  /* read SRR0 before touching stack */
571	ld	r1,PACAEMERGSP(r13)
572	subi	r1,r1,64+INT_FRAME_SIZE
573	std	r10,_NIP(r1)
574	std	r11,_MSR(r1)
575	ld	r10,PACA_EXGEN+EX_R1(r13) /* FIXME for crit & mcheck */
576	lwz	r11,PACA_EXGEN+EX_CR(r13) /* FIXME for crit & mcheck */
577	std	r10,GPR1(r1)
578	std	r11,_CCR(r1)
579	mfspr	r10,SPRN_DEAR
580	mfspr	r11,SPRN_ESR
581	std	r10,_DAR(r1)
582	std	r11,_DSISR(r1)
583	std	r0,GPR0(r1);		/* save r0 in stackframe */	    \
584	std	r2,GPR2(r1);		/* save r2 in stackframe */	    \
585	SAVE_4GPRS(3, r1);		/* save r3 - r6 in stackframe */    \
586	SAVE_2GPRS(7, r1);		/* save r7, r8 in stackframe */	    \
587	std	r9,GPR9(r1);		/* save r9 in stackframe */	    \
588	ld	r3,PACA_EXGEN+EX_R10(r13);/* get back r10 */		    \
589	ld	r4,PACA_EXGEN+EX_R11(r13);/* get back r11 */		    \
590	mfspr	r5,SPRN_SPRG_GEN_SCRATCH;/* get back r13 XXX can be wrong */ \
591	std	r3,GPR10(r1);		/* save r10 to stackframe */	    \
592	std	r4,GPR11(r1);		/* save r11 to stackframe */	    \
593	std	r12,GPR12(r1);		/* save r12 in stackframe */	    \
594	std	r5,GPR13(r1);		/* save it to stackframe */	    \
595	mflr	r10
596	mfctr	r11
597	mfxer	r12
598	std	r10,_LINK(r1)
599	std	r11,_CTR(r1)
600	std	r12,_XER(r1)
601	SAVE_10GPRS(14,r1)
602	SAVE_8GPRS(24,r1)
603	lhz	r12,PACA_TRAP_SAVE(r13)
604	std	r12,_TRAP(r1)
605	addi	r11,r1,INT_FRAME_SIZE
606	std	r11,0(r1)
607	li	r12,0
608	std	r12,0(r11)
609	ld	r2,PACATOC(r13)
6101:	addi	r3,r1,STACK_FRAME_OVERHEAD
611	bl	.kernel_bad_stack
612	b	1b
613
614/*
615 * Setup the initial TLB for a core. This current implementation
616 * assume that whatever we are running off will not conflict with
617 * the new mapping at PAGE_OFFSET.
618 */
619_GLOBAL(initial_tlb_book3e)
620
621	/* Look for the first TLB with IPROT set */
622	mfspr	r4,SPRN_TLB0CFG
623	andi.	r3,r4,TLBnCFG_IPROT
624	lis	r3,MAS0_TLBSEL(0)@h
625	bne	found_iprot
626
627	mfspr	r4,SPRN_TLB1CFG
628	andi.	r3,r4,TLBnCFG_IPROT
629	lis	r3,MAS0_TLBSEL(1)@h
630	bne	found_iprot
631
632	mfspr	r4,SPRN_TLB2CFG
633	andi.	r3,r4,TLBnCFG_IPROT
634	lis	r3,MAS0_TLBSEL(2)@h
635	bne	found_iprot
636
637	lis	r3,MAS0_TLBSEL(3)@h
638	mfspr	r4,SPRN_TLB3CFG
639	/* fall through */
640
641found_iprot:
642	andi.	r5,r4,TLBnCFG_HES
643	bne	have_hes
644
645	mflr	r8				/* save LR */
646/* 1. Find the index of the entry we're executing in
647 *
648 * r3 = MAS0_TLBSEL (for the iprot array)
649 * r4 = SPRN_TLBnCFG
650 */
651	bl	invstr				/* Find our address */
652invstr:	mflr	r6				/* Make it accessible */
653	mfmsr	r7
654	rlwinm	r5,r7,27,31,31			/* extract MSR[IS] */
655	mfspr	r7,SPRN_PID
656	slwi	r7,r7,16
657	or	r7,r7,r5
658	mtspr	SPRN_MAS6,r7
659	tlbsx	0,r6				/* search MSR[IS], SPID=PID */
660
661	mfspr	r3,SPRN_MAS0
662	rlwinm	r5,r3,16,20,31			/* Extract MAS0(Entry) */
663
664	mfspr	r7,SPRN_MAS1			/* Insure IPROT set */
665	oris	r7,r7,MAS1_IPROT@h
666	mtspr	SPRN_MAS1,r7
667	tlbwe
668
669/* 2. Invalidate all entries except the entry we're executing in
670 *
671 * r3 = MAS0 w/TLBSEL & ESEL for the entry we are running in
672 * r4 = SPRN_TLBnCFG
673 * r5 = ESEL of entry we are running in
674 */
675	andi.	r4,r4,TLBnCFG_N_ENTRY		/* Extract # entries */
676	li	r6,0				/* Set Entry counter to 0 */
6771:	mr	r7,r3				/* Set MAS0(TLBSEL) */
678	rlwimi	r7,r6,16,4,15			/* Setup MAS0 = TLBSEL | ESEL(r6) */
679	mtspr	SPRN_MAS0,r7
680	tlbre
681	mfspr	r7,SPRN_MAS1
682	rlwinm	r7,r7,0,2,31			/* Clear MAS1 Valid and IPROT */
683	cmpw	r5,r6
684	beq	skpinv				/* Dont update the current execution TLB */
685	mtspr	SPRN_MAS1,r7
686	tlbwe
687	isync
688skpinv:	addi	r6,r6,1				/* Increment */
689	cmpw	r6,r4				/* Are we done? */
690	bne	1b				/* If not, repeat */
691
692	/* Invalidate all TLBs */
693	PPC_TLBILX_ALL(0,0)
694	sync
695	isync
696
697/* 3. Setup a temp mapping and jump to it
698 *
699 * r3 = MAS0 w/TLBSEL & ESEL for the entry we are running in
700 * r5 = ESEL of entry we are running in
701 */
702	andi.	r7,r5,0x1	/* Find an entry not used and is non-zero */
703	addi	r7,r7,0x1
704	mr	r4,r3		/* Set MAS0(TLBSEL) = 1 */
705	mtspr	SPRN_MAS0,r4
706	tlbre
707
708	rlwimi	r4,r7,16,4,15	/* Setup MAS0 = TLBSEL | ESEL(r7) */
709	mtspr	SPRN_MAS0,r4
710
711	mfspr	r7,SPRN_MAS1
712	xori	r6,r7,MAS1_TS		/* Setup TMP mapping in the other Address space */
713	mtspr	SPRN_MAS1,r6
714
715	tlbwe
716
717	mfmsr	r6
718	xori	r6,r6,MSR_IS
719	mtspr	SPRN_SRR1,r6
720	bl	1f		/* Find our address */
7211:	mflr	r6
722	addi	r6,r6,(2f - 1b)
723	mtspr	SPRN_SRR0,r6
724	rfi
7252:
726
727/* 4. Clear out PIDs & Search info
728 *
729 * r3 = MAS0 w/TLBSEL & ESEL for the entry we started in
730 * r4 = MAS0 w/TLBSEL & ESEL for the temp mapping
731 * r5 = MAS3
732 */
733	li	r6,0
734	mtspr   SPRN_MAS6,r6
735	mtspr	SPRN_PID,r6
736
737/* 5. Invalidate mapping we started in
738 *
739 * r3 = MAS0 w/TLBSEL & ESEL for the entry we started in
740 * r4 = MAS0 w/TLBSEL & ESEL for the temp mapping
741 * r5 = MAS3
742 */
743	mtspr	SPRN_MAS0,r3
744	tlbre
745	mfspr	r6,SPRN_MAS1
746	rlwinm	r6,r6,0,2,0	/* clear IPROT */
747	mtspr	SPRN_MAS1,r6
748	tlbwe
749
750	/* Invalidate TLB1 */
751	PPC_TLBILX_ALL(0,0)
752	sync
753	isync
754
755/* The mapping only needs to be cache-coherent on SMP */
756#ifdef CONFIG_SMP
757#define M_IF_SMP	MAS2_M
758#else
759#define M_IF_SMP	0
760#endif
761
762/* 6. Setup KERNELBASE mapping in TLB[0]
763 *
764 * r3 = MAS0 w/TLBSEL & ESEL for the entry we started in
765 * r4 = MAS0 w/TLBSEL & ESEL for the temp mapping
766 * r5 = MAS3
767 */
768	rlwinm	r3,r3,0,16,3	/* clear ESEL */
769	mtspr	SPRN_MAS0,r3
770	lis	r6,(MAS1_VALID|MAS1_IPROT)@h
771	ori	r6,r6,(MAS1_TSIZE(BOOK3E_PAGESZ_1GB))@l
772	mtspr	SPRN_MAS1,r6
773
774	LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET | M_IF_SMP)
775	mtspr	SPRN_MAS2,r6
776
777	rlwinm	r5,r5,0,0,25
778	ori	r5,r5,MAS3_SR | MAS3_SW | MAS3_SX
779	mtspr	SPRN_MAS3,r5
780	li	r5,-1
781	rlwinm	r5,r5,0,0,25
782
783	tlbwe
784
785/* 7. Jump to KERNELBASE mapping
786 *
787 * r4 = MAS0 w/TLBSEL & ESEL for the temp mapping
788 */
789	/* Now we branch the new virtual address mapped by this entry */
790	LOAD_REG_IMMEDIATE(r6,2f)
791	lis	r7,MSR_KERNEL@h
792	ori	r7,r7,MSR_KERNEL@l
793	mtspr	SPRN_SRR0,r6
794	mtspr	SPRN_SRR1,r7
795	rfi				/* start execution out of TLB1[0] entry */
7962:
797
798/* 8. Clear out the temp mapping
799 *
800 * r4 = MAS0 w/TLBSEL & ESEL for the entry we are running in
801 */
802	mtspr	SPRN_MAS0,r4
803	tlbre
804	mfspr	r5,SPRN_MAS1
805	rlwinm	r5,r5,0,2,0	/* clear IPROT */
806	mtspr	SPRN_MAS1,r5
807	tlbwe
808
809	/* Invalidate TLB1 */
810	PPC_TLBILX_ALL(0,0)
811	sync
812	isync
813
814	/* We translate LR and return */
815	tovirt(r8,r8)
816	mtlr	r8
817	blr
818
819have_hes:
820	/* Setup MAS 0,1,2,3 and 7 for tlbwe of a 1G entry that maps the
821	 * kernel linear mapping. We also set MAS8 once for all here though
822	 * that will have to be made dependent on whether we are running under
823	 * a hypervisor I suppose.
824	 */
825	ori	r3,r3,MAS0_HES | MAS0_WQ_ALLWAYS
826	mtspr	SPRN_MAS0,r3
827	lis	r3,(MAS1_VALID | MAS1_IPROT)@h
828	ori	r3,r3,BOOK3E_PAGESZ_1GB << MAS1_TSIZE_SHIFT
829	mtspr	SPRN_MAS1,r3
830	LOAD_REG_IMMEDIATE(r3, PAGE_OFFSET | MAS2_M)
831	mtspr	SPRN_MAS2,r3
832	li	r3,MAS3_SR | MAS3_SW | MAS3_SX
833	mtspr	SPRN_MAS7_MAS3,r3
834	li	r3,0
835	mtspr	SPRN_MAS8,r3
836
837	/* Write the TLB entry */
838	tlbwe
839
840	/* Now we branch the new virtual address mapped by this entry */
841	LOAD_REG_IMMEDIATE(r3,1f)
842	mtctr	r3
843	bctr
844
8451:	/* We are now running at PAGE_OFFSET, clean the TLB of everything
846	 * else (XXX we should scan for bolted crap from the firmware too)
847	 */
848	PPC_TLBILX(0,0,0)
849	sync
850	isync
851
852	/* We translate LR and return */
853	mflr	r3
854	tovirt(r3,r3)
855	mtlr	r3
856	blr
857
858/*
859 * Main entry (boot CPU, thread 0)
860 *
861 * We enter here from head_64.S, possibly after the prom_init trampoline
862 * with r3 and r4 already saved to r31 and 30 respectively and in 64 bits
863 * mode. Anything else is as it was left by the bootloader
864 *
865 * Initial requirements of this port:
866 *
867 * - Kernel loaded at 0 physical
868 * - A good lump of memory mapped 0:0 by UTLB entry 0
869 * - MSR:IS & MSR:DS set to 0
870 *
871 * Note that some of the above requirements will be relaxed in the future
872 * as the kernel becomes smarter at dealing with different initial conditions
873 * but for now you have to be careful
874 */
875_GLOBAL(start_initialization_book3e)
876	mflr	r28
877
878	/* First, we need to setup some initial TLBs to map the kernel
879	 * text, data and bss at PAGE_OFFSET. We don't have a real mode
880	 * and always use AS 0, so we just set it up to match our link
881	 * address and never use 0 based addresses.
882	 */
883	bl	.initial_tlb_book3e
884
885	/* Init global core bits */
886	bl	.init_core_book3e
887
888	/* Init per-thread bits */
889	bl	.init_thread_book3e
890
891	/* Return to common init code */
892	tovirt(r28,r28)
893	mtlr	r28
894	blr
895
896
897/*
898 * Secondary core/processor entry
899 *
900 * This is entered for thread 0 of a secondary core, all other threads
901 * are expected to be stopped. It's similar to start_initialization_book3e
902 * except that it's generally entered from the holding loop in head_64.S
903 * after CPUs have been gathered by Open Firmware.
904 *
905 * We assume we are in 32 bits mode running with whatever TLB entry was
906 * set for us by the firmware or POR engine.
907 */
908_GLOBAL(book3e_secondary_core_init_tlb_set)
909	li	r4,1
910	b	.generic_secondary_smp_init
911
912_GLOBAL(book3e_secondary_core_init)
913	mflr	r28
914
915	/* Do we need to setup initial TLB entry ? */
916	cmplwi	r4,0
917	bne	2f
918
919	/* Setup TLB for this core */
920	bl	.initial_tlb_book3e
921
922	/* We can return from the above running at a different
923	 * address, so recalculate r2 (TOC)
924	 */
925	bl	.relative_toc
926
927	/* Init global core bits */
9282:	bl	.init_core_book3e
929
930	/* Init per-thread bits */
9313:	bl	.init_thread_book3e
932
933	/* Return to common init code at proper virtual address.
934	 *
935	 * Due to various previous assumptions, we know we entered this
936	 * function at either the final PAGE_OFFSET mapping or using a
937	 * 1:1 mapping at 0, so we don't bother doing a complicated check
938	 * here, we just ensure the return address has the right top bits.
939	 *
940	 * Note that if we ever want to be smarter about where we can be
941	 * started from, we have to be careful that by the time we reach
942	 * the code below we may already be running at a different location
943	 * than the one we were called from since initial_tlb_book3e can
944	 * have moved us already.
945	 */
946	cmpdi	cr0,r28,0
947	blt	1f
948	lis	r3,PAGE_OFFSET@highest
949	sldi	r3,r3,32
950	or	r28,r28,r3
9511:	mtlr	r28
952	blr
953
954_GLOBAL(book3e_secondary_thread_init)
955	mflr	r28
956	b	3b
957
958_STATIC(init_core_book3e)
959	/* Establish the interrupt vector base */
960	LOAD_REG_IMMEDIATE(r3, interrupt_base_book3e)
961	mtspr	SPRN_IVPR,r3
962	sync
963	blr
964
965_STATIC(init_thread_book3e)
966	lis	r3,(SPRN_EPCR_ICM | SPRN_EPCR_GICM)@h
967	mtspr	SPRN_EPCR,r3
968
969	/* Make sure interrupts are off */
970	wrteei	0
971
972	/* disable all timers and clear out status */
973	li	r3,0
974	mtspr	SPRN_TCR,r3
975	mfspr	r3,SPRN_TSR
976	mtspr	SPRN_TSR,r3
977
978	blr
979
980_GLOBAL(__setup_base_ivors)
981	SET_IVOR(0, 0x020) /* Critical Input */
982	SET_IVOR(1, 0x000) /* Machine Check */
983	SET_IVOR(2, 0x060) /* Data Storage */
984	SET_IVOR(3, 0x080) /* Instruction Storage */
985	SET_IVOR(4, 0x0a0) /* External Input */
986	SET_IVOR(5, 0x0c0) /* Alignment */
987	SET_IVOR(6, 0x0e0) /* Program */
988	SET_IVOR(7, 0x100) /* FP Unavailable */
989	SET_IVOR(8, 0x120) /* System Call */
990	SET_IVOR(9, 0x140) /* Auxiliary Processor Unavailable */
991	SET_IVOR(10, 0x160) /* Decrementer */
992	SET_IVOR(11, 0x180) /* Fixed Interval Timer */
993	SET_IVOR(12, 0x1a0) /* Watchdog Timer */
994	SET_IVOR(13, 0x1c0) /* Data TLB Error */
995	SET_IVOR(14, 0x1e0) /* Instruction TLB Error */
996	SET_IVOR(15, 0x040) /* Debug */
997
998	sync
999
1000	blr
1001