xref: /openbmc/linux/arch/sparc/kernel/ktlb.S (revision d2168146) 
1/* arch/sparc64/kernel/ktlb.S: Kernel mapping TLB miss handling.
2 *
3 * Copyright (C) 1995, 1997, 2005, 2008 David S. Miller <davem@davemloft.net>
4 * Copyright (C) 1996 Eddie C. Dost        (ecd@brainaid.de)
5 * Copyright (C) 1996 Miguel de Icaza      (miguel@nuclecu.unam.mx)
6 * Copyright (C) 1996,98,99 Jakub Jelinek  (jj@sunsite.mff.cuni.cz)
7 */
8
9#include <asm/head.h>
10#include <asm/asi.h>
11#include <asm/page.h>
12#include <asm/pgtable.h>
13#include <asm/tsb.h>
14
15	.text
16	.align		32
17
18kvmap_itlb:
19	/* g6: TAG TARGET */
20	mov		TLB_TAG_ACCESS, %g4
21	ldxa		[%g4] ASI_IMMU, %g4
22
23	/* sun4v_itlb_miss branches here with the missing virtual
24	 * address already loaded into %g4
25	 */
26kvmap_itlb_4v:
27
28	/* Catch kernel NULL pointer calls.  */
29	sethi		%hi(PAGE_SIZE), %g5
30	cmp		%g4, %g5
31	blu,pn		%xcc, kvmap_itlb_longpath
32	 nop
33
34	KERN_TSB_LOOKUP_TL1(%g4, %g6, %g5, %g1, %g2, %g3, kvmap_itlb_load)
35
36kvmap_itlb_tsb_miss:
37	sethi		%hi(LOW_OBP_ADDRESS), %g5
38	cmp		%g4, %g5
39	blu,pn		%xcc, kvmap_itlb_vmalloc_addr
40	 mov		0x1, %g5
41	sllx		%g5, 32, %g5
42	cmp		%g4, %g5
43	blu,pn		%xcc, kvmap_itlb_obp
44	 nop
45
46kvmap_itlb_vmalloc_addr:
47	KERN_PGTABLE_WALK(%g4, %g5, %g2, kvmap_itlb_longpath)
48
49	TSB_LOCK_TAG(%g1, %g2, %g7)
50
51	/* Load and check PTE.  */
52	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
53	mov		1, %g7
54	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
55	brgez,a,pn	%g5, kvmap_itlb_longpath
56	 TSB_STORE(%g1, %g7)
57
58	TSB_WRITE(%g1, %g5, %g6)
59
60	/* fallthrough to TLB load */
61
62kvmap_itlb_load:
63
64661:	stxa		%g5, [%g0] ASI_ITLB_DATA_IN
65	retry
66	.section	.sun4v_2insn_patch, "ax"
67	.word		661b
68	nop
69	nop
70	.previous
71
72	/* For sun4v the ASI_ITLB_DATA_IN store and the retry
73	 * instruction get nop'd out and we get here to branch
74	 * to the sun4v tlb load code.  The registers are setup
75	 * as follows:
76	 *
77	 * %g4: vaddr
78	 * %g5: PTE
79	 * %g6:	TAG
80	 *
81	 * The sun4v TLB load wants the PTE in %g3 so we fix that
82	 * up here.
83	 */
84	ba,pt		%xcc, sun4v_itlb_load
85	 mov		%g5, %g3
86
87kvmap_itlb_longpath:
88
89661:	rdpr	%pstate, %g5
90	wrpr	%g5, PSTATE_AG | PSTATE_MG, %pstate
91	.section .sun4v_2insn_patch, "ax"
92	.word	661b
93	SET_GL(1)
94	nop
95	.previous
96
97	rdpr	%tpc, %g5
98	ba,pt	%xcc, sparc64_realfault_common
99	 mov	FAULT_CODE_ITLB, %g4
100
101kvmap_itlb_obp:
102	OBP_TRANS_LOOKUP(%g4, %g5, %g2, %g3, kvmap_itlb_longpath)
103
104	TSB_LOCK_TAG(%g1, %g2, %g7)
105
106	TSB_WRITE(%g1, %g5, %g6)
107
108	ba,pt		%xcc, kvmap_itlb_load
109	 nop
110
111kvmap_dtlb_obp:
112	OBP_TRANS_LOOKUP(%g4, %g5, %g2, %g3, kvmap_dtlb_longpath)
113
114	TSB_LOCK_TAG(%g1, %g2, %g7)
115
116	TSB_WRITE(%g1, %g5, %g6)
117
118	ba,pt		%xcc, kvmap_dtlb_load
119	 nop
120
121	.align		32
122kvmap_dtlb_tsb4m_load:
123	TSB_LOCK_TAG(%g1, %g2, %g7)
124	TSB_WRITE(%g1, %g5, %g6)
125	ba,pt		%xcc, kvmap_dtlb_load
126	 nop
127
128kvmap_dtlb:
129	/* %g6: TAG TARGET */
130	mov		TLB_TAG_ACCESS, %g4
131	ldxa		[%g4] ASI_DMMU, %g4
132
133	/* sun4v_dtlb_miss branches here with the missing virtual
134	 * address already loaded into %g4
135	 */
136kvmap_dtlb_4v:
137	brgez,pn	%g4, kvmap_dtlb_nonlinear
138	 nop
139
140#ifdef CONFIG_DEBUG_PAGEALLOC
141	/* Index through the base page size TSB even for linear
142	 * mappings when using page allocation debugging.
143	 */
144	KERN_TSB_LOOKUP_TL1(%g4, %g6, %g5, %g1, %g2, %g3, kvmap_dtlb_load)
145#else
146	/* Correct TAG_TARGET is already in %g6, check 4mb TSB.  */
147	KERN_TSB4M_LOOKUP_TL1(%g6, %g5, %g1, %g2, %g3, kvmap_dtlb_load)
148#endif
149	/* TSB entry address left in %g1, lookup linear PTE.
150	 * Must preserve %g1 and %g6 (TAG).
151	 */
152kvmap_dtlb_tsb4m_miss:
153	/* Clear the PAGE_OFFSET top virtual bits, shift
154	 * down to get PFN, and make sure PFN is in range.
155	 */
156661:	sllx		%g4, 0, %g5
157	.section	.page_offset_shift_patch, "ax"
158	.word		661b
159	.previous
160
161	/* Check to see if we know about valid memory at the 4MB
162	 * chunk this physical address will reside within.
163	 */
164661:	srlx		%g5, MAX_PHYS_ADDRESS_BITS, %g2
165	.section	.page_offset_shift_patch, "ax"
166	.word		661b
167	.previous
168
169	brnz,pn		%g2, kvmap_dtlb_longpath
170	 nop
171
172	/* This unconditional branch and delay-slot nop gets patched
173	 * by the sethi sequence once the bitmap is properly setup.
174	 */
175	.globl		valid_addr_bitmap_insn
176valid_addr_bitmap_insn:
177	ba,pt		%xcc, 2f
178	 nop
179	.subsection	2
180	.globl		valid_addr_bitmap_patch
181valid_addr_bitmap_patch:
182	sethi		%hi(sparc64_valid_addr_bitmap), %g7
183	or		%g7, %lo(sparc64_valid_addr_bitmap), %g7
184	.previous
185
186661:	srlx		%g5, ILOG2_4MB, %g2
187	.section	.page_offset_shift_patch, "ax"
188	.word		661b
189	.previous
190
191	srlx		%g2, 6, %g5
192	and		%g2, 63, %g2
193	sllx		%g5, 3, %g5
194	ldx		[%g7 + %g5], %g5
195	mov		1, %g7
196	sllx		%g7, %g2, %g7
197	andcc		%g5, %g7, %g0
198	be,pn		%xcc, kvmap_dtlb_longpath
199
2002:	 sethi		%hi(kpte_linear_bitmap), %g2
201
202	/* Get the 256MB physical address index. */
203661:	sllx		%g4, 0, %g5
204	.section	.page_offset_shift_patch, "ax"
205	.word		661b
206	.previous
207
208	or		%g2, %lo(kpte_linear_bitmap), %g2
209
210661:	srlx		%g5, ILOG2_256MB, %g5
211	.section	.page_offset_shift_patch, "ax"
212	.word		661b
213	.previous
214
215	and		%g5, (32 - 1), %g7
216
217	/* Divide by 32 to get the offset into the bitmask.  */
218	srlx		%g5, 5, %g5
219	add		%g7, %g7, %g7
220	sllx		%g5, 3, %g5
221
222	/* kern_linear_pte_xor[(mask >> shift) & 3)] */
223	ldx		[%g2 + %g5], %g2
224	srlx		%g2, %g7, %g7
225	sethi		%hi(kern_linear_pte_xor), %g5
226	and		%g7, 3, %g7
227	or		%g5, %lo(kern_linear_pte_xor), %g5
228	sllx		%g7, 3, %g7
229	ldx		[%g5 + %g7], %g2
230
231	.globl		kvmap_linear_patch
232kvmap_linear_patch:
233	ba,pt		%xcc, kvmap_dtlb_tsb4m_load
234	 xor		%g2, %g4, %g5
235
236kvmap_dtlb_vmalloc_addr:
237	KERN_PGTABLE_WALK(%g4, %g5, %g2, kvmap_dtlb_longpath)
238
239	TSB_LOCK_TAG(%g1, %g2, %g7)
240
241	/* Load and check PTE.  */
242	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
243	mov		1, %g7
244	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
245	brgez,a,pn	%g5, kvmap_dtlb_longpath
246	 TSB_STORE(%g1, %g7)
247
248	TSB_WRITE(%g1, %g5, %g6)
249
250	/* fallthrough to TLB load */
251
252kvmap_dtlb_load:
253
254661:	stxa		%g5, [%g0] ASI_DTLB_DATA_IN	! Reload TLB
255	retry
256	.section	.sun4v_2insn_patch, "ax"
257	.word		661b
258	nop
259	nop
260	.previous
261
262	/* For sun4v the ASI_DTLB_DATA_IN store and the retry
263	 * instruction get nop'd out and we get here to branch
264	 * to the sun4v tlb load code.  The registers are setup
265	 * as follows:
266	 *
267	 * %g4: vaddr
268	 * %g5: PTE
269	 * %g6:	TAG
270	 *
271	 * The sun4v TLB load wants the PTE in %g3 so we fix that
272	 * up here.
273	 */
274	ba,pt		%xcc, sun4v_dtlb_load
275	 mov		%g5, %g3
276
277#ifdef CONFIG_SPARSEMEM_VMEMMAP
278kvmap_vmemmap:
279	sub		%g4, %g5, %g5
280	srlx		%g5, ILOG2_4MB, %g5
281	sethi		%hi(vmemmap_table), %g1
282	sllx		%g5, 3, %g5
283	or		%g1, %lo(vmemmap_table), %g1
284	ba,pt		%xcc, kvmap_dtlb_load
285	 ldx		[%g1 + %g5], %g5
286#endif
287
288kvmap_dtlb_nonlinear:
289	/* Catch kernel NULL pointer derefs.  */
290	sethi		%hi(PAGE_SIZE), %g5
291	cmp		%g4, %g5
292	bleu,pn		%xcc, kvmap_dtlb_longpath
293	 nop
294
295#ifdef CONFIG_SPARSEMEM_VMEMMAP
296	/* Do not use the TSB for vmemmap.  */
297	mov		(VMEMMAP_BASE >> 40), %g5
298	sllx		%g5, 40, %g5
299	cmp		%g4,%g5
300	bgeu,pn		%xcc, kvmap_vmemmap
301	 nop
302#endif
303
304	KERN_TSB_LOOKUP_TL1(%g4, %g6, %g5, %g1, %g2, %g3, kvmap_dtlb_load)
305
306kvmap_dtlb_tsbmiss:
307	sethi		%hi(MODULES_VADDR), %g5
308	cmp		%g4, %g5
309	blu,pn		%xcc, kvmap_dtlb_longpath
310	 mov		(VMALLOC_END >> 40), %g5
311	sllx		%g5, 40, %g5
312	cmp		%g4, %g5
313	bgeu,pn		%xcc, kvmap_dtlb_longpath
314	 nop
315
316kvmap_check_obp:
317	sethi		%hi(LOW_OBP_ADDRESS), %g5
318	cmp		%g4, %g5
319	blu,pn		%xcc, kvmap_dtlb_vmalloc_addr
320	 mov		0x1, %g5
321	sllx		%g5, 32, %g5
322	cmp		%g4, %g5
323	blu,pn		%xcc, kvmap_dtlb_obp
324	 nop
325	ba,pt		%xcc, kvmap_dtlb_vmalloc_addr
326	 nop
327
328kvmap_dtlb_longpath:
329
330661:	rdpr	%pstate, %g5
331	wrpr	%g5, PSTATE_AG | PSTATE_MG, %pstate
332	.section .sun4v_2insn_patch, "ax"
333	.word	661b
334	SET_GL(1)
335	ldxa		[%g0] ASI_SCRATCHPAD, %g5
336	.previous
337
338	rdpr	%tl, %g3
339	cmp	%g3, 1
340
341661:	mov	TLB_TAG_ACCESS, %g4
342	ldxa	[%g4] ASI_DMMU, %g5
343	.section .sun4v_2insn_patch, "ax"
344	.word	661b
345	ldx	[%g5 + HV_FAULT_D_ADDR_OFFSET], %g5
346	nop
347	.previous
348
349	be,pt	%xcc, sparc64_realfault_common
350	 mov	FAULT_CODE_DTLB, %g4
351	ba,pt	%xcc, winfix_trampoline
352	 nop
353