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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
28kvmap_itlb_nonlinear:
29	/* Catch kernel NULL pointer calls.  */
30	sethi		%hi(PAGE_SIZE), %g5
31	cmp		%g4, %g5
32	bleu,pn		%xcc, kvmap_dtlb_longpath
33	 nop
34
35	KERN_TSB_LOOKUP_TL1(%g4, %g6, %g5, %g1, %g2, %g3, kvmap_itlb_load)
36
37kvmap_itlb_tsb_miss:
38	sethi		%hi(LOW_OBP_ADDRESS), %g5
39	cmp		%g4, %g5
40	blu,pn		%xcc, kvmap_itlb_vmalloc_addr
41	 mov		0x1, %g5
42	sllx		%g5, 32, %g5
43	cmp		%g4, %g5
44	blu,pn		%xcc, kvmap_itlb_obp
45	 nop
46
47kvmap_itlb_vmalloc_addr:
48	KERN_PGTABLE_WALK(%g4, %g5, %g2, kvmap_itlb_longpath)
49
50	KTSB_LOCK_TAG(%g1, %g2, %g7)
51
52	/* Load and check PTE.  */
53	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
54	mov		1, %g7
55	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
56	brgez,a,pn	%g5, kvmap_itlb_longpath
57	 KTSB_STORE(%g1, %g7)
58
59	KTSB_WRITE(%g1, %g5, %g6)
60
61	/* fallthrough to TLB load */
62
63kvmap_itlb_load:
64
65661:	stxa		%g5, [%g0] ASI_ITLB_DATA_IN
66	retry
67	.section	.sun4v_2insn_patch, "ax"
68	.word		661b
69	nop
70	nop
71	.previous
72
73	/* For sun4v the ASI_ITLB_DATA_IN store and the retry
74	 * instruction get nop'd out and we get here to branch
75	 * to the sun4v tlb load code.  The registers are setup
76	 * as follows:
77	 *
78	 * %g4: vaddr
79	 * %g5: PTE
80	 * %g6:	TAG
81	 *
82	 * The sun4v TLB load wants the PTE in %g3 so we fix that
83	 * up here.
84	 */
85	ba,pt		%xcc, sun4v_itlb_load
86	 mov		%g5, %g3
87
88kvmap_itlb_longpath:
89
90661:	rdpr	%pstate, %g5
91	wrpr	%g5, PSTATE_AG | PSTATE_MG, %pstate
92	.section .sun4v_2insn_patch, "ax"
93	.word	661b
94	SET_GL(1)
95	nop
96	.previous
97
98	rdpr	%tpc, %g5
99	ba,pt	%xcc, sparc64_realfault_common
100	 mov	FAULT_CODE_ITLB, %g4
101
102kvmap_itlb_obp:
103	OBP_TRANS_LOOKUP(%g4, %g5, %g2, %g3, kvmap_itlb_longpath)
104
105	KTSB_LOCK_TAG(%g1, %g2, %g7)
106
107	KTSB_WRITE(%g1, %g5, %g6)
108
109	ba,pt		%xcc, kvmap_itlb_load
110	 nop
111
112kvmap_dtlb_obp:
113	OBP_TRANS_LOOKUP(%g4, %g5, %g2, %g3, kvmap_dtlb_longpath)
114
115	KTSB_LOCK_TAG(%g1, %g2, %g7)
116
117	KTSB_WRITE(%g1, %g5, %g6)
118
119	ba,pt		%xcc, kvmap_dtlb_load
120	 nop
121
122	.align		32
123kvmap_dtlb_tsb4m_load:
124	KTSB_LOCK_TAG(%g1, %g2, %g7)
125	KTSB_WRITE(%g1, %g5, %g6)
126	ba,pt		%xcc, kvmap_dtlb_load
127	 nop
128
129kvmap_dtlb:
130	/* %g6: TAG TARGET */
131	mov		TLB_TAG_ACCESS, %g4
132	ldxa		[%g4] ASI_DMMU, %g4
133
134	/* sun4v_dtlb_miss branches here with the missing virtual
135	 * address already loaded into %g4
136	 */
137kvmap_dtlb_4v:
138	brgez,pn	%g4, kvmap_dtlb_nonlinear
139	 nop
140
141#ifdef CONFIG_DEBUG_PAGEALLOC
142	/* Index through the base page size TSB even for linear
143	 * mappings when using page allocation debugging.
144	 */
145	KERN_TSB_LOOKUP_TL1(%g4, %g6, %g5, %g1, %g2, %g3, kvmap_dtlb_load)
146#else
147	/* Correct TAG_TARGET is already in %g6, check 4mb TSB.  */
148	KERN_TSB4M_LOOKUP_TL1(%g6, %g5, %g1, %g2, %g3, kvmap_dtlb_load)
149#endif
150	/* TSB entry address left in %g1, lookup linear PTE.
151	 * Must preserve %g1 and %g6 (TAG).
152	 */
153kvmap_dtlb_tsb4m_miss:
154	sethi		%hi(kpte_linear_bitmap), %g2
155	or		%g2, %lo(kpte_linear_bitmap), %g2
156
157	/* Clear the PAGE_OFFSET top virtual bits, then shift
158	 * down to get a 256MB physical address index.
159	 */
160	sllx		%g4, 21, %g5
161	mov		1, %g7
162	srlx		%g5, 21 + 28, %g5
163
164	/* Don't try this at home kids... this depends upon srlx
165	 * only taking the low 6 bits of the shift count in %g5.
166	 */
167	sllx		%g7, %g5, %g7
168
169	/* Divide by 64 to get the offset into the bitmask.  */
170	srlx		%g5, 6, %g5
171	sllx		%g5, 3, %g5
172
173	/* kern_linear_pte_xor[((mask & bit) ? 1 : 0)] */
174	ldx		[%g2 + %g5], %g2
175	andcc		%g2, %g7, %g0
176	sethi		%hi(kern_linear_pte_xor), %g5
177	or		%g5, %lo(kern_linear_pte_xor), %g5
178	bne,a,pt	%xcc, 1f
179	 add		%g5, 8, %g5
180
1811:	ldx		[%g5], %g2
182
183	.globl		kvmap_linear_patch
184kvmap_linear_patch:
185	ba,pt		%xcc, kvmap_dtlb_tsb4m_load
186	 xor		%g2, %g4, %g5
187
188kvmap_dtlb_vmalloc_addr:
189	KERN_PGTABLE_WALK(%g4, %g5, %g2, kvmap_dtlb_longpath)
190
191	KTSB_LOCK_TAG(%g1, %g2, %g7)
192
193	/* Load and check PTE.  */
194	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
195	mov		1, %g7
196	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
197	brgez,a,pn	%g5, kvmap_dtlb_longpath
198	 KTSB_STORE(%g1, %g7)
199
200	KTSB_WRITE(%g1, %g5, %g6)
201
202	/* fallthrough to TLB load */
203
204kvmap_dtlb_load:
205
206661:	stxa		%g5, [%g0] ASI_DTLB_DATA_IN	! Reload TLB
207	retry
208	.section	.sun4v_2insn_patch, "ax"
209	.word		661b
210	nop
211	nop
212	.previous
213
214	/* For sun4v the ASI_DTLB_DATA_IN store and the retry
215	 * instruction get nop'd out and we get here to branch
216	 * to the sun4v tlb load code.  The registers are setup
217	 * as follows:
218	 *
219	 * %g4: vaddr
220	 * %g5: PTE
221	 * %g6:	TAG
222	 *
223	 * The sun4v TLB load wants the PTE in %g3 so we fix that
224	 * up here.
225	 */
226	ba,pt		%xcc, sun4v_dtlb_load
227	 mov		%g5, %g3
228
229#ifdef CONFIG_SPARSEMEM_VMEMMAP
230kvmap_vmemmap:
231	sub		%g4, %g5, %g5
232	srlx		%g5, 22, %g5
233	sethi		%hi(vmemmap_table), %g1
234	sllx		%g5, 3, %g5
235	or		%g1, %lo(vmemmap_table), %g1
236	ba,pt		%xcc, kvmap_dtlb_load
237	 ldx		[%g1 + %g5], %g5
238#endif
239
240kvmap_dtlb_nonlinear:
241	/* Catch kernel NULL pointer derefs.  */
242	sethi		%hi(PAGE_SIZE), %g5
243	cmp		%g4, %g5
244	bleu,pn		%xcc, kvmap_dtlb_longpath
245	 nop
246
247#ifdef CONFIG_SPARSEMEM_VMEMMAP
248	/* Do not use the TSB for vmemmap.  */
249	mov		(VMEMMAP_BASE >> 24), %g5
250	sllx		%g5, 24, %g5
251	cmp		%g4,%g5
252	bgeu,pn		%xcc, kvmap_vmemmap
253	 nop
254#endif
255
256	KERN_TSB_LOOKUP_TL1(%g4, %g6, %g5, %g1, %g2, %g3, kvmap_dtlb_load)
257
258kvmap_dtlb_tsbmiss:
259	sethi		%hi(MODULES_VADDR), %g5
260	cmp		%g4, %g5
261	blu,pn		%xcc, kvmap_dtlb_longpath
262	 mov		(VMALLOC_END >> 24), %g5
263	sllx		%g5, 24, %g5
264	cmp		%g4, %g5
265	bgeu,pn		%xcc, kvmap_dtlb_longpath
266	 nop
267
268kvmap_check_obp:
269	sethi		%hi(LOW_OBP_ADDRESS), %g5
270	cmp		%g4, %g5
271	blu,pn		%xcc, kvmap_dtlb_vmalloc_addr
272	 mov		0x1, %g5
273	sllx		%g5, 32, %g5
274	cmp		%g4, %g5
275	blu,pn		%xcc, kvmap_dtlb_obp
276	 nop
277	ba,pt		%xcc, kvmap_dtlb_vmalloc_addr
278	 nop
279
280kvmap_dtlb_longpath:
281
282661:	rdpr	%pstate, %g5
283	wrpr	%g5, PSTATE_AG | PSTATE_MG, %pstate
284	.section .sun4v_2insn_patch, "ax"
285	.word	661b
286	SET_GL(1)
287	ldxa		[%g0] ASI_SCRATCHPAD, %g5
288	.previous
289
290	rdpr	%tl, %g3
291	cmp	%g3, 1
292
293661:	mov	TLB_TAG_ACCESS, %g4
294	ldxa	[%g4] ASI_DMMU, %g5
295	.section .sun4v_2insn_patch, "ax"
296	.word	661b
297	ldx	[%g5 + HV_FAULT_D_ADDR_OFFSET], %g5
298	nop
299	.previous
300
301	be,pt	%xcc, sparc64_realfault_common
302	 mov	FAULT_CODE_DTLB, %g4
303	ba,pt	%xcc, winfix_trampoline
304	 nop
305