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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: winfixup.S,v 1.30 2002/02/09 19:49:30 davem Exp $
2 *
3 * winfixup.S: Handle cases where user stack pointer is found to be bogus.
4 *
5 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
6 */
7
8#include <asm/asi.h>
9#include <asm/head.h>
10#include <asm/page.h>
11#include <asm/ptrace.h>
12#include <asm/processor.h>
13#include <asm/spitfire.h>
14#include <asm/thread_info.h>
15
16 .text
17
18set_pcontext:
David S. Miller0835ae02005-10-04 15:23:20 -070019 sethi %hi(sparc64_kern_pri_context), %l1
20 ldx [%l1 + %lo(sparc64_kern_pri_context)], %l1
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 mov PRIMARY_CONTEXT, %g1
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 stxa %l1, [%g1] ASI_DMMU
23 flush %g6
24 retl
25 nop
26
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 .align 32
28
29 /* Here are the rules, pay attention.
30 *
31 * The kernel is disallowed from touching user space while
32 * the trap level is greater than zero, except for from within
33 * the window spill/fill handlers. This must be followed
34 * so that we can easily detect the case where we tried to
35 * spill/fill with a bogus (or unmapped) user stack pointer.
36 *
37 * These are layed out in a special way for cache reasons,
38 * don't touch...
39 */
40 .globl fill_fixup, spill_fixup
41fill_fixup:
42 rdpr %tstate, %g1
43 andcc %g1, TSTATE_PRIV, %g0
44 or %g4, FAULT_CODE_WINFIXUP, %g4
45 be,pt %xcc, window_scheisse_from_user_common
46 and %g1, TSTATE_CWP, %g1
47
48 /* This is the extremely complex case, but it does happen from
49 * time to time if things are just right. Essentially the restore
50 * done in rtrap right before going back to user mode, with tl=1
51 * and that levels trap stack registers all setup, took a fill trap,
52 * the user stack was not mapped in the tlb, and tlb miss occurred,
53 * the pte found was not valid, and a simple ref bit watch update
54 * could not satisfy the miss, so we got here.
55 *
56 * We must carefully unwind the state so we get back to tl=0, preserve
57 * all the register values we were going to give to the user. Luckily
58 * most things are where they need to be, we also have the address
59 * which triggered the fault handy as well.
60 *
61 * Also note that we must preserve %l5 and %l6. If the user was
62 * returning from a system call, we must make it look this way
63 * after we process the fill fault on the users stack.
64 *
65 * First, get into the window where the original restore was executed.
66 */
67
68 rdpr %wstate, %g2 ! Grab user mode wstate.
69 wrpr %g1, %cwp ! Get into the right window.
70 sll %g2, 3, %g2 ! NORMAL-->OTHER
71
72 wrpr %g0, 0x0, %canrestore ! Standard etrap stuff.
73 wrpr %g2, 0x0, %wstate ! This must be consistent.
74 wrpr %g0, 0x0, %otherwin ! We know this.
75 call set_pcontext ! Change contexts...
76 nop
77 rdpr %pstate, %l1 ! Prepare to change globals.
78 mov %g6, %o7 ! Get current.
79
80 andn %l1, PSTATE_MM, %l1 ! We want to be in RMO
81 stb %g4, [%g6 + TI_FAULT_CODE]
82 stx %g5, [%g6 + TI_FAULT_ADDR]
83 wrpr %g0, 0x0, %tl ! Out of trap levels.
84 wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
85 mov %o7, %g6
86 ldx [%g6 + TI_TASK], %g4
87#ifdef CONFIG_SMP
88 mov TSB_REG, %g1
89 ldxa [%g1] ASI_IMMU, %g5
90#endif
91
92 /* This is the same as below, except we handle this a bit special
93 * since we must preserve %l5 and %l6, see comment above.
94 */
95 call do_sparc64_fault
96 add %sp, PTREGS_OFF, %o0
97 ba,pt %xcc, rtrap
98 nop ! yes, nop is correct
99
100 /* Be very careful about usage of the alternate globals here.
101 * You cannot touch %g4/%g5 as that has the fault information
102 * should this be from usermode. Also be careful for the case
103 * where we get here from the save instruction in etrap.S when
104 * coming from either user or kernel (does not matter which, it
105 * is the same problem in both cases). Essentially this means
106 * do not touch %g7 or %g2 so we handle the two cases fine.
107 */
108spill_fixup:
109 ldx [%g6 + TI_FLAGS], %g1
110 andcc %g1, _TIF_32BIT, %g0
111 ldub [%g6 + TI_WSAVED], %g1
112
113 sll %g1, 3, %g3
114 add %g6, %g3, %g3
115 stx %sp, [%g3 + TI_RWIN_SPTRS]
116 sll %g1, 7, %g3
117 bne,pt %xcc, 1f
118 add %g6, %g3, %g3
119 stx %l0, [%g3 + TI_REG_WINDOW + 0x00]
120 stx %l1, [%g3 + TI_REG_WINDOW + 0x08]
121
122 stx %l2, [%g3 + TI_REG_WINDOW + 0x10]
123 stx %l3, [%g3 + TI_REG_WINDOW + 0x18]
124 stx %l4, [%g3 + TI_REG_WINDOW + 0x20]
125 stx %l5, [%g3 + TI_REG_WINDOW + 0x28]
126 stx %l6, [%g3 + TI_REG_WINDOW + 0x30]
127 stx %l7, [%g3 + TI_REG_WINDOW + 0x38]
128 stx %i0, [%g3 + TI_REG_WINDOW + 0x40]
129 stx %i1, [%g3 + TI_REG_WINDOW + 0x48]
130
131 stx %i2, [%g3 + TI_REG_WINDOW + 0x50]
132 stx %i3, [%g3 + TI_REG_WINDOW + 0x58]
133 stx %i4, [%g3 + TI_REG_WINDOW + 0x60]
134 stx %i5, [%g3 + TI_REG_WINDOW + 0x68]
135 stx %i6, [%g3 + TI_REG_WINDOW + 0x70]
136 b,pt %xcc, 2f
137 stx %i7, [%g3 + TI_REG_WINDOW + 0x78]
1381: stw %l0, [%g3 + TI_REG_WINDOW + 0x00]
139
140 stw %l1, [%g3 + TI_REG_WINDOW + 0x04]
141 stw %l2, [%g3 + TI_REG_WINDOW + 0x08]
142 stw %l3, [%g3 + TI_REG_WINDOW + 0x0c]
143 stw %l4, [%g3 + TI_REG_WINDOW + 0x10]
144 stw %l5, [%g3 + TI_REG_WINDOW + 0x14]
145 stw %l6, [%g3 + TI_REG_WINDOW + 0x18]
146 stw %l7, [%g3 + TI_REG_WINDOW + 0x1c]
147 stw %i0, [%g3 + TI_REG_WINDOW + 0x20]
148
149 stw %i1, [%g3 + TI_REG_WINDOW + 0x24]
150 stw %i2, [%g3 + TI_REG_WINDOW + 0x28]
151 stw %i3, [%g3 + TI_REG_WINDOW + 0x2c]
152 stw %i4, [%g3 + TI_REG_WINDOW + 0x30]
153 stw %i5, [%g3 + TI_REG_WINDOW + 0x34]
154 stw %i6, [%g3 + TI_REG_WINDOW + 0x38]
155 stw %i7, [%g3 + TI_REG_WINDOW + 0x3c]
1562: add %g1, 1, %g1
157
158 stb %g1, [%g6 + TI_WSAVED]
159 rdpr %tstate, %g1
160 andcc %g1, TSTATE_PRIV, %g0
161 saved
162 and %g1, TSTATE_CWP, %g1
163 be,pn %xcc, window_scheisse_from_user_common
164 mov FAULT_CODE_WRITE | FAULT_CODE_DTLB | FAULT_CODE_WINFIXUP, %g4
165 retry
166
167window_scheisse_from_user_common:
168 stb %g4, [%g6 + TI_FAULT_CODE]
169 stx %g5, [%g6 + TI_FAULT_ADDR]
170 wrpr %g1, %cwp
171 ba,pt %xcc, etrap
172 rd %pc, %g7
173 call do_sparc64_fault
174 add %sp, PTREGS_OFF, %o0
175 ba,a,pt %xcc, rtrap_clr_l6
176
177 .globl winfix_mna, fill_fixup_mna, spill_fixup_mna
178winfix_mna:
179 andn %g3, 0x7f, %g3
180 add %g3, 0x78, %g3
181 wrpr %g3, %tnpc
182 done
183fill_fixup_mna:
184 rdpr %tstate, %g1
185 andcc %g1, TSTATE_PRIV, %g0
186 be,pt %xcc, window_mna_from_user_common
187 and %g1, TSTATE_CWP, %g1
188
189 /* Please, see fill_fixup commentary about why we must preserve
190 * %l5 and %l6 to preserve absolute correct semantics.
191 */
192 rdpr %wstate, %g2 ! Grab user mode wstate.
193 wrpr %g1, %cwp ! Get into the right window.
194 sll %g2, 3, %g2 ! NORMAL-->OTHER
195 wrpr %g0, 0x0, %canrestore ! Standard etrap stuff.
196
197 wrpr %g2, 0x0, %wstate ! This must be consistent.
198 wrpr %g0, 0x0, %otherwin ! We know this.
199 call set_pcontext ! Change contexts...
200 nop
201 rdpr %pstate, %l1 ! Prepare to change globals.
202 mov %g4, %o2 ! Setup args for
203 mov %g5, %o1 ! final call to mem_address_unaligned.
204 andn %l1, PSTATE_MM, %l1 ! We want to be in RMO
205
206 mov %g6, %o7 ! Stash away current.
207 wrpr %g0, 0x0, %tl ! Out of trap levels.
208 wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
209 mov %o7, %g6 ! Get current back.
210 ldx [%g6 + TI_TASK], %g4 ! Finish it.
211#ifdef CONFIG_SMP
212 mov TSB_REG, %g1
213 ldxa [%g1] ASI_IMMU, %g5
214#endif
215 call mem_address_unaligned
216 add %sp, PTREGS_OFF, %o0
217
218 b,pt %xcc, rtrap
219 nop ! yes, the nop is correct
220spill_fixup_mna:
221 ldx [%g6 + TI_FLAGS], %g1
222 andcc %g1, _TIF_32BIT, %g0
223 ldub [%g6 + TI_WSAVED], %g1
224 sll %g1, 3, %g3
225 add %g6, %g3, %g3
226 stx %sp, [%g3 + TI_RWIN_SPTRS]
227
228 sll %g1, 7, %g3
229 bne,pt %xcc, 1f
230 add %g6, %g3, %g3
231 stx %l0, [%g3 + TI_REG_WINDOW + 0x00]
232 stx %l1, [%g3 + TI_REG_WINDOW + 0x08]
233 stx %l2, [%g3 + TI_REG_WINDOW + 0x10]
234 stx %l3, [%g3 + TI_REG_WINDOW + 0x18]
235 stx %l4, [%g3 + TI_REG_WINDOW + 0x20]
236
237 stx %l5, [%g3 + TI_REG_WINDOW + 0x28]
238 stx %l6, [%g3 + TI_REG_WINDOW + 0x30]
239 stx %l7, [%g3 + TI_REG_WINDOW + 0x38]
240 stx %i0, [%g3 + TI_REG_WINDOW + 0x40]
241 stx %i1, [%g3 + TI_REG_WINDOW + 0x48]
242 stx %i2, [%g3 + TI_REG_WINDOW + 0x50]
243 stx %i3, [%g3 + TI_REG_WINDOW + 0x58]
244 stx %i4, [%g3 + TI_REG_WINDOW + 0x60]
245
246 stx %i5, [%g3 + TI_REG_WINDOW + 0x68]
247 stx %i6, [%g3 + TI_REG_WINDOW + 0x70]
248 stx %i7, [%g3 + TI_REG_WINDOW + 0x78]
249 b,pt %xcc, 2f
250 add %g1, 1, %g1
2511: std %l0, [%g3 + TI_REG_WINDOW + 0x00]
252 std %l2, [%g3 + TI_REG_WINDOW + 0x08]
253 std %l4, [%g3 + TI_REG_WINDOW + 0x10]
254
255 std %l6, [%g3 + TI_REG_WINDOW + 0x18]
256 std %i0, [%g3 + TI_REG_WINDOW + 0x20]
257 std %i2, [%g3 + TI_REG_WINDOW + 0x28]
258 std %i4, [%g3 + TI_REG_WINDOW + 0x30]
259 std %i6, [%g3 + TI_REG_WINDOW + 0x38]
260 add %g1, 1, %g1
2612: stb %g1, [%g6 + TI_WSAVED]
262 rdpr %tstate, %g1
263
264 andcc %g1, TSTATE_PRIV, %g0
265 saved
266 be,pn %xcc, window_mna_from_user_common
267 and %g1, TSTATE_CWP, %g1
268 retry
269window_mna_from_user_common:
270 wrpr %g1, %cwp
271 sethi %hi(109f), %g7
272 ba,pt %xcc, etrap
273109: or %g7, %lo(109b), %g7
274 mov %l4, %o2
275 mov %l5, %o1
276 call mem_address_unaligned
277 add %sp, PTREGS_OFF, %o0
278 ba,pt %xcc, rtrap
279 clr %l6
280
281 /* These are only needed for 64-bit mode processes which
282 * put their stack pointer into the VPTE area and there
283 * happens to be a VPTE tlb entry mapped there during
284 * a spill/fill trap to that stack frame.
285 */
286 .globl winfix_dax, fill_fixup_dax, spill_fixup_dax
287winfix_dax:
288 andn %g3, 0x7f, %g3
289 add %g3, 0x74, %g3
290 wrpr %g3, %tnpc
291 done
292fill_fixup_dax:
293 rdpr %tstate, %g1
294 andcc %g1, TSTATE_PRIV, %g0
295 be,pt %xcc, window_dax_from_user_common
296 and %g1, TSTATE_CWP, %g1
297
298 /* Please, see fill_fixup commentary about why we must preserve
299 * %l5 and %l6 to preserve absolute correct semantics.
300 */
301 rdpr %wstate, %g2 ! Grab user mode wstate.
302 wrpr %g1, %cwp ! Get into the right window.
303 sll %g2, 3, %g2 ! NORMAL-->OTHER
304 wrpr %g0, 0x0, %canrestore ! Standard etrap stuff.
305
306 wrpr %g2, 0x0, %wstate ! This must be consistent.
307 wrpr %g0, 0x0, %otherwin ! We know this.
308 call set_pcontext ! Change contexts...
309 nop
310 rdpr %pstate, %l1 ! Prepare to change globals.
311 mov %g4, %o1 ! Setup args for
David S. Miller6c52a962005-08-29 12:45:11 -0700312 mov %g5, %o2 ! final call to spitfire_data_access_exception.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 andn %l1, PSTATE_MM, %l1 ! We want to be in RMO
314
315 mov %g6, %o7 ! Stash away current.
316 wrpr %g0, 0x0, %tl ! Out of trap levels.
317 wrpr %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
318 mov %o7, %g6 ! Get current back.
319 ldx [%g6 + TI_TASK], %g4 ! Finish it.
320#ifdef CONFIG_SMP
321 mov TSB_REG, %g1
322 ldxa [%g1] ASI_IMMU, %g5
323#endif
David S. Miller6c52a962005-08-29 12:45:11 -0700324 call spitfire_data_access_exception
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 add %sp, PTREGS_OFF, %o0
326
327 b,pt %xcc, rtrap
328 nop ! yes, the nop is correct
329spill_fixup_dax:
330 ldx [%g6 + TI_FLAGS], %g1
331 andcc %g1, _TIF_32BIT, %g0
332 ldub [%g6 + TI_WSAVED], %g1
333 sll %g1, 3, %g3
334 add %g6, %g3, %g3
335 stx %sp, [%g3 + TI_RWIN_SPTRS]
336
337 sll %g1, 7, %g3
338 bne,pt %xcc, 1f
339 add %g6, %g3, %g3
340 stx %l0, [%g3 + TI_REG_WINDOW + 0x00]
341 stx %l1, [%g3 + TI_REG_WINDOW + 0x08]
342 stx %l2, [%g3 + TI_REG_WINDOW + 0x10]
343 stx %l3, [%g3 + TI_REG_WINDOW + 0x18]
344 stx %l4, [%g3 + TI_REG_WINDOW + 0x20]
345
346 stx %l5, [%g3 + TI_REG_WINDOW + 0x28]
347 stx %l6, [%g3 + TI_REG_WINDOW + 0x30]
348 stx %l7, [%g3 + TI_REG_WINDOW + 0x38]
349 stx %i0, [%g3 + TI_REG_WINDOW + 0x40]
350 stx %i1, [%g3 + TI_REG_WINDOW + 0x48]
351 stx %i2, [%g3 + TI_REG_WINDOW + 0x50]
352 stx %i3, [%g3 + TI_REG_WINDOW + 0x58]
353 stx %i4, [%g3 + TI_REG_WINDOW + 0x60]
354
355 stx %i5, [%g3 + TI_REG_WINDOW + 0x68]
356 stx %i6, [%g3 + TI_REG_WINDOW + 0x70]
357 stx %i7, [%g3 + TI_REG_WINDOW + 0x78]
358 b,pt %xcc, 2f
359 add %g1, 1, %g1
3601: std %l0, [%g3 + TI_REG_WINDOW + 0x00]
361 std %l2, [%g3 + TI_REG_WINDOW + 0x08]
362 std %l4, [%g3 + TI_REG_WINDOW + 0x10]
363
364 std %l6, [%g3 + TI_REG_WINDOW + 0x18]
365 std %i0, [%g3 + TI_REG_WINDOW + 0x20]
366 std %i2, [%g3 + TI_REG_WINDOW + 0x28]
367 std %i4, [%g3 + TI_REG_WINDOW + 0x30]
368 std %i6, [%g3 + TI_REG_WINDOW + 0x38]
369 add %g1, 1, %g1
3702: stb %g1, [%g6 + TI_WSAVED]
371 rdpr %tstate, %g1
372
373 andcc %g1, TSTATE_PRIV, %g0
374 saved
375 be,pn %xcc, window_dax_from_user_common
376 and %g1, TSTATE_CWP, %g1
377 retry
378window_dax_from_user_common:
379 wrpr %g1, %cwp
380 sethi %hi(109f), %g7
381 ba,pt %xcc, etrap
382109: or %g7, %lo(109b), %g7
383 mov %l4, %o1
384 mov %l5, %o2
David S. Miller6c52a962005-08-29 12:45:11 -0700385 call spitfire_data_access_exception
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 add %sp, PTREGS_OFF, %o0
387 ba,pt %xcc, rtrap
388 clr %l6