1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * etrap.S: Sparc trap window preparation for
4 * Linux kernel.
5 *
6 * Copyright (C) 1995 David S. Miller (davem@c
7 */
8
9 #include <asm/head.h>
10 #include <asm/asi.h>
11 #include <asm/contregs.h>
12 #include <asm/page.h>
13 #include <asm/psr.h>
14 #include <asm/ptrace.h>
15 #include <asm/winmacro.h>
16 #include <asm/asmmacro.h>
17 #include <asm/thread_info.h>
18
19 /* Registers to not touch at all. */
20 #define t_psr l0 /* Set by caller */
21 #define t_pc l1 /* Set by caller */
22 #define t_npc l2 /* Set by caller */
23 #define t_wim l3 /* Set by caller */
24 #define t_twinmask l4 /* Set at beginning of
25 #define t_kstack l5 /* Set right before pt
26 #define t_retpc l6 /* If you change this,
27 #define t_systable l7 /* Never touch this, c
28 #define curptr g6 /* Set after pt_regs f
29
30 .text
31 .align 4
32
33 /* SEVEN WINDOW PATCH INSTRUCTIONS */
34 .globl tsetup_7win_patch1, tsetup_7wi
35 .globl tsetup_7win_patch3, tsetup_7wi
36 .globl tsetup_7win_patch5, tsetup_7wi
37 tsetup_7win_patch1: sll %t_wim, 0x6, %
38 tsetup_7win_patch2: and %g2, 0x7f, %g2
39 tsetup_7win_patch3: and %g2, 0x7f, %g2
40 tsetup_7win_patch4: and %g1, 0x7f, %g1
41 tsetup_7win_patch5: sll %t_wim, 0x6, %
42 tsetup_7win_patch6: and %g2, 0x7f, %g2
43 /* END OF PATCH INSTRUCTIONS */
44
45 /* At trap time, interrupts and all ge
46 * following:
47 *
48 * rd %psr, %l0
49 * b some_handler
50 * rd %wim, %l3
51 * nop
52 *
53 * Then 'some_handler' if it needs a t
54 * to call c-code and the trap cannot
55 * then it does the SAVE_ALL macro in
56 *
57 * sethi %hi(trap_setup), %l4
58 * jmpl %l4 + %lo(trap_setup),
59 * nop
60 */
61
62 /* 2 3 4 window number
63 * -----
64 * O T S mnemonic
65 *
66 * O == Current window before trap
67 * T == Window entered when trap occur
68 * S == Window we will need to save if
69 *
70 * Before execution gets here, it must
71 * %l0 contains trap time %psr, %l1 an
72 * trap pc and npc, and %l3 contains t
73 */
74
75 .globl trap_setup, tsetup_patch1, tse
76 .globl tsetup_patch3, tsetup_patch4
77 .globl tsetup_patch5, tsetup_patch6
78 trap_setup:
79 /* Calculate mask of trap window. See
80 * or kernel and branch conditionally.
81 */
82 mov 1, %t_twinmask
83 andcc %t_psr, PSR_PS, %g0
84 be trap_setup_from_user
85 sll %t_twinmask, %t_psr, %t_twinma
86
87 /* From kernel, allocate more kernel s
88 * build a pt_regs trap frame.
89 */
90 sub %fp, (STACKFRAME_SZ + TRACEREG
91 STORE_PT_ALL(t_kstack, t_psr, t_pc, t_
92
93 /* See if we are in the trap window. *
94 andcc %t_twinmask, %t_wim, %g0
95 bne trap_setup_kernel_spill
96 nop
97
98 /* Trap from kernel with a window avai
99 * Just do it...
100 */
101 jmpl %t_retpc + 0x8, %g0 ! retu
102 mov %t_kstack, %sp ! jump
103
104 trap_setup_kernel_spill:
105 ld [%curptr + TI_UWINMASK], %g1
106 orcc %g0, %g1, %g0
107 bne trap_setup_user_spill ! ther
108 /* Spill from kernel, but only kernel
109 * %wim and go.
110 */
111 srl %t_wim, 0x1, %g2 ! begi
112 tsetup_patch1:
113 sll %t_wim, 0x7, %t_wim ! patc
114 or %t_wim, %g2, %g2
115 tsetup_patch2:
116 and %g2, 0xff, %g2 ! patc
117
118 save %g0, %g0, %g0
119
120 /* Set new %wim value */
121 wr %g2, 0x0, %wim
122
123 /* Save the kernel window onto the cor
124 STORE_WINDOW(sp)
125
126 restore %g0, %g0, %g0
127
128 jmpl %t_retpc + 0x8, %g0 ! retu
129 mov %t_kstack, %sp ! and
130
131 #define STACK_OFFSET (THREAD_SIZE - TRACEREG_S
132
133 trap_setup_from_user:
134 /* We can't use %curptr yet. */
135 LOAD_CURRENT(t_kstack, t_twinmask)
136
137 sethi %hi(STACK_OFFSET), %t_twinmask
138 or %t_twinmask, %lo(STACK_OFFSET)
139 add %t_kstack, %t_twinmask, %t_kst
140
141 mov 1, %t_twinmask
142 sll %t_twinmask, %t_psr, %t_twinma
143
144 /* Build pt_regs frame. */
145 STORE_PT_ALL(t_kstack, t_psr, t_pc, t_
146
147 #if 0
148 /* If we're sure every task_struct is
149 we can speed this up. */
150 sethi %hi(STACK_OFFSET), %curptr
151 or %curptr, %lo(STACK_OFFSET), %c
152 sub %t_kstack, %curptr, %curptr
153 #else
154 sethi %hi(~(THREAD_SIZE - 1)), %curp
155 and %t_kstack, %curptr, %curptr
156 #endif
157
158 /* Clear current_thread_info->w_saved
159 st %g0, [%curptr + TI_W_SAVED]
160
161 /* See if we are in the trap window. *
162 andcc %t_twinmask, %t_wim, %g0
163 bne trap_setup_user_spill
164 orn %g0, %t_twinmask, %g1
165
166 /* Trap from user, but not into the in
167 * Calculate new umask. The way this
168 * any window from the %wim at trap ti
169 * the window right before the one we
170 * is a user window. A diagram:
171 *
172 * 7 6 5 4 3 2 1 0 window numb
173 * ---------------
174 * I L T mnemonic
175 *
176 * Window 'I' is the invalid window in
177 * window 'L' is the window the user w
178 * the trap occurred, window T is the
179 * we are in now. So therefore, windo
180 * 3 are user windows. The following
181 * computes the user winmask to repres
182 */
183 subcc %t_wim, %t_twinmask, %g2
184 bneg,a 1f
185 sub %g2, 0x1, %g2
186 1:
187 andn %g2, %t_twinmask, %g2
188 tsetup_patch3:
189 and %g2, 0xff, %g2
190 st %g2, [%curptr + TI_UWINMASK]
191
192 jmpl %t_retpc + 0x8, %g0
193 mov %t_kstack, %sp
194
195 trap_setup_user_spill:
196 /* A spill occurred from either kernel
197 * and there exist some user windows t
198 * A mask of the currently valid user
199 * is in %g1 upon entry to here.
200 */
201
202 tsetup_patch4:
203 and %g1, 0xff, %g1 ! patc
204 srl %t_wim, 0x1, %g2 ! comp
205 tsetup_patch5:
206 sll %t_wim, 0x7, %t_wim ! patc
207 or %t_wim, %g2, %g2 ! %g2
208 tsetup_patch6:
209 and %g2, 0xff, %g2 ! patc
210 andn %g1, %g2, %g1 ! clea
211 st %g1, [%curptr + TI_UWINMASK]
212
213 save %g0, %g0, %g0
214
215 wr %g2, 0x0, %wim
216
217 /* Call MMU-architecture dependent sta
218 * routine.
219 */
220 b tsetup_srmmu_stackchk
221 andcc %sp, 0x7, %g0
222
223 /* Architecture specific stack checkin
224 * of these routines are called, the g
225 * as they have been safely stashed on
226 * pointer. Thus the definition below
227 */
228 #define glob_tmp g1
229
230 .globl tsetup_srmmu_stackchk
231 tsetup_srmmu_stackchk:
232 /* Check results of callers andcc %sp,
233 bne trap_setup_user_stack_is_bolix
234 sethi %hi(PAGE_OFFSET), %glob_tmp
235
236 cmp %glob_tmp, %sp
237 bleu,a 1f
238 LEON_PI( lda [%g0] ASI_LEON_MMUREGS, %glob_
239 SUN_PI_( lda [%g0] ASI_M_MMUREGS, %glob_tmp
240
241 trap_setup_user_stack_is_bolixed:
242 /* From user/kernel into invalid windo
243 * stack. Save bad user stack, and ret
244 */
245 SAVE_BOLIXED_USER_STACK(curptr, g3)
246 restore %g0, %g0, %g0
247
248 jmpl %t_retpc + 0x8, %g0
249 mov %t_kstack, %sp
250
251 1:
252 /* Clear the fault status and turn on
253 or %glob_tmp, 0x2, %glob_tmp
254 LEON_PI(sta %glob_tmp, [%g0] ASI_LEON_MMUR
255 SUN_PI_(sta %glob_tmp, [%g0] ASI_M_MMUREGS
256
257 /* Dump the registers and cross finger
258 STORE_WINDOW(sp)
259
260 /* Clear the no_fault bit and check th
261 andn %glob_tmp, 0x2, %glob_tmp
262 LEON_PI(sta %glob_tmp, [%g0] ASI_LEON_MMUR
263 SUN_PI_(sta %glob_tmp, [%g0] ASI_M_MMUREGS
264
265 mov AC_M_SFAR, %glob_tmp
266 LEON_PI(lda [%glob_tmp] ASI_LEON_MMUREGS,
267 SUN_PI_(lda [%glob_tmp] ASI_M_MMUREGS, %g0
268
269 mov AC_M_SFSR, %glob_tmp
270 LEON_PI(lda [%glob_tmp] ASI_LEON_MMUREGS,
271 SUN_PI_(lda [%glob_tmp] ASI_M_MMUREGS, %gl
272
273 andcc %glob_tmp, 0x2, %g0
274 bne trap_setup_user_stack_is_bolix
275 nop
276
277 restore %g0, %g0, %g0
278
279 jmpl %t_retpc + 0x8, %g0
280 mov %t_kstack, %sp
281
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