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