1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * HPMC (High Priority Machine Check) handler.
4 *
5 * Copyright (C) 1999 Philipp Rumpf <prumpf@tux.org>
6 * Copyright (C) 1999 Hewlett-Packard (Frank Rowand)
7 * Copyright (C) 2000 Hewlett-Packard (John Marvin)
8 */
9
10
11/*
12 * This HPMC handler retrieves the HPMC pim data, resets IO and
13 * returns to the default trap handler with code set to 1 (HPMC).
14 * The default trap handler calls handle interruption, which
15 * does a stack and register dump. This at least allows kernel
16 * developers to get back to C code in virtual mode, where they
17 * have the option to examine and print values from memory that
18 * would help in debugging an HPMC caused by a software bug.
19 *
20 * There is more to do here:
21 *
22 * 1) On MP systems we need to synchronize processors
23 * before calling pdc/iodc.
24 * 2) We should be checking the system state and not
25 * returning to the fault handler if things are really
26 * bad.
27 *
28 */
29
30 .level 1.1
31
32#include <asm/assembly.h>
33#include <asm/pdc.h>
34#include <asm/psw.h>
35
36#include <linux/linkage.h>
37#include <linux/init.h>
38
39 /*
40 * stack for os_hpmc, the HPMC handler.
41 * buffer for IODC procedures (for the HPMC handler).
42 *
43 * IODC requires 7K byte stack. That leaves 1K byte for os_hpmc.
44 */
45
46 .import toc_stack,data
47#define hpmc_stack toc_stack /* re-use the TOC stack */
48
49#define HPMC_IODC_BUF_SIZE 0x8000
50
51 __PAGE_ALIGNED_BSS
52 .align 4096
53hpmc_iodc_buf:
54 .block HPMC_IODC_BUF_SIZE
55
56 .section .bss
57 .align 8
58hpmc_raddr:
59 .block 128
60
61#define HPMC_PIM_DATA_SIZE 896 /* Enough to hold all architected 2.0 state */
62
63 .section .bss
64 .align 8
65ENTRY(hpmc_pim_data)
66 .block HPMC_PIM_DATA_SIZE
67END(hpmc_pim_data)
68
69 .text
70
71 .import intr_save, code
72 .align 16
73ENTRY(os_hpmc)
74.os_hpmc:
75
76 /*
77 * registers modified:
78 *
79 * Using callee saves registers without saving them. The
80 * original values are in the pim dump if we need them.
81 *
82 * r2 (rp) return pointer
83 * r3 address of PDCE_PROC
84 * r4 scratch
85 * r5 scratch
86 * r23 (arg3) procedure arg
87 * r24 (arg2) procedure arg
88 * r25 (arg1) procedure arg
89 * r26 (arg0) procedure arg
90 * r30 (sp) stack pointer
91 *
92 * registers read:
93 *
94 * r26 contains address of PDCE_PROC on entry
95 * r28 (ret0) return value from procedure
96 */
97
98 copy arg0, %r3 /* save address of PDCE_PROC */
99
100 /*
101 * disable nested HPMCs
102 *
103 * Increment os_hpmc checksum to invalidate it.
104 * Do this before turning the PSW M bit off.
105 */
106
107 mfctl %cr14, %r4
108 ldw 52(%r4),%r5
109 addi 1,%r5,%r5
110 stw %r5,52(%r4)
111
112 /* MP_FIXME: synchronize all processors. */
113
114 /* Setup stack pointer. */
115
116 load32 PA(hpmc_stack),sp
117
118 ldo 128(sp),sp /* leave room for arguments */
119
120 /*
121 * Most PDC routines require that the M bit be off.
122 * So turn on the Q bit and turn off the M bit.
123 */
124
125 ldi PSW_SM_Q,%r4 /* PSW Q on, PSW M off */
126 mtctl %r4,ipsw
127 mtctl %r0,pcsq
128 mtctl %r0,pcsq
129 load32 PA(os_hpmc_1),%r4
130 mtctl %r4,pcoq
131 ldo 4(%r4),%r4
132 mtctl %r4,pcoq
133 rfi
134 nop
135
136os_hpmc_1:
137
138 /* Call PDC_PIM to get HPMC pim info */
139
140 /*
141 * Note that on some newer boxes, PDC_PIM must be called
142 * before PDC_IO if you want IO to be reset. PDC_PIM sets
143 * a flag that PDC_IO examines.
144 */
145
146 ldo PDC_PIM(%r0), arg0
147 ldo PDC_PIM_HPMC(%r0),arg1 /* Transfer HPMC data */
148 load32 PA(hpmc_raddr),arg2
149 load32 PA(hpmc_pim_data),arg3
150 load32 HPMC_PIM_DATA_SIZE,%r4
151 stw %r4,-52(sp)
152
153 ldil L%PA(os_hpmc_2), rp
154 bv (r3) /* call pdce_proc */
155 ldo R%PA(os_hpmc_2)(rp), rp
156
157os_hpmc_2:
158 comib,<> 0,ret0, os_hpmc_fail
159
160 /* Reset IO by calling the hversion dependent PDC_IO routine */
161
162 ldo PDC_IO(%r0),arg0
163 ldo 0(%r0),arg1 /* log IO errors */
164 ldo 0(%r0),arg2 /* reserved */
165 ldo 0(%r0),arg3 /* reserved */
166 stw %r0,-52(sp) /* reserved */
167
168 ldil L%PA(os_hpmc_3),rp
169 bv (%r3) /* call pdce_proc */
170 ldo R%PA(os_hpmc_3)(rp),rp
171
172os_hpmc_3:
173
174 /* FIXME? Check for errors from PDC_IO (-1 might be OK) */
175
176 /*
177 * Initialize the IODC console device (HPA,SPA, path etc.
178 * are stored on page 0.
179 */
180
181 /*
182 * Load IODC into hpmc_iodc_buf by calling PDC_IODC.
183 * Note that PDC_IODC handles flushing the appropriate
184 * data and instruction cache lines.
185 */
186
187 ldo PDC_IODC(%r0),arg0
188 ldo PDC_IODC_READ(%r0),arg1
189 load32 PA(hpmc_raddr),arg2
190 ldw BOOT_CONSOLE_HPA_OFFSET(%r0),arg3 /* console hpa */
191 ldo PDC_IODC_RI_INIT(%r0),%r4
192 stw %r4,-52(sp)
193 load32 PA(hpmc_iodc_buf),%r4
194 stw %r4,-56(sp)
195 load32 HPMC_IODC_BUF_SIZE,%r4
196 stw %r4,-60(sp)
197
198 ldil L%PA(os_hpmc_4),rp
199 bv (%r3) /* call pdce_proc */
200 ldo R%PA(os_hpmc_4)(rp),rp
201
202os_hpmc_4:
203 comib,<> 0,ret0,os_hpmc_fail
204
205 /* Call the entry init (just loaded by PDC_IODC) */
206
207 ldw BOOT_CONSOLE_HPA_OFFSET(%r0),arg0 /* console hpa */
208 ldo ENTRY_INIT_MOD_DEV(%r0), arg1
209 ldw BOOT_CONSOLE_SPA_OFFSET(%r0),arg2 /* console spa */
210 depi 0,31,11,arg2 /* clear bits 21-31 */
211 ldo BOOT_CONSOLE_PATH_OFFSET(%r0),arg3 /* console path */
212 load32 PA(hpmc_raddr),%r4
213 stw %r4, -52(sp)
214 stw %r0, -56(sp) /* HV */
215 stw %r0, -60(sp) /* HV */
216 stw %r0, -64(sp) /* HV */
217 stw %r0, -68(sp) /* lang, must be zero */
218
219 load32 PA(hpmc_iodc_buf),%r5
220 ldil L%PA(os_hpmc_5),rp
221 bv (%r5)
222 ldo R%PA(os_hpmc_5)(rp),rp
223
224os_hpmc_5:
225 comib,<> 0,ret0,os_hpmc_fail
226
227 /* Prepare to call intr_save */
228
229 /*
230 * Load kernel page directory (load into user also, since
231 * we don't intend to ever return to user land anyway)
232 */
233
234 load32 PA(swapper_pg_dir),%r4
235 mtctl %r4,%cr24 /* Initialize kernel root pointer */
236 mtctl %r4,%cr25 /* Initialize user root pointer */
237
238 /* Clear sr4-sr7 */
239
240 mtsp %r0, %sr4
241 mtsp %r0, %sr5
242 mtsp %r0, %sr6
243 mtsp %r0, %sr7
244
245 tovirt_r1 %r30 /* make sp virtual */
246
247 rsm PSW_SM_Q,%r0 /* Clear Q bit */
248 ldi 1,%r8 /* Set trap code to "1" for HPMC */
249 load32 PA(intr_save),%r1
250 be 0(%sr7,%r1)
251 nop
252
253os_hpmc_fail:
254
255 /*
256 * Reset the system
257 *
258 * Some systems may lockup from a broadcast reset, so try the
259 * hversion PDC_BROADCAST_RESET() first.
260 * MP_FIXME: reset all processors if more than one central bus.
261 */
262
263 /* PDC_BROADCAST_RESET() */
264
265 ldo PDC_BROADCAST_RESET(%r0),arg0
266 ldo 0(%r0),arg1 /* do reset */
267
268 ldil L%PA(os_hpmc_6),rp
269 bv (%r3) /* call pdce_proc */
270 ldo R%PA(os_hpmc_6)(rp),rp
271
272os_hpmc_6:
273
274 /*
275 * possible return values:
276 * -1 non-existent procedure
277 * -2 non-existent option
278 * -16 unaligned stack
279 *
280 * If call returned, do a broadcast reset.
281 */
282
283 ldil L%0xfffc0000,%r4 /* IO_BROADCAST */
284 ldo 5(%r0),%r5
285 stw %r5,48(%r4) /* CMD_RESET to IO_COMMAND offset */
286
287 b .
288 nop
289 .align 16 /* make function length multiple of 16 bytes */
290

source code of linux/arch/parisc/kernel/hpmc.S