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 __PAGE_ALIGNED_BSS 47 .align 4096 48hpmc_stack: 49 .block 16384 50 51#define HPMC_IODC_BUF_SIZE 0x8000 52 53 __PAGE_ALIGNED_BSS 54 .align 4096 55hpmc_iodc_buf: 56 .block HPMC_IODC_BUF_SIZE 57 58 .section .bss 59 .align 8 60hpmc_raddr: 61 .block 128 62 63#define HPMC_PIM_DATA_SIZE 896 /* Enough to hold all architected 2.0 state */ 64 65 .section .bss 66 .align 8 67ENTRY(hpmc_pim_data) 68 .block HPMC_PIM_DATA_SIZE 69END(hpmc_pim_data) 70 71 .text 72 73 .import intr_save, code 74 .align 16 75ENTRY(os_hpmc) 76.os_hpmc: 77 78 /* 79 * registers modified: 80 * 81 * Using callee saves registers without saving them. The 82 * original values are in the pim dump if we need them. 83 * 84 * r2 (rp) return pointer 85 * r3 address of PDCE_PROC 86 * r4 scratch 87 * r5 scratch 88 * r23 (arg3) procedure arg 89 * r24 (arg2) procedure arg 90 * r25 (arg1) procedure arg 91 * r26 (arg0) procedure arg 92 * r30 (sp) stack pointer 93 * 94 * registers read: 95 * 96 * r26 contains address of PDCE_PROC on entry 97 * r28 (ret0) return value from procedure 98 */ 99 100 copy arg0, %r3 /* save address of PDCE_PROC */ 101 102 /* 103 * disable nested HPMCs 104 * 105 * Increment os_hpmc checksum to invalidate it. 106 * Do this before turning the PSW M bit off. 107 */ 108 109 mfctl %cr14, %r4 110 ldw 52(%r4),%r5 111 addi 1,%r5,%r5 112 stw %r5,52(%r4) 113 114 /* MP_FIXME: synchronize all processors. */ 115 116 /* Setup stack pointer. */ 117 118 load32 PA(hpmc_stack),sp 119 120 ldo 128(sp),sp /* leave room for arguments */ 121 122 /* 123 * Most PDC routines require that the M bit be off. 124 * So turn on the Q bit and turn off the M bit. 125 */ 126 127 ldi PSW_SM_Q,%r4 /* PSW Q on, PSW M off */ 128 mtctl %r4,ipsw 129 mtctl %r0,pcsq 130 mtctl %r0,pcsq 131 load32 PA(os_hpmc_1),%r4 132 mtctl %r4,pcoq 133 ldo 4(%r4),%r4 134 mtctl %r4,pcoq 135 rfi 136 nop 137 138os_hpmc_1: 139 140 /* Call PDC_PIM to get HPMC pim info */ 141 142 /* 143 * Note that on some newer boxes, PDC_PIM must be called 144 * before PDC_IO if you want IO to be reset. PDC_PIM sets 145 * a flag that PDC_IO examines. 146 */ 147 148 ldo PDC_PIM(%r0), arg0 149 ldo PDC_PIM_HPMC(%r0),arg1 /* Transfer HPMC data */ 150 load32 PA(hpmc_raddr),arg2 151 load32 PA(hpmc_pim_data),arg3 152 load32 HPMC_PIM_DATA_SIZE,%r4 153 stw %r4,-52(sp) 154 155 ldil L%PA(os_hpmc_2), rp 156 bv (r3) /* call pdce_proc */ 157 ldo R%PA(os_hpmc_2)(rp), rp 158 159os_hpmc_2: 160 comib,<> 0,ret0, os_hpmc_fail 161 162 /* Reset IO by calling the hversion dependent PDC_IO routine */ 163 164 ldo PDC_IO(%r0),arg0 165 ldo 0(%r0),arg1 /* log IO errors */ 166 ldo 0(%r0),arg2 /* reserved */ 167 ldo 0(%r0),arg3 /* reserved */ 168 stw %r0,-52(sp) /* reserved */ 169 170 ldil L%PA(os_hpmc_3),rp 171 bv (%r3) /* call pdce_proc */ 172 ldo R%PA(os_hpmc_3)(rp),rp 173 174os_hpmc_3: 175 176 /* FIXME? Check for errors from PDC_IO (-1 might be OK) */ 177 178 /* 179 * Initialize the IODC console device (HPA,SPA, path etc. 180 * are stored on page 0. 181 */ 182 183 /* 184 * Load IODC into hpmc_iodc_buf by calling PDC_IODC. 185 * Note that PDC_IODC handles flushing the appropriate 186 * data and instruction cache lines. 187 */ 188 189 ldo PDC_IODC(%r0),arg0 190 ldo PDC_IODC_READ(%r0),arg1 191 load32 PA(hpmc_raddr),arg2 192 ldw BOOT_CONSOLE_HPA_OFFSET(%r0),arg3 /* console hpa */ 193 ldo PDC_IODC_RI_INIT(%r0),%r4 194 stw %r4,-52(sp) 195 load32 PA(hpmc_iodc_buf),%r4 196 stw %r4,-56(sp) 197 load32 HPMC_IODC_BUF_SIZE,%r4 198 stw %r4,-60(sp) 199 200 ldil L%PA(os_hpmc_4),rp 201 bv (%r3) /* call pdce_proc */ 202 ldo R%PA(os_hpmc_4)(rp),rp 203 204os_hpmc_4: 205 comib,<> 0,ret0,os_hpmc_fail 206 207 /* Call the entry init (just loaded by PDC_IODC) */ 208 209 ldw BOOT_CONSOLE_HPA_OFFSET(%r0),arg0 /* console hpa */ 210 ldo ENTRY_INIT_MOD_DEV(%r0), arg1 211 ldw BOOT_CONSOLE_SPA_OFFSET(%r0),arg2 /* console spa */ 212 depi 0,31,11,arg2 /* clear bits 21-31 */ 213 ldo BOOT_CONSOLE_PATH_OFFSET(%r0),arg3 /* console path */ 214 load32 PA(hpmc_raddr),%r4 215 stw %r4, -52(sp) 216 stw %r0, -56(sp) /* HV */ 217 stw %r0, -60(sp) /* HV */ 218 stw %r0, -64(sp) /* HV */ 219 stw %r0, -68(sp) /* lang, must be zero */ 220 221 load32 PA(hpmc_iodc_buf),%r5 222 ldil L%PA(os_hpmc_5),rp 223 bv (%r5) 224 ldo R%PA(os_hpmc_5)(rp),rp 225 226os_hpmc_5: 227 comib,<> 0,ret0,os_hpmc_fail 228 229 /* Prepare to call intr_save */ 230 231 /* 232 * Load kernel page directory (load into user also, since 233 * we don't intend to ever return to user land anyway) 234 */ 235 236 load32 PA(swapper_pg_dir),%r4 237 mtctl %r4,%cr24 /* Initialize kernel root pointer */ 238 mtctl %r4,%cr25 /* Initialize user root pointer */ 239 240 /* Clear sr4-sr7 */ 241 242 mtsp %r0, %sr4 243 mtsp %r0, %sr5 244 mtsp %r0, %sr6 245 mtsp %r0, %sr7 246 247 tovirt_r1 %r30 /* make sp virtual */ 248 249 rsm PSW_SM_Q,%r0 /* Clear Q bit */ 250 ldi 1,%r8 /* Set trap code to "1" for HPMC */ 251 load32 PA(intr_save),%r1 252 be 0(%sr7,%r1) 253 nop 254 255os_hpmc_fail: 256 257 /* 258 * Reset the system 259 * 260 * Some systems may lockup from a broadcast reset, so try the 261 * hversion PDC_BROADCAST_RESET() first. 262 * MP_FIXME: reset all processors if more than one central bus. 263 */ 264 265 /* PDC_BROADCAST_RESET() */ 266 267 ldo PDC_BROADCAST_RESET(%r0),arg0 268 ldo 0(%r0),arg1 /* do reset */ 269 270 ldil L%PA(os_hpmc_6),rp 271 bv (%r3) /* call pdce_proc */ 272 ldo R%PA(os_hpmc_6)(rp),rp 273 274os_hpmc_6: 275 276 /* 277 * possible return values: 278 * -1 non-existent procedure 279 * -2 non-existent option 280 * -16 unaligned stack 281 * 282 * If call returned, do a broadcast reset. 283 */ 284 285 ldil L%0xfffc0000,%r4 /* IO_BROADCAST */ 286 ldo 5(%r0),%r5 287 stw %r5,48(%r4) /* CMD_RESET to IO_COMMAND offset */ 288 289 b . 290 nop 291 .align 16 /* make function length multiple of 16 bytes */ 292.os_hpmc_end: 293 294 295 __INITRODATA 296.globl os_hpmc_size 297 .align 4 298 .type os_hpmc_size, @object 299 .size os_hpmc_size, 4 300os_hpmc_size: 301 .word .os_hpmc_end-.os_hpmc 302