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   1 #ifndef _ASM_POWERPC_EXCEPTION_H
   2 #define _ASM_POWERPC_EXCEPTION_H
   3 /*
   4  * Extracted from head_64.S
   5  *
   6  *  PowerPC version
   7  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   8  *
   9  *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
  10  *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
  11  *  Adapted for Power Macintosh by Paul Mackerras.
  12  *  Low-level exception handlers and MMU support
  13  *  rewritten by Paul Mackerras.
  14  *    Copyright (C) 1996 Paul Mackerras.
  15  *
  16  *  Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and
  17  *    Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com
  18  *
  19  *  This file contains the low-level support and setup for the
  20  *  PowerPC-64 platform, including trap and interrupt dispatch.
  21  *
  22  *  This program is free software; you can redistribute it and/or
  23  *  modify it under the terms of the GNU General Public License
  24  *  as published by the Free Software Foundation; either version
  25  *  2 of the License, or (at your option) any later version.
  26  */
  27 /*
  28  * The following macros define the code that appears as
  29  * the prologue to each of the exception handlers.  They
  30  * are split into two parts to allow a single kernel binary
  31  * to be used for pSeries and iSeries.
  32  *
  33  * We make as much of the exception code common between native
  34  * exception handlers (including pSeries LPAR) and iSeries LPAR
  35  * implementations as possible.
  36  */
  37
  38 #define EX_R9           0
  39 #define EX_R10          8
  40 #define EX_R11          16
  41 #define EX_R12          24
  42 #define EX_R13          32
  43 #define EX_SRR0         40
  44 #define EX_DAR          48
  45 #define EX_DSISR        56
  46 #define EX_CCR          60
  47 #define EX_R3           64
  48 #define EX_LR           72
  49
  50 /*
  51  * We're short on space and time in the exception prolog, so we can't
  52  * use the normal SET_REG_IMMEDIATE macro. Normally we just need the
  53  * low halfword of the address, but for Kdump we need the whole low
  54  * word.
  55  */
  56 #ifdef CONFIG_CRASH_DUMP
  57 #define LOAD_HANDLER(reg, label)                                        \
  58         oris    reg,reg,(label)@h;      /* virt addr of handler ... */  \
  59         ori     reg,reg,(label)@l;      /* .. and the rest */
  60 #else
  61 #define LOAD_HANDLER(reg, label)                                        \
  62         ori     reg,reg,(label)@l;      /* virt addr of handler ... */
  63 #endif
  64
  65 #define EXCEPTION_PROLOG_1(area)                                \
  66         mfspr   r13,SPRN_SPRG3;         /* get paca address into r13 */ \
  67         std     r9,area+EX_R9(r13);     /* save r9 - r12 */             \
  68         std     r10,area+EX_R10(r13);                                   \
  69         std     r11,area+EX_R11(r13);                                   \
  70         std     r12,area+EX_R12(r13);                                   \
  71         mfspr   r9,SPRN_SPRG1;                                          \
  72         std     r9,area+EX_R13(r13);                                    \
  73         mfcr    r9
  74
  75 /*
  76  * Equal to EXCEPTION_PROLOG_PSERIES, except that it forces 64bit mode.
  77  * The firmware calls the registered system_reset_fwnmi and
  78  * machine_check_fwnmi handlers in 32bit mode if the cpu happens to run
  79  * a 32bit application at the time of the event.
  80  * This firmware bug is present on POWER4 and JS20.
  81  */
  82 #define EXCEPTION_PROLOG_PSERIES_FORCE_64BIT(area, label)               \
  83         EXCEPTION_PROLOG_1(area);                                       \
  84         clrrdi  r12,r13,32;             /* get high part of &label */   \
  85         mfmsr   r10;                                                    \
  86         /* force 64bit mode */                                          \
  87         li      r11,5;                  /* MSR_SF_LG|MSR_ISF_LG */      \
  88         rldimi  r10,r11,61,0;           /* insert into top 3 bits */    \
  89         /* done 64bit mode */                                           \
  90         mfspr   r11,SPRN_SRR0;          /* save SRR0 */                 \
  91         LOAD_HANDLER(r12,label)                                         \
  92         ori     r10,r10,MSR_IR|MSR_DR|MSR_RI;                           \
  93         mtspr   SPRN_SRR0,r12;                                          \
  94         mfspr   r12,SPRN_SRR1;          /* and SRR1 */                  \
  95         mtspr   SPRN_SRR1,r10;                                          \
  96         rfid;                                                           \
  97         b       .       /* prevent speculative execution */
  98
  99 #define EXCEPTION_PROLOG_PSERIES(area, label)                           \
 100         EXCEPTION_PROLOG_1(area);                                       \
 101         clrrdi  r12,r13,32;             /* get high part of &label */   \
 102         mfmsr   r10;                                                    \
 103         mfspr   r11,SPRN_SRR0;          /* save SRR0 */                 \
 104         LOAD_HANDLER(r12,label)                                         \
 105         ori     r10,r10,MSR_IR|MSR_DR|MSR_RI;                           \
 106         mtspr   SPRN_SRR0,r12;                                          \
 107         mfspr   r12,SPRN_SRR1;          /* and SRR1 */                  \
 108         mtspr   SPRN_SRR1,r10;                                          \
 109         rfid;                                                           \
 110         b       .       /* prevent speculative execution */
 111
 112 /*
 113  * The common exception prolog is used for all except a few exceptions
 114  * such as a segment miss on a kernel address.  We have to be prepared
 115  * to take another exception from the point where we first touch the
 116  * kernel stack onwards.
 117  *
 118  * On entry r13 points to the paca, r9-r13 are saved in the paca,
 119  * r9 contains the saved CR, r11 and r12 contain the saved SRR0 and
 120  * SRR1, and relocation is on.
 121  */
 122 #define EXCEPTION_PROLOG_COMMON(n, area)                                   \
 123         andi.   r10,r12,MSR_PR;         /* See if coming from user      */ \
 124         mr      r10,r1;                 /* Save r1                      */ \
 125         subi    r1,r1,INT_FRAME_SIZE;   /* alloc frame on kernel stack  */ \
 126         beq-    1f;                                                        \
 127         ld      r1,PACAKSAVE(r13);      /* kernel stack to use          */ \
 128 1:      cmpdi   cr1,r1,0;               /* check if r1 is in userspace  */ \
 129         bge-    cr1,2f;                 /* abort if it is               */ \
 130         b       3f;                                                        \
 131 2:      li      r1,(n);                 /* will be reloaded later       */ \
 132         sth     r1,PACA_TRAP_SAVE(r13);                                    \
 133         b       bad_stack;                                                 \
 134 3:      std     r9,_CCR(r1);            /* save CR in stackframe        */ \
 135         std     r11,_NIP(r1);           /* save SRR0 in stackframe      */ \
 136         std     r12,_MSR(r1);           /* save SRR1 in stackframe      */ \
 137         std     r10,0(r1);              /* make stack chain pointer     */ \
 138         std     r0,GPR0(r1);            /* save r0 in stackframe        */ \
 139         std     r10,GPR1(r1);           /* save r1 in stackframe        */ \
 140         ACCOUNT_CPU_USER_ENTRY(r9, r10);                                   \
 141         std     r2,GPR2(r1);            /* save r2 in stackframe        */ \
 142         SAVE_4GPRS(3, r1);              /* save r3 - r6 in stackframe   */ \
 143         SAVE_2GPRS(7, r1);              /* save r7, r8 in stackframe    */ \
 144         ld      r9,area+EX_R9(r13);     /* move r9, r10 to stackframe   */ \
 145         ld      r10,area+EX_R10(r13);                                      \
 146         std     r9,GPR9(r1);                                               \
 147         std     r10,GPR10(r1);                                             \
 148         ld      r9,area+EX_R11(r13);    /* move r11 - r13 to stackframe */ \
 149         ld      r10,area+EX_R12(r13);                                      \
 150         ld      r11,area+EX_R13(r13);                                      \
 151         std     r9,GPR11(r1);                                              \
 152         std     r10,GPR12(r1);                                             \
 153         std     r11,GPR13(r1);                                             \
 154         ld      r2,PACATOC(r13);        /* get kernel TOC into r2       */ \
 155         mflr    r9;                     /* save LR in stackframe        */ \
 156         std     r9,_LINK(r1);                                              \
 157         mfctr   r10;                    /* save CTR in stackframe       */ \
 158         std     r10,_CTR(r1);                                              \
 159         lbz     r10,PACASOFTIRQEN(r13);                            \
 160         mfspr   r11,SPRN_XER;           /* save XER in stackframe       */ \
 161         std     r10,SOFTE(r1);                                             \
 162         std     r11,_XER(r1);                                              \
 163         li      r9,(n)+1;                                                  \
 164         std     r9,_TRAP(r1);           /* set trap number              */ \
 165         li      r10,0;                                                     \
 166         ld      r11,exception_marker@toc(r2);                              \
 167         std     r10,RESULT(r1);         /* clear regs->result           */ \
 168         std     r11,STACK_FRAME_OVERHEAD-16(r1); /* mark the frame      */
 169
 170 /*
 171  * Exception vectors.
 172  */
 173 #define STD_EXCEPTION_PSERIES(n, label)                 \
 174         . = n;                                          \
 175         .globl label##_pSeries;                         \
 176 label##_pSeries:                                        \
 177         HMT_MEDIUM;                                     \
 178         mtspr   SPRN_SPRG1,r13;         /* save r13 */  \
 179         EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)
 180
 181 #define HSTD_EXCEPTION_PSERIES(n, label)                \
 182         . = n;                                          \
 183         .globl label##_pSeries;                         \
 184 label##_pSeries:                                        \
 185         HMT_MEDIUM;                                     \
 186         mtspr   SPRN_SPRG1,r20;         /* save r20 */  \
 187         mfspr   r20,SPRN_HSRR0;         /* copy HSRR0 to SRR0 */ \
 188         mtspr   SPRN_SRR0,r20;                          \
 189         mfspr   r20,SPRN_HSRR1;         /* copy HSRR0 to SRR0 */ \
 190         mtspr   SPRN_SRR1,r20;                          \
 191         mfspr   r20,SPRN_SPRG1;         /* restore r20 */ \
 192         mtspr   SPRN_SPRG1,r13;         /* save r13 */  \
 193         EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)
 194
 195
 196 #define MASKABLE_EXCEPTION_PSERIES(n, label)                            \
 197         . = n;                                                          \
 198         .globl label##_pSeries;                                         \
 199 label##_pSeries:                                                        \
 200         HMT_MEDIUM;                                                     \
 201         mtspr   SPRN_SPRG1,r13;         /* save r13 */                  \
 202         mfspr   r13,SPRN_SPRG3;         /* get paca address into r13 */ \
 203         std     r9,PACA_EXGEN+EX_R9(r13);       /* save r9, r10 */      \
 204         std     r10,PACA_EXGEN+EX_R10(r13);                             \
 205         lbz     r10,PACASOFTIRQEN(r13);                                 \
 206         mfcr    r9;                                                     \
 207         cmpwi   r10,0;                                                  \
 208         beq     masked_interrupt;                                       \
 209         mfspr   r10,SPRN_SPRG1;                                         \
 210         std     r10,PACA_EXGEN+EX_R13(r13);                             \
 211         std     r11,PACA_EXGEN+EX_R11(r13);                             \
 212         std     r12,PACA_EXGEN+EX_R12(r13);                             \
 213         clrrdi  r12,r13,32;             /* get high part of &label */   \
 214         mfmsr   r10;                                                    \
 215         mfspr   r11,SPRN_SRR0;          /* save SRR0 */                 \
 216         LOAD_HANDLER(r12,label##_common)                                \
 217         ori     r10,r10,MSR_IR|MSR_DR|MSR_RI;                           \
 218         mtspr   SPRN_SRR0,r12;                                          \
 219         mfspr   r12,SPRN_SRR1;          /* and SRR1 */                  \
 220         mtspr   SPRN_SRR1,r10;                                          \
 221         rfid;                                                           \
 222         b       .       /* prevent speculative execution */
 223
 224 #ifdef CONFIG_PPC_ISERIES
 225 #define DISABLE_INTS                            \
 226         li      r11,0;                          \
 227         stb     r11,PACASOFTIRQEN(r13);         \
 228 BEGIN_FW_FTR_SECTION;                           \
 229         stb     r11,PACAHARDIRQEN(r13);         \
 230 END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES);   \
 231         TRACE_DISABLE_INTS;                     \
 232 BEGIN_FW_FTR_SECTION;                           \
 233         mfmsr   r10;                            \
 234         ori     r10,r10,MSR_EE;                 \
 235         mtmsrd  r10,1;                          \
 236 END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
 237 #else
 238 #define DISABLE_INTS                            \
 239         li      r11,0;                          \
 240         stb     r11,PACASOFTIRQEN(r13);         \
 241         stb     r11,PACAHARDIRQEN(r13);         \
 242         TRACE_DISABLE_INTS
 243 #endif /* CONFIG_PPC_ISERIES */
 244
 245 #define ENABLE_INTS                             \
 246         ld      r12,_MSR(r1);                   \
 247         mfmsr   r11;                            \
 248         rlwimi  r11,r12,0,MSR_EE;               \
 249         mtmsrd  r11,1
 250
 251 #define STD_EXCEPTION_COMMON(trap, label, hdlr)         \
 252         .align  7;                                      \
 253         .globl label##_common;                          \
 254 label##_common:                                         \
 255         EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
 256         DISABLE_INTS;                                   \
 257         bl      .save_nvgprs;                           \
 258         addi    r3,r1,STACK_FRAME_OVERHEAD;             \
 259         bl      hdlr;                                   \
 260         b       .ret_from_except
 261
 262 /*
 263  * Like STD_EXCEPTION_COMMON, but for exceptions that can occur
 264  * in the idle task and therefore need the special idle handling.
 265  */
 266 #define STD_EXCEPTION_COMMON_IDLE(trap, label, hdlr)    \
 267         .align  7;                                      \
 268         .globl label##_common;                          \
 269 label##_common:                                         \
 270         EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
 271         FINISH_NAP;                                     \
 272         DISABLE_INTS;                                   \
 273         bl      .save_nvgprs;                           \
 274         addi    r3,r1,STACK_FRAME_OVERHEAD;             \
 275         bl      hdlr;                                   \
 276         b       .ret_from_except
 277
 278 #define STD_EXCEPTION_COMMON_LITE(trap, label, hdlr)    \
 279         .align  7;                                      \
 280         .globl label##_common;                          \
 281 label##_common:                                         \
 282         EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
 283         FINISH_NAP;                                     \
 284         DISABLE_INTS;                                   \
 285 BEGIN_FTR_SECTION                                       \
 286         bl      .ppc64_runlatch_on;                     \
 287 END_FTR_SECTION_IFSET(CPU_FTR_CTRL)                     \
 288         addi    r3,r1,STACK_FRAME_OVERHEAD;             \
 289         bl      hdlr;                                   \
 290         b       .ret_from_except_lite
 291
 292 /*
 293  * When the idle code in power4_idle puts the CPU into NAP mode,
 294  * it has to do so in a loop, and relies on the external interrupt
 295  * and decrementer interrupt entry code to get it out of the loop.
 296  * It sets the _TLF_NAPPING bit in current_thread_info()->local_flags
 297  * to signal that it is in the loop and needs help to get out.
 298  */
 299 #ifdef CONFIG_PPC_970_NAP
 300 #define FINISH_NAP                              \
 301 BEGIN_FTR_SECTION                               \
 302         clrrdi  r11,r1,THREAD_SHIFT;            \
 303         ld      r9,TI_LOCAL_FLAGS(r11);         \
 304         andi.   r10,r9,_TLF_NAPPING;            \
 305         bnel    power4_fixup_nap;               \
 306 END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
 307 #else
 308 #define FINISH_NAP
 309 #endif
 310
 311 #endif  /* _ASM_POWERPC_EXCEPTION_H */