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exception.h

#ifndef _ASM_POWERPC_EXCEPTION_H
#define _ASM_POWERPC_EXCEPTION_H
/*
 * Extracted from head_64.S
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
 *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
 *  Adapted for Power Macintosh by Paul Mackerras.
 *  Low-level exception handlers and MMU support
 *  rewritten by Paul Mackerras.
 *    Copyright (C) 1996 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and
 *    Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com
 *
 *  This file contains the low-level support and setup for the
 *  PowerPC-64 platform, including trap and interrupt dispatch.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */
/*
 * The following macros define the code that appears as
 * the prologue to each of the exception handlers.  They
 * are split into two parts to allow a single kernel binary
 * to be used for pSeries and iSeries.
 *
 * We make as much of the exception code common between native
 * exception handlers (including pSeries LPAR) and iSeries LPAR
 * implementations as possible.
 */

#define EX_R9           0
#define EX_R10          8
#define EX_R11          16
#define EX_R12          24
#define EX_R13          32
#define EX_SRR0         40
#define EX_DAR          48
#define EX_DSISR  56
#define EX_CCR          60
#define EX_R3           64
#define EX_LR           72

/*
 * We're short on space and time in the exception prolog, so we can't
 * use the normal SET_REG_IMMEDIATE macro. Normally we just need the
 * low halfword of the address, but for Kdump we need the whole low
 * word.
 */
#define LOAD_HANDLER(reg, label)                            \
      addi  reg,reg,(label)-_stext; /* virt addr of handler ... */

#define EXCEPTION_PROLOG_1(area)                      \
      mfspr r13,SPRN_SPRG3;         /* get paca address into r13 */     \
      std   r9,area+EX_R9(r13);     /* save r9 - r12 */           \
      std   r10,area+EX_R10(r13);                           \
      std   r11,area+EX_R11(r13);                           \
      std   r12,area+EX_R12(r13);                           \
      mfspr r9,SPRN_SPRG1;                                  \
      std   r9,area+EX_R13(r13);                            \
      mfcr  r9

#define EXCEPTION_PROLOG_PSERIES(area, label)                     \
      EXCEPTION_PROLOG_1(area);                             \
      ld    r12,PACAKBASE(r13);     /* get high part of &label */ \
      ld    r10,PACAKMSR(r13);      /* get MSR value for kernel */      \
      mfspr r11,SPRN_SRR0;          /* save SRR0 */               \
      LOAD_HANDLER(r12,label)                               \
      mtspr SPRN_SRR0,r12;                                  \
      mfspr r12,SPRN_SRR1;          /* and SRR1 */                \
      mtspr SPRN_SRR1,r10;                                  \
      rfid;                                           \
      b     .     /* prevent speculative execution */

/*
 * The common exception prolog is used for all except a few exceptions
 * such as a segment miss on a kernel address.  We have to be prepared
 * to take another exception from the point where we first touch the
 * kernel stack onwards.
 *
 * On entry r13 points to the paca, r9-r13 are saved in the paca,
 * r9 contains the saved CR, r11 and r12 contain the saved SRR0 and
 * SRR1, and relocation is on.
 */
#define EXCEPTION_PROLOG_COMMON(n, area)                       \
      andi. r10,r12,MSR_PR;         /* See if coming from user    */ \
      mr    r10,r1;                 /* Save r1              */ \
      subi  r1,r1,INT_FRAME_SIZE;   /* alloc frame on kernel stack      */ \
      beq-  1f;                                          \
      ld    r1,PACAKSAVE(r13);      /* kernel stack to use        */ \
1:    cmpdi cr1,r1,0;         /* check if r1 is in userspace      */ \
      bge-  cr1,2f;                 /* abort if it is       */ \
      b     3f;                                          \
2:    li    r1,(n);                 /* will be reloaded later     */ \
      sth   r1,PACA_TRAP_SAVE(r13);                            \
      b     bad_stack;                                   \
3:    std   r9,_CCR(r1);            /* save CR in stackframe      */ \
      std   r11,_NIP(r1);           /* save SRR0 in stackframe    */ \
      std   r12,_MSR(r1);           /* save SRR1 in stackframe    */ \
      std   r10,0(r1);        /* make stack chain pointer   */ \
      std   r0,GPR0(r1);            /* save r0 in stackframe      */ \
      std   r10,GPR1(r1);           /* save r1 in stackframe      */ \
      ACCOUNT_CPU_USER_ENTRY(r9, r10);                         \
      std   r2,GPR2(r1);            /* save r2 in stackframe      */ \
      SAVE_4GPRS(3, r1);            /* save r3 - r6 in stackframe */ \
      SAVE_2GPRS(7, r1);            /* save r7, r8 in stackframe  */ \
      ld    r9,area+EX_R9(r13);     /* move r9, r10 to stackframe */ \
      ld    r10,area+EX_R10(r13);                              \
      std   r9,GPR9(r1);                                       \
      std   r10,GPR10(r1);                                     \
      ld    r9,area+EX_R11(r13);    /* move r11 - r13 to stackframe     */ \
      ld    r10,area+EX_R12(r13);                              \
      ld    r11,area+EX_R13(r13);                              \
      std   r9,GPR11(r1);                                      \
      std   r10,GPR12(r1);                                     \
      std   r11,GPR13(r1);                                     \
      ld    r2,PACATOC(r13);  /* get kernel TOC into r2     */ \
      mflr  r9;               /* save LR in stackframe      */ \
      std   r9,_LINK(r1);                                      \
      mfctr r10;              /* save CTR in stackframe     */ \
      std   r10,_CTR(r1);                                      \
      lbz   r10,PACASOFTIRQEN(r13);                      \
      mfspr r11,SPRN_XER;           /* save XER in stackframe     */ \
      std   r10,SOFTE(r1);                                     \
      std   r11,_XER(r1);                                      \
      li    r9,(n)+1;                                    \
      std   r9,_TRAP(r1);           /* set trap number            */ \
      li    r10,0;                                             \
      ld    r11,exception_marker@toc(r2);                      \
      std   r10,RESULT(r1);         /* clear regs->result         */ \
      std   r11,STACK_FRAME_OVERHEAD-16(r1); /* mark the frame    */

/*
 * Exception vectors.
 */
#define STD_EXCEPTION_PSERIES(n, label)               \
      . = n;                                    \
      .globl label##_pSeries;                   \
label##_pSeries:                          \
      HMT_MEDIUM;                         \
      mtspr SPRN_SPRG1,r13;         /* save r13 */    \
      EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)

#define HSTD_EXCEPTION_PSERIES(n, label)        \
      . = n;                                    \
      .globl label##_pSeries;                   \
label##_pSeries:                          \
      HMT_MEDIUM;                         \
      mtspr SPRN_SPRG1,r20;         /* save r20 */    \
      mfspr r20,SPRN_HSRR0;         /* copy HSRR0 to SRR0 */ \
      mtspr SPRN_SRR0,r20;                      \
      mfspr r20,SPRN_HSRR1;         /* copy HSRR0 to SRR0 */ \
      mtspr SPRN_SRR1,r20;                      \
      mfspr r20,SPRN_SPRG1;         /* restore r20 */ \
      mtspr SPRN_SPRG1,r13;         /* save r13 */    \
      EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)


#define MASKABLE_EXCEPTION_PSERIES(n, label)                      \
      . = n;                                                \
      .globl label##_pSeries;                               \
label##_pSeries:                                      \
      HMT_MEDIUM;                                     \
      mtspr SPRN_SPRG1,r13;         /* save r13 */                \
      mfspr r13,SPRN_SPRG3;         /* get paca address into r13 */     \
      std   r9,PACA_EXGEN+EX_R9(r13);     /* save r9, r10 */      \
      std   r10,PACA_EXGEN+EX_R10(r13);                     \
      lbz   r10,PACASOFTIRQEN(r13);                         \
      mfcr  r9;                                       \
      cmpwi r10,0;                                          \
      beq   masked_interrupt;                         \
      mfspr r10,SPRN_SPRG1;                                 \
      std   r10,PACA_EXGEN+EX_R13(r13);                     \
      std   r11,PACA_EXGEN+EX_R11(r13);                     \
      std   r12,PACA_EXGEN+EX_R12(r13);                     \
      ld    r12,PACAKBASE(r13);     /* get high part of &label */ \
      ld    r10,PACAKMSR(r13);      /* get MSR value for kernel */      \
      mfspr r11,SPRN_SRR0;          /* save SRR0 */               \
      LOAD_HANDLER(r12,label##_common)                      \
      mtspr SPRN_SRR0,r12;                                  \
      mfspr r12,SPRN_SRR1;          /* and SRR1 */                \
      mtspr SPRN_SRR1,r10;                                  \
      rfid;                                           \
      b     .     /* prevent speculative execution */

#ifdef CONFIG_PPC_ISERIES
#define DISABLE_INTS                      \
      li    r11,0;                        \
      stb   r11,PACASOFTIRQEN(r13);       \
BEGIN_FW_FTR_SECTION;                     \
      stb   r11,PACAHARDIRQEN(r13);       \
END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES);   \
      TRACE_DISABLE_INTS;                 \
BEGIN_FW_FTR_SECTION;                     \
      mfmsr r10;                    \
      ori   r10,r10,MSR_EE;               \
      mtmsrd      r10,1;                        \
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#else
#define DISABLE_INTS                      \
      li    r11,0;                        \
      stb   r11,PACASOFTIRQEN(r13);       \
      stb   r11,PACAHARDIRQEN(r13);       \
      TRACE_DISABLE_INTS
#endif /* CONFIG_PPC_ISERIES */

#define ENABLE_INTS                       \
      ld    r12,_MSR(r1);                 \
      mfmsr r11;                    \
      rlwimi      r11,r12,0,MSR_EE;       \
      mtmsrd      r11,1

#define STD_EXCEPTION_COMMON(trap, label, hdlr)       \
      .align      7;                            \
      .globl label##_common;                    \
label##_common:                                 \
      EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
      DISABLE_INTS;                             \
      bl    .save_nvgprs;                       \
      addi  r3,r1,STACK_FRAME_OVERHEAD;         \
      bl    hdlr;                         \
      b     .ret_from_except

/*
 * Like STD_EXCEPTION_COMMON, but for exceptions that can occur
 * in the idle task and therefore need the special idle handling.
 */
#define STD_EXCEPTION_COMMON_IDLE(trap, label, hdlr)  \
      .align      7;                            \
      .globl label##_common;                    \
label##_common:                                 \
      EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
      FINISH_NAP;                         \
      DISABLE_INTS;                             \
      bl    .save_nvgprs;                       \
      addi  r3,r1,STACK_FRAME_OVERHEAD;         \
      bl    hdlr;                         \
      b     .ret_from_except

#define STD_EXCEPTION_COMMON_LITE(trap, label, hdlr)  \
      .align      7;                            \
      .globl label##_common;                    \
label##_common:                                 \
      EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
      FINISH_NAP;                         \
      DISABLE_INTS;                             \
BEGIN_FTR_SECTION                         \
      bl    .ppc64_runlatch_on;                 \
END_FTR_SECTION_IFSET(CPU_FTR_CTRL)             \
      addi  r3,r1,STACK_FRAME_OVERHEAD;         \
      bl    hdlr;                         \
      b     .ret_from_except_lite

/*
 * When the idle code in power4_idle puts the CPU into NAP mode,
 * it has to do so in a loop, and relies on the external interrupt
 * and decrementer interrupt entry code to get it out of the loop.
 * It sets the _TLF_NAPPING bit in current_thread_info()->local_flags
 * to signal that it is in the loop and needs help to get out.
 */
#ifdef CONFIG_PPC_970_NAP
#define FINISH_NAP                        \
BEGIN_FTR_SECTION                   \
      clrrdi      r11,r1,THREAD_SHIFT;          \
      ld    r9,TI_LOCAL_FLAGS(r11);       \
      andi. r10,r9,_TLF_NAPPING;          \
      bnel  power4_fixup_nap;       \
END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
#else
#define FINISH_NAP
#endif

#endif      /* _ASM_POWERPC_EXCEPTION_H */

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