LXR linux/arch/ia64/kernel/unwind

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Copyright (C) 2000, 2002-2003 Hewlett-Packard Co
   4 *      David Mosberger-Tang <davidm@hpl.hp.com>
   5 *
   6 * Kernel unwind support.
   7 */
   8
   9#define UNW_VER(x)              ((x) >> 48)
  10#define UNW_FLAG_MASK           0x0000ffff00000000
  11#define UNW_FLAG_OSMASK         0x0000f00000000000
  12#define UNW_FLAG_EHANDLER(x)    ((x) & 0x0000000100000000L)
  13#define UNW_FLAG_UHANDLER(x)    ((x) & 0x0000000200000000L)
  14#define UNW_LENGTH(x)           ((x) & 0x00000000ffffffffL)
  15
  16enum unw_register_index {
  17        /* primary unat: */
  18        UNW_REG_PRI_UNAT_GR,
  19        UNW_REG_PRI_UNAT_MEM,
  20
  21        /* register stack */
  22        UNW_REG_BSP,                                    /* register stack pointer */
  23        UNW_REG_BSPSTORE,
  24        UNW_REG_PFS,                                    /* previous function state */
  25        UNW_REG_RNAT,
  26        /* memory stack */
  27        UNW_REG_PSP,                                    /* previous memory stack pointer */
  28        /* return pointer: */
  29        UNW_REG_RP,
  30
  31        /* preserved registers: */
  32        UNW_REG_R4, UNW_REG_R5, UNW_REG_R6, UNW_REG_R7,
  33        UNW_REG_UNAT, UNW_REG_PR, UNW_REG_LC, UNW_REG_FPSR,
  34        UNW_REG_B1, UNW_REG_B2, UNW_REG_B3, UNW_REG_B4, UNW_REG_B5,
  35        UNW_REG_F2, UNW_REG_F3, UNW_REG_F4, UNW_REG_F5,
  36        UNW_REG_F16, UNW_REG_F17, UNW_REG_F18, UNW_REG_F19,
  37        UNW_REG_F20, UNW_REG_F21, UNW_REG_F22, UNW_REG_F23,
  38        UNW_REG_F24, UNW_REG_F25, UNW_REG_F26, UNW_REG_F27,
  39        UNW_REG_F28, UNW_REG_F29, UNW_REG_F30, UNW_REG_F31,
  40        UNW_NUM_REGS
  41};
  42
  43struct unw_info_block {
  44        u64 header;
  45        u64 desc[0];            /* unwind descriptors */
  46        /* personality routine and language-specific data follow behind descriptors */
  47};
  48
  49struct unw_table {
  50        struct unw_table *next;         /* must be first member! */
  51        const char *name;
  52        unsigned long gp;               /* global pointer for this load-module */
  53        unsigned long segment_base;     /* base for offsets in the unwind table entries */
  54        unsigned long start;
  55        unsigned long end;
  56        const struct unw_table_entry *array;
  57        unsigned long length;
  58};
  59
  60enum unw_where {
  61        UNW_WHERE_NONE,                 /* register isn't saved at all */
  62        UNW_WHERE_GR,                   /* register is saved in a general register */
  63        UNW_WHERE_FR,                   /* register is saved in a floating-point register */
  64        UNW_WHERE_BR,                   /* register is saved in a branch register */
  65        UNW_WHERE_SPREL,                /* register is saved on memstack (sp-relative) */
  66        UNW_WHERE_PSPREL,               /* register is saved on memstack (psp-relative) */
  67        /*
  68         * At the end of each prologue these locations get resolved to
  69         * UNW_WHERE_PSPREL and UNW_WHERE_GR, respectively:
  70         */
  71        UNW_WHERE_SPILL_HOME,           /* register is saved in its spill home */
  72        UNW_WHERE_GR_SAVE               /* register is saved in next general register */
  73};
  74
  75#define UNW_WHEN_NEVER  0x7fffffff
  76
  77struct unw_reg_info {
  78        unsigned long val;              /* save location: register number or offset */
  79        enum unw_where where;           /* where the register gets saved */
  80        int when;                       /* when the register gets saved */
  81};
  82
  83struct unw_reg_state {
  84        struct unw_reg_state *next;             /* next (outer) element on state stack */
  85        struct unw_reg_info reg[UNW_NUM_REGS];  /* register save locations */
  86};
  87
  88struct unw_labeled_state {
  89        struct unw_labeled_state *next;         /* next labeled state (or NULL) */
  90        unsigned long label;                    /* label for this state */
  91        struct unw_reg_state saved_state;
  92};
  93
  94struct unw_state_record {
  95        unsigned int first_region : 1;  /* is this the first region? */
  96        unsigned int done : 1;          /* are we done scanning descriptors? */
  97        unsigned int any_spills : 1;    /* got any register spills? */
  98        unsigned int in_body : 1;       /* are we inside a body (as opposed to a prologue)? */
  99        unsigned long flags;            /* see UNW_FLAG_* in unwind.h */
 100
 101        u8 *imask;                      /* imask of spill_mask record or NULL */
 102        unsigned long pr_val;           /* predicate values */
 103        unsigned long pr_mask;          /* predicate mask */
 104        long spill_offset;              /* psp-relative offset for spill base */
 105        int region_start;
 106        int region_len;
 107        int epilogue_start;
 108        int epilogue_count;
 109        int when_target;
 110
 111        u8 gr_save_loc;                 /* next general register to use for saving a register */
 112        u8 return_link_reg;             /* branch register in which the return link is passed */
 113
 114        struct unw_labeled_state *labeled_states;       /* list of all labeled states */
 115        struct unw_reg_state curr;      /* current state */
 116};
 117
 118enum unw_nat_type {
 119        UNW_NAT_NONE,           /* NaT not represented */
 120        UNW_NAT_VAL,            /* NaT represented by NaT value (fp reg) */
 121        UNW_NAT_MEMSTK,         /* NaT value is in unat word at offset OFF  */
 122        UNW_NAT_REGSTK          /* NaT is in rnat */
 123};
 124
 125enum unw_insn_opcode {
 126        UNW_INSN_ADD,                   /* s[dst] += val */
 127        UNW_INSN_ADD_PSP,               /* s[dst] = (s.psp + val) */
 128        UNW_INSN_ADD_SP,                /* s[dst] = (s.sp + val) */
 129        UNW_INSN_MOVE,                  /* s[dst] = s[val] */
 130        UNW_INSN_MOVE2,                 /* s[dst] = s[val]; s[dst+1] = s[val+1] */
 131        UNW_INSN_MOVE_STACKED,          /* s[dst] = ia64_rse_skip(*s.bsp, val) */
 132        UNW_INSN_SETNAT_MEMSTK,         /* s[dst+1].nat.type = MEMSTK;
 133                                           s[dst+1].nat.off = *s.pri_unat - s[dst] */
 134        UNW_INSN_SETNAT_TYPE,           /* s[dst+1].nat.type = val */
 135        UNW_INSN_LOAD,                  /* s[dst] = *s[val] */
 136        UNW_INSN_MOVE_SCRATCH,          /* s[dst] = scratch reg "val" */
 137        UNW_INSN_MOVE_CONST,            /* s[dst] = constant reg "val" */
 138};
 139
 140struct unw_insn {
 141        unsigned int opc        :  4;
 142        unsigned int dst        :  9;
 143        signed int val          : 19;
 144};
 145
 146/*
 147 * Preserved general static registers (r4-r7) give rise to two script
 148 * instructions; everything else yields at most one instruction; at
 149 * the end of the script, the psp gets popped, accounting for one more
 150 * instruction.
 151 */
 152#define UNW_MAX_SCRIPT_LEN      (UNW_NUM_REGS + 5)
 153
 154struct unw_script {
 155        unsigned long ip;               /* ip this script is for */
 156        unsigned long pr_mask;          /* mask of predicates script depends on */
 157        unsigned long pr_val;           /* predicate values this script is for */
 158        rwlock_t lock;
 159        unsigned int flags;             /* see UNW_FLAG_* in unwind.h */
 160        unsigned short lru_chain;       /* used for least-recently-used chain */
 161        unsigned short coll_chain;      /* used for hash collisions */
 162        unsigned short hint;            /* hint for next script to try (or -1) */
 163        unsigned short count;           /* number of instructions in script */
 164        struct unw_insn insn[UNW_MAX_SCRIPT_LEN];
 165};
 166