unwind_i.h

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/*
 * Copyright (C) 2000, 2002-2003 Hewlett-Packard Co
 *  David Mosberger-Tang <[email protected]>
 *
 * Kernel unwind support.
 */

#define UNW_VER(x)      ((x) >> 48)
#define UNW_FLAG_MASK       0x0000ffff00000000
#define UNW_FLAG_OSMASK     0x0000f00000000000
#define UNW_FLAG_EHANDLER(x)    ((x) & 0x0000000100000000L)
#define UNW_FLAG_UHANDLER(x)    ((x) & 0x0000000200000000L)
#define UNW_LENGTH(x)       ((x) & 0x00000000ffffffffL)

enum unw_register_index {
    /* primary unat: */
    UNW_REG_PRI_UNAT_GR,
    UNW_REG_PRI_UNAT_MEM,

    /* register stack */
    UNW_REG_BSP,                    /* register stack pointer */
    UNW_REG_BSPSTORE,
    UNW_REG_PFS,                    /* previous function state */
    UNW_REG_RNAT,
    /* memory stack */
    UNW_REG_PSP,                    /* previous memory stack pointer */
    /* return pointer: */
    UNW_REG_RP,

    /* preserved registers: */
    UNW_REG_R4, UNW_REG_R5, UNW_REG_R6, UNW_REG_R7,
    UNW_REG_UNAT, UNW_REG_PR, UNW_REG_LC, UNW_REG_FPSR,
    UNW_REG_B1, UNW_REG_B2, UNW_REG_B3, UNW_REG_B4, UNW_REG_B5,
    UNW_REG_F2, UNW_REG_F3, UNW_REG_F4, UNW_REG_F5,
    UNW_REG_F16, UNW_REG_F17, UNW_REG_F18, UNW_REG_F19,
    UNW_REG_F20, UNW_REG_F21, UNW_REG_F22, UNW_REG_F23,
    UNW_REG_F24, UNW_REG_F25, UNW_REG_F26, UNW_REG_F27,
    UNW_REG_F28, UNW_REG_F29, UNW_REG_F30, UNW_REG_F31,
    UNW_NUM_REGS
};

struct unw_info_block {
    u64 header;
    u64 desc[0];        /* unwind descriptors */
    /* personality routine and language-specific data follow behind descriptors */
};

struct unw_table {
    struct unw_table *next;     /* must be first member! */
    const char *name;
    unsigned long gp;       /* global pointer for this load-module */
    unsigned long segment_base; /* base for offsets in the unwind table entries */
    unsigned long start;
    unsigned long end;
    const struct unw_table_entry *array;
    unsigned long length;
};

enum unw_where {
    UNW_WHERE_NONE,         /* register isn't saved at all */
    UNW_WHERE_GR,           /* register is saved in a general register */
    UNW_WHERE_FR,           /* register is saved in a floating-point register */
    UNW_WHERE_BR,           /* register is saved in a branch register */
    UNW_WHERE_SPREL,        /* register is saved on memstack (sp-relative) */
    UNW_WHERE_PSPREL,       /* register is saved on memstack (psp-relative) */
    /*
     * At the end of each prologue these locations get resolved to
     * UNW_WHERE_PSPREL and UNW_WHERE_GR, respectively:
     */
    UNW_WHERE_SPILL_HOME,       /* register is saved in its spill home */
    UNW_WHERE_GR_SAVE       /* register is saved in next general register */
};

#define UNW_WHEN_NEVER  0x7fffffff

struct unw_reg_info {
    unsigned long val;      /* save location: register number or offset */
    enum unw_where where;       /* where the register gets saved */
    int when;           /* when the register gets saved */
};

struct unw_reg_state {
    struct unw_reg_state *next;     /* next (outer) element on state stack */
    struct unw_reg_info reg[UNW_NUM_REGS];  /* register save locations */
};

struct unw_labeled_state {
    struct unw_labeled_state *next;     /* next labeled state (or NULL) */
    unsigned long label;            /* label for this state */
    struct unw_reg_state saved_state;
};

struct unw_state_record {
    unsigned int first_region : 1;  /* is this the first region? */
    unsigned int done : 1;      /* are we done scanning descriptors? */
    unsigned int any_spills : 1;    /* got any register spills? */
    unsigned int in_body : 1;   /* are we inside a body (as opposed to a prologue)? */
    unsigned long flags;        /* see UNW_FLAG_* in unwind.h */

    u8 *imask;          /* imask of spill_mask record or NULL */
    unsigned long pr_val;       /* predicate values */
    unsigned long pr_mask;      /* predicate mask */
    long spill_offset;      /* psp-relative offset for spill base */
    int region_start;
    int region_len;
    int epilogue_start;
    int epilogue_count;
    int when_target;

    u8 gr_save_loc;         /* next general register to use for saving a register */
    u8 return_link_reg;     /* branch register in which the return link is passed */

    struct unw_labeled_state *labeled_states;   /* list of all labeled states */
    struct unw_reg_state curr;  /* current state */
};

enum unw_nat_type {
    UNW_NAT_NONE,       /* NaT not represented */
    UNW_NAT_VAL,        /* NaT represented by NaT value (fp reg) */
    UNW_NAT_MEMSTK,     /* NaT value is in unat word at offset OFF  */
    UNW_NAT_REGSTK      /* NaT is in rnat */
};

enum unw_insn_opcode {
    UNW_INSN_ADD,           /* s[dst] += val */
    UNW_INSN_ADD_PSP,       /* s[dst] = (s.psp + val) */
    UNW_INSN_ADD_SP,        /* s[dst] = (s.sp + val) */
    UNW_INSN_MOVE,          /* s[dst] = s[val] */
    UNW_INSN_MOVE2,         /* s[dst] = s[val]; s[dst+1] = s[val+1] */
    UNW_INSN_MOVE_STACKED,      /* s[dst] = ia64_rse_skip(*s.bsp, val) */
    UNW_INSN_SETNAT_MEMSTK,     /* s[dst+1].nat.type = MEMSTK;
                       s[dst+1].nat.off = *s.pri_unat - s[dst] */
    UNW_INSN_SETNAT_TYPE,       /* s[dst+1].nat.type = val */
    UNW_INSN_LOAD,          /* s[dst] = *s[val] */
    UNW_INSN_MOVE_SCRATCH,      /* s[dst] = scratch reg "val" */
    UNW_INSN_MOVE_CONST,            /* s[dst] = constant reg "val" */
};

struct unw_insn {
    unsigned int opc    :  4;
    unsigned int dst    :  9;
    signed int val      : 19;
};

/*
 * Preserved general static registers (r4-r7) give rise to two script
 * instructions; everything else yields at most one instruction; at
 * the end of the script, the psp gets popped, accounting for one more
 * instruction.
 */
#define UNW_MAX_SCRIPT_LEN  (UNW_NUM_REGS + 5)

struct unw_script {
    unsigned long ip;       /* ip this script is for */
    unsigned long pr_mask;      /* mask of predicates script depends on */
    unsigned long pr_val;       /* predicate values this script is for */
    rwlock_t lock;
    unsigned int flags;     /* see UNW_FLAG_* in unwind.h */
    unsigned short lru_chain;   /* used for least-recently-used chain */
    unsigned short coll_chain;  /* used for hash collisions */
    unsigned short hint;        /* hint for next script to try (or -1) */
    unsigned short count;       /* number of instructions in script */
    struct unw_insn insn[UNW_MAX_SCRIPT_LEN];
};