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
16 enum 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
43 struct unw_info_block {
44 u64 header;
45 u64 desc[0]; /* unwind descriptors */
46 /* personality routine and language-specific data follow behind descriptors */
47 };
48
49 struct 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
60 enum 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
77 struct 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
83 struct 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
88 struct 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
94 struct 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
118 enum 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
125 enum 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
140 struct 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
154 struct 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 };