1/*
2 * Copyright (C) 2000, 2002 Hewlett-Packard Co
3 *	David Mosberger-Tang <davidm@hpl.hp.com>
4 *
5 * Kernel unwind support.
6 */
7
8#define UNW_VER(x)		((x) >> 48)
9#define UNW_FLAG_MASK		0x0000ffff00000000
10#define UNW_FLAG_OSMASK		0x0000f00000000000
11#define UNW_FLAG_EHANDLER(x)	((x) & 0x0000000100000000L)
12#define UNW_FLAG_UHANDLER(x)	((x) & 0x0000000200000000L)
13#define UNW_LENGTH(x)		((x) & 0x00000000ffffffffL)
14
15enum unw_register_index {
16	/* primary unat: */
17	UNW_REG_PRI_UNAT_GR,
18	UNW_REG_PRI_UNAT_MEM,
19
20	/* register stack */
21	UNW_REG_BSP,					/* register stack pointer */
22	UNW_REG_BSPSTORE,
23	UNW_REG_PFS,					/* previous function state */
24	UNW_REG_RNAT,
25	/* memory stack */
26	UNW_REG_PSP,					/* previous memory stack pointer */
27	/* return pointer: */
28	UNW_REG_RP,
29
30	/* preserved registers: */
31	UNW_REG_R4, UNW_REG_R5, UNW_REG_R6, UNW_REG_R7,
32	UNW_REG_UNAT, UNW_REG_PR, UNW_REG_LC, UNW_REG_FPSR,
33	UNW_REG_B1, UNW_REG_B2, UNW_REG_B3, UNW_REG_B4, UNW_REG_B5,
34	UNW_REG_F2, UNW_REG_F3, UNW_REG_F4, UNW_REG_F5,
35	UNW_REG_F16, UNW_REG_F17, UNW_REG_F18, UNW_REG_F19,
36	UNW_REG_F20, UNW_REG_F21, UNW_REG_F22, UNW_REG_F23,
37	UNW_REG_F24, UNW_REG_F25, UNW_REG_F26, UNW_REG_F27,
38	UNW_REG_F28, UNW_REG_F29, UNW_REG_F30, UNW_REG_F31,
39	UNW_NUM_REGS
40};
41
42struct unw_info_block {
43	u64 header;
44	u64 desc[0];		/* unwind descriptors */
45	/* personality routine and language-specific data follow behind descriptors */
46};
47
48struct unw_table_entry {
49	u64 start_offset;
50	u64 end_offset;
51	u64 info_offset;
52};
53
54struct unw_table {
55	struct unw_table *next;		/* must be first member! */
56	const char *name;
57	unsigned long gp;		/* global pointer for this load-module */
58	unsigned long segment_base;	/* base for offsets in the unwind table entries */
59	unsigned long start;
60	unsigned long end;
61	const struct unw_table_entry *array;
62	unsigned long length;
63};
64
65enum unw_where {
66	UNW_WHERE_NONE,			/* register isn't saved at all */
67	UNW_WHERE_GR,			/* register is saved in a general register */
68	UNW_WHERE_FR,			/* register is saved in a floating-point register */
69	UNW_WHERE_BR,			/* register is saved in a branch register */
70	UNW_WHERE_SPREL,		/* register is saved on memstack (sp-relative) */
71	UNW_WHERE_PSPREL,		/* register is saved on memstack (psp-relative) */
72	/*
73	 * At the end of each prologue these locations get resolved to
74	 * UNW_WHERE_PSPREL and UNW_WHERE_GR, respectively:
75	 */
76	UNW_WHERE_SPILL_HOME,		/* register is saved in its spill home */
77	UNW_WHERE_GR_SAVE		/* register is saved in next general register */
78};
79
80#define UNW_WHEN_NEVER	0x7fffffff
81
82struct unw_reg_info {
83	unsigned long val;		/* save location: register number or offset */
84	enum unw_where where;		/* where the register gets saved */
85	int when;			/* when the register gets saved */
86};
87
88struct unw_reg_state {
89	struct unw_reg_state *next;		/* next (outer) element on state stack */
90	struct unw_reg_info reg[UNW_NUM_REGS];	/* register save locations */
91};
92
93struct unw_labeled_state {
94	struct unw_labeled_state *next;		/* next labeled state (or NULL) */
95	unsigned long label;			/* label for this state */
96	struct unw_reg_state saved_state;
97};
98
99struct unw_state_record {
100	unsigned int first_region : 1;	/* is this the first region? */
101	unsigned int done : 1;		/* are we done scanning descriptors? */
102	unsigned int any_spills : 1;	/* got any register spills? */
103	unsigned int in_body : 1;	/* are we inside a body (as opposed to a prologue)? */
104	unsigned long flags;		/* see UNW_FLAG_* in unwind.h */
105
106	u8 *imask;			/* imask of spill_mask record or NULL */
107	unsigned long pr_val;		/* predicate values */
108	unsigned long pr_mask;		/* predicate mask */
109	long spill_offset;		/* psp-relative offset for spill base */
110	int region_start;
111	int region_len;
112	int epilogue_start;
113	int epilogue_count;
114	int when_target;
115
116	u8 gr_save_loc;			/* next general register to use for saving a register */
117	u8 return_link_reg;		/* branch register in which the return link is passed */
118
119	struct unw_labeled_state *labeled_states;	/* list of all labeled states */
120	struct unw_reg_state curr;	/* current state */
121};
122
123enum unw_nat_type {
124	UNW_NAT_NONE,		/* NaT not represented */
125	UNW_NAT_VAL,		/* NaT represented by NaT value (fp reg) */
126	UNW_NAT_MEMSTK,		/* NaT value is in unat word at offset OFF  */
127	UNW_NAT_REGSTK		/* NaT is in rnat */
128};
129
130enum unw_insn_opcode {
131	UNW_INSN_ADD,			/* s[dst] += val */
132	UNW_INSN_ADD_PSP,		/* s[dst] = (s.psp + val) */
133	UNW_INSN_ADD_SP,		/* s[dst] = (s.sp + val) */
134	UNW_INSN_MOVE,			/* s[dst] = s[val] */
135	UNW_INSN_MOVE2,			/* s[dst] = s[val]; s[dst+1] = s[val+1] */
136	UNW_INSN_MOVE_STACKED,		/* s[dst] = ia64_rse_skip(*s.bsp, val) */
137	UNW_INSN_SETNAT_MEMSTK,		/* s[dst+1].nat.type = MEMSTK;
138					   s[dst+1].nat.off = *s.pri_unat - s[dst] */
139	UNW_INSN_SETNAT_TYPE,		/* s[dst+1].nat.type = val */
140	UNW_INSN_LOAD			/* s[dst] = *s[val] */
141};
142
143struct unw_insn {
144	unsigned int opc	:  4;
145	unsigned int dst	:  9;
146	signed int val		: 19;
147};
148
149/*
150 * Preserved general static registers (r2-r5) give rise to two script
151 * instructions; everything else yields at most one instruction; at
152 * the end of the script, the psp gets popped, accounting for one more
153 * instruction.
154 */
155#define UNW_MAX_SCRIPT_LEN	(UNW_NUM_REGS + 5)
156
157struct unw_script {
158	unsigned long ip;		/* ip this script is for */
159	unsigned long pr_mask;		/* mask of predicates script depends on */
160	unsigned long pr_val;		/* predicate values this script is for */
161	rwlock_t lock;
162	unsigned int flags;		/* see UNW_FLAG_* in unwind.h */
163	unsigned short lru_chain;	/* used for least-recently-used chain */
164	unsigned short coll_chain;	/* used for hash collisions */
165	unsigned short hint;		/* hint for next script to try (or -1) */
166	unsigned short count;		/* number of instructions in script */
167	struct unw_insn insn[UNW_MAX_SCRIPT_LEN];
168};
169