xref: /linux/arch/mips/include/asm/branch.h (revision 4b4193256c8d3bc3a5397b5cd9494c2ad386317d)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1996, 1997, 1998, 2001 by Ralf Baechle
7  */
8 #ifndef _ASM_BRANCH_H
9 #define _ASM_BRANCH_H
10 
11 #include <asm/cpu-features.h>
12 #include <asm/mipsregs.h>
13 #include <asm/ptrace.h>
14 #include <asm/inst.h>
15 
16 extern int __isa_exception_epc(struct pt_regs *regs);
17 extern int __compute_return_epc(struct pt_regs *regs);
18 extern int __compute_return_epc_for_insn(struct pt_regs *regs,
19 					 union mips_instruction insn);
20 extern int __microMIPS_compute_return_epc(struct pt_regs *regs);
21 extern int __MIPS16e_compute_return_epc(struct pt_regs *regs);
22 
23 /*
24  * microMIPS bitfields
25  */
26 #define MM_POOL32A_MINOR_MASK	0x3f
27 #define MM_POOL32A_MINOR_SHIFT	0x6
28 #define MM_MIPS32_COND_FC	0x30
29 
30 int isBranchInstr(struct pt_regs *regs,
31 	struct mm_decoded_insn dec_insn, unsigned long *contpc);
32 
33 extern int __mm_isBranchInstr(struct pt_regs *regs,
34 	struct mm_decoded_insn dec_insn, unsigned long *contpc);
35 
mm_isBranchInstr(struct pt_regs * regs,struct mm_decoded_insn dec_insn,unsigned long * contpc)36 static inline int mm_isBranchInstr(struct pt_regs *regs,
37 	struct mm_decoded_insn dec_insn, unsigned long *contpc)
38 {
39 	if (!cpu_has_mmips)
40 		return 0;
41 
42 	return __mm_isBranchInstr(regs, dec_insn, contpc);
43 }
44 
delay_slot(struct pt_regs * regs)45 static inline int delay_slot(struct pt_regs *regs)
46 {
47 	return regs->cp0_cause & CAUSEF_BD;
48 }
49 
clear_delay_slot(struct pt_regs * regs)50 static inline void clear_delay_slot(struct pt_regs *regs)
51 {
52 	regs->cp0_cause &= ~CAUSEF_BD;
53 }
54 
set_delay_slot(struct pt_regs * regs)55 static inline void set_delay_slot(struct pt_regs *regs)
56 {
57 	regs->cp0_cause |= CAUSEF_BD;
58 }
59 
exception_epc(struct pt_regs * regs)60 static inline unsigned long exception_epc(struct pt_regs *regs)
61 {
62 	if (likely(!delay_slot(regs)))
63 		return regs->cp0_epc;
64 
65 	if (get_isa16_mode(regs->cp0_epc))
66 		return __isa_exception_epc(regs);
67 
68 	return regs->cp0_epc + 4;
69 }
70 
71 #define BRANCH_LIKELY_TAKEN 0x0001
72 
compute_return_epc(struct pt_regs * regs)73 static inline int compute_return_epc(struct pt_regs *regs)
74 {
75 	if (get_isa16_mode(regs->cp0_epc)) {
76 		if (cpu_has_mmips)
77 			return __microMIPS_compute_return_epc(regs);
78 		if (cpu_has_mips16)
79 			return __MIPS16e_compute_return_epc(regs);
80 	} else if (!delay_slot(regs)) {
81 		regs->cp0_epc += 4;
82 		return 0;
83 	}
84 
85 	return __compute_return_epc(regs);
86 }
87 
MIPS16e_compute_return_epc(struct pt_regs * regs,union mips16e_instruction * inst)88 static inline int MIPS16e_compute_return_epc(struct pt_regs *regs,
89 					     union mips16e_instruction *inst)
90 {
91 	if (likely(!delay_slot(regs))) {
92 		if (inst->ri.opcode == MIPS16e_extend_op) {
93 			regs->cp0_epc += 4;
94 			return 0;
95 		}
96 		regs->cp0_epc += 2;
97 		return 0;
98 	}
99 
100 	return __MIPS16e_compute_return_epc(regs);
101 }
102 
103 #endif /* _ASM_BRANCH_H */
104