1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
MIPS: allow disabling the kernel FPU emulator
This patch allows turning off the in-kernel Algorithmics
FPU emulator support, which allows one to save a couple of
precious blocks on an embedded system.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
--
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -935,6 +935,17 @@ config I8259
config MIPS_BONITO64
bool
+config MIPS_FPU_EMU
+ bool "Enable FPU emulation"
+ default y
+ help
+ This option allows building a kernel with or without the Algorithmics
+ FPU emulator enabled. Turning off this option results in a kernel which
+ does not catch floating operations exceptions. Make sure that your toolchain
+ is configured to enable software floating point emulation in that case.
+
+ If unsure say Y here.
+
config MIPS_MSC
bool
--- a/arch/mips/math-emu/Makefile
+++ b/arch/mips/math-emu/Makefile
@@ -2,10 +2,12 @@
# Makefile for the Linux/MIPS kernel FPU emulation.
#
-obj-y := cp1emu.o ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
+obj-y := kernel_linkage.o
+
+obj-$(CONFIG_MIPS_FPU_EMU) += ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
ieee754xcpt.o dp_frexp.o dp_modf.o dp_div.o dp_mul.o dp_sub.o \
dp_add.o dp_fsp.o dp_cmp.o dp_logb.o dp_scalb.o dp_simple.o \
dp_tint.o dp_fint.o dp_tlong.o dp_flong.o sp_frexp.o sp_modf.o \
sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_logb.o \
sp_scalb.o sp_simple.o sp_tint.o sp_fint.o sp_tlong.o sp_flong.o \
- dp_sqrt.o sp_sqrt.o kernel_linkage.o dsemul.o
+ dp_sqrt.o sp_sqrt.o dsemul.o cp1emu.o
--- a/arch/mips/math-emu/kernel_linkage.c
+++ b/arch/mips/math-emu/kernel_linkage.c
@@ -29,6 +29,7 @@
#define SIGNALLING_NAN 0x7ff800007ff80000LL
+#ifdef CONFIG_MIPS_FPU_EMU
void fpu_emulator_init_fpu(void)
{
static int first = 1;
@@ -115,3 +116,36 @@ int fpu_emulator_restore_context32(struc
return err;
}
#endif
+
+#else
+
+void fpu_emulator_init_fpu(void)
+{
+ printk(KERN_INFO "FPU emulator disabled, make sure your toolchain"
+ "was compiled with software floating point support (soft-float)\n");
+ return;
+}
+
+int fpu_emulator_save_context(struct sigcontext __user *sc)
+{
+ return 0;
+}
+
+int fpu_emulator_restore_context(struct sigcontext __user *sc)
+{
+ return 0;
+}
+
+#ifdef CONFIG_64BIT
+int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
+{
+ return 0;
+}
+
+int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
+{
+ return 0;
+}
+#endif /* CONFIG_64BIT */
+
+#endif /* CONFIG_MIPS_FPU_EMU */
--- a/arch/mips/include/asm/fpu_emulator.h
+++ b/arch/mips/include/asm/fpu_emulator.h
@@ -27,6 +27,8 @@
#include <asm/inst.h>
#include <asm/local.h>
+#ifdef CONFIG_MIPS_FPU_EMU
+
#ifdef CONFIG_DEBUG_FS
struct mips_fpu_emulator_stats {
@@ -60,6 +62,38 @@ extern int fpu_emulator_cop1Handler(stru
int process_fpemu_return(int sig, void __user *fault_addr);
int mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
unsigned long *contpc);
+#else
+static inline int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
+ unsigned long cpc)
+{
+ return 0;
+}
+
+static inline int do_dsemulret(struct pt_regs *xcp)
+{
+ return 0;
+}
+
+static inline int fpu_emulator_cop1Handler(struct pt_regs *xcp,
+ struct mips_fpu_struct *ctx,
+ int has_fpu,
+ void *__user *fault_addr)
+{
+ return 0;
+}
+
+static inline int process_fpemu_return(int sig, void __user *fault_addr)
+{
+ return -EINVAL;
+}
+
+static inline int mm_isBranchInstr(struct pt_regs *regs,
+ struct mm_decoded_insn dec_insn,
+ unsigned long *contpc)
+{
+ return 0;
+}
+#endif /* CONFIG_MIPS_FPU_EMU */
/*
* Instruction inserted following the badinst to further tag the sequence
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -701,6 +701,7 @@ asmlinkage void do_ov(struct pt_regs *re
exception_exit(prev_state);
}
+#ifdef CONFIG_MIPS_FPU_EMU
int process_fpemu_return(int sig, void __user *fault_addr)
{
if (sig == SIGSEGV || sig == SIGBUS) {
@@ -724,6 +725,7 @@ int process_fpemu_return(int sig, void _
return 0;
}
}
+#endif /* CONFIG_MIPS_FPU_EMU */
/*
* XXX Delayed fp exceptions when doing a lazy ctx switch XXX
|
