summaryrefslogtreecommitdiff
path: root/target/linux/generic/patches-2.6.38/025-mips_disable_fpu.patch
blob: d1f60df64d212ccea42aa009a830f5ca5c07bb69 (plain)
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
@@ -887,6 +887,17 @@ 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
@@ -2,11 +2,13 @@
 # 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 dsemul.o cp1emu.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
 
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -58,7 +58,11 @@
 #define __mips 4
 
 /* Function which emulates a floating point instruction. */
+#ifdef CONFIG_DEBUG_FS
+DEFINE_PER_CPU(struct mips_fpu_emulator_stats, fpuemustats);
+#endif
 
+#ifdef CONFIG_MIPS_FPU_EMU
 static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
 	mips_instruction);
 
@@ -69,10 +73,6 @@ static int fpux_emu(struct pt_regs *,
 
 /* Further private data for which no space exists in mips_fpu_struct */
 
-#ifdef CONFIG_DEBUG_FS
-DEFINE_PER_CPU(struct mips_fpu_emulator_stats, fpuemustats);
-#endif
-
 /* Control registers */
 
 #define FPCREG_RID	0	/* $0  = revision id */
@@ -1361,7 +1361,6 @@ int fpu_emulator_cop1Handler(struct pt_r
 
 	return sig;
 }
-
 #ifdef CONFIG_DEBUG_FS
 
 static int fpuemu_stat_get(void *data, u64 *val)
@@ -1410,4 +1409,11 @@ static int __init debugfs_fpuemu(void)
 	return 0;
 }
 __initcall(debugfs_fpuemu);
-#endif
+#endif /* CONFIG_DEBUGFS */
+#else
+int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
+        int has_fpu)
+{
+	return 0;
+}
+#endif /* CONFIG_MIPS_FPU_EMU */
--- a/arch/mips/math-emu/dsemul.c
+++ b/arch/mips/math-emu/dsemul.c
@@ -109,6 +109,7 @@ int mips_dsemul(struct pt_regs *regs, mi
 	return SIGILL;		/* force out of emulation loop */
 }
 
+#ifdef CONFIG_MIPS_FPU_EMU
 int do_dsemulret(struct pt_regs *xcp)
 {
 	struct emuframe __user *fr;
@@ -165,3 +166,9 @@ int do_dsemulret(struct pt_regs *xcp)
 
 	return 1;
 }
+#else
+int do_dsemulret(struct pt_regs *xcp)
+{
+	return 0;
+}
+#endif /* CONFIG_MIPS_FPU_EMU */
--- 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;
@@ -112,4 +113,36 @@ int fpu_emulator_restore_context32(struc
 
 	return err;
 }
-#endif
+#endif	/* CONFIG_64BIT */
+#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;
+}
+
+int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
+{
+	return 0;
+}
+
+int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
+{
+	return 0;
+}
+
+#ifdef CONFIG_64BIT
+#endif	/* CONFIG_64BIT */
+#endif /* CONFIG_MIPS_FPU_EMU */