[backfire] backport r26906
[openwrt/svn-archive/archive.git] / target / linux / generic-2.6 / patches-2.6.32 / 025-mips_disable_fpu.patch
1 MIPS: allow disabling the kernel FPU emulator
2
3 This patch allows turning off the in-kernel Algorithmics
4 FPU emulator support, which allows one to save a couple of
5 precious blocks on an embedded system.
6
7 Signed-off-by: Florian Fainelli <florian@openwrt.org>
8 --
9 --- a/arch/mips/Kconfig
10 +++ b/arch/mips/Kconfig
11 @@ -842,6 +842,17 @@ config I8259
12 config MIPS_BONITO64
13 bool
14
15 +config MIPS_FPU_EMU
16 + bool "Enable FPU emulation"
17 + default y
18 + help
19 + This option allows building a kernel with or without the Algorithmics
20 + FPU emulator enabled. Turning off this option results in a kernel which
21 + does not catch floating operations exceptions. Make sure that your toolchain
22 + is configured to enable software floating point emulation in that case.
23 +
24 + If unsure say Y here.
25 +
26 config MIPS_MSC
27 bool
28
29 --- a/arch/mips/math-emu/Makefile
30 +++ b/arch/mips/math-emu/Makefile
31 @@ -2,12 +2,14 @@
32 # Makefile for the Linux/MIPS kernel FPU emulation.
33 #
34
35 -obj-y := cp1emu.o ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
36 +obj-y := kernel_linkage.o dsemul.o cp1emu.o
37 +
38 +obj-$(CONFIG_MIPS_FPU_EMU) += ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
39 ieee754xcpt.o dp_frexp.o dp_modf.o dp_div.o dp_mul.o dp_sub.o \
40 dp_add.o dp_fsp.o dp_cmp.o dp_logb.o dp_scalb.o dp_simple.o \
41 dp_tint.o dp_fint.o dp_tlong.o dp_flong.o sp_frexp.o sp_modf.o \
42 sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_logb.o \
43 sp_scalb.o sp_simple.o sp_tint.o sp_fint.o sp_tlong.o sp_flong.o \
44 - dp_sqrt.o sp_sqrt.o kernel_linkage.o dsemul.o
45 + dp_sqrt.o sp_sqrt.o
46
47 EXTRA_CFLAGS += -Werror
48 --- a/arch/mips/math-emu/cp1emu.c
49 +++ b/arch/mips/math-emu/cp1emu.c
50 @@ -56,6 +56,12 @@
51 #endif
52 #define __mips 4
53
54 +/* Further private data for which no space exists in mips_fpu_struct */
55 +
56 +struct mips_fpu_emulator_stats fpuemustats;
57 +
58 +#ifdef CONFIG_MIPS_FPU_EMU
59 +
60 /* Function which emulates a floating point instruction. */
61
62 static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
63 @@ -66,10 +72,6 @@ static int fpux_emu(struct pt_regs *,
64 struct mips_fpu_struct *, mips_instruction);
65 #endif
66
67 -/* Further private data for which no space exists in mips_fpu_struct */
68 -
69 -struct mips_fpu_emulator_stats fpuemustats;
70 -
71 /* Control registers */
72
73 #define FPCREG_RID 0 /* $0 = revision id */
74 @@ -1281,6 +1283,13 @@ int fpu_emulator_cop1Handler(struct pt_r
75
76 return sig;
77 }
78 +#else
79 +int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
80 + int has_fpu)
81 +{
82 + return 0;
83 +}
84 +#endif /* CONFIG_MIPS_FPU_EMU */
85
86 #ifdef CONFIG_DEBUG_FS
87 extern struct dentry *mips_debugfs_dir;
88 --- a/arch/mips/math-emu/dsemul.c
89 +++ b/arch/mips/math-emu/dsemul.c
90 @@ -109,6 +109,7 @@ int mips_dsemul(struct pt_regs *regs, mi
91 return SIGILL; /* force out of emulation loop */
92 }
93
94 +#ifdef CONFIG_MIPS_FPU_EMU
95 int do_dsemulret(struct pt_regs *xcp)
96 {
97 struct emuframe __user *fr;
98 @@ -165,3 +166,9 @@ int do_dsemulret(struct pt_regs *xcp)
99
100 return 1;
101 }
102 +#else
103 +int do_dsemulret(struct pt_regs *xcp)
104 +{
105 + return 0;
106 +}
107 +#endif /* CONFIG_MIPS_FPU_EMU */
108 --- a/arch/mips/math-emu/kernel_linkage.c
109 +++ b/arch/mips/math-emu/kernel_linkage.c
110 @@ -29,6 +29,7 @@
111
112 #define SIGNALLING_NAN 0x7ff800007ff80000LL
113
114 +#ifdef CONFIG_MIPS_FPU_EMU
115 void fpu_emulator_init_fpu(void)
116 {
117 static int first = 1;
118 @@ -112,4 +113,36 @@ int fpu_emulator_restore_context32(struc
119
120 return err;
121 }
122 -#endif
123 +#endif /* CONFIG_64BIT */
124 +#else
125 +
126 +void fpu_emulator_init_fpu(void)
127 +{
128 + printk(KERN_INFO "FPU emulator disabled, make sure your toolchain"
129 + "was compiled with software floating point support (soft-float)\n");
130 + return;
131 +}
132 +
133 +int fpu_emulator_save_context(struct sigcontext __user *sc)
134 +{
135 + return 0;
136 +}
137 +
138 +int fpu_emulator_restore_context(struct sigcontext __user *sc)
139 +{
140 + return 0;
141 +}
142 +
143 +int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
144 +{
145 + return 0;
146 +}
147 +
148 +int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
149 +{
150 + return 0;
151 +}
152 +
153 +#ifdef CONFIG_64BIT
154 +#endif /* CONFIG_64BIT */
155 +#endif /* CONFIG_MIPS_FPU_EMU */