1 MIPS: allow disabling the kernel FPU emulator
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.
7 Signed-off-by: Florian Fainelli <florian@openwrt.org>
9 --- a/arch/mips/Kconfig
10 +++ b/arch/mips/Kconfig
11 @@ -791,6 +791,17 @@ config I8259
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.
24 + If unsure say Y here.
29 --- a/arch/mips/math-emu/Makefile
30 +++ b/arch/mips/math-emu/Makefile
32 # Makefile for the Linux/MIPS kernel FPU emulation.
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
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
47 EXTRA_CFLAGS += -Werror
48 --- a/arch/mips/math-emu/cp1emu.c
49 +++ b/arch/mips/math-emu/cp1emu.c
54 +/* Further private data for which no space exists in mips_fpu_struct */
56 +struct mips_fpu_emulator_stats fpuemustats;
58 +#ifdef CONFIG_MIPS_FPU_EMU
60 /* Function which emulates a floating point instruction. */
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);
67 -/* Further private data for which no space exists in mips_fpu_struct */
69 -struct mips_fpu_emulator_stats fpuemustats;
71 /* Control registers */
73 #define FPCREG_RID 0 /* $0 = revision id */
74 @@ -1273,6 +1275,13 @@ int fpu_emulator_cop1Handler(struct pt_r
79 +int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
84 +#endif /* CONFIG_MIPS_FPU_EMU */
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 */
94 +#ifdef CONFIG_MIPS_FPU_EMU
95 int do_dsemulret(struct pt_regs *xcp)
97 struct emuframe __user *fr;
98 @@ -165,3 +166,9 @@ int do_dsemulret(struct pt_regs *xcp)
103 +int do_dsemulret(struct pt_regs *xcp)
107 +#endif /* CONFIG_MIPS_FPU_EMU */
108 --- a/arch/mips/math-emu/kernel_linkage.c
109 +++ b/arch/mips/math-emu/kernel_linkage.c
112 #define SIGNALLING_NAN 0x7ff800007ff80000LL
114 +#ifdef CONFIG_MIPS_FPU_EMU
115 void fpu_emulator_init_fpu(void)
117 static int first = 1;
118 @@ -112,4 +113,36 @@ int fpu_emulator_restore_context32(struc
123 +#endif /* CONFIG_64BIT */
126 +void fpu_emulator_init_fpu(void)
128 + printk(KERN_INFO "FPU emulator disabled, make sure your toolchain"
129 + "was compiled with software floating point support (soft-float)\n");
133 +int fpu_emulator_save_context(struct sigcontext __user *sc)
138 +int fpu_emulator_restore_context(struct sigcontext __user *sc)
143 +int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
148 +int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
154 +#endif /* CONFIG_64BIT */
155 +#endif /* CONFIG_MIPS_FPU_EMU */