[kernel] turn off the Algorithmics FPU emulator by default now that we have software floating point enabled in the toolchain, please recompile your toolchains and kernels

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@16605 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 163 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/patches-2.6.30/025-mips_disable_fpu.patch b/target/linux/generic-2.6/patches-2.6.30/025-mips_disable_fpu.patch
new file mode 100644
index 0000000000..e71bf48f21
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.30/025-mips_disable_fpu.patch
@@ -0,0 +1,163 @@
+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>
+--
+diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
+index 65d3b19..a467ee5 100644
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -811,6 +811,17 @@ config I8259
+ config MIPS_BONITO64
+ 	bool
+ 
++config MIPS_FPU_EMU
++	bool
++	default n
++	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
+ 
+diff --git a/arch/mips/math-emu/Makefile b/arch/mips/math-emu/Makefile
+index d547efd..7fdef24 100644
+--- a/arch/mips/math-emu/Makefile
++++ b/arch/mips/math-emu/Makefile
+@@ -2,12 +2,14 @@
+ # 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
+ 
+ EXTRA_CFLAGS += -Werror
+diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
+index 890f779..9f4c767 100644
+--- a/arch/mips/math-emu/cp1emu.c
++++ b/arch/mips/math-emu/cp1emu.c
+@@ -56,6 +56,12 @@
+ #endif
+ #define __mips 4
+ 
++/* Further private data for which no space exists in mips_fpu_struct */
++
++struct mips_fpu_emulator_stats fpuemustats;
++
++#ifdef CONFIG_MIPS_FPU_EMU
++
+ /* Function which emulates a floating point instruction. */
+ 
+ static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
+@@ -66,10 +72,6 @@ static int fpux_emu(struct pt_regs *,
+ 	struct mips_fpu_struct *, mips_instruction);
+ #endif
+ 
+-/* Further private data for which no space exists in mips_fpu_struct */
+-
+-struct mips_fpu_emulator_stats fpuemustats;
+-
+ /* Control registers */
+ 
+ #define FPCREG_RID	0	/* $0  = revision id */
+@@ -1273,6 +1275,13 @@ int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
+ 
+ 	return sig;
+ }
++#else
++int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
++        int has_fpu)
++{
++	return 0;
++}
++#endif /* CONFIG_MIPS_FPU_EMU */
+ 
+ #ifdef CONFIG_DEBUG_FS
+ extern struct dentry *mips_debugfs_dir;
+diff --git a/arch/mips/math-emu/dsemul.c b/arch/mips/math-emu/dsemul.c
+index df7b9d9..9b42bfd 100644
+--- 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, mips_instruction ir, unsigned long cpc)
+ 	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 */
+diff --git a/arch/mips/math-emu/kernel_linkage.c b/arch/mips/math-emu/kernel_linkage.c
+index 52e6c58..211a399 100644
+--- 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 +113,34 @@ int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
+ 
+ 	return err;
+ }
+-#endif
++#endif	/* CONFIG_64BIT */
++#else
++
++void fpu_emulator_init_fpu(void)
++{
++	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 */