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openwrt-xburst/target/linux/generic-2.6/patches-2.6.21/024-mips_disable_fpu.patch
hauke c8e4b6534a [amazon] Add some build fixes for kernel 2.6.21 and the infineon amazon target.
Now it compiles with the new toolchain.
These are mostly backports from mainline linux and newer linux kernels from openwrt.


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@18345 3c298f89-4303-0410-b956-a3cf2f4a3e73
2009-11-08 21:56:59 +00:00

151 lines
3.9 KiB
Diff

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
@@ -938,6 +938,17 @@ config LIMITED_DMA
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
--- a/arch/mips/math-emu/Makefile
+++ b/arch/mips/math-emu/Makefile
@@ -1,11 +1,12 @@
#
# Makefile for the Linux/MIPS kernel FPU emulation.
#
+obj-y := kernel_linkage.o dsemul.o cp1emu.o
-obj-y := cp1emu.o ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.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
@@ -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 */
@@ -1277,3 +1279,10 @@ int fpu_emulator_cop1Handler(struct pt_r
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 */
--- a/arch/mips/math-emu/dsemul.c
+++ b/arch/mips/math-emu/dsemul.c
@@ -112,6 +112,7 @@ 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 *fr;
@@ -167,3 +168,9 @@ 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
@@ -28,6 +28,7 @@
#define SIGNALLING_NAN 0x7ff800007ff80000LL
+#ifdef CONFIG_MIPS_FPU_EMU
void fpu_emulator_init_fpu(void)
{
static int first = 1;
@@ -111,4 +112,36 @@ 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 */