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-rw-r--r--target/linux/generic/patches-3.12/304-mips_disable_fpu.patch160
1 files changed, 160 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.12/304-mips_disable_fpu.patch b/target/linux/generic/patches-3.12/304-mips_disable_fpu.patch
new file mode 100644
index 0000000..b524e79
--- /dev/null
+++ b/target/linux/generic/patches-3.12/304-mips_disable_fpu.patch
@@ -0,0 +1,160 @@
+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
+@@ -945,6 +945,17 @@ 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
+@@ -2,10 +2,12 @@
+ # 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
++
++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 dsemul.o cp1emu.o
+--- 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;
+@@ -113,3 +114,36 @@ int fpu_emulator_restore_context32(struc
+ return err;
+ }
+ #endif
++
++#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;
++}
++
++#ifdef CONFIG_64BIT
++int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
++{
++ return 0;
++}
++
++int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
++{
++ return 0;
++}
++#endif /* CONFIG_64BIT */
++
++#endif /* CONFIG_MIPS_FPU_EMU */
+--- a/arch/mips/include/asm/fpu_emulator.h
++++ b/arch/mips/include/asm/fpu_emulator.h
+@@ -27,6 +27,8 @@
+ #include <asm/inst.h>
+ #include <asm/local.h>
+
++#ifdef CONFIG_MIPS_FPU_EMU
++
+ #ifdef CONFIG_DEBUG_FS
+
+ struct mips_fpu_emulator_stats {
+@@ -60,6 +62,38 @@ extern int fpu_emulator_cop1Handler(stru
+ int process_fpemu_return(int sig, void __user *fault_addr);
+ int mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
+ unsigned long *contpc);
++#else
++static inline int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
++ unsigned long cpc)
++{
++ return 0;
++}
++
++static inline int do_dsemulret(struct pt_regs *xcp)
++{
++ return 0;
++}
++
++static inline int fpu_emulator_cop1Handler(struct pt_regs *xcp,
++ struct mips_fpu_struct *ctx,
++ int has_fpu,
++ void *__user *fault_addr)
++{
++ return 0;
++}
++
++static inline int process_fpemu_return(int sig, void __user *fault_addr)
++{
++ return -EINVAL;
++}
++
++static inline int mm_isBranchInstr(struct pt_regs *regs,
++ struct mm_decoded_insn dec_insn,
++ unsigned long *contpc)
++{
++ return 0;
++}
++#endif /* CONFIG_MIPS_FPU_EMU */
+
+ /*
+ * Instruction inserted following the badinst to further tag the sequence
+--- a/arch/mips/kernel/traps.c
++++ b/arch/mips/kernel/traps.c
+@@ -694,6 +694,7 @@ asmlinkage void do_ov(struct pt_regs *re
+ exception_exit(prev_state);
+ }
+
++#ifdef CONFIG_MIPS_FPU_EMU
+ int process_fpemu_return(int sig, void __user *fault_addr)
+ {
+ if (sig == SIGSEGV || sig == SIGBUS) {
+@@ -717,6 +718,7 @@ int process_fpemu_return(int sig, void _
+ return 0;
+ }
+ }
++#endif /* CONFIG_MIPS_FPU_EMU */
+
+ /*
+ * XXX Delayed fp exceptions when doing a lazy ctx switch XXX