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@@ -0,0 +1,155 @@
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+MIPS: allow disabling the kernel FPU emulator
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+
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+This patch allows turning off the in-kernel Algorithmics
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+FPU emulator support, which allows one to save a couple of
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+precious blocks on an embedded system.
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+
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+Signed-off-by: Florian Fainelli <[email protected]>
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+--
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+--- a/arch/mips/Kconfig
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++++ b/arch/mips/Kconfig
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+@@ -831,6 +831,17 @@ config I8259
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+ config MIPS_BONITO64
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+ bool
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+
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++config MIPS_FPU_EMU
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++ bool "Enable FPU emulation"
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++ default y
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++ help
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++ This option allows building a kernel with or without the Algorithmics
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++ FPU emulator enabled. Turning off this option results in a kernel which
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++ does not catch floating operations exceptions. Make sure that your toolchain
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++ is configured to enable software floating point emulation in that case.
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++
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++ If unsure say Y here.
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++
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+ config MIPS_MSC
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+ bool
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+
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+--- a/arch/mips/math-emu/Makefile
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++++ b/arch/mips/math-emu/Makefile
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+@@ -2,12 +2,14 @@
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+ # Makefile for the Linux/MIPS kernel FPU emulation.
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+ #
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+
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+-obj-y := cp1emu.o ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
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++obj-y := kernel_linkage.o dsemul.o cp1emu.o
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++
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++obj-$(CONFIG_MIPS_FPU_EMU) += ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
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+ ieee754xcpt.o dp_frexp.o dp_modf.o dp_div.o dp_mul.o dp_sub.o \
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+ dp_add.o dp_fsp.o dp_cmp.o dp_logb.o dp_scalb.o dp_simple.o \
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+ dp_tint.o dp_fint.o dp_tlong.o dp_flong.o sp_frexp.o sp_modf.o \
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+ sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_logb.o \
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+ sp_scalb.o sp_simple.o sp_tint.o sp_fint.o sp_tlong.o sp_flong.o \
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+- dp_sqrt.o sp_sqrt.o kernel_linkage.o dsemul.o
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++ dp_sqrt.o sp_sqrt.o
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+
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+ EXTRA_CFLAGS += -Werror
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+--- a/arch/mips/math-emu/cp1emu.c
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++++ b/arch/mips/math-emu/cp1emu.c
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+@@ -57,6 +57,12 @@
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+ #endif
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+ #define __mips 4
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+
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++/* Further private data for which no space exists in mips_fpu_struct */
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++
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++struct mips_fpu_emulator_stats fpuemustats;
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++
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++#ifdef CONFIG_MIPS_FPU_EMU
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++
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+ /* Function which emulates a floating point instruction. */
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+
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+ static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
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+@@ -67,10 +73,6 @@ static int fpux_emu(struct pt_regs *,
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+ struct mips_fpu_struct *, mips_instruction);
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+ #endif
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+
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+-/* Further private data for which no space exists in mips_fpu_struct */
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+-
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+-struct mips_fpu_emulator_stats fpuemustats;
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+-
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+ /* Control registers */
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+
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+ #define FPCREG_RID 0 /* $0 = revision id */
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+@@ -1277,6 +1279,13 @@ int fpu_emulator_cop1Handler(struct pt_r
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+
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+ return sig;
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+ }
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++#else
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++int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
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++ int has_fpu)
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++{
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++ return 0;
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++}
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++#endif /* CONFIG_MIPS_FPU_EMU */
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+
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+ #ifdef CONFIG_DEBUG_FS
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+ extern struct dentry *mips_debugfs_dir;
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+--- a/arch/mips/math-emu/dsemul.c
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++++ b/arch/mips/math-emu/dsemul.c
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+@@ -110,6 +110,7 @@ int mips_dsemul(struct pt_regs *regs, mi
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+ return SIGILL; /* force out of emulation loop */
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+ }
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+
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++#ifdef CONFIG_MIPS_FPU_EMU
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+ int do_dsemulret(struct pt_regs *xcp)
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+ {
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+ struct emuframe __user *fr;
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+@@ -166,3 +167,9 @@ int do_dsemulret(struct pt_regs *xcp)
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+
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+ return 1;
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+ }
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++#else
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++int do_dsemulret(struct pt_regs *xcp)
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++{
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++ return 0;
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++}
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++#endif /* CONFIG_MIPS_FPU_EMU */
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+--- a/arch/mips/math-emu/kernel_linkage.c
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++++ b/arch/mips/math-emu/kernel_linkage.c
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+@@ -28,6 +28,7 @@
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+
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+ #define SIGNALLING_NAN 0x7ff800007ff80000LL
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+
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++#ifdef CONFIG_MIPS_FPU_EMU
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+ void fpu_emulator_init_fpu(void)
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+ {
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+ static int first = 1;
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+@@ -111,4 +112,36 @@ int fpu_emulator_restore_context32(struc
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+
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+ return err;
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+ }
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+-#endif
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++#endif /* CONFIG_64BIT */
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++#else
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++
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++void fpu_emulator_init_fpu(void)
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++{
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++ printk(KERN_INFO "FPU emulator disabled, make sure your toolchain"
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++ "was compiled with software floating point support (soft-float)\n");
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++ return;
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++}
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++
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++int fpu_emulator_save_context(struct sigcontext __user *sc)
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++{
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++ return 0;
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++}
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++
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++int fpu_emulator_restore_context(struct sigcontext __user *sc)
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++{
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++ return 0;
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++}
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++
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++#ifdef CONFIG_64BIT
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++int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
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++{
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++ return 0;
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++}
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++
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++int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
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++{
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++ return 0;
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++}
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++
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++#endif /* CONFIG_64BIT */
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++#endif /* CONFIG_MIPS_FPU_EMU */
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Hauke Mehrtens