156 lines
4.0 KiB
Diff
156 lines
4.0 KiB
Diff
MIPS: allow disabling the kernel FPU emulator
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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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Signed-off-by: Florian Fainelli <florian@openwrt.org>
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--
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -827,6 +827,17 @@ config I8259
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config MIPS_BONITO64
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bool
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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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--- 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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-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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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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@@ -56,6 +56,12 @@
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#endif
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#define __mips 4
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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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static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
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@@ -66,10 +72,6 @@ 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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-/* 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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#define FPCREG_RID 0 /* $0 = revision id */
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@@ -1273,6 +1275,13 @@ int fpu_emulator_cop1Handler(struct pt_r
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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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#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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@@ -109,6 +109,7 @@ 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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+#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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@@ -165,3 +166,9 @@ int do_dsemulret(struct pt_regs *xcp)
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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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@@ -29,6 +29,7 @@
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#define SIGNALLING_NAN 0x7ff800007ff80000LL
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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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@@ -112,4 +113,36 @@ int fpu_emulator_restore_context32(struc
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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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+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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+#ifdef CONFIG_64BIT
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+#endif /* CONFIG_64BIT */
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+#endif /* CONFIG_MIPS_FPU_EMU */
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