diff options
Diffstat (limited to 'target/linux/generic/patches-3.18/304-mips_disable_fpu.patch')
| -rw-r--r-- | target/linux/generic/patches-3.18/304-mips_disable_fpu.patch | 207 |
1 files changed, 76 insertions, 131 deletions
diff --git a/target/linux/generic/patches-3.18/304-mips_disable_fpu.patch b/target/linux/generic/patches-3.18/304-mips_disable_fpu.patch index 4536ce6dae..980eaf0b7e 100644 --- a/target/linux/generic/patches-3.18/304-mips_disable_fpu.patch +++ b/target/linux/generic/patches-3.18/304-mips_disable_fpu.patch @@ -1,160 +1,105 @@ -MIPS: allow disabling the kernel FPU emulator +From: Manuel Lauss <manuel.lauss@gmail.com> +Subject: [RFC PATCH v4 2/2] MIPS: make FPU emulator optional +Date: Mon, 7 Apr 2014 12:57:04 +0200 +Message-Id: <1396868224-252888-2-git-send-email-manuel.lauss@gmail.com> -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. +This small patch makes the MIPS FPU emulator optional. The kernel +kills float-users on systems without a hardware FPU by sending a SIGILL. + +Disabling the emulator shrinks vmlinux by about 54kBytes (32bit, +optimizing for size). + +Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com> +--- +v4: rediffed because of patch 1/2, should now work with micromips as well +v3: updated patch description with size savings. +v2: incorporated changes suggested by Jonas Gorski + force the fpu emulator on for micromips: relocating the parts + of the mmips code in the emulator to other areas would be a + much larger change; I went the cheap route instead with this. + + arch/mips/Kbuild | 2 +- + arch/mips/Kconfig | 14 ++++++++++++++ + arch/mips/include/asm/fpu.h | 5 +++-- + arch/mips/include/asm/fpu_emulator.h | 15 +++++++++++++++ + 4 files changed, 33 insertions(+), 3 deletions(-) -Signed-off-by: Florian Fainelli <florian@openwrt.org> --- --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig -@@ -934,6 +934,17 @@ config I8259 - config MIPS_BONITO64 - bool +@@ -2484,6 +2484,20 @@ config MIPS_O32_FP64_SUPPORT + + If unsure, say N. -+config MIPS_FPU_EMU -+ bool "Enable FPU emulation" ++config MIPS_FPU_EMULATOR ++ bool "MIPS FPU Emulator" + 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. ++ This option lets you disable the built-in MIPS FPU (Coprocessor 1) ++ emulator, which handles floating-point instructions on processors ++ without a hardware FPU. It is generally a good idea to keep the ++ emulator built-in, unless you are perfectly sure you have a ++ complete soft-float environment. With the emulator disabled, all ++ users of float operations will be killed with an illegal instr- ++ uction exception. + -+ If unsure say Y here. ++ Say Y, please. + - config MIPS_MSC + config USE_OF bool + select OF +--- a/arch/mips/Makefile ++++ b/arch/mips/Makefile +@@ -266,7 +266,7 @@ OBJCOPYFLAGS += --remove-section=.regin + head-y := arch/mips/kernel/head.o ---- a/arch/mips/math-emu/Makefile -+++ b/arch/mips/math-emu/Makefile -@@ -2,10 +2,12 @@ - # Makefile for the Linux/MIPS kernel FPU emulation. - # + libs-y += arch/mips/lib/ +-libs-y += arch/mips/math-emu/ ++libs-$(CONFIG_MIPS_FPU_EMULATOR) += arch/mips/math-emu/ --obj-y := cp1emu.o ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \ -+obj-y := kernel_linkage.o -+ -+obj-$(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 @@ + # See arch/mips/Kbuild for content of core part of the kernel + core-y += arch/mips/ +--- a/arch/mips/include/asm/fpu.h ++++ b/arch/mips/include/asm/fpu.h +@@ -168,8 +168,10 @@ static inline int init_fpu(void) + ret = __own_fpu(); + if (!ret) + _init_fpu(); +- } else ++ } else if (IS_ENABLED(CONFIG_MIPS_FPU_EMULATOR)) + fpu_emulator_init_fpu(); ++ else ++ ret = SIGILL; - #define SIGNALLING_NAN 0x7ff800007ff80000LL - -+#ifdef CONFIG_MIPS_FPU_EMU - void fpu_emulator_init_fpu(void) - { - static int first = 1; -@@ -115,3 +116,36 @@ int fpu_emulator_restore_context32(struc - return err; + return ret; } - #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> +@@ -30,6 +30,7 @@ #include <asm/local.h> + #include <asm/processor.h> -+#ifdef CONFIG_MIPS_FPU_EMU -+ ++#ifdef CONFIG_MIPS_FPU_EMULATOR #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; -+} -+ +@@ -65,6 +66,20 @@ extern int do_dsemulret(struct pt_regs * + extern int fpu_emulator_cop1Handler(struct pt_regs *xcp, + struct mips_fpu_struct *ctx, int has_fpu, + void *__user *fault_addr); ++#else /* no CONFIG_MIPS_FPU_EMULATOR */ +static inline int do_dsemulret(struct pt_regs *xcp) +{ -+ return 0; ++ return 0; /* 0 means error, should never get here anyway */ +} + +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) ++ struct mips_fpu_struct *ctx, int has_fpu, ++ void *__user *fault_addr) +{ -+ return -EINVAL; ++ return SIGILL; /* we don't speak MIPS FPU */ +} ++#endif /* CONFIG_MIPS_FPU_EMULATOR */ + -+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 -@@ -701,6 +701,7 @@ 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) { -@@ -724,6 +725,7 @@ 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 + 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); |