arch/nds32/kernel/fpu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (C) 2005-2018 Andes Technology Corporation

 #include <linux/sched.h>
 #include <linux/signal.h>
 #include <linux/sched/signal.h>
 #include <asm/processor.h>
 #include <asm/user.h>
 #include <asm/io.h>
 #include <asm/bitfield.h>
 #include <asm/fpu.h>

 const struct fpu_struct init_fpuregs = {
 	.fd_regs = {[0 ... 31] = sNAN64},
 	.fpcsr = FPCSR_INIT,
 #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
 	.UDF_IEX_trap = 0
 #endif
 };

 void save_fpu(struct task_struct *tsk)
 {
 	unsigned int fpcfg, fpcsr;

 	enable_fpu();
 	fpcfg = ((__nds32__fmfcfg() & FPCFG_mskFREG) >> FPCFG_offFREG);
 	switch (fpcfg) {
 	case SP32_DP32_reg:
 		asm volatile ("fsdi $fd31, [%0+0xf8]\n\t"
 			      "fsdi $fd30, [%0+0xf0]\n\t"
 			      "fsdi $fd29, [%0+0xe8]\n\t"
 			      "fsdi $fd28, [%0+0xe0]\n\t"
 			      "fsdi $fd27, [%0+0xd8]\n\t"
 			      "fsdi $fd26, [%0+0xd0]\n\t"
 			      "fsdi $fd25, [%0+0xc8]\n\t"
 			      "fsdi $fd24, [%0+0xc0]\n\t"
 			      "fsdi $fd23, [%0+0xb8]\n\t"
 			      "fsdi $fd22, [%0+0xb0]\n\t"
 			      "fsdi $fd21, [%0+0xa8]\n\t"
 			      "fsdi $fd20, [%0+0xa0]\n\t"
 			      "fsdi $fd19, [%0+0x98]\n\t"
 			      "fsdi $fd18, [%0+0x90]\n\t"
 			      "fsdi $fd17, [%0+0x88]\n\t"
 			      "fsdi $fd16, [%0+0x80]\n\t"
 			      :	/* no output */
 			      : "r" (&tsk->thread.fpu)
 			      : "memory");
 		fallthrough;
 	case SP32_DP16_reg:
 		asm volatile ("fsdi $fd15, [%0+0x78]\n\t"
 			      "fsdi $fd14, [%0+0x70]\n\t"
 			      "fsdi $fd13, [%0+0x68]\n\t"
 			      "fsdi $fd12, [%0+0x60]\n\t"
 			      "fsdi $fd11, [%0+0x58]\n\t"
 			      "fsdi $fd10, [%0+0x50]\n\t"
 			      "fsdi $fd9,  [%0+0x48]\n\t"
 			      "fsdi $fd8,  [%0+0x40]\n\t"
 			      :	/* no output */
 			      : "r" (&tsk->thread.fpu)
 			      : "memory");
 		fallthrough;
 	case SP16_DP8_reg:
 		asm volatile ("fsdi $fd7,  [%0+0x38]\n\t"
 			      "fsdi $fd6,  [%0+0x30]\n\t"
 			      "fsdi $fd5,  [%0+0x28]\n\t"
 			      "fsdi $fd4,  [%0+0x20]\n\t"
 			      :	/* no output */
 			      : "r" (&tsk->thread.fpu)
 			      : "memory");
 		fallthrough;
 	case SP8_DP4_reg:
 		asm volatile ("fsdi $fd3,  [%1+0x18]\n\t"
 			      "fsdi $fd2,  [%1+0x10]\n\t"
 			      "fsdi $fd1,  [%1+0x8]\n\t"
 			      "fsdi $fd0,  [%1+0x0]\n\t"
 			      "fmfcsr	%0\n\t"
 			      "swi  %0, [%1+0x100]\n\t"
 			      : "=&r" (fpcsr)
 			      : "r"(&tsk->thread.fpu)
 			      : "memory");
 	}
 	disable_fpu();
 }

 void load_fpu(const struct fpu_struct *fpregs)
 {
 	unsigned int fpcfg, fpcsr;

 	enable_fpu();
 	fpcfg = ((__nds32__fmfcfg() & FPCFG_mskFREG) >> FPCFG_offFREG);
 	switch (fpcfg) {
 	case SP32_DP32_reg:
 		asm volatile ("fldi $fd31, [%0+0xf8]\n\t"
 			      "fldi $fd30, [%0+0xf0]\n\t"
 			      "fldi $fd29, [%0+0xe8]\n\t"
 			      "fldi $fd28, [%0+0xe0]\n\t"
 			      "fldi $fd27, [%0+0xd8]\n\t"
 			      "fldi $fd26, [%0+0xd0]\n\t"
 			      "fldi $fd25, [%0+0xc8]\n\t"
 			      "fldi $fd24, [%0+0xc0]\n\t"
 			      "fldi $fd23, [%0+0xb8]\n\t"
 			      "fldi $fd22, [%0+0xb0]\n\t"
 			      "fldi $fd21, [%0+0xa8]\n\t"
 			      "fldi $fd20, [%0+0xa0]\n\t"
 			      "fldi $fd19, [%0+0x98]\n\t"
 			      "fldi $fd18, [%0+0x90]\n\t"
 			      "fldi $fd17, [%0+0x88]\n\t"
 			      "fldi $fd16, [%0+0x80]\n\t"
 			      :	/* no output */
 			      : "r" (fpregs));
 		fallthrough;
 	case SP32_DP16_reg:
 		asm volatile ("fldi $fd15, [%0+0x78]\n\t"
 			      "fldi $fd14, [%0+0x70]\n\t"
 			      "fldi $fd13, [%0+0x68]\n\t"
 			      "fldi $fd12, [%0+0x60]\n\t"
 			      "fldi $fd11, [%0+0x58]\n\t"
 			      "fldi $fd10, [%0+0x50]\n\t"
 			      "fldi $fd9,  [%0+0x48]\n\t"
 			      "fldi $fd8,  [%0+0x40]\n\t"
 			      :	/* no output */
 			      : "r" (fpregs));
 		fallthrough;
 	case SP16_DP8_reg:
 		asm volatile ("fldi $fd7,  [%0+0x38]\n\t"
 			      "fldi $fd6,  [%0+0x30]\n\t"
 			      "fldi $fd5,  [%0+0x28]\n\t"
 			      "fldi $fd4,  [%0+0x20]\n\t"
 			      :	/* no output */
 			      : "r" (fpregs));
 		fallthrough;
 	case SP8_DP4_reg:
 		asm volatile ("fldi $fd3,  [%1+0x18]\n\t"
 			      "fldi $fd2,  [%1+0x10]\n\t"
 			      "fldi $fd1,  [%1+0x8]\n\t"
 			      "fldi $fd0,  [%1+0x0]\n\t"
 			      "lwi  %0, [%1+0x100]\n\t"
 			      "fmtcsr	%0\n\t":"=&r" (fpcsr)
 			      : "r"(fpregs));
 	}
 	disable_fpu();
 }
 void store_fpu_for_suspend(void)
 {
 #ifdef CONFIG_LAZY_FPU
 	if (last_task_used_math != NULL)
 		save_fpu(last_task_used_math);
 	last_task_used_math = NULL;
 #else
 	if (!used_math())
 		return;
 	unlazy_fpu(current);
 #endif
 	clear_fpu(task_pt_regs(current));
 }
 inline void do_fpu_context_switch(struct pt_regs *regs)
 {
 	/* Enable to use FPU. */

 	if (!user_mode(regs)) {
 		pr_err("BUG: FPU is used in kernel mode.\n");
 		BUG();
 		return;
 	}

 	enable_ptreg_fpu(regs);
 #ifdef CONFIG_LAZY_FPU	//Lazy FPU is used
 	if (last_task_used_math == current)
 		return;
 	if (last_task_used_math != NULL)
 		/* Other processes fpu state, save away */
 		save_fpu(last_task_used_math);
 	last_task_used_math = current;
 #endif
 	if (used_math()) {
 		load_fpu(&current->thread.fpu);
 	} else {
 		/* First time FPU user.  */
 		load_fpu(&init_fpuregs);
 #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
 		current->thread.fpu.UDF_IEX_trap = init_fpuregs.UDF_IEX_trap;
 #endif
 		set_used_math();
 	}

 }

 inline void fill_sigfpe_signo(unsigned int fpcsr, int *signo)
 {
 	if (fpcsr & FPCSR_mskOVFT)
 		*signo = FPE_FLTOVF;
 #ifndef CONFIG_SUPPORT_DENORMAL_ARITHMETIC
 	else if (fpcsr & FPCSR_mskUDFT)
 		*signo = FPE_FLTUND;
 #endif
 	else if (fpcsr & FPCSR_mskIVOT)
 		*signo = FPE_FLTINV;
 	else if (fpcsr & FPCSR_mskDBZT)
 		*signo = FPE_FLTDIV;
 	else if (fpcsr & FPCSR_mskIEXT)
 		*signo = FPE_FLTRES;
 }

 inline void handle_fpu_exception(struct pt_regs *regs)
 {
 	unsigned int fpcsr;
 	int si_code = 0, si_signo = SIGFPE;
 #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
 	unsigned long redo_except = FPCSR_mskDNIT|FPCSR_mskUDFT|FPCSR_mskIEXT;
 #else
 	unsigned long redo_except = FPCSR_mskDNIT;
 #endif

 	lose_fpu();
 	fpcsr = current->thread.fpu.fpcsr;

 	if (fpcsr & redo_except) {
 		si_signo = do_fpuemu(regs, &current->thread.fpu);
 		fpcsr = current->thread.fpu.fpcsr;
 		if (!si_signo) {
 			current->thread.fpu.fpcsr &= ~(redo_except);
 			goto done;
 		}
 	} else if (fpcsr & FPCSR_mskRIT) {
 		if (!user_mode(regs))
 			do_exit(SIGILL);
 		si_signo = SIGILL;
 	}

 	switch (si_signo) {
 	case SIGFPE:
 		fill_sigfpe_signo(fpcsr, &si_code);
 		break;
 	case SIGILL:
 		show_regs(regs);
 		si_code = ILL_COPROC;
 		break;
 	case SIGBUS:
 		si_code = BUS_ADRERR;
 		break;
 	default:
 		break;
 	}

 	force_sig_fault(si_signo, si_code,
 			(void __user *)instruction_pointer(regs));
 done:
 	own_fpu();
 }

 bool do_fpu_exception(unsigned int subtype, struct pt_regs *regs)
 {
 	int done = true;
 	/* Coprocessor disabled exception */
 	if (subtype == FPU_DISABLE_EXCEPTION) {
 		preempt_disable();
 		do_fpu_context_switch(regs);
 		preempt_enable();
 	}
 	/* Coprocessor exception such as underflow and overflow */
 	else if (subtype == FPU_EXCEPTION)
 		handle_fpu_exception(regs);
 	else
 		done = false;
 	return done;
 }
	// SPDX-License-Identifier: GPL-2.0
	// Copyright (C) 2005-2018 Andes Technology Corporation

	#include <linux/sched.h>
	#include <linux/signal.h>
	#include <linux/sched/signal.h>
	#include <asm/processor.h>
	#include <asm/user.h>
	#include <asm/io.h>
	#include <asm/bitfield.h>
	#include <asm/fpu.h>

	const struct fpu_struct init_fpuregs = {
	.fd_regs = {[0 ... 31] = sNAN64},
	.fpcsr = FPCSR_INIT,
	#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
	.UDF_IEX_trap = 0
	#endif
	};

	void save_fpu(struct task_struct *tsk)
	{
	unsigned int fpcfg, fpcsr;

	enable_fpu();
	fpcfg = ((__nds32__fmfcfg() & FPCFG_mskFREG) >> FPCFG_offFREG);
	switch (fpcfg) {
	case SP32_DP32_reg:
	asm volatile ("fsdi $fd31, [%0+0xf8]\n\t"
	"fsdi $fd30, [%0+0xf0]\n\t"
	"fsdi $fd29, [%0+0xe8]\n\t"
	"fsdi $fd28, [%0+0xe0]\n\t"
	"fsdi $fd27, [%0+0xd8]\n\t"
	"fsdi $fd26, [%0+0xd0]\n\t"
	"fsdi $fd25, [%0+0xc8]\n\t"
	"fsdi $fd24, [%0+0xc0]\n\t"
	"fsdi $fd23, [%0+0xb8]\n\t"
	"fsdi $fd22, [%0+0xb0]\n\t"
	"fsdi $fd21, [%0+0xa8]\n\t"
	"fsdi $fd20, [%0+0xa0]\n\t"
	"fsdi $fd19, [%0+0x98]\n\t"
	"fsdi $fd18, [%0+0x90]\n\t"
	"fsdi $fd17, [%0+0x88]\n\t"
	"fsdi $fd16, [%0+0x80]\n\t"
	: /* no output */
	: "r" (&tsk->thread.fpu)
	: "memory");
	fallthrough;
	case SP32_DP16_reg:
	asm volatile ("fsdi $fd15, [%0+0x78]\n\t"
	"fsdi $fd14, [%0+0x70]\n\t"
	"fsdi $fd13, [%0+0x68]\n\t"
	"fsdi $fd12, [%0+0x60]\n\t"
	"fsdi $fd11, [%0+0x58]\n\t"
	"fsdi $fd10, [%0+0x50]\n\t"
	"fsdi $fd9, [%0+0x48]\n\t"
	"fsdi $fd8, [%0+0x40]\n\t"
	: /* no output */
	: "r" (&tsk->thread.fpu)
	: "memory");
	fallthrough;
	case SP16_DP8_reg:
	asm volatile ("fsdi $fd7, [%0+0x38]\n\t"
	"fsdi $fd6, [%0+0x30]\n\t"
	"fsdi $fd5, [%0+0x28]\n\t"
	"fsdi $fd4, [%0+0x20]\n\t"
	: /* no output */
	: "r" (&tsk->thread.fpu)
	: "memory");
	fallthrough;
	case SP8_DP4_reg:
	asm volatile ("fsdi $fd3, [%1+0x18]\n\t"
	"fsdi $fd2, [%1+0x10]\n\t"
	"fsdi $fd1, [%1+0x8]\n\t"
	"fsdi $fd0, [%1+0x0]\n\t"
	"fmfcsr %0\n\t"
	"swi %0, [%1+0x100]\n\t"
	: "=&r" (fpcsr)
	: "r"(&tsk->thread.fpu)
	: "memory");
	}
	disable_fpu();
	}

	void load_fpu(const struct fpu_struct *fpregs)
	{
	unsigned int fpcfg, fpcsr;

	enable_fpu();
	fpcfg = ((__nds32__fmfcfg() & FPCFG_mskFREG) >> FPCFG_offFREG);
	switch (fpcfg) {
	case SP32_DP32_reg:
	asm volatile ("fldi $fd31, [%0+0xf8]\n\t"
	"fldi $fd30, [%0+0xf0]\n\t"
	"fldi $fd29, [%0+0xe8]\n\t"
	"fldi $fd28, [%0+0xe0]\n\t"
	"fldi $fd27, [%0+0xd8]\n\t"
	"fldi $fd26, [%0+0xd0]\n\t"
	"fldi $fd25, [%0+0xc8]\n\t"
	"fldi $fd24, [%0+0xc0]\n\t"
	"fldi $fd23, [%0+0xb8]\n\t"
	"fldi $fd22, [%0+0xb0]\n\t"
	"fldi $fd21, [%0+0xa8]\n\t"
	"fldi $fd20, [%0+0xa0]\n\t"
	"fldi $fd19, [%0+0x98]\n\t"
	"fldi $fd18, [%0+0x90]\n\t"
	"fldi $fd17, [%0+0x88]\n\t"
	"fldi $fd16, [%0+0x80]\n\t"
	: /* no output */
	: "r" (fpregs));
	fallthrough;
	case SP32_DP16_reg:
	asm volatile ("fldi $fd15, [%0+0x78]\n\t"
	"fldi $fd14, [%0+0x70]\n\t"
	"fldi $fd13, [%0+0x68]\n\t"
	"fldi $fd12, [%0+0x60]\n\t"
	"fldi $fd11, [%0+0x58]\n\t"
	"fldi $fd10, [%0+0x50]\n\t"
	"fldi $fd9, [%0+0x48]\n\t"
	"fldi $fd8, [%0+0x40]\n\t"
	: /* no output */
	: "r" (fpregs));
	fallthrough;
	case SP16_DP8_reg:
	asm volatile ("fldi $fd7, [%0+0x38]\n\t"
	"fldi $fd6, [%0+0x30]\n\t"
	"fldi $fd5, [%0+0x28]\n\t"
	"fldi $fd4, [%0+0x20]\n\t"
	: /* no output */
	: "r" (fpregs));
	fallthrough;
	case SP8_DP4_reg:
	asm volatile ("fldi $fd3, [%1+0x18]\n\t"
	"fldi $fd2, [%1+0x10]\n\t"
	"fldi $fd1, [%1+0x8]\n\t"
	"fldi $fd0, [%1+0x0]\n\t"
	"lwi %0, [%1+0x100]\n\t"
	"fmtcsr %0\n\t":"=&r" (fpcsr)
	: "r"(fpregs));
	}
	disable_fpu();
	}
	void store_fpu_for_suspend(void)
	{
	#ifdef CONFIG_LAZY_FPU
	if (last_task_used_math != NULL)
	save_fpu(last_task_used_math);
	last_task_used_math = NULL;
	#else
	if (!used_math())
	return;
	unlazy_fpu(current);
	#endif
	clear_fpu(task_pt_regs(current));
	}
	inline void do_fpu_context_switch(struct pt_regs *regs)
	{
	/* Enable to use FPU. */

	if (!user_mode(regs)) {
	pr_err("BUG: FPU is used in kernel mode.\n");
	BUG();
	return;
	}

	enable_ptreg_fpu(regs);
	#ifdef CONFIG_LAZY_FPU //Lazy FPU is used
	if (last_task_used_math == current)
	return;
	if (last_task_used_math != NULL)
	/* Other processes fpu state, save away */
	save_fpu(last_task_used_math);
	last_task_used_math = current;
	#endif
	if (used_math()) {
	load_fpu(&current->thread.fpu);
	} else {
	/* First time FPU user. */
	load_fpu(&init_fpuregs);
	#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
	current->thread.fpu.UDF_IEX_trap = init_fpuregs.UDF_IEX_trap;
	#endif
	set_used_math();
	}

	}

	inline void fill_sigfpe_signo(unsigned int fpcsr, int *signo)
	{
	if (fpcsr & FPCSR_mskOVFT)
	*signo = FPE_FLTOVF;
	#ifndef CONFIG_SUPPORT_DENORMAL_ARITHMETIC
	else if (fpcsr & FPCSR_mskUDFT)
	*signo = FPE_FLTUND;
	#endif
	else if (fpcsr & FPCSR_mskIVOT)
	*signo = FPE_FLTINV;
	else if (fpcsr & FPCSR_mskDBZT)
	*signo = FPE_FLTDIV;
	else if (fpcsr & FPCSR_mskIEXT)
	*signo = FPE_FLTRES;
	}

	inline void handle_fpu_exception(struct pt_regs *regs)
	{
	unsigned int fpcsr;
	int si_code = 0, si_signo = SIGFPE;
	#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
	unsigned long redo_except = FPCSR_mskDNIT\|FPCSR_mskUDFT\|FPCSR_mskIEXT;
	#else
	unsigned long redo_except = FPCSR_mskDNIT;
	#endif

	lose_fpu();
	fpcsr = current->thread.fpu.fpcsr;

	if (fpcsr & redo_except) {
	si_signo = do_fpuemu(regs, &current->thread.fpu);
	fpcsr = current->thread.fpu.fpcsr;
	if (!si_signo) {
	current->thread.fpu.fpcsr &= ~(redo_except);
	goto done;
	}
	} else if (fpcsr & FPCSR_mskRIT) {
	if (!user_mode(regs))
	do_exit(SIGILL);
	si_signo = SIGILL;
	}

	switch (si_signo) {
	case SIGFPE:
	fill_sigfpe_signo(fpcsr, &si_code);
	break;
	case SIGILL:
	show_regs(regs);
	si_code = ILL_COPROC;
	break;
	case SIGBUS:
	si_code = BUS_ADRERR;
	break;
	default:
	break;
	}

	force_sig_fault(si_signo, si_code,
	(void __user *)instruction_pointer(regs));
	done:
	own_fpu();
	}

	bool do_fpu_exception(unsigned int subtype, struct pt_regs *regs)
	{
	int done = true;
	/* Coprocessor disabled exception */
	if (subtype == FPU_DISABLE_EXCEPTION) {
	preempt_disable();
	do_fpu_context_switch(regs);
	preempt_enable();
	}
	/* Coprocessor exception such as underflow and overflow */
	else if (subtype == FPU_EXCEPTION)
	handle_fpu_exception(regs);
	else
	done = false;
	return done;
	}