diff options
Diffstat (limited to 'arch/sh/kernel/cpu/sh4/fpu.c')
| -rw-r--r-- | arch/sh/kernel/cpu/sh4/fpu.c | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh4/fpu.c b/arch/sh/kernel/cpu/sh4/fpu.c new file mode 100644 index 000000000..03ffd8cdf --- /dev/null +++ b/arch/sh/kernel/cpu/sh4/fpu.c @@ -0,0 +1,425 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Save/restore floating point context for signal handlers. + * + * Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka + * Copyright (C) 2006 ST Microelectronics Ltd. (denorm support) + * + * FIXME! These routines have not been tested for big endian case. + */ +#include <linux/sched/signal.h> +#include <linux/io.h> +#include <cpu/fpu.h> +#include <asm/processor.h> +#include <asm/fpu.h> +#include <asm/traps.h> + +/* The PR (precision) bit in the FP Status Register must be clear when + * an frchg instruction is executed, otherwise the instruction is undefined. + * Executing frchg with PR set causes a trap on some SH4 implementations. + */ + +#define FPSCR_RCHG 0x00000000 +extern unsigned long long float64_div(unsigned long long a, + unsigned long long b); +extern unsigned long int float32_div(unsigned long int a, unsigned long int b); +extern unsigned long long float64_mul(unsigned long long a, + unsigned long long b); +extern unsigned long int float32_mul(unsigned long int a, unsigned long int b); +extern unsigned long long float64_add(unsigned long long a, + unsigned long long b); +extern unsigned long int float32_add(unsigned long int a, unsigned long int b); +extern unsigned long long float64_sub(unsigned long long a, + unsigned long long b); +extern unsigned long int float32_sub(unsigned long int a, unsigned long int b); +extern unsigned long int float64_to_float32(unsigned long long a); +static unsigned int fpu_exception_flags; + +/* + * Save FPU registers onto task structure. + */ +void save_fpu(struct task_struct *tsk) +{ + unsigned long dummy; + + enable_fpu(); + asm volatile ("sts.l fpul, @-%0\n\t" + "sts.l fpscr, @-%0\n\t" + "lds %2, fpscr\n\t" + "frchg\n\t" + "fmov.s fr15, @-%0\n\t" + "fmov.s fr14, @-%0\n\t" + "fmov.s fr13, @-%0\n\t" + "fmov.s fr12, @-%0\n\t" + "fmov.s fr11, @-%0\n\t" + "fmov.s fr10, @-%0\n\t" + "fmov.s fr9, @-%0\n\t" + "fmov.s fr8, @-%0\n\t" + "fmov.s fr7, @-%0\n\t" + "fmov.s fr6, @-%0\n\t" + "fmov.s fr5, @-%0\n\t" + "fmov.s fr4, @-%0\n\t" + "fmov.s fr3, @-%0\n\t" + "fmov.s fr2, @-%0\n\t" + "fmov.s fr1, @-%0\n\t" + "fmov.s fr0, @-%0\n\t" + "frchg\n\t" + "fmov.s fr15, @-%0\n\t" + "fmov.s fr14, @-%0\n\t" + "fmov.s fr13, @-%0\n\t" + "fmov.s fr12, @-%0\n\t" + "fmov.s fr11, @-%0\n\t" + "fmov.s fr10, @-%0\n\t" + "fmov.s fr9, @-%0\n\t" + "fmov.s fr8, @-%0\n\t" + "fmov.s fr7, @-%0\n\t" + "fmov.s fr6, @-%0\n\t" + "fmov.s fr5, @-%0\n\t" + "fmov.s fr4, @-%0\n\t" + "fmov.s fr3, @-%0\n\t" + "fmov.s fr2, @-%0\n\t" + "fmov.s fr1, @-%0\n\t" + "fmov.s fr0, @-%0\n\t" + "lds %3, fpscr\n\t":"=r" (dummy) + :"0"((char *)(&tsk->thread.xstate->hardfpu.status)), + "r"(FPSCR_RCHG), "r"(FPSCR_INIT) + :"memory"); + + disable_fpu(); +} + +void restore_fpu(struct task_struct *tsk) +{ + unsigned long dummy; + + enable_fpu(); + asm volatile ("lds %2, fpscr\n\t" + "fmov.s @%0+, fr0\n\t" + "fmov.s @%0+, fr1\n\t" + "fmov.s @%0+, fr2\n\t" + "fmov.s @%0+, fr3\n\t" + "fmov.s @%0+, fr4\n\t" + "fmov.s @%0+, fr5\n\t" + "fmov.s @%0+, fr6\n\t" + "fmov.s @%0+, fr7\n\t" + "fmov.s @%0+, fr8\n\t" + "fmov.s @%0+, fr9\n\t" + "fmov.s @%0+, fr10\n\t" + "fmov.s @%0+, fr11\n\t" + "fmov.s @%0+, fr12\n\t" + "fmov.s @%0+, fr13\n\t" + "fmov.s @%0+, fr14\n\t" + "fmov.s @%0+, fr15\n\t" + "frchg\n\t" + "fmov.s @%0+, fr0\n\t" + "fmov.s @%0+, fr1\n\t" + "fmov.s @%0+, fr2\n\t" + "fmov.s @%0+, fr3\n\t" + "fmov.s @%0+, fr4\n\t" + "fmov.s @%0+, fr5\n\t" + "fmov.s @%0+, fr6\n\t" + "fmov.s @%0+, fr7\n\t" + "fmov.s @%0+, fr8\n\t" + "fmov.s @%0+, fr9\n\t" + "fmov.s @%0+, fr10\n\t" + "fmov.s @%0+, fr11\n\t" + "fmov.s @%0+, fr12\n\t" + "fmov.s @%0+, fr13\n\t" + "fmov.s @%0+, fr14\n\t" + "fmov.s @%0+, fr15\n\t" + "frchg\n\t" + "lds.l @%0+, fpscr\n\t" + "lds.l @%0+, fpul\n\t" + :"=r" (dummy) + :"0" (tsk->thread.xstate), "r" (FPSCR_RCHG) + :"memory"); + disable_fpu(); +} + +/** + * denormal_to_double - Given denormalized float number, + * store double float + * + * @fpu: Pointer to sh_fpu_hard structure + * @n: Index to FP register + */ +static void denormal_to_double(struct sh_fpu_hard_struct *fpu, int n) +{ + unsigned long du, dl; + unsigned long x = fpu->fpul; + int exp = 1023 - 126; + + if (x != 0 && (x & 0x7f800000) == 0) { + du = (x & 0x80000000); + while ((x & 0x00800000) == 0) { + x <<= 1; + exp--; + } + x &= 0x007fffff; + du |= (exp << 20) | (x >> 3); + dl = x << 29; + + fpu->fp_regs[n] = du; + fpu->fp_regs[n + 1] = dl; + } +} + +/** + * ieee_fpe_handler - Handle denormalized number exception + * + * @regs: Pointer to register structure + * + * Returns 1 when it's handled (should not cause exception). + */ +static int ieee_fpe_handler(struct pt_regs *regs) +{ + unsigned short insn = *(unsigned short *)regs->pc; + unsigned short finsn; + unsigned long nextpc; + int nib[4] = { + (insn >> 12) & 0xf, + (insn >> 8) & 0xf, + (insn >> 4) & 0xf, + insn & 0xf + }; + + if (nib[0] == 0xb || (nib[0] == 0x4 && nib[2] == 0x0 && nib[3] == 0xb)) + regs->pr = regs->pc + 4; /* bsr & jsr */ + + if (nib[0] == 0xa || nib[0] == 0xb) { + /* bra & bsr */ + nextpc = regs->pc + 4 + ((short)((insn & 0xfff) << 4) >> 3); + finsn = *(unsigned short *)(regs->pc + 2); + } else if (nib[0] == 0x8 && nib[1] == 0xd) { + /* bt/s */ + if (regs->sr & 1) + nextpc = regs->pc + 4 + ((char)(insn & 0xff) << 1); + else + nextpc = regs->pc + 4; + finsn = *(unsigned short *)(regs->pc + 2); + } else if (nib[0] == 0x8 && nib[1] == 0xf) { + /* bf/s */ + if (regs->sr & 1) + nextpc = regs->pc + 4; + else + nextpc = regs->pc + 4 + ((char)(insn & 0xff) << 1); + finsn = *(unsigned short *)(regs->pc + 2); + } else if (nib[0] == 0x4 && nib[3] == 0xb && + (nib[2] == 0x0 || nib[2] == 0x2)) { + /* jmp & jsr */ + nextpc = regs->regs[nib[1]]; + finsn = *(unsigned short *)(regs->pc + 2); + } else if (nib[0] == 0x0 && nib[3] == 0x3 && + (nib[2] == 0x0 || nib[2] == 0x2)) { + /* braf & bsrf */ + nextpc = regs->pc + 4 + regs->regs[nib[1]]; + finsn = *(unsigned short *)(regs->pc + 2); + } else if (insn == 0x000b) { + /* rts */ + nextpc = regs->pr; + finsn = *(unsigned short *)(regs->pc + 2); + } else { + nextpc = regs->pc + instruction_size(insn); + finsn = insn; + } + + if ((finsn & 0xf1ff) == 0xf0ad) { + /* fcnvsd */ + struct task_struct *tsk = current; + + if ((tsk->thread.xstate->hardfpu.fpscr & FPSCR_CAUSE_ERROR)) + /* FPU error */ + denormal_to_double(&tsk->thread.xstate->hardfpu, + (finsn >> 8) & 0xf); + else + return 0; + + regs->pc = nextpc; + return 1; + } else if ((finsn & 0xf00f) == 0xf002) { + /* fmul */ + struct task_struct *tsk = current; + int fpscr; + int n, m, prec; + unsigned int hx, hy; + + n = (finsn >> 8) & 0xf; + m = (finsn >> 4) & 0xf; + hx = tsk->thread.xstate->hardfpu.fp_regs[n]; + hy = tsk->thread.xstate->hardfpu.fp_regs[m]; + fpscr = tsk->thread.xstate->hardfpu.fpscr; + prec = fpscr & FPSCR_DBL_PRECISION; + + if ((fpscr & FPSCR_CAUSE_ERROR) + && (prec && ((hx & 0x7fffffff) < 0x00100000 + || (hy & 0x7fffffff) < 0x00100000))) { + long long llx, lly; + + /* FPU error because of denormal (doubles) */ + llx = ((long long)hx << 32) + | tsk->thread.xstate->hardfpu.fp_regs[n + 1]; + lly = ((long long)hy << 32) + | tsk->thread.xstate->hardfpu.fp_regs[m + 1]; + llx = float64_mul(llx, lly); + tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32; + tsk->thread.xstate->hardfpu.fp_regs[n + 1] = llx & 0xffffffff; + } else if ((fpscr & FPSCR_CAUSE_ERROR) + && (!prec && ((hx & 0x7fffffff) < 0x00800000 + || (hy & 0x7fffffff) < 0x00800000))) { + /* FPU error because of denormal (floats) */ + hx = float32_mul(hx, hy); + tsk->thread.xstate->hardfpu.fp_regs[n] = hx; + } else + return 0; + + regs->pc = nextpc; + return 1; + } else if ((finsn & 0xf00e) == 0xf000) { + /* fadd, fsub */ + struct task_struct *tsk = current; + int fpscr; + int n, m, prec; + unsigned int hx, hy; + + n = (finsn >> 8) & 0xf; + m = (finsn >> 4) & 0xf; + hx = tsk->thread.xstate->hardfpu.fp_regs[n]; + hy = tsk->thread.xstate->hardfpu.fp_regs[m]; + fpscr = tsk->thread.xstate->hardfpu.fpscr; + prec = fpscr & FPSCR_DBL_PRECISION; + + if ((fpscr & FPSCR_CAUSE_ERROR) + && (prec && ((hx & 0x7fffffff) < 0x00100000 + || (hy & 0x7fffffff) < 0x00100000))) { + long long llx, lly; + + /* FPU error because of denormal (doubles) */ + llx = ((long long)hx << 32) + | tsk->thread.xstate->hardfpu.fp_regs[n + 1]; + lly = ((long long)hy << 32) + | tsk->thread.xstate->hardfpu.fp_regs[m + 1]; + if ((finsn & 0xf00f) == 0xf000) + llx = float64_add(llx, lly); + else + llx = float64_sub(llx, lly); + tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32; + tsk->thread.xstate->hardfpu.fp_regs[n + 1] = llx & 0xffffffff; + } else if ((fpscr & FPSCR_CAUSE_ERROR) + && (!prec && ((hx & 0x7fffffff) < 0x00800000 + || (hy & 0x7fffffff) < 0x00800000))) { + /* FPU error because of denormal (floats) */ + if ((finsn & 0xf00f) == 0xf000) + hx = float32_add(hx, hy); + else + hx = float32_sub(hx, hy); + tsk->thread.xstate->hardfpu.fp_regs[n] = hx; + } else + return 0; + + regs->pc = nextpc; + return 1; + } else if ((finsn & 0xf003) == 0xf003) { + /* fdiv */ + struct task_struct *tsk = current; + int fpscr; + int n, m, prec; + unsigned int hx, hy; + + n = (finsn >> 8) & 0xf; + m = (finsn >> 4) & 0xf; + hx = tsk->thread.xstate->hardfpu.fp_regs[n]; + hy = tsk->thread.xstate->hardfpu.fp_regs[m]; + fpscr = tsk->thread.xstate->hardfpu.fpscr; + prec = fpscr & FPSCR_DBL_PRECISION; + + if ((fpscr & FPSCR_CAUSE_ERROR) + && (prec && ((hx & 0x7fffffff) < 0x00100000 + || (hy & 0x7fffffff) < 0x00100000))) { + long long llx, lly; + + /* FPU error because of denormal (doubles) */ + llx = ((long long)hx << 32) + | tsk->thread.xstate->hardfpu.fp_regs[n + 1]; + lly = ((long long)hy << 32) + | tsk->thread.xstate->hardfpu.fp_regs[m + 1]; + + llx = float64_div(llx, lly); + + tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32; + tsk->thread.xstate->hardfpu.fp_regs[n + 1] = llx & 0xffffffff; + } else if ((fpscr & FPSCR_CAUSE_ERROR) + && (!prec && ((hx & 0x7fffffff) < 0x00800000 + || (hy & 0x7fffffff) < 0x00800000))) { + /* FPU error because of denormal (floats) */ + hx = float32_div(hx, hy); + tsk->thread.xstate->hardfpu.fp_regs[n] = hx; + } else + return 0; + + regs->pc = nextpc; + return 1; + } else if ((finsn & 0xf0bd) == 0xf0bd) { + /* fcnvds - double to single precision convert */ + struct task_struct *tsk = current; + int m; + unsigned int hx; + + m = (finsn >> 8) & 0x7; + hx = tsk->thread.xstate->hardfpu.fp_regs[m]; + + if ((tsk->thread.xstate->hardfpu.fpscr & FPSCR_CAUSE_ERROR) + && ((hx & 0x7fffffff) < 0x00100000)) { + /* subnormal double to float conversion */ + long long llx; + + llx = ((long long)tsk->thread.xstate->hardfpu.fp_regs[m] << 32) + | tsk->thread.xstate->hardfpu.fp_regs[m + 1]; + + tsk->thread.xstate->hardfpu.fpul = float64_to_float32(llx); + } else + return 0; + + regs->pc = nextpc; + return 1; + } + + return 0; +} + +void float_raise(unsigned int flags) +{ + fpu_exception_flags |= flags; +} + +int float_rounding_mode(void) +{ + struct task_struct *tsk = current; + int roundingMode = FPSCR_ROUNDING_MODE(tsk->thread.xstate->hardfpu.fpscr); + return roundingMode; +} + +BUILD_TRAP_HANDLER(fpu_error) +{ + struct task_struct *tsk = current; + TRAP_HANDLER_DECL; + + __unlazy_fpu(tsk, regs); + fpu_exception_flags = 0; + if (ieee_fpe_handler(regs)) { + tsk->thread.xstate->hardfpu.fpscr &= + ~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK); + tsk->thread.xstate->hardfpu.fpscr |= fpu_exception_flags; + /* Set the FPSCR flag as well as cause bits - simply + * replicate the cause */ + tsk->thread.xstate->hardfpu.fpscr |= (fpu_exception_flags >> 10); + grab_fpu(regs); + restore_fpu(tsk); + task_thread_info(tsk)->status |= TS_USEDFPU; + if ((((tsk->thread.xstate->hardfpu.fpscr & FPSCR_ENABLE_MASK) >> 7) & + (fpu_exception_flags >> 2)) == 0) { + return; + } + } + + force_sig(SIGFPE); +} |