cregit-Linux how code gets into the kernel

Release 4.14 arch/unicore32/kernel/fpu-ucf64.c

/*
 * linux/arch/unicore32/kernel/fpu-ucf64.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched/signal.h>
#include <linux/init.h>

#include <asm/fpu-ucf64.h>

/*
 * A special flag to tell the normalisation code not to normalise.
 */

#define F64_NAN_FLAG	0x100

/*
 * A bit pattern used to indicate the initial (unset) value of the
 * exception mask, in case nothing handles an instruction.  This
 * doesn't include the NAN flag, which get masked out before
 * we check for an error.
 */

#define F64_EXCEPTION_ERROR	((u32)-1 & ~F64_NAN_FLAG)

/*
 * Since we aren't building with -mfpu=f64, we need to code
 * these instructions using their MRC/MCR equivalents.
 */

#define f64reg(_f64_) #_f64_


#define cff(_f64_) ({                      \
        u32 __v;                        \
        asm("cff %0, " f64reg(_f64_) "@ fmrx    %0, " #_f64_    \
            : "=r" (__v) : : "cc");     \
        __v;                            \
        })


#define ctf(_f64_, _var_)		\
	asm("ctf %0, " f64reg(_f64_) "@ fmxr    " #_f64_ ", %0" \
           : : "r" (_var_) : "cc")

/*
 * Raise a SIGFPE for the current process.
 * sicode describes the signal being raised.
 */

void ucf64_raise_sigfpe(unsigned int sicode, struct pt_regs *regs) { siginfo_t info; memset(&info, 0, sizeof(info)); info.si_signo = SIGFPE; info.si_code = sicode; info.si_addr = (void __user *)(instruction_pointer(regs) - 4); /* * This is the same as NWFPE, because it's not clear what * this is used for */ current->thread.error_code = 0; current->thread.trap_no = 6; send_sig_info(SIGFPE, &info, current); }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao87100.00%1100.00%
Total87100.00%1100.00%

/* * Handle exceptions of UniCore-F64. */
void ucf64_exchandler(u32 inst, u32 fpexc, struct pt_regs *regs) { u32 tmp = fpexc; u32 exc = F64_EXCEPTION_ERROR & fpexc; pr_debug("UniCore-F64: instruction %08x fpscr %08x\n", inst, fpexc); if (exc & FPSCR_CMPINSTR_BIT) { if (exc & FPSCR_CON) tmp |= FPSCR_CON; else tmp &= ~(FPSCR_CON); exc &= ~(FPSCR_CMPINSTR_BIT | FPSCR_CON); } else { pr_debug("UniCore-F64 Error: unhandled exceptions\n"); pr_debug("UniCore-F64 FPSCR 0x%08x INST 0x%08x\n", cff(FPSCR), inst); ucf64_raise_sigfpe(0, regs); return; } /* * Update the FPSCR with the additional exception flags. * Comparison instructions always return at least one of * these flags set. */ tmp &= ~(FPSCR_TRAP | FPSCR_IOS | FPSCR_OFS | FPSCR_UFS | FPSCR_IXS | FPSCR_HIS | FPSCR_IOC | FPSCR_OFC | FPSCR_UFC | FPSCR_IXC | FPSCR_HIC); tmp |= exc; ctf(FPSCR, tmp); }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao139100.00%1100.00%
Total139100.00%1100.00%

/* * F64 support code initialisation. */
static int __init ucf64_init(void) { ctf(FPSCR, 0x0); /* FPSCR_UFE | FPSCR_NDE perhaps better */ printk(KERN_INFO "Enable UniCore-F64 support.\n"); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao26100.00%1100.00%
Total26100.00%1100.00%

late_initcall(ucf64_init);

Overall Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao31699.68%150.00%
Ingo Molnar10.32%150.00%
Total317100.00%2100.00%
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