2 * linux/arch/unicore32/kernel/fpu-ucf64.c
4 * Code specific to PKUnity SoC and UniCore ISA
6 * Copyright (C) 2001-2010 GUAN Xue-tao
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/signal.h>
16 #include <linux/sched/signal.h>
17 #include <linux/init.h>
19 #include <asm/fpu-ucf64.h>
22 * A special flag to tell the normalisation code not to normalise.
24 #define F64_NAN_FLAG 0x100
27 * A bit pattern used to indicate the initial (unset) value of the
28 * exception mask, in case nothing handles an instruction. This
29 * doesn't include the NAN flag, which get masked out before
30 * we check for an error.
32 #define F64_EXCEPTION_ERROR ((u32)-1 & ~F64_NAN_FLAG)
35 * Since we aren't building with -mfpu=f64, we need to code
36 * these instructions using their MRC/MCR equivalents.
38 #define f64reg(_f64_) #_f64_
40 #define cff(_f64_) ({ \
42 asm("cff %0, " f64reg(_f64_) "@ fmrx %0, " #_f64_ \
43 : "=r" (__v) : : "cc"); \
47 #define ctf(_f64_, _var_) \
48 asm("ctf %0, " f64reg(_f64_) "@ fmxr " #_f64_ ", %0" \
49 : : "r" (_var_) : "cc")
52 * Raise a SIGFPE for the current process.
53 * sicode describes the signal being raised.
55 void ucf64_raise_sigfpe(unsigned int sicode
, struct pt_regs
*regs
)
59 memset(&info
, 0, sizeof(info
));
61 info
.si_signo
= SIGFPE
;
62 info
.si_code
= sicode
;
63 info
.si_addr
= (void __user
*)(instruction_pointer(regs
) - 4);
66 * This is the same as NWFPE, because it's not clear what
69 current
->thread
.error_code
= 0;
70 current
->thread
.trap_no
= 6;
72 send_sig_info(SIGFPE
, &info
, current
);
76 * Handle exceptions of UniCore-F64.
78 void ucf64_exchandler(u32 inst
, u32 fpexc
, struct pt_regs
*regs
)
81 u32 exc
= F64_EXCEPTION_ERROR
& fpexc
;
83 pr_debug("UniCore-F64: instruction %08x fpscr %08x\n",
86 if (exc
& FPSCR_CMPINSTR_BIT
) {
91 exc
&= ~(FPSCR_CMPINSTR_BIT
| FPSCR_CON
);
93 pr_debug("UniCore-F64 Error: unhandled exceptions\n");
94 pr_debug("UniCore-F64 FPSCR 0x%08x INST 0x%08x\n",
97 ucf64_raise_sigfpe(0, regs
);
102 * Update the FPSCR with the additional exception flags.
103 * Comparison instructions always return at least one of
106 tmp
&= ~(FPSCR_TRAP
| FPSCR_IOS
| FPSCR_OFS
| FPSCR_UFS
|
107 FPSCR_IXS
| FPSCR_HIS
| FPSCR_IOC
| FPSCR_OFC
|
108 FPSCR_UFC
| FPSCR_IXC
| FPSCR_HIC
);
115 * F64 support code initialisation.
117 static int __init
ucf64_init(void)
119 ctf(FPSCR
, 0x0); /* FPSCR_UFE | FPSCR_NDE perhaps better */
121 printk(KERN_INFO
"Enable UniCore-F64 support.\n");
126 late_initcall(ucf64_init
);