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178 lines
4.6 KiB
178 lines
4.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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NetWinder Floating Point Emulator |
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(c) Rebel.com, 1998-1999 |
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(c) Philip Blundell, 1998-1999 |
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Direct questions, comments to Scott Bambrough <[email protected]> |
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*/ |
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#include "fpa11.h" |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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/* XXX */ |
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#include <linux/errno.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/signal.h> |
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#include <linux/sched/signal.h> |
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#include <linux/init.h> |
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#include <asm/thread_notify.h> |
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#include "softfloat.h" |
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#include "fpopcode.h" |
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#include "fpmodule.h" |
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#include "fpa11.inl" |
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/* kernel symbols required for signal handling */ |
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#ifdef CONFIG_FPE_NWFPE_XP |
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#define NWFPE_BITS "extended" |
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#else |
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#define NWFPE_BITS "double" |
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#endif |
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#ifdef MODULE |
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void fp_send_sig(unsigned long sig, struct task_struct *p, int priv); |
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#else |
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#define fp_send_sig send_sig |
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#define kern_fp_enter fp_enter |
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extern char fpe_type[]; |
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#endif |
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static int nwfpe_notify(struct notifier_block *self, unsigned long cmd, void *v) |
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{ |
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struct thread_info *thread = v; |
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if (cmd == THREAD_NOTIFY_FLUSH) |
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nwfpe_init_fpa(&thread->fpstate); |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block nwfpe_notifier_block = { |
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.notifier_call = nwfpe_notify, |
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}; |
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/* kernel function prototypes required */ |
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void fp_setup(void); |
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/* external declarations for saved kernel symbols */ |
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extern void (*kern_fp_enter)(void); |
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/* Original value of fp_enter from kernel before patched by fpe_init. */ |
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static void (*orig_fp_enter)(void); |
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/* forward declarations */ |
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extern void nwfpe_enter(void); |
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static int __init fpe_init(void) |
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{ |
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if (sizeof(FPA11) > sizeof(union fp_state)) { |
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pr_err("nwfpe: bad structure size\n"); |
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return -EINVAL; |
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} |
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if (sizeof(FPREG) != 12) { |
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pr_err("nwfpe: bad register size\n"); |
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return -EINVAL; |
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} |
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if (fpe_type[0] && strcmp(fpe_type, "nwfpe")) |
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return 0; |
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/* Display title, version and copyright information. */ |
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pr_info("NetWinder Floating Point Emulator V0.97 (" |
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NWFPE_BITS " precision)\n"); |
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thread_register_notifier(&nwfpe_notifier_block); |
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/* Save pointer to the old FP handler and then patch ourselves in */ |
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orig_fp_enter = kern_fp_enter; |
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kern_fp_enter = nwfpe_enter; |
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return 0; |
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} |
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static void __exit fpe_exit(void) |
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{ |
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thread_unregister_notifier(&nwfpe_notifier_block); |
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/* Restore the values we saved earlier. */ |
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kern_fp_enter = orig_fp_enter; |
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} |
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/* |
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ScottB: November 4, 1998 |
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Moved this function out of softfloat-specialize into fpmodule.c. |
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This effectively isolates all the changes required for integrating with the |
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Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying |
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fpmodule.c to integrate with the NetBSD kernel (I hope!). |
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[1/1/99: Not quite true any more unfortunately. There is Linux-specific |
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code to access data in user space in some other source files at the |
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moment (grep for get_user / put_user calls). --philb] |
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This function is called by the SoftFloat routines to raise a floating |
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point exception. We check the trap enable byte in the FPSR, and raise |
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a SIGFPE exception if necessary. If not the relevant bits in the |
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cumulative exceptions flag byte are set and we return. |
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*/ |
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#ifdef CONFIG_DEBUG_USER |
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/* By default, ignore inexact errors as there are far too many of them to log */ |
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static int debug = ~BIT_IXC; |
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#endif |
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void float_raise(signed char flags) |
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{ |
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register unsigned int fpsr, cumulativeTraps; |
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#ifdef CONFIG_DEBUG_USER |
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if (flags & debug) |
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printk(KERN_DEBUG |
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"NWFPE: %s[%d] takes exception %08x at %ps from %08lx\n", |
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current->comm, current->pid, flags, |
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__builtin_return_address(0), GET_USERREG()->ARM_pc); |
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#endif |
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/* Read fpsr and initialize the cumulativeTraps. */ |
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fpsr = readFPSR(); |
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cumulativeTraps = 0; |
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/* For each type of exception, the cumulative trap exception bit is only |
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set if the corresponding trap enable bit is not set. */ |
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if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC)) |
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cumulativeTraps |= BIT_IXC; |
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if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC)) |
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cumulativeTraps |= BIT_UFC; |
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if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC)) |
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cumulativeTraps |= BIT_OFC; |
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if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC)) |
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cumulativeTraps |= BIT_DZC; |
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if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC)) |
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cumulativeTraps |= BIT_IOC; |
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/* Set the cumulative exceptions flags. */ |
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if (cumulativeTraps) |
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writeFPSR(fpsr | cumulativeTraps); |
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/* Raise an exception if necessary. */ |
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if (fpsr & (flags << 16)) |
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fp_send_sig(SIGFPE, current, 1); |
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} |
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module_init(fpe_init); |
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module_exit(fpe_exit); |
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MODULE_AUTHOR("Scott Bambrough <[email protected]>"); |
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MODULE_DESCRIPTION("NWFPE floating point emulator (" NWFPE_BITS " precision)"); |
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MODULE_LICENSE("GPL"); |
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#ifdef CONFIG_DEBUG_USER |
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module_param(debug, int, 0644); |
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#endif
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