2006-12-13 Samuel Thibault <samuel.thibault@ens-lyon.org>

Drop useless and broken FPE support.

	* i386/configfrac.ac (FPE): Don't define.
	* i386/i386/gdt.h (FPE_CS, USER_FPREGS): Remove macros.
	* i386/i386/fpu.c (init_fpu, fpu_set_state, fpu_get_state): Remove FPE
	support.
	* i386/i386/fpu.h: Likewise.
	* i386/i386/trap.c (user_trap, i386_exception): Likewise.
	* i386/i386/fpe_linkage.c: Remove file.
	* i386/Makefrag.am: Remove i386/i386/fpe_linkage.c.
	* Makefile.in: Regenerate.

7 files changed, 2 insertions, 479 deletions

diff --git a/i386/Makefrag.am b/i386/Makefrag.am
index f34c7cc..50b7afd 100644
--- a/i386/Makefrag.am
+++ b/i386/Makefrag.am
@@ -80,7 +80,6 @@ libkernel_a_SOURCES += \
 	i386/i386/debug_i386.c \
 	i386/i386/debug_trace.S \
 	i386/i386/eflags.h \
-	i386/i386/fpe_linkage.c \
 	i386/i386/fpu.c \
 	i386/i386/fpu.h \
 	i386/i386/gdt.c \
diff --git a/i386/configfrag.ac b/i386/configfrag.ac
index d32f2b8..a82ce5c 100644
--- a/i386/configfrag.ac
+++ b/i386/configfrag.ac
@@ -28,9 +28,6 @@ AC_DEFINE([i386], [1], [i386])
 # i386/bogus/com.h
 AC_DEFINE([NCOM], [4], [NCOM])
 
-# i386/bogus/fpe.h
-AC_DEFINE([FPE], [0], [We do not have a floating point implementation.])
-
 # i386/bogus/lpr.h
 AC_DEFINE([NLPR], [1], [NLPR])
 
diff --git a/i386/i386/fpe_linkage.c b/i386/i386/fpe_linkage.c
deleted file mode 100644
index f0ac34e..0000000
--- a/i386/i386/fpe_linkage.c
+++ /dev/null
@@ -1,363 +0,0 @@
-/* 
- * Mach Operating System
- * Copyright (c) 1991 Carnegie Mellon University
- * All Rights Reserved.
- * 
- * Permission to use, copy, modify and distribute this software and its
- * documentation is hereby granted, provided that both the copyright
- * notice and this permission notice appear in all copies of the
- * software, derivative works or modified versions, and any portions
- * thereof, and that both notices appear in supporting documentation.
- * 
- * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
- * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
- * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- * 
- * Carnegie Mellon requests users of this software to return to
- * 
- *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
- *  School of Computer Science
- *  Carnegie Mellon University
- *  Pittsburgh PA 15213-3890
- * 
- * any improvements or extensions that they make and grant Carnegie Mellon 
- * the rights to redistribute these changes.
- */
-
-/*
- * Support routines for FP emulator.
- */
-
-#if FPE
-
-#include <cpus.h>
-
-#include <mach/std_types.h>
-#include <mach/exception.h>
-#include <mach/thread_status.h>
-
-#include <kern/cpu_number.h>
-#include <kern/debug.h>
-#include <kern/thread.h>
-
-#include <vm/vm_kern.h>
-
-#include <mach/machine/eflags.h>
-#include "vm_param.h"
-#include <i386/pmap.h>
-#include <i386/thread.h>
-#include <i386/fpu.h>
-#include "proc_reg.h"
-#include "seg.h"
-#include "idt.h"
-#include "gdt.h"
-
-#if	NCPUS > 1
-#include <i386/mp_desc.h>
-#endif
-
-extern vm_offset_t	kvtophys();
-
-/*
- * Symbols exported from FPE emulator.
- */
-extern char	fpe_start[];	/* start of emulator text;
-				   also emulation entry point */
-extern char	fpe_end[];	/* end of emulator text */
-extern int	fpe_reg_segment;
-				/* word holding segment number for
-				   FPE register/status area */
-extern char	fpe_recover[];	/* emulation fault recovery entry point */
-
-extern void	fix_desc();
-
-#if	NCPUS > 1
-#define	curr_gdt(mycpu)		(mp_gdt[mycpu])
-#define	curr_idt(mycpu)		(mp_desc_table[mycpu]->idt)
-#else
-#define	curr_gdt(mycpu)		(gdt)
-#define	curr_idt(mycpu)		(idt)
-#endif
-
-#define	gdt_desc_p(mycpu,sel) \
-	((struct real_descriptor *)&curr_gdt(mycpu)[sel_idx(sel)])
-#define	idt_desc_p(mycpu,idx) \
-	((struct real_gate *)&curr_idt(mycpu)[idx])
-
-void	set_user_access();	/* forward */
-void	enable_fpe(register struct i386_fpsave_state *ifps);
-
-/*
- * long pointer for calling FPE register recovery routine.
- */
-struct long_ptr {
-	unsigned long	offset;
-	unsigned short	segment;
-};
-
-struct long_ptr fpe_recover_ptr;
-
-/*
- * Initialize descriptors for FP emulator.
- */
-void
-fpe_init()
-{
-	register struct real_descriptor *gdt_p;
-	register struct real_gate *idt_p;
-
-	/*
-	 * Map in the pages for the FP emulator:
-	 * read-only, user-accessible.
-	 */
-	set_user_access(pmap_kernel(),
-			(vm_offset_t)fpe_start,
-			(vm_offset_t)fpe_end,
-			FALSE);
-
-	/*
-	 * Put the USER_FPREGS segment value in the FP emulator.
-	 */
-	fpe_reg_segment = USER_FPREGS;
-
-	/*
-	 * Change exception 7 gate (coprocessor not present)
-	 * to a trap gate to the FPE code segment.
-	 */
-	idt_p = idt_desc_p(cpu_number(), 7);
-	idt_p->offset_low  = 0;			/* offset of FPE entry */
-	idt_p->offset_high = 0;
-	idt_p->selector	  = FPE_CS;		/* FPE code segment */
-	idt_p->word_count = 0;
-	idt_p->access 	  = ACC_P|ACC_PL_K|ACC_TRAP_GATE;
-						/* trap gate */
-						/* kernel privileges only,
-						   so INT $7 does not call
-						   the emulator */
-
-	/*
-	 * Build GDT entry for FP code segment.
-	 */
-	gdt_p = gdt_desc_p(cpu_number(), FPE_CS);
-	gdt_p->base_low   = ((vm_offset_t) fpe_start) & 0xffff;
-	gdt_p->base_med   = (((vm_offset_t) fpe_start) >> 16) & 0xff;
-	gdt_p->base_high  = ((vm_offset_t) fpe_start) >> 24;
-	gdt_p->limit_low  = (vm_offset_t) fpe_end
-			  - (vm_offset_t) fpe_start
-			  - 1;
-	gdt_p->limit_high = 0;
-	gdt_p->granularity = SZ_32;
-	gdt_p->access	  = ACC_P|ACC_PL_K|ACC_CODE_CR;
-						/* conforming segment,
-						   usable by kernel */
-
-	/*
-	 * Build GDT entry for user FP state area - template,
-	 * since each thread has its own.
-	 */
-	gdt_p = gdt_desc_p(cpu_number(), USER_FPREGS);
-	/* descriptor starts as 0 */
-	gdt_p->limit_low  = sizeof(struct i386_fp_save)
-			  + sizeof(struct i386_fp_regs)
-			  - 1;
-	gdt_p->limit_high = 0;
-	gdt_p->granularity = 0;
-	gdt_p->access = ACC_PL_U|ACC_DATA_W;
-					/* start as "not present" */
-
-	/*
-	 * Set up the recovery routine pointer
-	 */
-	fpe_recover_ptr.offset = fpe_recover - fpe_start;
-	fpe_recover_ptr.segment = FPE_CS;
-
-	/*
-	 * Set i386 to emulate coprocessor.
-	 */
-	set_cr0((get_cr0() & ~CR0_MP) | CR0_EM);
-}
-
-/*
- * Enable FPE use for a new thread.
- * Allocates the FP save area.
- */
-boolean_t
-fp_emul_error(regs)
-	struct i386_saved_state *regs;
-{
-	register struct i386_fpsave_state *ifps;
-	register vm_offset_t	start_va;
-
-	if ((regs->err & 0xfffc) != (USER_FPREGS & ~SEL_PL))
-	    return FALSE;
-
-	/*
-	 * Make the FPU save area user-accessible (by FPE)
-	 */
-	ifps = current_thread()->pcb->ims.ifps;
-	if (ifps == 0) {
-	    /*
-	     * No FP register state yet - allocate it.
-	     */
-	    fp_state_alloc();
-	    ifps = current_thread()->pcb->ims.ifps;
-	}
-	    
-	panic("fp_emul_error: FP emulation is probably broken because of VM changes; fix! XXX");
-	start_va = (vm_offset_t) &ifps->fp_save_state;
-	set_user_access(current_map()->pmap,
-		start_va,
-		start_va + sizeof(struct i386_fp_save),
-		TRUE);
-
-	/*
-	 * Enable FPE use for this thread
-	 */
-	enable_fpe(ifps);
-
-	return TRUE;
-}
-
-/*
- * Enable FPE use.  ASSUME that kernel does NOT use FPU
- * except to handle user exceptions.
- */
-void
-enable_fpe(ifps)
-	register struct i386_fpsave_state *ifps;
-{
-	struct real_descriptor *dp;
-	vm_offset_t	start_va;
-
-	dp = gdt_desc_p(cpu_number(), USER_FPREGS);
-	start_va = (vm_offset_t)&ifps->fp_save_state;
-
-	dp->base_low = start_va & 0xffff;
-	dp->base_med = (start_va >> 16) & 0xff;
-	dp->base_high = start_va >> 24;
-	dp->access |= ACC_P;
-}
-
-void
-disable_fpe()
-{
-	/*
-	 *	The kernel might be running with fs & gs segments
-	 *	which refer to USER_FPREGS, if we entered the kernel
-	 *	from a FP-using thread.  We have to clear these segments
-	 *	lest we get a Segment Not Present trap.  This would happen
-	 *	if the kernel took an interrupt or fault after clearing
-	 *	the present bit but before exiting to user space (which
-	 *	would reset fs & gs from the current user thread).
-	 */
-
-	asm volatile("xorw %ax, %ax\n\t"
-	             "movw %ax, %fs\n\t"
-	             "movw %ax, %gs\n\t":::"ax");
-
-	gdt_desc_p(cpu_number(), USER_FPREGS)->access &= ~ACC_P;
-}
-
-void
-set_user_access(pmap, start, end, writable)
-	pmap_t		pmap;
-	vm_offset_t	start;
-	vm_offset_t	end;
-	boolean_t	writable;
-{
-	register vm_offset_t	va;
-	register pt_entry_t *	dirbase = pmap->dirbase;
-	register pt_entry_t *	ptep;
-	register pt_entry_t *	pdep;
-
-	start = i386_trunc_page(start);
-	end   = i386_round_page(end);
-
-	for (va = start; va < end; va += I386_PGBYTES) {
-
-	    pdep = &dirbase[lin2pdenum(kvtolin(va))];
-	    *pdep |= INTEL_PTE_USER;
-	    ptep = (pt_entry_t *)ptetokv(*pdep);
-	    ptep = &ptep[ptenum(va)];
-	    *ptep |= INTEL_PTE_USER;
-	    if (!writable)
-		*ptep &= ~INTEL_PTE_WRITE;
-	}
-}
-
-/*
- * Route exception through emulator fixup routine if
- * it occured within the emulator.
- */
-extern void exception();
-
-void
-fpe_exception_fixup(exc, code, subcode)
-	int	exc, code, subcode;
-{
-	thread_t	thread = current_thread();
-	pcb_t		pcb = thread->pcb;
-
-	if (pcb->iss.efl & EFL_VM) {
-	    /*
-	     * The emulator doesn`t handle V86 mode.
-	     * If this is a GP fault on the emulator`s
-	     * code segment, change it to an FP not present
-	     * fault.
-	     */
-	    if (exc == EXC_BAD_INSTRUCTION
-	     && code == EXC_I386_GPFLT
-	     && subcode == FPE_CS + 1)
-	    {
-		exc = EXC_ARITHMETIC;	/* arithmetic error: */
-		code = EXC_I386_NOEXT;	/* no FPU */
-		subcode = 0;
-	    }
-	}
-	else
-	if ((pcb->iss.cs & 0xfffc) == FPE_CS) {
-	    /*
-	     * Pass registers to emulator,
-	     * to let it fix them up.
-	     * The emulator fixup routine knows about
-	     * an i386_thread_state.
-	     */
-	    struct i386_thread_state	tstate;
-	    unsigned int		count;
-
-	    count = i386_THREAD_STATE_COUNT;
-	    (void) thread_getstatus(thread,
-				i386_REGS_SEGS_STATE,
-				(thread_state_t) &tstate,
-				&count);
-
-	    /*
-	     * long call to emulator register recovery routine
-	     */
-	    asm volatile("pushl %0; lcall %1; addl $4,%%esp"
-			:
-			: "r" (&tstate),
-			  "m" (fpe_recover_ptr) );
-
-	    (void) thread_setstatus(thread,
-				i386_REGS_SEGS_STATE,
-				(thread_state_t) &tstate,
-				count);
-	    /*
-	     * In addition, check for a GP fault on 'int 16' in
-	     * the emulator, since the interrupt gate is protected.
-	     * If so, change it to an arithmetic error.
-	     */
-	    if (exc == EXC_BAD_INSTRUCTION
-	     && code == EXC_I386_GPFLT
-	     && subcode == 8*16+2)	/* idt[16] */
-	    {
-		exc = EXC_ARITHMETIC;
-		code = EXC_I386_EXTERR;
-		subcode = pcb->ims.ifps->fp_save_state.fp_status;
-	    }
-	}
-	exception(exc, code, subcode);
-}
-#endif /* FPE.  */
-
diff --git a/i386/i386/fpu.c b/i386/i386/fpu.c
index 17f5dab..ad88a5d 100644
--- a/i386/i386/fpu.c
+++ b/i386/i386/fpu.c
@@ -138,19 +138,11 @@ init_fpu()
 	    set_cr0(get_cr0() | CR0_TS | CR0_MP);
 	}
 	else {
-#if	FPE
-	    /*
-	     * Use the floating-point emulator.
-	     */
-	    fp_kind = FP_SOFT;
-	    fpe_init();
-#else	/* no fpe */
 	    /*
 	     * NO FPU.
 	     */
 	    fp_kind = FP_NO;
 	    set_cr0(get_cr0() | CR0_EM);
-#endif
 	}
 }
 
@@ -277,39 +269,7 @@ ASSERT_IPL(SPL0);
 	    ifps->fp_save_state.fp_opcode  = user_fp_state->fp_opcode;
 	    ifps->fp_save_state.fp_dp      = user_fp_state->fp_dp;
 	    ifps->fp_save_state.fp_ds      = user_fp_state->fp_ds;
-
-#if	FPE
-	    if (fp_kind == FP_SOFT) {
-		/*
-		 * The emulator stores the registers by physical
-		 * register number, not from top-of-stack.
-		 * Shuffle the registers into the correct order.
-		 */
-		register char *src;	/* user regs */
-		register char *dst;	/* kernel regs */
-		int	i;
-
-		src = (char *)user_fp_regs;
-		dst = (char *)&ifps->fp_regs;
-		i = (ifps->fp_save_state.fp_status & FPS_TOS)
-			>> FPS_TOS_SHIFT;	/* physical register
-						   for st(0) */
-		if (i == 0)
-		    memcpy(dst, src, 8 * 10);
-		else {
-		    memcpy(dst + 10 * i,
-			  src, 
-			  10 * (8 - i));
-		    memcpy(dst, 
-			  src + 10 * (8 - i),
-			  10 * i);
-		}
-	    }
-	    else
-		ifps->fp_regs = *user_fp_regs;
-#else	/* no FPE */
 	    ifps->fp_regs = *user_fp_regs;
-#endif	/* FPE */
 
 	    simple_unlock(&pcb->lock);
 	    if (new_ifps != 0)
@@ -387,39 +347,7 @@ ASSERT_IPL(SPL0);
 	    user_fp_state->fp_opcode  = ifps->fp_save_state.fp_opcode;
 	    user_fp_state->fp_dp      = ifps->fp_save_state.fp_dp;
 	    user_fp_state->fp_ds      = ifps->fp_save_state.fp_ds;
-
-#if	FPE
-	    if (fp_kind == FP_SOFT) {
-		/*
-		 * The emulator stores the registers by physical
-		 * register number, not from top-of-stack.
-		 * Shuffle the registers into the correct order.
-		 */
-		register char *src;	/* kernel regs */
-		register char *dst;	/* user regs */
-		int	i;
-
-		src = (char *)&ifps->fp_regs;
-		dst = (char *)user_fp_regs;
-		i = (ifps->fp_save_state.fp_status & FPS_TOS)
-			>> FPS_TOS_SHIFT;	/* physical register
-						   for st(0) */
-		if (i == 0)
-		    memcpy(dst, src, 8 * 10);
-		else {
-		    memcpy(dst, 
-			  src + 10 * i,
-			  10 * (8 - i));
-		    memcpy(dst + 10 * (8 - i), 
-			  src, 
-			  10 * i);
-		}
-	    }
-	    else
-		*user_fp_regs = ifps->fp_regs;
-#else	/* no FPE */
 	    *user_fp_regs = ifps->fp_regs;
-#endif	/* FPE */
 	}
 	simple_unlock(&pcb->lock);
 
diff --git a/i386/i386/fpu.h b/i386/i386/fpu.h
index bb332ad..3e92de7 100644
--- a/i386/i386/fpu.h
+++ b/i386/i386/fpu.h
@@ -69,32 +69,6 @@
 #define fwait() \
     	asm("fwait");
 
-/*
- * If floating-point instructions are emulated,
- * we must load the floating-point register selector
- * when switching to a new thread.
- */
-#if	FPE
-extern void	disable_fpe();
-extern void	enable_fpe();
-
-#define	fpu_save_context(thread) \
-    { \
-	if (fp_kind == FP_SOFT) \
-	    disable_fpe(); \
-	else \
-	    set_ts(); \
-    }
-
-#define	fpu_load_context(pcb) \
-    { \
-	register struct i386_fpsave_state *ifps; \
-	if (fp_kind == FP_SOFT && (ifps = pcb->ims.ifps) != 0) \
-	    enable_fpe(ifps); \
-    }
-
-#else	/* no FPE */
-
 #define	fpu_load_context(pcb)
 
 /*
@@ -124,8 +98,6 @@ extern void	enable_fpe();
 
 #endif	/* NCPUS == 1 */
 
-#endif	/* no FPE */
-
 extern int	fp_kind;
 
 #endif	/* _I386_FPU_H_ */
diff --git a/i386/i386/gdt.h b/i386/i386/gdt.h
index 4715759..558bd15 100644
--- a/i386/i386/gdt.h
+++ b/i386/i386/gdt.h
@@ -45,9 +45,8 @@
 #define	USER_LDT	0x28		/* place for per-thread LDT */
 #define	USER_TSS	0x30		/* place for per-thread TSS
 					   that holds IO bitmap */
-#define	FPE_CS		0x38		/* floating-point emulator code */
-#define	USER_FPREGS	0x40		/* user-mode access to saved
-					   floating-point registers */
+/*			0x38		   was FPE_CS, now free */
+/*			0x40		   was USER_FPREGS, now free */
 
 #define	USER_GDT	0x48		/* user-defined GDT entries */
 #define	USER_GDT_SLOTS	2
diff --git a/i386/i386/trap.c b/i386/i386/trap.c
index 068a0b3..bd0d8e0 100644
--- a/i386/i386/trap.c
+++ b/i386/i386/trap.c
@@ -480,11 +480,6 @@ printf("user trap %d error %d sub %08x\n", type, code, subcode);
 		break;
 
 	    case T_SEGMENT_NOT_PRESENT:
-#if	FPE
-		if (fp_emul_error(regs))
-		    return 0;
-#endif	/* FPE */
-
 		exc = EXC_BAD_INSTRUCTION;
 		code = EXC_I386_SEGNPFLT;
 		subcode = regs->err & 0xffff;
@@ -1035,11 +1030,7 @@ i386_exception(exc, code, subcode)
 	ast_off(cpu_number(), AST_I386_FP);
 	splx(s);
 
-#if	FPE
-	fpe_exception_fixup(exc, code, subcode);
-#else
 	exception(exc, code, subcode);
-#endif
 	/*NOTREACHED*/
 }