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718f5d0030
desc_struct is a union of u32 fields and bitfields. The access to the u32 fields is done with magic macros. Convert it to use the bitfields and replace the macro magic with parseable inline functions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170828064958.042406718@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
400 lines
10 KiB
C
400 lines
10 KiB
C
/*---------------------------------------------------------------------------+
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| get_address.c |
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| Get the effective address from an FPU instruction. |
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| Copyright (C) 1992,1993,1994,1997 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@suburbia.net |
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+---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------+
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| Note: |
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| The file contains code which accesses user memory. |
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| Emulator static data may change when user memory is accessed, due to |
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| other processes using the emulator while swapping is in progress. |
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+---------------------------------------------------------------------------*/
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#include <linux/stddef.h>
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#include <linux/uaccess.h>
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#include <asm/vm86.h>
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#include "fpu_system.h"
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#include "exception.h"
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#include "fpu_emu.h"
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#define FPU_WRITE_BIT 0x10
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static int reg_offset[] = {
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offsetof(struct pt_regs, ax),
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offsetof(struct pt_regs, cx),
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offsetof(struct pt_regs, dx),
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offsetof(struct pt_regs, bx),
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offsetof(struct pt_regs, sp),
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offsetof(struct pt_regs, bp),
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offsetof(struct pt_regs, si),
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offsetof(struct pt_regs, di)
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};
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#define REG_(x) (*(long *)(reg_offset[(x)] + (u_char *)FPU_info->regs))
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static int reg_offset_vm86[] = {
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offsetof(struct pt_regs, cs),
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offsetof(struct kernel_vm86_regs, ds),
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offsetof(struct kernel_vm86_regs, es),
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offsetof(struct kernel_vm86_regs, fs),
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offsetof(struct kernel_vm86_regs, gs),
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offsetof(struct pt_regs, ss),
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offsetof(struct kernel_vm86_regs, ds)
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};
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#define VM86_REG_(x) (*(unsigned short *) \
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(reg_offset_vm86[((unsigned)x)] + (u_char *)FPU_info->regs))
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static int reg_offset_pm[] = {
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offsetof(struct pt_regs, cs),
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offsetof(struct pt_regs, ds),
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offsetof(struct pt_regs, es),
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offsetof(struct pt_regs, fs),
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offsetof(struct pt_regs, ds), /* dummy, not saved on stack */
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offsetof(struct pt_regs, ss),
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offsetof(struct pt_regs, ds)
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};
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#define PM_REG_(x) (*(unsigned short *) \
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(reg_offset_pm[((unsigned)x)] + (u_char *)FPU_info->regs))
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/* Decode the SIB byte. This function assumes mod != 0 */
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static int sib(int mod, unsigned long *fpu_eip)
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{
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u_char ss, index, base;
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long offset;
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(1);
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FPU_get_user(base, (u_char __user *) (*fpu_eip)); /* The SIB byte */
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RE_ENTRANT_CHECK_ON;
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(*fpu_eip)++;
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ss = base >> 6;
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index = (base >> 3) & 7;
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base &= 7;
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if ((mod == 0) && (base == 5))
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offset = 0; /* No base register */
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else
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offset = REG_(base);
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if (index == 4) {
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/* No index register */
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/* A non-zero ss is illegal */
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if (ss)
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EXCEPTION(EX_Invalid);
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} else {
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offset += (REG_(index)) << ss;
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}
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if (mod == 1) {
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/* 8 bit signed displacement */
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long displacement;
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(1);
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FPU_get_user(displacement, (signed char __user *)(*fpu_eip));
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offset += displacement;
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RE_ENTRANT_CHECK_ON;
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(*fpu_eip)++;
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} else if (mod == 2 || base == 5) { /* The second condition also has mod==0 */
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/* 32 bit displacement */
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long displacement;
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(4);
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FPU_get_user(displacement, (long __user *)(*fpu_eip));
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offset += displacement;
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RE_ENTRANT_CHECK_ON;
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(*fpu_eip) += 4;
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}
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return offset;
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}
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static unsigned long vm86_segment(u_char segment, struct address *addr)
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{
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segment--;
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#ifdef PARANOID
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if (segment > PREFIX_SS_) {
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EXCEPTION(EX_INTERNAL | 0x130);
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math_abort(FPU_info, SIGSEGV);
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}
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#endif /* PARANOID */
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addr->selector = VM86_REG_(segment);
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return (unsigned long)VM86_REG_(segment) << 4;
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}
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/* This should work for 16 and 32 bit protected mode. */
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static long pm_address(u_char FPU_modrm, u_char segment,
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struct address *addr, long offset)
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{
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struct desc_struct descriptor;
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unsigned long base_address, limit, address, seg_top;
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segment--;
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#ifdef PARANOID
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/* segment is unsigned, so this also detects if segment was 0: */
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if (segment > PREFIX_SS_) {
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EXCEPTION(EX_INTERNAL | 0x132);
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math_abort(FPU_info, SIGSEGV);
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}
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#endif /* PARANOID */
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switch (segment) {
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case PREFIX_GS_ - 1:
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/* user gs handling can be lazy, use special accessors */
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addr->selector = get_user_gs(FPU_info->regs);
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break;
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default:
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addr->selector = PM_REG_(segment);
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}
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descriptor = FPU_get_ldt_descriptor(addr->selector);
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base_address = seg_get_base(&descriptor);
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address = base_address + offset;
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limit = seg_get_limit(&descriptor) + 1;
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limit *= seg_get_granularity(&descriptor);
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limit += base_address - 1;
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if (limit < base_address)
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limit = 0xffffffff;
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if (seg_expands_down(&descriptor)) {
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if (descriptor.g) {
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seg_top = 0xffffffff;
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} else {
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seg_top = base_address + (1 << 20);
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if (seg_top < base_address)
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seg_top = 0xffffffff;
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}
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access_limit =
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(address <= limit) || (address >= seg_top) ? 0 :
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((seg_top - address) >= 255 ? 255 : seg_top - address);
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} else {
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access_limit =
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(address > limit) || (address < base_address) ? 0 :
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((limit - address) >= 254 ? 255 : limit - address + 1);
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}
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if (seg_execute_only(&descriptor) ||
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(!seg_writable(&descriptor) && (FPU_modrm & FPU_WRITE_BIT))) {
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access_limit = 0;
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}
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return address;
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}
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/*
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MOD R/M byte: MOD == 3 has a special use for the FPU
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SIB byte used iff R/M = 100b
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7 6 5 4 3 2 1 0
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..... ......... .........
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MOD OPCODE(2) R/M
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SIB byte
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7 6 5 4 3 2 1 0
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..... ......... .........
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SS INDEX BASE
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*/
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void __user *FPU_get_address(u_char FPU_modrm, unsigned long *fpu_eip,
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struct address *addr, fpu_addr_modes addr_modes)
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{
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u_char mod;
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unsigned rm = FPU_modrm & 7;
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long *cpu_reg_ptr;
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int address = 0; /* Initialized just to stop compiler warnings. */
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/* Memory accessed via the cs selector is write protected
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in `non-segmented' 32 bit protected mode. */
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if (!addr_modes.default_mode && (FPU_modrm & FPU_WRITE_BIT)
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&& (addr_modes.override.segment == PREFIX_CS_)) {
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math_abort(FPU_info, SIGSEGV);
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}
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addr->selector = FPU_DS; /* Default, for 32 bit non-segmented mode. */
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mod = (FPU_modrm >> 6) & 3;
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if (rm == 4 && mod != 3) {
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address = sib(mod, fpu_eip);
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} else {
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cpu_reg_ptr = ®_(rm);
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switch (mod) {
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case 0:
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if (rm == 5) {
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/* Special case: disp32 */
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(4);
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FPU_get_user(address,
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(unsigned long __user
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*)(*fpu_eip));
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(*fpu_eip) += 4;
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RE_ENTRANT_CHECK_ON;
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addr->offset = address;
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return (void __user *)address;
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} else {
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address = *cpu_reg_ptr; /* Just return the contents
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of the cpu register */
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addr->offset = address;
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return (void __user *)address;
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}
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case 1:
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/* 8 bit signed displacement */
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(1);
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FPU_get_user(address, (signed char __user *)(*fpu_eip));
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RE_ENTRANT_CHECK_ON;
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(*fpu_eip)++;
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break;
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case 2:
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/* 32 bit displacement */
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(4);
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FPU_get_user(address, (long __user *)(*fpu_eip));
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(*fpu_eip) += 4;
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RE_ENTRANT_CHECK_ON;
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break;
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case 3:
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/* Not legal for the FPU */
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EXCEPTION(EX_Invalid);
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}
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address += *cpu_reg_ptr;
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}
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addr->offset = address;
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switch (addr_modes.default_mode) {
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case 0:
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break;
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case VM86:
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address += vm86_segment(addr_modes.override.segment, addr);
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break;
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case PM16:
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case SEG32:
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address = pm_address(FPU_modrm, addr_modes.override.segment,
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addr, address);
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break;
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default:
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EXCEPTION(EX_INTERNAL | 0x133);
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}
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return (void __user *)address;
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}
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void __user *FPU_get_address_16(u_char FPU_modrm, unsigned long *fpu_eip,
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struct address *addr, fpu_addr_modes addr_modes)
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{
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u_char mod;
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unsigned rm = FPU_modrm & 7;
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int address = 0; /* Default used for mod == 0 */
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/* Memory accessed via the cs selector is write protected
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in `non-segmented' 32 bit protected mode. */
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if (!addr_modes.default_mode && (FPU_modrm & FPU_WRITE_BIT)
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&& (addr_modes.override.segment == PREFIX_CS_)) {
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math_abort(FPU_info, SIGSEGV);
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}
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addr->selector = FPU_DS; /* Default, for 32 bit non-segmented mode. */
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mod = (FPU_modrm >> 6) & 3;
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switch (mod) {
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case 0:
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if (rm == 6) {
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/* Special case: disp16 */
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(2);
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FPU_get_user(address,
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(unsigned short __user *)(*fpu_eip));
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(*fpu_eip) += 2;
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RE_ENTRANT_CHECK_ON;
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goto add_segment;
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}
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break;
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case 1:
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/* 8 bit signed displacement */
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(1);
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FPU_get_user(address, (signed char __user *)(*fpu_eip));
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RE_ENTRANT_CHECK_ON;
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(*fpu_eip)++;
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break;
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case 2:
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/* 16 bit displacement */
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RE_ENTRANT_CHECK_OFF;
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FPU_code_access_ok(2);
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FPU_get_user(address, (unsigned short __user *)(*fpu_eip));
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(*fpu_eip) += 2;
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RE_ENTRANT_CHECK_ON;
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break;
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case 3:
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/* Not legal for the FPU */
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EXCEPTION(EX_Invalid);
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break;
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}
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switch (rm) {
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case 0:
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address += FPU_info->regs->bx + FPU_info->regs->si;
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break;
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case 1:
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address += FPU_info->regs->bx + FPU_info->regs->di;
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break;
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case 2:
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address += FPU_info->regs->bp + FPU_info->regs->si;
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if (addr_modes.override.segment == PREFIX_DEFAULT)
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addr_modes.override.segment = PREFIX_SS_;
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break;
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case 3:
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address += FPU_info->regs->bp + FPU_info->regs->di;
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if (addr_modes.override.segment == PREFIX_DEFAULT)
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addr_modes.override.segment = PREFIX_SS_;
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break;
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case 4:
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address += FPU_info->regs->si;
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break;
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case 5:
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address += FPU_info->regs->di;
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break;
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case 6:
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address += FPU_info->regs->bp;
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if (addr_modes.override.segment == PREFIX_DEFAULT)
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addr_modes.override.segment = PREFIX_SS_;
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break;
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case 7:
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address += FPU_info->regs->bx;
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break;
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}
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add_segment:
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address &= 0xffff;
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addr->offset = address;
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switch (addr_modes.default_mode) {
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case 0:
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break;
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case VM86:
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address += vm86_segment(addr_modes.override.segment, addr);
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break;
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case PM16:
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case SEG32:
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address = pm_address(FPU_modrm, addr_modes.override.segment,
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addr, address);
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break;
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default:
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EXCEPTION(EX_INTERNAL | 0x131);
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}
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return (void __user *)address;
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}
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