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linux/arch/x86/math-emu/get_address.c
Ingo Molnar 3d0d14f983 x86: lindent arch/i386/math-emu 
lindent these files:
                                       errors   lines of code   errors/KLOC
 arch/x86/math-emu/                      2236            9424         237.2
 arch/x86/math-emu/                       128            8706          14.7

no other changes. No code changed:

   text    data     bss     dec     hex filename
   5589802  612739 3833856 10036397         9924ad vmlinux.before
   5589802  612739 3833856 10036397         9924ad vmlinux.after

the intent of this patch is to ease the automated tracking of kernel
code quality - it's just much easier for us to maintain it if every file
in arch/x86 is supposed to be clean.

NOTE: it is a known problem of lindent that it causes some style damage
of its own, but it's a safe tool (well, except for the gcc array range
initializers extension), so we did the bulk of the changes via lindent,
and did the manual fixups in a followup patch.

the resulting math-emu code has been tested by Thomas Gleixner on a real
386 DX CPU as well, and it works fine.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:11 +01:00

404 lines
10 KiB
C
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/*---------------------------------------------------------------------------+
| get_address.c |
| |
| Get the effective address from an FPU instruction. |
| |
| Copyright (C) 1992,1993,1994,1997 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
| Australia. E-mail billm@suburbia.net |
| |
| |
+---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------+
| Note: |
| The file contains code which accesses user memory. |
| Emulator static data may change when user memory is accessed, due to |
| other processes using the emulator while swapping is in progress. |
+---------------------------------------------------------------------------*/
#include <linux/stddef.h>
#include <asm/uaccess.h>
#include <asm/desc.h>
#include "fpu_system.h"
#include "exception.h"
#include "fpu_emu.h"
#define FPU_WRITE_BIT 0x10
static int reg_offset[] = {
offsetof(struct info, ___eax),
offsetof(struct info, ___ecx),
offsetof(struct info, ___edx),
offsetof(struct info, ___ebx),
offsetof(struct info, ___esp),
offsetof(struct info, ___ebp),
offsetof(struct info, ___esi),
offsetof(struct info, ___edi)
};
#define REG_(x) (*(long *)(reg_offset[(x)]+(u_char *) FPU_info))
static int reg_offset_vm86[] = {
offsetof(struct info, ___cs),
offsetof(struct info, ___vm86_ds),
offsetof(struct info, ___vm86_es),
offsetof(struct info, ___vm86_fs),
offsetof(struct info, ___vm86_gs),
offsetof(struct info, ___ss),
offsetof(struct info, ___vm86_ds)
};
#define VM86_REG_(x) (*(unsigned short *) \
(reg_offset_vm86[((unsigned)x)]+(u_char *) FPU_info))
/* This dummy, gs is not saved on the stack. */
#define ___GS ___ds
static int reg_offset_pm[] = {
offsetof(struct info, ___cs),
offsetof(struct info, ___ds),
offsetof(struct info, ___es),
offsetof(struct info, ___fs),
offsetof(struct info, ___GS),
offsetof(struct info, ___ss),
offsetof(struct info, ___ds)
};
#define PM_REG_(x) (*(unsigned short *) \
(reg_offset_pm[((unsigned)x)]+(u_char *) FPU_info))
/* Decode the SIB byte. This function assumes mod != 0 */
static int sib(int mod, unsigned long *fpu_eip)
{
u_char ss, index, base;
long offset;
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(1);
FPU_get_user(base, (u_char __user *) (*fpu_eip)); /* The SIB byte */
RE_ENTRANT_CHECK_ON;
(*fpu_eip)++;
ss = base >> 6;
index = (base >> 3) & 7;
base &= 7;
if ((mod == 0) && (base == 5))
offset = 0; /* No base register */
else
offset = REG_(base);
if (index == 4) {
/* No index register */
/* A non-zero ss is illegal */
if (ss)
EXCEPTION(EX_Invalid);
} else {
offset += (REG_(index)) << ss;
}
if (mod == 1) {
/* 8 bit signed displacement */
long displacement;
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(1);
FPU_get_user(displacement, (signed char __user *)(*fpu_eip));
offset += displacement;
RE_ENTRANT_CHECK_ON;
(*fpu_eip)++;
} else if (mod == 2 || base == 5) { /* The second condition also has mod==0 */
/* 32 bit displacement */
long displacement;
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(4);
FPU_get_user(displacement, (long __user *)(*fpu_eip));
offset += displacement;
RE_ENTRANT_CHECK_ON;
(*fpu_eip) += 4;
}
return offset;
}
static unsigned long vm86_segment(u_char segment, struct address *addr)
{
segment--;
#ifdef PARANOID
if (segment > PREFIX_SS_) {
EXCEPTION(EX_INTERNAL | 0x130);
math_abort(FPU_info, SIGSEGV);
}
#endif /* PARANOID */
addr->selector = VM86_REG_(segment);
return (unsigned long)VM86_REG_(segment) << 4;
}
/* This should work for 16 and 32 bit protected mode. */
static long pm_address(u_char FPU_modrm, u_char segment,
struct address *addr, long offset)
{
struct desc_struct descriptor;
unsigned long base_address, limit, address, seg_top;
segment--;
#ifdef PARANOID
/* segment is unsigned, so this also detects if segment was 0: */
if (segment > PREFIX_SS_) {
EXCEPTION(EX_INTERNAL | 0x132);
math_abort(FPU_info, SIGSEGV);
}
#endif /* PARANOID */
switch (segment) {
/* gs isn't used by the kernel, so it still has its
user-space value. */
case PREFIX_GS_ - 1:
/* N.B. - movl %seg, mem is a 2 byte write regardless of prefix */
savesegment(gs, addr->selector);
break;
default:
addr->selector = PM_REG_(segment);
}
descriptor = LDT_DESCRIPTOR(PM_REG_(segment));
base_address = SEG_BASE_ADDR(descriptor);
address = base_address + offset;
limit = base_address
+ (SEG_LIMIT(descriptor) + 1) * SEG_GRANULARITY(descriptor) - 1;
if (limit < base_address)
limit = 0xffffffff;
if (SEG_EXPAND_DOWN(descriptor)) {
if (SEG_G_BIT(descriptor))
seg_top = 0xffffffff;
else {
seg_top = base_address + (1 << 20);
if (seg_top < base_address)
seg_top = 0xffffffff;
}
access_limit =
(address <= limit) || (address >= seg_top) ? 0 :
((seg_top - address) >= 255 ? 255 : seg_top - address);
} else {
access_limit =
(address > limit) || (address < base_address) ? 0 :
((limit - address) >= 254 ? 255 : limit - address + 1);
}
if (SEG_EXECUTE_ONLY(descriptor) ||
(!SEG_WRITE_PERM(descriptor) && (FPU_modrm & FPU_WRITE_BIT))) {
access_limit = 0;
}
return address;
}
/*
MOD R/M byte: MOD == 3 has a special use for the FPU
SIB byte used iff R/M = 100b
7 6 5 4 3 2 1 0
..... ......... .........
MOD OPCODE(2) R/M
SIB byte
7 6 5 4 3 2 1 0
..... ......... .........
SS INDEX BASE
*/
void __user *FPU_get_address(u_char FPU_modrm, unsigned long *fpu_eip,
struct address *addr, fpu_addr_modes addr_modes)
{
u_char mod;
unsigned rm = FPU_modrm & 7;
long *cpu_reg_ptr;
int address = 0; /* Initialized just to stop compiler warnings. */
/* Memory accessed via the cs selector is write protected
in `non-segmented' 32 bit protected mode. */
if (!addr_modes.default_mode && (FPU_modrm & FPU_WRITE_BIT)
&& (addr_modes.override.segment == PREFIX_CS_)) {
math_abort(FPU_info, SIGSEGV);
}
addr->selector = FPU_DS; /* Default, for 32 bit non-segmented mode. */
mod = (FPU_modrm >> 6) & 3;
if (rm == 4 && mod != 3) {
address = sib(mod, fpu_eip);
} else {
cpu_reg_ptr = &REG_(rm);
switch (mod) {
case 0:
if (rm == 5) {
/* Special case: disp32 */
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(4);
FPU_get_user(address,
(unsigned long __user
*)(*fpu_eip));
(*fpu_eip) += 4;
RE_ENTRANT_CHECK_ON;
addr->offset = address;
return (void __user *)address;
} else {
address = *cpu_reg_ptr; /* Just return the contents
of the cpu register */
addr->offset = address;
return (void __user *)address;
}
case 1:
/* 8 bit signed displacement */
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(1);
FPU_get_user(address, (signed char __user *)(*fpu_eip));
RE_ENTRANT_CHECK_ON;
(*fpu_eip)++;
break;
case 2:
/* 32 bit displacement */
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(4);
FPU_get_user(address, (long __user *)(*fpu_eip));
(*fpu_eip) += 4;
RE_ENTRANT_CHECK_ON;
break;
case 3:
/* Not legal for the FPU */
EXCEPTION(EX_Invalid);
}
address += *cpu_reg_ptr;
}
addr->offset = address;
switch (addr_modes.default_mode) {
case 0:
break;
case VM86:
address += vm86_segment(addr_modes.override.segment, addr);
break;
case PM16:
case SEG32:
address = pm_address(FPU_modrm, addr_modes.override.segment,
addr, address);
break;
default:
EXCEPTION(EX_INTERNAL | 0x133);
}
return (void __user *)address;
}
void __user *FPU_get_address_16(u_char FPU_modrm, unsigned long *fpu_eip,
struct address *addr, fpu_addr_modes addr_modes)
{
u_char mod;
unsigned rm = FPU_modrm & 7;
int address = 0; /* Default used for mod == 0 */
/* Memory accessed via the cs selector is write protected
in `non-segmented' 32 bit protected mode. */
if (!addr_modes.default_mode && (FPU_modrm & FPU_WRITE_BIT)
&& (addr_modes.override.segment == PREFIX_CS_)) {
math_abort(FPU_info, SIGSEGV);
}
addr->selector = FPU_DS; /* Default, for 32 bit non-segmented mode. */
mod = (FPU_modrm >> 6) & 3;
switch (mod) {
case 0:
if (rm == 6) {
/* Special case: disp16 */
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(2);
FPU_get_user(address,
(unsigned short __user *)(*fpu_eip));
(*fpu_eip) += 2;
RE_ENTRANT_CHECK_ON;
goto add_segment;
}
break;
case 1:
/* 8 bit signed displacement */
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(1);
FPU_get_user(address, (signed char __user *)(*fpu_eip));
RE_ENTRANT_CHECK_ON;
(*fpu_eip)++;
break;
case 2:
/* 16 bit displacement */
RE_ENTRANT_CHECK_OFF;
FPU_code_access_ok(2);
FPU_get_user(address, (unsigned short __user *)(*fpu_eip));
(*fpu_eip) += 2;
RE_ENTRANT_CHECK_ON;
break;
case 3:
/* Not legal for the FPU */
EXCEPTION(EX_Invalid);
break;
}
switch (rm) {
case 0:
address += FPU_info->___ebx + FPU_info->___esi;
break;
case 1:
address += FPU_info->___ebx + FPU_info->___edi;
break;
case 2:
address += FPU_info->___ebp + FPU_info->___esi;
if (addr_modes.override.segment == PREFIX_DEFAULT)
addr_modes.override.segment = PREFIX_SS_;
break;
case 3:
address += FPU_info->___ebp + FPU_info->___edi;
if (addr_modes.override.segment == PREFIX_DEFAULT)
addr_modes.override.segment = PREFIX_SS_;
break;
case 4:
address += FPU_info->___esi;
break;
case 5:
address += FPU_info->___edi;
break;
case 6:
address += FPU_info->___ebp;
if (addr_modes.override.segment == PREFIX_DEFAULT)
addr_modes.override.segment = PREFIX_SS_;
break;
case 7:
address += FPU_info->___ebx;
break;
}
add_segment:
address &= 0xffff;
addr->offset = address;
switch (addr_modes.default_mode) {
case 0:
break;
case VM86:
address += vm86_segment(addr_modes.override.segment, addr);
break;
case PM16:
case SEG32:
address = pm_address(FPU_modrm, addr_modes.override.segment,
addr, address);
break;
default:
EXCEPTION(EX_INTERNAL | 0x131);
}
return (void __user *)address;
}
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