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/* SPDX-License-Identifier: GPL-2.0-or-later */
/******************************************************************************
* blk.c - helper for x86_emulate.c
*
* Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
*/
#include "private.h"
#if !defined(X86EMUL_NO_FPU) || !defined(X86EMUL_NO_MMX) || \
!defined(X86EMUL_NO_SIMD)
# ifdef __XEN__
# include <asm/xstate.h>
# define FXSAVE_AREA current->arch.fpu_ctxt
# else
# define FXSAVE_AREA get_fpu_save_area()
# endif
#endif
int x86_emul_blk(
void *ptr,
void *data,
unsigned int bytes,
uint32_t *eflags,
struct x86_emulate_state *s,
struct x86_emulate_ctxt *ctxt)
{
int rc = X86EMUL_OKAY;
switch ( s->blk )
{
bool zf;
#ifndef X86EMUL_NO_FPU
struct {
struct x87_env32 env;
struct {
uint8_t bytes[10];
} freg[8];
} fpstate;
#endif
/*
* Throughout this switch(), memory clobbers are used to compensate
* that other operands may not properly express the (full) memory
* ranges covered.
*/
case blk_enqcmd:
ASSERT(bytes == 64);
if ( ((unsigned long)ptr & 0x3f) )
{
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
}
*eflags &= ~EFLAGS_MASK;
#ifdef HAVE_AS_ENQCMD
asm ( "enqcmds (%[src]), %[dst]" ASM_FLAG_OUT(, "; setz %[zf]")
: [zf] ASM_FLAG_OUT("=@ccz", "=qm") (zf)
: [src] "r" (data), [dst] "r" (ptr) : "memory" );
#else
/* enqcmds (%rsi), %rdi */
asm ( ".byte 0xf3, 0x0f, 0x38, 0xf8, 0x3e"
ASM_FLAG_OUT(, "; setz %[zf]")
: [zf] ASM_FLAG_OUT("=@ccz", "=qm") (zf)
: "S" (data), "D" (ptr) : "memory" );
#endif
if ( zf )
*eflags |= X86_EFLAGS_ZF;
break;
#ifndef X86EMUL_NO_FPU
case blk_fld:
ASSERT(!data);
/* s->rex_prefix carries CR0.PE && !EFLAGS.VM setting */
switch ( bytes )
{
case sizeof(fpstate.env): /* 32-bit FLDENV */
case sizeof(fpstate): /* 32-bit FRSTOR */
memcpy(&fpstate.env, ptr, sizeof(fpstate.env));
if ( !s->rex_prefix )
{
/* Convert 32-bit real/vm86 to 32-bit prot format. */
unsigned int fip = fpstate.env.mode.real.fip_lo +
(fpstate.env.mode.real.fip_hi << 16);
unsigned int fdp = fpstate.env.mode.real.fdp_lo +
(fpstate.env.mode.real.fdp_hi << 16);
unsigned int fop = fpstate.env.mode.real.fop;
fpstate.env.mode.prot.fip = fip & 0xf;
fpstate.env.mode.prot.fcs = fip >> 4;
fpstate.env.mode.prot.fop = fop;
fpstate.env.mode.prot.fdp = fdp & 0xf;
fpstate.env.mode.prot.fds = fdp >> 4;
}
if ( bytes == sizeof(fpstate.env) )
ptr = NULL;
else
ptr += sizeof(fpstate.env);
break;
case sizeof(struct x87_env16): /* 16-bit FLDENV */
case sizeof(struct x87_env16) + sizeof(fpstate.freg): /* 16-bit FRSTOR */
{
const struct x87_env16 *env = ptr;
fpstate.env.fcw = env->fcw;
fpstate.env.fsw = env->fsw;
fpstate.env.ftw = env->ftw;
if ( s->rex_prefix )
{
/* Convert 16-bit prot to 32-bit prot format. */
fpstate.env.mode.prot.fip = env->mode.prot.fip;
fpstate.env.mode.prot.fcs = env->mode.prot.fcs;
fpstate.env.mode.prot.fdp = env->mode.prot.fdp;
fpstate.env.mode.prot.fds = env->mode.prot.fds;
fpstate.env.mode.prot.fop = 0; /* unknown */
}
else
{
/* Convert 16-bit real/vm86 to 32-bit prot format. */
unsigned int fip = env->mode.real.fip_lo +
(env->mode.real.fip_hi << 16);
unsigned int fdp = env->mode.real.fdp_lo +
(env->mode.real.fdp_hi << 16);
unsigned int fop = env->mode.real.fop;
fpstate.env.mode.prot.fip = fip & 0xf;
fpstate.env.mode.prot.fcs = fip >> 4;
fpstate.env.mode.prot.fop = fop;
fpstate.env.mode.prot.fdp = fdp & 0xf;
fpstate.env.mode.prot.fds = fdp >> 4;
}
if ( bytes == sizeof(*env) )
ptr = NULL;
else
ptr += sizeof(*env);
break;
}
default:
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
}
if ( ptr )
{
memcpy(fpstate.freg, ptr, sizeof(fpstate.freg));
asm volatile ( "frstor %0" :: "m" (fpstate) );
}
else
asm volatile ( "fldenv %0" :: "m" (fpstate.env) );
break;
case blk_fst:
ASSERT(!data);
/* Don't chance consuming uninitialized data. */
memset(&fpstate, 0, sizeof(fpstate));
if ( bytes > sizeof(fpstate.env) )
asm ( "fnsave %0" : "+m" (fpstate) );
else
asm ( "fnstenv %0" : "+m" (fpstate.env) );
/* s->rex_prefix carries CR0.PE && !EFLAGS.VM setting */
switch ( bytes )
{
case sizeof(fpstate.env): /* 32-bit FNSTENV */
case sizeof(fpstate): /* 32-bit FNSAVE */
if ( !s->rex_prefix )
{
/* Convert 32-bit prot to 32-bit real/vm86 format. */
unsigned int fip = fpstate.env.mode.prot.fip +
(fpstate.env.mode.prot.fcs << 4);
unsigned int fdp = fpstate.env.mode.prot.fdp +
(fpstate.env.mode.prot.fds << 4);
unsigned int fop = fpstate.env.mode.prot.fop;
memset(&fpstate.env.mode, 0, sizeof(fpstate.env.mode));
fpstate.env.mode.real.fip_lo = fip;
fpstate.env.mode.real.fip_hi = fip >> 16;
fpstate.env.mode.real.fop = fop;
fpstate.env.mode.real.fdp_lo = fdp;
fpstate.env.mode.real.fdp_hi = fdp >> 16;
}
memcpy(ptr, &fpstate.env, sizeof(fpstate.env));
if ( bytes == sizeof(fpstate.env) )
ptr = NULL;
else
ptr += sizeof(fpstate.env);
break;
case sizeof(struct x87_env16): /* 16-bit FNSTENV */
case sizeof(struct x87_env16) + sizeof(fpstate.freg): /* 16-bit FNSAVE */
if ( s->rex_prefix )
{
/* Convert 32-bit prot to 16-bit prot format. */
struct x87_env16 *env = ptr;
env->fcw = fpstate.env.fcw;
env->fsw = fpstate.env.fsw;
env->ftw = fpstate.env.ftw;
env->mode.prot.fip = fpstate.env.mode.prot.fip;
env->mode.prot.fcs = fpstate.env.mode.prot.fcs;
env->mode.prot.fdp = fpstate.env.mode.prot.fdp;
env->mode.prot.fds = fpstate.env.mode.prot.fds;
}
else
{
/* Convert 32-bit prot to 16-bit real/vm86 format. */
unsigned int fip = fpstate.env.mode.prot.fip +
(fpstate.env.mode.prot.fcs << 4);
unsigned int fdp = fpstate.env.mode.prot.fdp +
(fpstate.env.mode.prot.fds << 4);
struct x87_env16 env = {
.fcw = fpstate.env.fcw,
.fsw = fpstate.env.fsw,
.ftw = fpstate.env.ftw,
.mode.real.fip_lo = fip,
.mode.real.fip_hi = fip >> 16,
.mode.real.fop = fpstate.env.mode.prot.fop,
.mode.real.fdp_lo = fdp,
.mode.real.fdp_hi = fdp >> 16
};
memcpy(ptr, &env, sizeof(env));
}
if ( bytes == sizeof(struct x87_env16) )
ptr = NULL;
else
ptr += sizeof(struct x87_env16);
break;
default:
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
}
if ( ptr )
memcpy(ptr, fpstate.freg, sizeof(fpstate.freg));
break;
#endif /* X86EMUL_NO_FPU */
#if !defined(X86EMUL_NO_FPU) || !defined(X86EMUL_NO_MMX) || \
!defined(X86EMUL_NO_SIMD)
case blk_fxrstor:
{
struct x86_fxsr *fxsr = FXSAVE_AREA;
ASSERT(!data);
ASSERT(bytes == sizeof(*fxsr));
ASSERT(s->op_bytes <= bytes);
if ( s->op_bytes < sizeof(*fxsr) )
{
if ( s->rex_prefix & REX_W )
{
/*
* The only way to force fxsaveq on a wide range of gas
* versions. On older versions the rex64 prefix works only if
* we force an addressing mode that doesn't require extended
* registers.
*/
asm volatile ( ".byte 0x48; fxsave (%1)"
: "=m" (*fxsr) : "R" (fxsr) );
}
else
asm volatile ( "fxsave %0" : "=m" (*fxsr) );
}
/*
* Don't chance the reserved or available ranges to contain any
* data FXRSTOR may actually consume in some way: Copy only the
* defined portion, and zero the rest.
*/
memcpy(fxsr, ptr, min(s->op_bytes,
(unsigned int)offsetof(struct x86_fxsr, rsvd)));
memset(fxsr->rsvd, 0, sizeof(*fxsr) - offsetof(struct x86_fxsr, rsvd));
generate_exception_if(fxsr->mxcsr & ~mxcsr_mask, X86_EXC_GP, 0);
if ( s->rex_prefix & REX_W )
{
/* See above for why operand/constraints are this way. */
asm volatile ( ".byte 0x48; fxrstor (%1)"
:: "m" (*fxsr), "R" (fxsr) );
}
else
asm volatile ( "fxrstor %0" :: "m" (*fxsr) );
break;
}
case blk_fxsave:
{
struct x86_fxsr *fxsr = FXSAVE_AREA;
ASSERT(!data);
ASSERT(bytes == sizeof(*fxsr));
ASSERT(s->op_bytes <= bytes);
if ( s->op_bytes < sizeof(*fxsr) )
/* Don't chance consuming uninitialized data. */
memset(fxsr, 0, s->op_bytes);
else
fxsr = ptr;
if ( s->rex_prefix & REX_W )
{
/* See above for why operand/constraints are this way. */
asm volatile ( ".byte 0x48; fxsave (%1)"
: "=m" (*fxsr) : "R" (fxsr) );
}
else
asm volatile ( "fxsave %0" : "=m" (*fxsr) );
if ( fxsr != ptr ) /* i.e. s->op_bytes < sizeof(*fxsr) */
memcpy(ptr, fxsr, s->op_bytes);
break;
}
#endif /* X86EMUL_NO_{FPU,MMX,SIMD} */
case blk_movdir:
switch ( bytes )
{
#ifdef __x86_64__
case sizeof(uint32_t):
# ifdef HAVE_AS_MOVDIR
asm ( "movdiri %0, (%1)"
:: "r" (*(uint32_t *)data), "r" (ptr) : "memory" );
# else
/* movdiri %esi, (%rdi) */
asm ( ".byte 0x0f, 0x38, 0xf9, 0x37"
:: "S" (*(uint32_t *)data), "D" (ptr) : "memory" );
# endif
break;
#endif
case sizeof(unsigned long):
#ifdef HAVE_AS_MOVDIR
asm ( "movdiri %0, (%1)"
:: "r" (*(unsigned long *)data), "r" (ptr) : "memory" );
#else
/* movdiri %rsi, (%rdi) */
asm ( ".byte 0x48, 0x0f, 0x38, 0xf9, 0x37"
:: "S" (*(unsigned long *)data), "D" (ptr) : "memory" );
#endif
break;
case 64:
if ( ((unsigned long)ptr & 0x3f) )
{
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
}
#ifdef HAVE_AS_MOVDIR
asm ( "movdir64b (%0), %1" :: "r" (data), "r" (ptr) : "memory" );
#else
/* movdir64b (%rsi), %rdi */
asm ( ".byte 0x66, 0x0f, 0x38, 0xf8, 0x3e"
:: "S" (data), "D" (ptr) : "memory" );
#endif
break;
default:
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
}
break;
default:
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
}
done: __maybe_unused;
return rc;
}
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