xref: /freebsd/sys/amd64/ia32/ia32_reg.c (revision fdafd315ad0d0f28a11b9fb4476a9ab059c62b92)

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 Peter Wemm
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/elf.h>
#include <sys/exec.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mman.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/procfs.h>
#include <sys/reg.h>
#include <sys/resourcevar.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/vnode.h>

#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>

#include <compat/freebsd32/freebsd32_util.h>
#include <compat/freebsd32/freebsd32_proto.h>
#include <machine/fpu.h>
#include <machine/psl.h>
#include <machine/segments.h>
#include <machine/specialreg.h>
#include <machine/frame.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/cpufunc.h>

int
fill_regs32(struct thread *td, struct reg32 *regs)
{
	struct trapframe *tp;

	tp = td->td_frame;
	if (tp->tf_flags & TF_HASSEGS) {
		regs->r_gs = tp->tf_gs;
		regs->r_fs = tp->tf_fs;
		regs->r_es = tp->tf_es;
		regs->r_ds = tp->tf_ds;
	} else {
		regs->r_gs = _ugssel;
		regs->r_fs = _ufssel;
		regs->r_es = _udatasel;
		regs->r_ds = _udatasel;
	}
	regs->r_edi = tp->tf_rdi;
	regs->r_esi = tp->tf_rsi;
	regs->r_ebp = tp->tf_rbp;
	regs->r_ebx = tp->tf_rbx;
	regs->r_edx = tp->tf_rdx;
	regs->r_ecx = tp->tf_rcx;
	regs->r_eax = tp->tf_rax;
	regs->r_eip = tp->tf_rip;
	regs->r_cs = tp->tf_cs;
	regs->r_eflags = tp->tf_rflags;
	regs->r_esp = tp->tf_rsp;
	regs->r_ss = tp->tf_ss;
	regs->r_err = 0;
	regs->r_trapno = 0;
	return (0);
}

int
set_regs32(struct thread *td, struct reg32 *regs)
{
	struct trapframe *tp;

	tp = td->td_frame;
	if (!EFL_SECURE(regs->r_eflags, tp->tf_rflags) || !CS_SECURE(regs->r_cs))
		return (EINVAL);
	tp->tf_gs = regs->r_gs;
	tp->tf_fs = regs->r_fs;
	tp->tf_es = regs->r_es;
	tp->tf_ds = regs->r_ds;
	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
	tp->tf_flags = TF_HASSEGS;
	tp->tf_rdi = regs->r_edi;
	tp->tf_rsi = regs->r_esi;
	tp->tf_rbp = regs->r_ebp;
	tp->tf_rbx = regs->r_ebx;
	tp->tf_rdx = regs->r_edx;
	tp->tf_rcx = regs->r_ecx;
	tp->tf_rax = regs->r_eax;
	tp->tf_rip = regs->r_eip;
	tp->tf_cs = regs->r_cs;
	tp->tf_rflags = regs->r_eflags;
	tp->tf_rsp = regs->r_esp;
	tp->tf_ss = regs->r_ss;
	return (0);
}

int
fill_fpregs32(struct thread *td, struct fpreg32 *regs)
{
	struct savefpu *sv_fpu;
	struct save87 *sv_87;
	struct env87 *penv_87;
	struct envxmm *penv_xmm;
	struct fpacc87 *fx_reg;
	int i, st;
	uint64_t mantissa;
	uint16_t tw, exp;
	uint8_t ab_tw;

	bzero(regs, sizeof(*regs));
	sv_87 = (struct save87 *)regs;
	penv_87 = &sv_87->sv_env;
	fpugetregs(td);
	sv_fpu = get_pcb_user_save_td(td);
	penv_xmm = &sv_fpu->sv_env;

	/* FPU control/status */
	penv_87->en_cw = penv_xmm->en_cw;
	penv_87->en_sw = penv_xmm->en_sw;

	/*
	 * XXX for en_fip/fcs/foo/fos, check if the fxsave format
	 * uses the old-style layout for 32 bit user apps.  If so,
	 * read the ip and operand segment registers from there.
	 * For now, use the process's %cs/%ds.
	 */
	penv_87->en_fip = penv_xmm->en_rip;
	penv_87->en_fcs = td->td_frame->tf_cs;
	penv_87->en_opcode = penv_xmm->en_opcode;
	penv_87->en_foo = penv_xmm->en_rdp;
	/* Entry into the kernel always sets TF_HASSEGS */
	penv_87->en_fos = td->td_frame->tf_ds;

	/*
	 * FPU registers and tags.
	 * For ST(i), i = fpu_reg - top; we start with fpu_reg=7.
	 */
	st = 7 - ((penv_xmm->en_sw >> 11) & 7);
	ab_tw = penv_xmm->en_tw;
	tw = 0;
	for (i = 0x80; i != 0; i >>= 1) {
		sv_87->sv_ac[st] = sv_fpu->sv_fp[st].fp_acc;
		tw <<= 2;
		if ((ab_tw & i) != 0) {
			/* Non-empty - we need to check ST(i) */
			fx_reg = &sv_fpu->sv_fp[st].fp_acc;
			/* The first 64 bits contain the mantissa. */
			mantissa = *((uint64_t *)fx_reg->fp_bytes);
			/*
			 * The final 16 bits contain the sign bit and the exponent.
			 * Mask the sign bit since it is of no consequence to these
			 * tests.
			 */
			exp = *((uint16_t *)&fx_reg->fp_bytes[8]) & 0x7fff;
			if (exp == 0) {
				if (mantissa == 0)
					tw |= 1; /* Zero */
				else
					tw |= 2; /* Denormal */
			} else if (exp == 0x7fff)
				tw |= 2; /* Infinity or NaN */
		} else
			tw |= 3; /* Empty */
		st = (st - 1) & 7;
	}
	penv_87->en_tw = tw;

	return (0);
}

int
set_fpregs32(struct thread *td, struct fpreg32 *regs)
{
	struct save87 *sv_87 = (struct save87 *)regs;
	struct env87 *penv_87 = &sv_87->sv_env;
	struct savefpu *sv_fpu = get_pcb_user_save_td(td);
	struct envxmm *penv_xmm = &sv_fpu->sv_env;
	int i;

	/* FPU control/status */
	penv_xmm->en_cw = penv_87->en_cw;
	penv_xmm->en_sw = penv_87->en_sw;
	penv_xmm->en_rip = penv_87->en_fip;
	/* penv_87->en_fcs and en_fos ignored, see above */
	penv_xmm->en_opcode = penv_87->en_opcode;
	penv_xmm->en_rdp = penv_87->en_foo;

	/* FPU registers and tags */
	penv_xmm->en_tw = 0;
	for (i = 0; i < 8; ++i) {
		sv_fpu->sv_fp[i].fp_acc = sv_87->sv_ac[i];
		if ((penv_87->en_tw & (3 << i * 2)) != (3 << i * 2))
			penv_xmm->en_tw |= 1 << i;
	}

	for (i = 8; i < 16; ++i)
		bzero(&sv_fpu->sv_fp[i].fp_acc, sizeof(sv_fpu->sv_fp[i].fp_acc));
	fpuuserinited(td);

	return (0);
}

int
fill_dbregs32(struct thread *td, struct dbreg32 *regs)
{
	struct dbreg dr;
	int err, i;

	err = fill_dbregs(td, &dr);
	for (i = 0; i < 8; i++)
		regs->dr[i] = dr.dr[i];
	return (err);
}

int
set_dbregs32(struct thread *td, struct dbreg32 *regs)
{
	struct dbreg dr;
	int i;

	for (i = 0; i < 8; i++)
		dr.dr[i] = regs->dr[i];
	for (i = 8; i < 16; i++)
		dr.dr[i] = 0;
	return (set_dbregs(td, &dr));
}

static bool
get_i386_segbases(struct regset *rs, struct thread *td, void *buf,
    size_t *sizep)
{
	struct segbasereg32 *reg;
	struct pcb *pcb;

	if (buf != NULL) {
		KASSERT(*sizep == sizeof(*reg), ("%s: invalid size", __func__));
		reg = buf;

		pcb = td->td_pcb;
		if (td == curthread)
			update_pcb_bases(pcb);
		reg->r_fsbase = pcb->pcb_fsbase;
		reg->r_gsbase = pcb->pcb_gsbase;
	}
	*sizep = sizeof(*reg);
	return (true);
}

static bool
set_i386_segbases(struct regset *rs, struct thread *td, void *buf,
    size_t size)
{
	struct segbasereg32 *reg;
	struct pcb *pcb;

	KASSERT(size == sizeof(*reg), ("%s: invalid size", __func__));
	reg = buf;

	pcb = td->td_pcb;
	set_pcb_flags(pcb, PCB_FULL_IRET);
	pcb->pcb_fsbase = reg->r_fsbase;
	td->td_frame->tf_fs = _ufssel;
	pcb->pcb_gsbase = reg->r_gsbase;
	td->td_frame->tf_gs = _ugssel;

	return (true);
}

static struct regset regset_i386_segbases = {
	.note = NT_X86_SEGBASES,
	.size = sizeof(struct segbasereg),
	.get = get_i386_segbases,
	.set = set_i386_segbases,
};
ELF32_REGSET(regset_i386_segbases);