freebsd-dev/sys/amd64/include/asmacros.h

/* -*- mode: asm -*- */
/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1993 The Regents of the University of California.
 * All rights reserved.
 *
 * Copyright (c) 2018 The FreeBSD Foundation
 * All rights reserved.
 *
 * Portions of this software were developed by
 * Konstantin Belousov <kib@FreeBSD.org> under sponsorship from
 * the FreeBSD Foundation.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * $FreeBSD$
 */

#ifndef _MACHINE_ASMACROS_H_
#define _MACHINE_ASMACROS_H_

#include <sys/cdefs.h>

/* XXX too much duplication in various asm*.h's. */

/*
 * CNAME is used to manage the relationship between symbol names in C
 * and the equivalent assembly language names.  CNAME is given a name as
 * it would be used in a C program.  It expands to the equivalent assembly
 * language name.
 */
#define CNAME(csym)		csym

#define ALIGN_DATA	.p2align 3	/* 8 byte alignment, zero filled */
#ifdef GPROF
#define ALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
#else
#define ALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
#endif
#define SUPERALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */

#define GEN_ENTRY(name)		ALIGN_TEXT; .globl CNAME(name); \
				.type CNAME(name),@function; CNAME(name):
#define NON_GPROF_ENTRY(name)	GEN_ENTRY(name)
#define NON_GPROF_RET		.byte 0xc3	/* opcode for `ret' */

#define	END(name)		.size name, . - name

#ifdef GPROF
/*
 * __mcount is like [.]mcount except that doesn't require its caller to set
 * up a frame pointer.  It must be called before pushing anything onto the
 * stack.  gcc should eventually generate code to call __mcount in most
 * cases.  This would make -pg in combination with -fomit-frame-pointer
 * useful.  gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
 * allow profiling before setting up the frame pointer, but this is
 * inadequate for good handling of special cases, e.g., -fpic works best
 * with profiling after the prologue.
 *
 * [.]mexitcount is a new function to support non-statistical profiling if an
 * accurate clock is available.  For C sources, calls to it are generated
 * by the FreeBSD extension `-mprofiler-epilogue' to gcc.  It is best to
 * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
 * but gcc currently generates calls to it at the start of the epilogue to
 * avoid problems with -fpic.
 *
 * [.]mcount and __mcount may clobber the call-used registers and %ef.
 * [.]mexitcount may clobber %ecx and %ef.
 *
 * Cross-jumping makes non-statistical profiling timing more complicated.
 * It is handled in many cases by calling [.]mexitcount before jumping.  It
 * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
 * It is handled for some fault-handling jumps by not sharing the exit
 * routine.
 *
 * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
 * the main entry point.  Note that alt entries are counted twice.  They
 * have to be counted as ordinary entries for gprof to get the call times
 * right for the ordinary entries.
 *
 * High local labels are used in macros to avoid clashes with local labels
 * in functions.
 *
 * Ordinary `ret' is used instead of a macro `RET' because there are a lot
 * of `ret's.  0xc3 is the opcode for `ret' (`#define ret ... ret' can't
 * be used because this file is sometimes preprocessed in traditional mode).
 * `ret' clobbers eflags but this doesn't matter.
 */
#define ALTENTRY(name)		GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
#define	CROSSJUMP(jtrue, label, jfalse) \
	jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
#define CROSSJUMPTARGET(label) \
	ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
#define ENTRY(name)		GEN_ENTRY(name) ; 9: ; MCOUNT
#define FAKE_MCOUNT(caller)	pushq caller ; call __mcount ; popq %rcx
#define MCOUNT			call __mcount
#define MCOUNT_LABEL(name)	GEN_ENTRY(name) ; nop ; ALIGN_TEXT
#ifdef GUPROF
#define MEXITCOUNT		call .mexitcount
#define ret			MEXITCOUNT ; NON_GPROF_RET
#else
#define MEXITCOUNT
#endif

#else /* !GPROF */
/*
 * ALTENTRY() has to align because it is before a corresponding ENTRY().
 * ENTRY() has to align to because there may be no ALTENTRY() before it.
 * If there is a previous ALTENTRY() then the alignment code for ENTRY()
 * is empty.
 */
#define ALTENTRY(name)		GEN_ENTRY(name)
#define	CROSSJUMP(jtrue, label, jfalse)	jtrue label
#define	CROSSJUMPTARGET(label)
#define ENTRY(name)		GEN_ENTRY(name)
#define FAKE_MCOUNT(caller)
#define MCOUNT
#define MCOUNT_LABEL(name)
#define MEXITCOUNT
#endif /* GPROF */

/*
 * Convenience for adding frame pointers to hand-coded ASM.  Useful for
 * DTrace, HWPMC, and KDB.
 */
#define PUSH_FRAME_POINTER	\
	pushq	%rbp ;		\
	movq	%rsp, %rbp ;
#define POP_FRAME_POINTER	\
	popq	%rbp

#ifdef LOCORE
/*
 * Access per-CPU data.
 */
#define	PCPU(member)	%gs:PC_ ## member
#define	PCPU_ADDR(member, reg)					\
	movq %gs:PC_PRVSPACE, reg ;				\
	addq $PC_ ## member, reg

/*
 * Convenience macro for declaring interrupt entry points.
 */
#define	IDTVEC(name)	ALIGN_TEXT; .globl __CONCAT(X,name); \
			.type __CONCAT(X,name),@function; __CONCAT(X,name):

	.macro	SAVE_SEGS
	movw	%fs,TF_FS(%rsp)
	movw	%gs,TF_GS(%rsp)
	movw	%es,TF_ES(%rsp)
	movw	%ds,TF_DS(%rsp)
	.endm

	.macro	MOVE_STACKS qw
	.L.offset=0
	.rept	\qw
	movq	.L.offset(%rsp),%rdx
	movq	%rdx,.L.offset(%rax)
	.L.offset=.L.offset+8
	.endr
	.endm

	.macro	PTI_UUENTRY has_err
	movq	PCPU(KCR3),%rax
	movq	%rax,%cr3
	movq	PCPU(RSP0),%rax
	subq	$PTI_SIZE - 8 * (1 - \has_err),%rax
	MOVE_STACKS	((PTI_SIZE / 8) - 1 + \has_err)
	movq	%rax,%rsp
	popq	%rdx
	popq	%rax
	.endm

	.macro	PTI_UENTRY has_err
	swapgs
	cmpq	$~0,PCPU(UCR3)
	je	1f
	pushq	%rax
	pushq	%rdx
	PTI_UUENTRY \has_err
1:
	.endm

	.macro	PTI_ENTRY name, cont, has_err=0
	ALIGN_TEXT
	.globl	X\name\()_pti
	.type	X\name\()_pti,@function
X\name\()_pti:
	/* %rax, %rdx and possibly err not yet pushed */
	testb	$SEL_RPL_MASK,PTI_CS-(2+1-\has_err)*8(%rsp)
	jz	\cont
	PTI_UENTRY \has_err
	swapgs
	jmp	\cont
	.endm

	.macro	PTI_INTRENTRY vec_name
	SUPERALIGN_TEXT
	.globl	X\vec_name\()_pti
	.type	X\vec_name\()_pti,@function
X\vec_name\()_pti:
	testb	$SEL_RPL_MASK,PTI_CS-3*8(%rsp) /* err, %rax, %rdx not pushed */
	jz	.L\vec_name\()_u
	PTI_UENTRY has_err=0
	jmp	.L\vec_name\()_u
	.endm

	.macro	INTR_PUSH_FRAME vec_name
	SUPERALIGN_TEXT
	.globl	X\vec_name
	.type	X\vec_name,@function
X\vec_name:
	testb	$SEL_RPL_MASK,PTI_CS-3*8(%rsp) /* come from kernel? */
	jz	.L\vec_name\()_u		/* Yes, dont swapgs again */
	swapgs
.L\vec_name\()_u:
	subq	$TF_RIP,%rsp	/* skip dummy tf_err and tf_trapno */
	movq	%rdi,TF_RDI(%rsp)
	movq	%rsi,TF_RSI(%rsp)
	movq	%rdx,TF_RDX(%rsp)
	movq	%rcx,TF_RCX(%rsp)
	movq	%r8,TF_R8(%rsp)
	movq	%r9,TF_R9(%rsp)
	movq	%rax,TF_RAX(%rsp)
	movq	%rbx,TF_RBX(%rsp)
	movq	%rbp,TF_RBP(%rsp)
	movq	%r10,TF_R10(%rsp)
	movq	%r11,TF_R11(%rsp)
	movq	%r12,TF_R12(%rsp)
	movq	%r13,TF_R13(%rsp)
	movq	%r14,TF_R14(%rsp)
	movq	%r15,TF_R15(%rsp)
	SAVE_SEGS
	movl	$TF_HASSEGS,TF_FLAGS(%rsp)
	pushfq
	andq	$~(PSL_D|PSL_AC),(%rsp)
	popfq
	testb	$SEL_RPL_MASK,TF_CS(%rsp)  /* come from kernel ? */
	jz	1f		/* yes, leave PCB_FULL_IRET alone */
	movq	PCPU(CURPCB),%r8
	andl	$~PCB_FULL_IRET,PCB_FLAGS(%r8)
	call	handle_ibrs_entry
1:
	.endm

	.macro	INTR_HANDLER vec_name
	.text
	PTI_INTRENTRY	\vec_name
	INTR_PUSH_FRAME	\vec_name
	.endm

	.macro	RESTORE_REGS
	movq	TF_RDI(%rsp),%rdi
	movq	TF_RSI(%rsp),%rsi
	movq	TF_RDX(%rsp),%rdx
	movq	TF_RCX(%rsp),%rcx
	movq	TF_R8(%rsp),%r8
	movq	TF_R9(%rsp),%r9
	movq	TF_RAX(%rsp),%rax
	movq	TF_RBX(%rsp),%rbx
	movq	TF_RBP(%rsp),%rbp
	movq	TF_R10(%rsp),%r10
	movq	TF_R11(%rsp),%r11
	movq	TF_R12(%rsp),%r12
	movq	TF_R13(%rsp),%r13
	movq	TF_R14(%rsp),%r14
	movq	TF_R15(%rsp),%r15
	.endm

#endif /* LOCORE */

#ifdef __STDC__
#define ELFNOTE(name, type, desctype, descdata...) \
.pushsection .note.name                 ;       \
  .align 4                              ;       \
  .long 2f - 1f         /* namesz */    ;       \
  .long 4f - 3f         /* descsz */    ;       \
  .long type                            ;       \
1:.asciz #name                          ;       \
2:.align 4                              ;       \
3:desctype descdata                     ;       \
4:.align 4                              ;       \
.popsection
#else /* !__STDC__, i.e. -traditional */
#define ELFNOTE(name, type, desctype, descdata) \
.pushsection .note.name                 ;       \
  .align 4                              ;       \
  .long 2f - 1f         /* namesz */    ;       \
  .long 4f - 3f         /* descsz */    ;       \
  .long type                            ;       \
1:.asciz "name"                         ;       \
2:.align 4                              ;       \
3:desctype descdata                     ;       \
4:.align 4                              ;       \
.popsection
#endif /* __STDC__ */

#endif /* !_MACHINE_ASMACROS_H_ */