xref: /src/sys/arch/arm/include/asm.h

/*	$NetBSD: asm.h,v 1.35.2.1 2025/08/02 05:55:28 perseant Exp $	*/

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * 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.
 *
 *	from: @(#)asm.h	5.5 (Berkeley) 5/7/91
 */

#ifndef _ARM_ASM_H_
#define _ARM_ASM_H_

#include <arm/cdefs.h>
#if defined(_KERNEL_OPT)
#include "opt_cpuoptions.h"
#endif

#ifdef __thumb__
#define THUMB_INSN(n)	n
#define _INSN_SIZE	(2)
#else
#define THUMB_INSN(n)
#define _INSN_SIZE	(4)
#endif

#define	__BIT(n)	(1 << (n))
#define __BITS(hi,lo)	((~((~0)<<((hi)+1)))&((~0)<<(lo)))

#define __LOWEST_SET_BIT(__mask) ((((__mask) - 1) & (__mask)) ^ (__mask))
#define __SHIFTOUT(__x, __mask) (((__x) & (__mask)) / __LOWEST_SET_BIT(__mask))
#define __SHIFTIN(__x, __mask) ((__x) * __LOWEST_SET_BIT(__mask))

#define _C_LABEL(x)	x
#define	_ASM_LABEL(x)	x

#ifdef __STDC__
# define __CONCAT(x,y)	x ## y
# define __STRING(x)	#x
#else
# define __CONCAT(x,y)	x/**/y
# define __STRING(x)	"x"
#endif

#ifndef _ALIGN_TEXT
# define _ALIGN_TEXT .align 2
#endif

#ifndef _TEXT_SECTION
#define _TEXT_SECTION	.text
#endif

#ifdef __arm__

	.syntax		unified

/*
 * gas/arm uses @ as a single comment character and thus cannot be used here
 * Instead it recognised the # instead of an @ symbols in .type directives
 * We define a couple of macros so that assembly code will not be dependent
 * on one or the other.
 */
#define _ASM_TYPE_FUNCTION	%function
#define _ASM_TYPE_OBJECT	%object
#define _THUMB_ENTRY(x) \
	_TEXT_SECTION; _ALIGN_TEXT; .globl x; .type x,_ASM_TYPE_FUNCTION; \
	.thumb_func; .code 16; x:
#define _ARM_ENTRY(x) \
	_TEXT_SECTION; _ALIGN_TEXT; .globl x; .type x,_ASM_TYPE_FUNCTION; \
	.code 32; x:
#ifdef __thumb__
#define	_ENTRY(x)	_THUMB_ENTRY(x)
#else
#define	_ENTRY(x)	_ARM_ENTRY(x)
#endif
#define	_END(x)		.size x,.-x

#ifdef GPROF
# define _PROF_PROLOGUE	\
	mov ip, lr; bl __mcount
#else
# define _PROF_PROLOGUE
#endif
#endif

#ifdef __aarch64__
#define _ASM_TYPE_FUNCTION	@function
#define _ASM_TYPE_OBJECT	@object
#define _ENTRY(x) \
	_TEXT_SECTION; _ALIGN_TEXT; .globl x; .type x,_ASM_TYPE_FUNCTION; x:
#define	_END(x)		.size x,.-x

#ifdef GPROF
# define _PROF_PROLOGUE	\
	stp	x29, x30, [sp, #-16]!;	\
	mov	fp, sp;			\
	bl	__mcount; 		\
	ldp	x29, x30, [sp], #16;
#else
# define _PROF_PROLOGUE
#endif

#ifdef __PIC__
#define GOTREF(x)		:got:x
#define GOTLO12(x)		:got_lo12:x
#else
#define GOTREF(x)		x
#define GOTLO12(x)		:lo12:x
#endif
#endif

#ifdef ARMV85_BTI
#define	_BTI_PROLOGUE \
	.byte	0x5F, 0x24, 0x03, 0xD5	/* the "bti c" instruction */
#else
#define	_BTI_PROLOGUE		/* nothing */
#endif

#define	ENTRY(y)		_ENTRY(_C_LABEL(y)); _BTI_PROLOGUE ; _PROF_PROLOGUE
#define	ENTRY_NP(y)		_ENTRY(_C_LABEL(y)); _BTI_PROLOGUE
#define	ENTRY_NBTI(y)		_ENTRY(_C_LABEL(y))
#define	END(y)			_END(_C_LABEL(y))
#define	ARM_ENTRY(y)		_ARM_ENTRY(_C_LABEL(y)); _PROF_PROLOGUE
#define	ARM_ENTRY_NP(y)		_ARM_ENTRY(_C_LABEL(y))
#define	THUMB_ENTRY(y)		_THUMB_ENTRY(_C_LABEL(y)); _PROF_PROLOGUE
#define	THUMB_ENTRY_NP(y)	_THUMB_ENTRY(_C_LABEL(y))
#define	ASENTRY(y)		_ENTRY(_ASM_LABEL(y)); _PROF_PROLOGUE
#define	ASENTRY_NP(y)		_ENTRY(_ASM_LABEL(y))
#define	ASEND(y)		_END(_ASM_LABEL(y))
#define	ARM_ASENTRY(y)		_ARM_ENTRY(_ASM_LABEL(y)); _PROF_PROLOGUE
#define	ARM_ASENTRY_NP(y)	_ARM_ENTRY(_ASM_LABEL(y))
#define	THUMB_ASENTRY(y)	_THUMB_ENTRY(_ASM_LABEL(y)); _PROF_PROLOGUE
#define	THUMB_ASENTRY_NP(y)	_THUMB_ENTRY(_ASM_LABEL(y))

#define	ASMSTR		.asciz

#ifdef __PIC__
#define	REL_SYM(a, b)	((a) - (b))
#define	PLT_SYM(x)	x
#define	GOT_SYM(x)	PIC_SYM(x, GOT)
#define	GOT_GET(x,got,sym)	\
	ldr	x, sym;		\
	ldr	x, [x, got]

/*
 * Load _GLOBAL_OFFSET_TABLE_ address into register:
 *
 * 0:	GOT_INIT(rX, .Lgot)
 *	...
 *
 *      // and in the data after the function
 *	GOT_INITSYM(.Lgot, 0b)
 */
#define	GOT_INIT(Rgot, gotsym)	  \
	ldr	Rgot, gotsym	; \
	add	Rgot, Rgot, pc
#define	GOT_INITSYM(gotsym, initlabel)	\
	.align 0;		\
	gotsym:	.word _C_LABEL(_GLOBAL_OFFSET_TABLE_) - (initlabel+(1+2)*_INSN_SIZE)

#ifdef __STDC__
#define	PIC_SYM(x,y)	x(y)
#else
#define	PIC_SYM(x,y)	x/**/(/**/y/**/)
#endif

#else
#define	REL_SYM(a, b)	(a)
#define	PLT_SYM(x)	x
#define	GOT_SYM(x)	x
#define	GOT_GET(x,got,sym)	\
	ldr	x, sym;
#define	GOT_INIT(Rgot, gotsym)
#define	GOT_INITSYM(gotsym, initlabel)
#define	PIC_SYM(x,y)	x
#endif	/* __PIC__ */

/*
 * Annoyingly, gas on arm seems to generate _two_ NUL-terminated
 * strings for
 *
 *	.asciz "foo" "bar"
 *
 * instead of concatenating it into a single NUL-terminated string as
 * on other architectures.
 *
 * To work around this, we concatenate into a single NUL-terminated by:
 *
 *	.ascii "foo"
 *	.asciz "bar"
 */
#define _IDENTSTR(x)	.pushsection ".ident","MS",%progbits,1;		\
			x;						\
			.popsection

#ifdef _NETBSD_REVISIONID
#define	RCSID(_s)							\
	_IDENTSTR(.asciz _s);						\
	_IDENTSTR(.ascii "$"; .ascii "NetBSD: "; .ascii __FILE__;	\
	    .ascii " "; .ascii _NETBSD_REVISIONID; .asciz " $")
#else
#define	RCSID(_s)	_IDENTSTR(.asciz _s)
#endif

#define	WEAK_ALIAS(alias,sym)						\
	.weak alias;							\
	alias = sym

/*
 * STRONG_ALIAS: create a strong alias.
 */
#define STRONG_ALIAS(alias,sym)						\
	.globl alias;							\
	alias = sym

#ifdef __STDC__
#define	WARN_REFERENCES(sym,msg)					\
	.pushsection .gnu.warning.sym;					\
	.ascii msg;							\
	.popsection
#else
#define	WARN_REFERENCES(sym,msg)					\
	.pushsection .gnu.warning./**/sym;				\
	.ascii msg;							\
	.popsection
#endif /* __STDC__ */

#ifdef __thumb__
# define XPUSH		push
# define XPOP		pop
# define XPOPRET	pop	{pc}
#else
# define XPUSH		stmfd	sp!,
# define XPOP		ldmfd	sp!,
# ifdef _ARM_ARCH_5
#  define XPOPRET	ldmfd	sp!, {pc}
# else
#  define XPOPRET	ldmfd	sp!, {lr}; mov pc, lr
# endif
#endif

#if defined(__aarch64__)
# define RET		ret
#elif defined (_ARM_ARCH_4T)
# define RET		bx		lr
# define RETr(r)	bx		r
# if defined(__thumb__)
#  if defined(_ARM_ARCH_7)
#   define RETc(c)	it c; __CONCAT(bx,c)	lr
#  endif
# else
#  define RETc(c)	__CONCAT(bx,c)	lr
# endif
#else
# define RET		mov		pc, lr
# define RETr(r)	mov		pc, r
# define RETc(c)	__CONCAT(mov,c)	pc, lr
#endif

#ifdef _ARM_ARCH_7
#define KMODTRAMPOLINE(n)			\
_ENTRY(__wrap_ ## n)				\
	movw	ip, #:lower16:n;	\
	movt	ip, #:upper16:n;	\
	bx	ip
#elif defined(_ARM_ARCH_4T)
#define KMODTRAMPOLINE(n)	\
_ENTRY(__wrap_ ## n)		\
	ldr	ip, [pc];	\
	bx	ip;		\
	.word	n
#else
#define KMODTRAMPOLINE(n)	\
_ENTRY(__wrap_ ## n)		\
	ldr	pc, [pc, #-4];	\
	.word	n
#endif

#endif /* !_ARM_ASM_H_ */