xref: /freebsd/sys/i386/include/asmacros.h (revision 895f86f15fbf6540071feb9328c3c50ed1f027b8)
1 /*-
2  * Copyright (c) 1993 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 #ifndef _MACHINE_ASMACROS_H_
33 #define _MACHINE_ASMACROS_H_
34 
35 #include <sys/cdefs.h>
36 
37 /* XXX too much duplication in various asm*.h's. */
38 
39 /*
40  * CNAME is used to manage the relationship between symbol names in C
41  * and the equivalent assembly language names.  CNAME is given a name as
42  * it would be used in a C program.  It expands to the equivalent assembly
43  * language name.
44  */
45 #define CNAME(csym)		csym
46 
47 #define ALIGN_DATA	.p2align 2	/* 4 byte alignment, zero filled */
48 #ifdef GPROF
49 #define ALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
50 #else
51 #define ALIGN_TEXT	.p2align 2,0x90	/* 4-byte alignment, nop filled */
52 #endif
53 #define SUPERALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
54 
55 #define GEN_ENTRY(name)		ALIGN_TEXT; .globl CNAME(name); \
56 				.type CNAME(name),@function; CNAME(name):
57 #define NON_GPROF_ENTRY(name)	GEN_ENTRY(name)
58 #define NON_GPROF_RET		.byte 0xc3	/* opcode for `ret' */
59 
60 #define	END(name)		.size name, . - name
61 
62 #ifdef GPROF
63 /*
64  * __mcount is like [.]mcount except that doesn't require its caller to set
65  * up a frame pointer.  It must be called before pushing anything onto the
66  * stack.  gcc should eventually generate code to call __mcount in most
67  * cases.  This would make -pg in combination with -fomit-frame-pointer
68  * useful.  gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
69  * allow profiling before setting up the frame pointer, but this is
70  * inadequate for good handling of special cases, e.g., -fpic works best
71  * with profiling after the prologue.
72  *
73  * [.]mexitcount is a new function to support non-statistical profiling if an
74  * accurate clock is available.  For C sources, calls to it are generated
75  * by the FreeBSD extension `-mprofiler-epilogue' to gcc.  It is best to
76  * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
77  * but gcc currently generates calls to it at the start of the epilogue to
78  * avoid problems with -fpic.
79  *
80  * [.]mcount and __mcount may clobber the call-used registers and %ef.
81  * [.]mexitcount may clobber %ecx and %ef.
82  *
83  * Cross-jumping makes non-statistical profiling timing more complicated.
84  * It is handled in many cases by calling [.]mexitcount before jumping.  It
85  * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
86  * It is handled for some fault-handling jumps by not sharing the exit
87  * routine.
88  *
89  * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
90  * the main entry point.  Note that alt entries are counted twice.  They
91  * have to be counted as ordinary entries for gprof to get the call times
92  * right for the ordinary entries.
93  *
94  * High local labels are used in macros to avoid clashes with local labels
95  * in functions.
96  *
97  * Ordinary `ret' is used instead of a macro `RET' because there are a lot
98  * of `ret's.  0xc3 is the opcode for `ret' (`#define ret ... ret' can't
99  * be used because this file is sometimes preprocessed in traditional mode).
100  * `ret' clobbers eflags but this doesn't matter.
101  */
102 #define ALTENTRY(name)		GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
103 #define	CROSSJUMP(jtrue, label, jfalse) \
104 	jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
105 #define CROSSJUMPTARGET(label) \
106 	ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
107 #define ENTRY(name)		GEN_ENTRY(name) ; 9: ; MCOUNT
108 #define FAKE_MCOUNT(caller)	pushl caller ; call __mcount ; popl %ecx
109 #define MCOUNT			call __mcount
110 #define MCOUNT_LABEL(name)	GEN_ENTRY(name) ; nop ; ALIGN_TEXT
111 #ifdef GUPROF
112 #define MEXITCOUNT		call .mexitcount
113 #define ret			MEXITCOUNT ; NON_GPROF_RET
114 #else
115 #define MEXITCOUNT
116 #endif
117 
118 #else /* !GPROF */
119 /*
120  * ALTENTRY() has to align because it is before a corresponding ENTRY().
121  * ENTRY() has to align to because there may be no ALTENTRY() before it.
122  * If there is a previous ALTENTRY() then the alignment code for ENTRY()
123  * is empty.
124  */
125 #define ALTENTRY(name)		GEN_ENTRY(name)
126 #define	CROSSJUMP(jtrue, label, jfalse)	jtrue label
127 #define	CROSSJUMPTARGET(label)
128 #define ENTRY(name)		GEN_ENTRY(name)
129 #define FAKE_MCOUNT(caller)
130 #define MCOUNT
131 #define MCOUNT_LABEL(name)
132 #define MEXITCOUNT
133 #endif /* GPROF */
134 
135 #ifdef LOCORE
136 /*
137  * Convenience macro for declaring interrupt entry points.
138  */
139 #define	IDTVEC(name)	ALIGN_TEXT; .globl __CONCAT(X,name); \
140 			.type __CONCAT(X,name),@function; __CONCAT(X,name):
141 
142 /*
143  * Macros to create and destroy a trap frame.
144  */
145 #define	PUSH_FRAME							\
146 	pushl	$0 ;		/* dummy error code */			\
147 	pushl	$0 ;		/* dummy trap type */			\
148 	pushal ;		/* 8 ints */				\
149 	pushl	$0 ;		/* save data and extra segments ... */	\
150 	movw	%ds,(%esp) ;						\
151 	pushl	$0 ;							\
152 	movw	%es,(%esp) ;						\
153 	pushl	$0 ;							\
154 	movw	%fs,(%esp)
155 
156 #define	POP_FRAME							\
157 	popl	%fs ;							\
158 	popl	%es ;							\
159 	popl	%ds ;							\
160 	popal ;								\
161 	addl	$4+4,%esp
162 
163 /*
164  * Access per-CPU data.
165  */
166 #define	PCPU(member)	%fs:PC_ ## member
167 
168 #define	PCPU_ADDR(member, reg)						\
169 	movl %fs:PC_PRVSPACE, reg ;					\
170 	addl $PC_ ## member, reg
171 
172 /*
173  * Setup the kernel segment registers.
174  */
175 #define	SET_KERNEL_SREGS						\
176 	movl	$KDSEL, %eax ;	/* reload with kernel's data segment */	\
177 	movl	%eax, %ds ;						\
178 	movl	%eax, %es ;						\
179 	movl	$KPSEL, %eax ;	/* reload with per-CPU data segment */	\
180 	movl	%eax, %fs
181 
182 #endif /* LOCORE */
183 
184 #ifdef __STDC__
185 #define ELFNOTE(name, type, desctype, descdata...) \
186 .pushsection .note.name                 ;       \
187   .align 4                              ;       \
188   .long 2f - 1f         /* namesz */    ;       \
189   .long 4f - 3f         /* descsz */    ;       \
190   .long type                            ;       \
191 1:.asciz #name                          ;       \
192 2:.align 4                              ;       \
193 3:desctype descdata                     ;       \
194 4:.align 4                              ;       \
195 .popsection
196 #else /* !__STDC__, i.e. -traditional */
197 #define ELFNOTE(name, type, desctype, descdata) \
198 .pushsection .note.name                 ;       \
199   .align 4                              ;       \
200   .long 2f - 1f         /* namesz */    ;       \
201   .long 4f - 3f         /* descsz */    ;       \
202   .long type                            ;       \
203 1:.asciz "name"                         ;       \
204 2:.align 4                              ;       \
205 3:desctype descdata                     ;       \
206 4:.align 4                              ;       \
207 .popsection
208 #endif /* __STDC__ */
209 
210 #endif /* !_MACHINE_ASMACROS_H_ */
211