2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1993 The Regents of the University of California.
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8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
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19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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34 #ifndef _MACHINE_ASMACROS_H_
35 #define _MACHINE_ASMACROS_H_
37 #include <sys/cdefs.h>
39 /* XXX too much duplication in various asm*.h's. */
42 * CNAME is used to manage the relationship between symbol names in C
43 * and the equivalent assembly language names. CNAME is given a name as
44 * it would be used in a C program. It expands to the equivalent assembly
47 #define CNAME(csym) csym
49 #define ALIGN_DATA .p2align 2 /* 4 byte alignment, zero filled */
51 #define ALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */
53 #define ALIGN_TEXT .p2align 2,0x90 /* 4-byte alignment, nop filled */
55 #define SUPERALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */
57 #define GEN_ENTRY(name) ALIGN_TEXT; .globl CNAME(name); \
58 .type CNAME(name),@function; CNAME(name):
59 #define NON_GPROF_ENTRY(name) GEN_ENTRY(name)
60 #define NON_GPROF_RET .byte 0xc3 /* opcode for `ret' */
62 #define END(name) .size name, . - name
66 * __mcount is like [.]mcount except that doesn't require its caller to set
67 * up a frame pointer. It must be called before pushing anything onto the
68 * stack. gcc should eventually generate code to call __mcount in most
69 * cases. This would make -pg in combination with -fomit-frame-pointer
70 * useful. gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
71 * allow profiling before setting up the frame pointer, but this is
72 * inadequate for good handling of special cases, e.g., -fpic works best
73 * with profiling after the prologue.
75 * [.]mexitcount is a new function to support non-statistical profiling if an
76 * accurate clock is available. For C sources, calls to it are generated
77 * by the FreeBSD extension `-mprofiler-epilogue' to gcc. It is best to
78 * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
79 * but gcc currently generates calls to it at the start of the epilogue to
80 * avoid problems with -fpic.
82 * [.]mcount and __mcount may clobber the call-used registers and %ef.
83 * [.]mexitcount may clobber %ecx and %ef.
85 * Cross-jumping makes non-statistical profiling timing more complicated.
86 * It is handled in many cases by calling [.]mexitcount before jumping. It
87 * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
88 * It is handled for some fault-handling jumps by not sharing the exit
91 * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
92 * the main entry point. Note that alt entries are counted twice. They
93 * have to be counted as ordinary entries for gprof to get the call times
94 * right for the ordinary entries.
96 * High local labels are used in macros to avoid clashes with local labels
99 * Ordinary `ret' is used instead of a macro `RET' because there are a lot
100 * of `ret's. 0xc3 is the opcode for `ret' (`#define ret ... ret' can't
101 * be used because this file is sometimes preprocessed in traditional mode).
102 * `ret' clobbers eflags but this doesn't matter.
104 #define ALTENTRY(name) GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
105 #define CROSSJUMP(jtrue, label, jfalse) \
106 jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
107 #define CROSSJUMPTARGET(label) \
108 ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
109 #define ENTRY(name) GEN_ENTRY(name) ; 9: ; MCOUNT
110 #define FAKE_MCOUNT(caller) pushl caller ; call __mcount ; popl %ecx
111 #define MCOUNT call __mcount
112 #define MCOUNT_LABEL(name) GEN_ENTRY(name) ; nop ; ALIGN_TEXT
114 #define MEXITCOUNT call .mexitcount
115 #define ret MEXITCOUNT ; NON_GPROF_RET
122 * ALTENTRY() has to align because it is before a corresponding ENTRY().
123 * ENTRY() has to align to because there may be no ALTENTRY() before it.
124 * If there is a previous ALTENTRY() then the alignment code for ENTRY()
127 #define ALTENTRY(name) GEN_ENTRY(name)
128 #define CROSSJUMP(jtrue, label, jfalse) jtrue label
129 #define CROSSJUMPTARGET(label)
130 #define ENTRY(name) GEN_ENTRY(name)
131 #define FAKE_MCOUNT(caller)
133 #define MCOUNT_LABEL(name)
139 * Convenience macro for declaring interrupt entry points.
141 #define IDTVEC(name) ALIGN_TEXT; .globl __CONCAT(X,name); \
142 .type __CONCAT(X,name),@function; __CONCAT(X,name):
145 * Macros to create and destroy a trap frame.
148 pushl $0 ; /* dummy error code */ \
149 pushl $0 ; /* dummy trap type */ \
150 pushal ; /* 8 ints */ \
151 pushl $0 ; /* save data and extra segments ... */ \
159 * Access per-CPU data.
161 #define PCPU(member) %fs:PC_ ## member
163 #define PCPU_ADDR(member, reg) \
164 movl %fs:PC_PRVSPACE, reg ; \
165 addl $PC_ ## member, reg
168 * Setup the kernel segment registers.
170 #define SET_KERNEL_SREGS \
171 movl $KDSEL, %eax ; /* reload with kernel's data segment */ \
174 movl $KPSEL, %eax ; /* reload with per-CPU data segment */ \
180 #define ELFNOTE(name, type, desctype, descdata...) \
181 .pushsection .note.name ; \
183 .long 2f - 1f /* namesz */ ; \
184 .long 4f - 3f /* descsz */ ; \
188 3:desctype descdata ; \
191 #else /* !__STDC__, i.e. -traditional */
192 #define ELFNOTE(name, type, desctype, descdata) \
193 .pushsection .note.name ; \
195 .long 2f - 1f /* namesz */ ; \
196 .long 4f - 3f /* descsz */ ; \
200 3:desctype descdata ; \
203 #endif /* __STDC__ */
205 #endif /* !_MACHINE_ASMACROS_H_ */