osfmk/arm/asm.h

   1 /*
   2  * Copyright (c) 2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56
  57 #ifndef _ARM_ASM_H_
  58 #define _ARM_ASM_H_
  59
  60 #include <arm/arch.h>
  61
  62 #define FRAME   pushl %ebp; movl %esp, %ebp
  63 #define EMARF   leave
  64
  65
  66 /* There is another definition of ALIGN for .c sources */
  67 #ifdef ASSEMBLER
  68 #define ALIGN 2
  69 #endif /* ASSEMBLER */
  70
  71 #ifndef FALIGN
  72 #define FALIGN ALIGN
  73 #endif
  74
  75 #define LB(x,n) n
  76 #if     __STDC__
  77 #ifndef __NO_UNDERSCORES__
  78 #define LCL(x)  L ## x
  79 #define EXT(x) _ ## x
  80 #define LEXT(x) _ ## x ## :
  81 #else
  82 #define LCL(x)  .L ## x
  83 #define EXT(x) x
  84 #define LEXT(x) x ## :
  85 #endif
  86 #define LBc(x,n) n ## :
  87 #define LBb(x,n) n ## b
  88 #define LBf(x,n) n ## f
  89 #else /* __STDC__ */
  90 #ifndef __NO_UNDERSCORES__
  91 #define LCL(x) L/**/x
  92 #define EXT(x) _/**/x
  93 #define LEXT(x) _/**/x/**/:
  94 #else /* __NO_UNDERSCORES__ */
  95 #define LCL(x)  .L/**/x
  96 #define EXT(x) x
  97 #define LEXT(x) x/**/:
  98 #endif /* __NO_UNDERSCORES__ */
  99 #define LBc(x,n) n/**/:
 100 #define LBb(x,n) n/**/b
 101 #define LBf(x,n) n/**/f
 102 #endif /* __STDC__ */
 103
 104 #define String  .asciz
 105 #define Value   .word
 106 #define Times(a,b) (a*b)
 107 #define Divide(a,b) (a/b)
 108
 109 #if 0 /* TOTOJK */
 110 #ifdef __ELF__
 111 #define ELF_FUNC(x)     .type x,@function
 112 #define ELF_DATA(x)     .type x,@object
 113 #define ELF_SIZE(x,s)   .size x,s
 114 #else
 115 #define ELF_FUNC(x)
 116 #define ELF_DATA(x)
 117 #define ELF_SIZE(x,s)
 118 #endif
 119 #else
 120 #define ELF_FUNC(x)
 121 #define ELF_DATA(x)
 122 #define ELF_SIZE(x,s)
 123 #endif /* TODOJK */
 124
 125 #define Entry(x)        .globl EXT(x); ELF_FUNC(EXT(x)); .align FALIGN; LEXT(x)
 126 #define ENTRY(x)        Entry(x) MCOUNT
 127 #define ENTRY2(x,y)     .globl EXT(x); .globl EXT(y); \
 128                         ELF_FUNC(EXT(x)); ELF_FUNC(EXT(y)); \
 129                         .align FALIGN; LEXT(x); LEXT(y) \
 130                         MCOUNT
 131 #if __STDC__
 132 #define ASENTRY(x)      .globl x; .align FALIGN; x ## : ELF_FUNC(x) MCOUNT
 133 #else
 134 #define ASENTRY(x)      .globl x; .align FALIGN; x: ELF_FUNC(x) MCOUNT
 135 #endif /* __STDC__ */
 136
 137 #define DATA(x)         .globl EXT(x); ELF_DATA(EXT(x)); .align ALIGN; LEXT(x)
 138
 139 #define End(x)          ELF_SIZE(x,.-x)
 140 #define END(x)          End(EXT(x))
 141 #define ENDDATA(x)      END(x)
 142 #define Enddata(x)      End(x)
 143
 144 #ifdef ASSEMBLER
 145
 146 #define MCOUNT
 147
 148 #else /* NOT ASSEMBLER */
 149
 150 /* These defines are here for .c files that wish to reference global symbols
 151  * within __asm__ statements.
 152  */
 153 #ifndef __NO_UNDERSCORES__
 154 #define CC_SYM_PREFIX "_"
 155 #else
 156 #define CC_SYM_PREFIX ""
 157 #endif /* __NO_UNDERSCORES__ */
 158 #endif /* ASSEMBLER */
 159
 160 #ifdef ASSEMBLER
 161
 162 #if defined (_ARM_ARCH_4T)
 163 # define RET    bx      lr
 164 # define RETeq  bxeq    lr
 165 # define RETne  bxne    lr
 166 # ifdef __STDC__
 167 #  define RETc(c) bx##c lr
 168 # else
 169 #  define RETc(c) bx/**/c       lr
 170 # endif
 171 #else
 172 # define RET    mov     pc, lr
 173 # define RETeq  moveq   pc, lr
 174 # define RETne  movne   pc, lr
 175 # ifdef __STDC__
 176 #  define RETc(c) mov##c        pc, lr
 177 # else
 178 #  define RETc(c) mov/**/c      pc, lr
 179 # endif
 180 #endif
 181
 182 #if defined (__thumb__)
 183 /* Provide a PI mechanism for thumb branching. */
 184 # define BRANCH_EXTERN(x)       ldr     pc, [pc, #-4] ; \
 185                                 .long   EXT(x)
 186 #else
 187 # define BRANCH_EXTERN(x)       b       EXT(x)
 188 #endif
 189
 190 /*
 191  * arg0: Register for thread pointer
 192  */
 193 .macro READ_THREAD
 194         mrc p15, 0, $0, c13, c0, 4  /* Read TPIDRPRW */
 195 .endmacro
 196
 197
 198 /* Macros for loading up addresses that are external to the .s file.
 199  * LOAD_ADDR:  loads the address for (label) into (reg). Not safe for
 200  *   loading to the PC.
 201  * LOAD_ADDR_PC:  Variant for loading to the PC; load the address of (label)
 202  *   into the pc.
 203  * LOAD_ADDR_GEN_DEF:  The general definition needed to support loading
 204  *   a label address.
 205  *
 206  * Usage:  For any label accessed, we require one (and only one) instance
 207  *   of LOAD_ADDR_GEN_DEF(label).
 208  *
 209  * Example:
 210  *   LOAD_ADDR(r0, arm_init)
 211  *   LOAD_ADDR(lr, arm_init_cpu)
 212  *   LOAD_ADDR_PC(arm_init)
 213  *   ...
 214  *
 215  *   LOAD_ADDR_GEN_DEF(arm_init)
 216  *   LOAD_ADDR_GEN_DEF(arm_init_cpu)
 217  */
 218
 219 #if SLIDABLE
 220 /* Definitions for a position dependent kernel using non-lazy pointers.
 221  */
 222
 223 /* TODO: Make this work with thumb .s files. */
 224 #define PC_INC  0x8
 225
 226 /* We need wrapper macros in order to ensure that __LINE__ is expanded.
 227  *
 228  * There is some small potential for duplicate labels here, but because
 229  *   we do not export the generated labels, it should not be an issue.
 230  */
 231
 232 #define GLUE_LABEL_GUTS(label, tag) L_##label##_##tag##_glue
 233 #define GLUE_LABEL(label, tag) GLUE_LABEL_GUTS(label, tag)
 234
 235 #define LOAD_ADDR(reg, label)                                                                   \
 236         movw    reg, :lower16:(label##$non_lazy_ptr - (GLUE_LABEL(label, __LINE__) + PC_INC)) ; \
 237         movt    reg, :upper16:(label##$non_lazy_ptr - (GLUE_LABEL(label, __LINE__) + PC_INC)) ; \
 238 GLUE_LABEL(label, __LINE__): ;                                                                  \
 239         ldr     reg, [pc, reg]
 240
 241 /* Designed with the understanding that directly branching to thumb code
 242  *   is unreliable; this should allow for dealing with __thumb__ in
 243  *   assembly; the non-thumb variant still needs to provide the glue label
 244  *   to avoid failing to build on undefined symbols.
 245  *
 246  * TODO: Make this actually use a scratch register; this macro is convenient
 247  *   for translating (ldr pc, [?]) to a slidable format without the risk of
 248  *   clobbering registers, but it is also wasteful.
 249  */
 250 #if defined(__thumb__)
 251 #define LOAD_ADDR_PC(label)    \
 252         stmfd   sp!, { r0 } ;  \
 253         stmfd   sp!, { r0 } ;  \
 254         LOAD_ADDR(r0, label) ; \
 255         str     r0, [sp, #4] ; \
 256         ldmfd   sp!, { r0 } ;  \
 257         ldmfd   sp!, { pc }
 258 #else
 259 #define LOAD_ADDR_PC(label) \
 260         b       EXT(label)
 261 #endif
 262
 263 #define LOAD_ADDR_GEN_DEF(label)                                   \
 264         .section __DATA,__nl_symbol_ptr,non_lazy_symbol_pointers ; \
 265         .align 2 ;                                                 \
 266 label##$non_lazy_ptr: ;                                            \
 267         .indirect_symbol        EXT(label) ;                       \
 268         .long                   0
 269
 270 #else /* !SLIDABLE */
 271
 272 /* Definitions for a position dependent kernel */
 273 #define LOAD_ADDR(reg, label)  \
 274         ldr     reg, L_##label
 275
 276 #if defined(__thumb__)
 277 #define LOAD_ADDR_PC(label)   \
 278         ldr     pc, L_##label
 279 #else
 280 #define LOAD_ADDR_PC(label) \
 281         b       EXT(label)
 282 #endif
 283
 284 #define LOAD_ADDR_GEN_DEF(label)  \
 285         .text ;                   \
 286         .align 2 ;                \
 287 L_##label: ;                      \
 288         .long   EXT(label)
 289
 290 #endif /* SLIDABLE */
 291
 292 /* The linker can deal with branching from ARM to thumb in unconditional
 293  *   branches, but not in conditional branches.  To support this in our
 294  *   assembly (which allows us to build xnu without -mno-thumb), use the
 295  *   following macros for branching conditionally to external symbols.
 296  *   These macros are used just like the corresponding conditional branch
 297  *   instructions.
 298  */
 299
 300 #define SHIM_LABEL_GUTS(line_num) L_cond_extern_##line_num##_shim
 301 #define SHIM_LABEL(line_num) SHIM_LABEL_GUTS(line_num)
 302
 303 #define COND_EXTERN_BEQ(label)         \
 304         bne     SHIM_LABEL(__LINE__) ; \
 305         b       EXT(label) ;           \
 306 SHIM_LABEL(__LINE__):
 307
 308 #define COND_EXTERN_BLNE(label)        \
 309         beq     SHIM_LABEL(__LINE__) ; \
 310         bl      EXT(label) ;           \
 311 SHIM_LABEL(__LINE__):
 312
 313 #define COND_EXTERN_BLGT(label)        \
 314         ble     SHIM_LABEL(__LINE__) ; \
 315         bl      EXT(label) ;           \
 316 SHIM_LABEL(__LINE__):
 317
 318 #endif /* ASSEMBLER */
 319
 320 #endif /* _ARM_ASM_H_ */