分析system_call中断处理过程
本篇文章从上篇的 getpid() 说起。
我们在之前的 MenuOS 中加入 getpid() 功能。然后在 getpid 处打断点，然后看看这系统调用详细是怎么运作的。
一、实验步骤
首先修改 MenuOS 中 test.c 中的代码。在 test.c 中添加上 g_pid() 和 g_pid_asm() 两个方法。test.c是MenuOS的执行文件。
在 main 函数中添加两行命令：
修改后输入 make rootfs 编译运行。结果如下：
可以看到输入 getpid 时可以看到当前的 pid。
然后我们在 sys_getpid 上打上断点。
到最后我们发现我们无法继续跟踪调试汇编部分的代码，这里 system_call() 并不是一个普通的函数，gdb 并不能在此停下，所以剩下的还需要我们自己分析。
二、system_call()对应汇编代码工作过程
这一过程中，库函数触发了中断，并给出了系统调用号。然后系统通过中断描述符找到对应的中断处理函数。
然后我们发现了 ENTRY(system_call)。其位置是 /linux-3.18.6/include/linux/linkage.h
对应代码为：
1 #ifndef _LINUX_LINKAGE_H 2 #define _LINUX_LINKAGE_H
3
4 #include <linux/compiler.h>
5 #include <linux/stringify.h>
6 #include <linux/export.h>
7 #include <asm/linkage.h>
8
9 /* Some toolchains use other characters (e.g. '`') to mark new line in macro */
10 #ifndef ASM_NL 11 #define ASM_NL ;
12 #endif
13
14 #ifdef __cplusplus 15 #define CPP_ASMLINKAGE extern "C"
16 #else
17 #define CPP_ASMLINKAGE
18 #endif
19
20 #ifndef asmlinkage 21 #define asmlinkage CPP_ASMLINKAGE
22 #endif
23
24 #ifndef cond_syscall 25 #define cond_syscall(x) asm( \
26 ".weak " VMLINUX_SYMBOL_STR(x) "\n\t" \ 27 ".set " VMLINUX_SYMBOL_STR(x) "," \ 28 VMLINUX_SYMBOL_STR(sys_ni_syscall)) 29 #endif
30
31 #ifndef SYSCALL_ALIAS 32 #define SYSCALL_ALIAS(alias, name) asm( \
33 ".globl " VMLINUX_SYMBOL_STR(alias) "\n\t" \ 34 ".set " VMLINUX_SYMBOL_STR(alias) "," \ 35 VMLINUX_SYMBOL_STR(name)) 36 #endif
37
38 #define __page_aligned_data __section(.data..page_aligned) __aligned(PAGE_SIZE)
39 #define __page_aligned_bss __section(.bss..page_aligned) __aligned(PAGE_SIZE)
40
41 /*
42 * For assembly routines. 43 * 44 * Note when using these that you must specify the appropriate 45 * alignment directives yourself 46 */
47 #define __PAGE_ALIGNED_DATA .section ".data..page_aligned", "aw"
48 #define __PAGE_ALIGNED_BSS .section ".bss..page_aligned", "aw"
49
50 /*
51 * This is used by architectures to keep arguments on the stack 52 * untouched by the compiler by keeping them live until the end. 53 * The argument stack may be owned by the assembly-language 54 * caller, not the callee, and gcc doesn't always understand 55 * that. 56 * 57 * We have the return value, and a maximum of six arguments. 58 * 59 * This should always be followed by a "return ret" for the 60 * protection to work (ie no more work that the compiler might 61 * end up needing stack temporaries for). 62 */
63 /* Assembly files may be compiled with -traditional .. */
64 #ifndef __ASSEMBLY__ 65 #ifndef asmlinkage_protect 66 # define asmlinkage_protect(n, ret, args...) do { } while (0) 67 #endif
68 #endif
69
70 #ifndef __ALIGN 71 #define __ALIGN .align 4,0x90
72 #define __ALIGN_STR ".align 4,0x90"
73 #endif
74
75 #ifdef __ASSEMBLY__ 76
77 #ifndef LINKER_SCRIPT 78 #define ALIGN __ALIGN
79 #define ALIGN_STR __ALIGN_STR
80
81 #ifndef ENTRY 82 #define ENTRY(name) \
83 .globl name ASM_NL \ 84 ALIGN ASM_NL \ 85 name: 86 #endif
87 #endif /* LINKER_SCRIPT */
88
89 #ifndef WEAK 90 #define WEAK(name) \
91 .weak name ASM_NL \ 92 name: 93 #endif
94
95 #ifndef END 96 #define END(name) \
97 .size name, .-name 98 #endif
99
100 /* If symbol 'name' is treated as a subroutine (gets called, and returns) 101 * then please use ENDPROC to mark 'name' as STT_FUNC for the benefit of 102 * static analysis tools such as stack depth analyzer. 103 */
104 #ifndef ENDPROC 105 #define ENDPROC(name) \
106 .type name, @function ASM_NL \ 107 END(name) 108 #endif
109
110 #endif
111
112 #endif
下面是系统调用表 /linux-3.18.6/arch/frv/kernel/entry.S
1 /* entry.S: FR-V entry 2 * 3 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells ([email protected]) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * 12 * Entry to the kernel is "interesting": 13 * (1) There are no stack pointers, not even for the kernel 14 * (2) General Registers should not be clobbered 15 * (3) There are no kernel-only data registers 16 * (4) Since all addressing modes are wrt to a General Register, no global 17 * variables can be reached 18 * 19 * We deal with this by declaring that we shall kill GR28 on entering the 20 * kernel from userspace 21 * 22 * However, since break interrupts can interrupt the CPU even when PSR.ET==0, 23 * they can't rely on GR28 to be anything useful, and so need to clobber a 24 * separate register (GR31). Break interrupts are managed in break.S 25 * 26 * GR29 _is_ saved, and holds the current task pointer globally 27 * 28 */
29
30 #include <linux/linkage.h>
31 #include <asm/thread_info.h>
32 #include <asm/setup.h>
33 #include <asm/segment.h>
34 #include <asm/ptrace.h>
35 #include <asm/errno.h>
36 #include <asm/cache.h>
37 #include <asm/spr-regs.h>
38
39 #define nr_syscalls ((syscall_table_size)/4)
40
41 .section .text..entry 42 .balign 4
43
44 .macro LEDS val 45 # sethi.p %hi(0xe1200004),gr30 46 # setlo %lo(0xe1200004),gr30 47 # setlos #~\val,gr31 48 # st gr31,@(gr30,gr0) 49 # sethi.p %hi(0xffc00100),gr30 50 # setlo %lo(0xffc00100),gr30 51 # sth gr0,@(gr30,gr0) 52 # membar 53 .endm 54
55 .macro LEDS32 56 # not gr31,gr31 57 # sethi.p %hi(0xe1200004),gr30 58 # setlo %lo(0xe1200004),gr30 59 # st.p gr31,@(gr30,gr0) 60 # srli gr31,#16,gr31 61 # sethi.p %hi(0xffc00100),gr30 62 # setlo %lo(0xffc00100),gr30 63 # sth gr31,@(gr30,gr0) 64 # membar 65 .endm 66
67 ############################################################################### 68 # 69 # entry point for External interrupts received whilst executing userspace code 70 # 71 ############################################################################### 72 .globl __entry_uspace_external_interrupt 73 .type __entry_uspace_external_interrupt,@function 74 __entry_uspace_external_interrupt: 75 LEDS 0x6200
76 sethi.p %hi(__kernel_frame0_ptr),gr28 77 setlo %lo(__kernel_frame0_ptr),gr28 78 ldi @(gr28,#0),gr28 79
80 # handle h/w single-step through exceptions 81 sti gr0,@(gr28,#REG__STATUS) 82
83 .globl __entry_uspace_external_interrupt_reentry 84 __entry_uspace_external_interrupt_reentry: 85 LEDS 0x6201
86
87 setlos #REG__END,gr30 88 dcpl gr28,gr30,#0
89
90 # finish building the exception frame 91 sti sp, @(gr28,#REG_SP) 92 stdi gr2, @(gr28,#REG_GR(2)) 93 stdi gr4, @(gr28,#REG_GR(4)) 94 stdi gr6, @(gr28,#REG_GR(6)) 95 stdi gr8, @(gr28,#REG_GR(8)) 96 stdi gr10,@(gr28,#REG_GR(10)) 97 stdi gr12,@(gr28,#REG_GR(12)) 98 stdi gr14,@(gr28,#REG_GR(14)) 99 stdi gr16,@(gr28,#REG_GR(16)) 100 stdi gr18,@(gr28,#REG_GR(18)) 101 stdi gr20,@(gr28,#REG_GR(20)) 102 stdi gr22,@(gr28,#REG_GR(22)) 103 stdi gr24,@(gr28,#REG_GR(24)) 104 stdi gr26,@(gr28,#REG_GR(26)) 105 sti gr0, @(gr28,#REG_GR(28)) 106 sti gr29,@(gr28,#REG_GR(29)) 107 stdi.p gr30,@(gr28,#REG_GR(30)) 108
109 # set up the kernel stack pointer 110 ori gr28,0,sp 111
112 movsg tbr ,gr20 113 movsg psr ,gr22 114 movsg pcsr,gr21 115 movsg isr ,gr23 116 movsg ccr ,gr24 117 movsg cccr,gr25 118 movsg lr ,gr26 119 movsg lcr ,gr27 120
121 setlos.p #-1,gr4 122 andi gr22,#PSR_PS,gr5 /* try to rebuild original PSR value */
123 andi.p gr22,#~(PSR_PS|PSR_S),gr6 124 slli gr5,#1,gr5 125 or gr6,gr5,gr5 126 andi gr5,#~PSR_ET,gr5 127
128 sti gr20,@(gr28,#REG_TBR) 129 sti gr21,@(gr28,#REG_PC) 130 sti gr5 ,@(gr28,#REG_PSR) 131 sti gr23,@(gr28,#REG_ISR) 132 stdi gr24,@(gr28,#REG_CCR) 133 stdi gr26,@(gr28,#REG_LR) 134 sti gr4 ,@(gr28,#REG_SYSCALLNO) 135
136 movsg iacc0h,gr4 137 movsg iacc0l,gr5 138 stdi gr4,@(gr28,#REG_IACC0) 139
140 movsg gner0,gr4 141 movsg gner1,gr5 142 stdi.p gr4,@(gr28,#REG_GNER0) 143
144 # interrupts start off fully disabled in the interrupt handler 145 subcc gr0,gr0,gr0,icc2 /* set Z and clear C */
146
147 # set up kernel global registers 148 sethi.p %hi(__kernel_current_task),gr5 149 setlo %lo(__kernel_current_task),gr5 150 sethi.p %hi(_gp),gr16 151 setlo %lo(_gp),gr16 152 ldi @(gr5,#0),gr29 153 ldi.p @(gr29,#4),gr15 ; __current_thread_info = current->thread_info 154
155 # make sure we (the kernel) get div-zero and misalignment exceptions 156 setlos #ISR_EDE|ISR_DTT_DIVBYZERO|ISR_EMAM_EXCEPTION,gr5 157 movgs gr5,isr 158
159 # switch to the kernel trap table 160 sethi.p %hi(__entry_kerneltrap_table),gr6 161 setlo %lo(__entry_kerneltrap_table),gr6 162 movgs gr6,tbr 163
164 # set the return address 165 sethi.p %hi(__entry_return_from_user_interrupt),gr4 166 setlo %lo(__entry_return_from_user_interrupt),gr4 167 movgs gr4,lr 168
169 # raise the minimum interrupt priority to 15 (NMI only) and enable exceptions 170 movsg psr,gr4 171
172 ori gr4,#PSR_PIL_14,gr4 173 movgs gr4,psr 174 ori gr4,#PSR_PIL_14|PSR_ET,gr4 175 movgs gr4,psr 176
177 LEDS 0x6202
178 bra do_IRQ 179
180 .size __entry_uspace_external_interrupt,.-__entry_uspace_external_interrupt 181
182 ############################################################################### 183 # 184 # entry point for External interrupts received whilst executing kernel code 185 # - on arriving here, the following registers should already be set up: 186 # GR15 - current thread_info struct pointer 187 # GR16 - kernel GP-REL pointer 188 # GR29 - current task struct pointer 189 # TBR - kernel trap vector table 190 # ISR - kernel's preferred integer controls
191 # 192 ############################################################################### 193 .globl __entry_kernel_external_interrupt 194 .type __entry_kernel_external_interrupt,@function 195 __entry_kernel_external_interrupt: 196 LEDS 0x6210
197 // sub sp,gr15,gr31 198 // LEDS32
199
200 # set up the stack pointer 201 or.p sp,gr0,gr30 202 subi sp,#REG__END,sp 203 sti gr30,@(sp,#REG_SP) 204
205 # handle h/w single-step through exceptions 206 sti gr0,@(sp,#REG__STATUS) 207
208 .globl __entry_kernel_external_interrupt_reentry 209 __entry_kernel_external_interrupt_reentry: 210 LEDS 0x6211
211
212 # set up the exception frame 213 setlos #REG__END,gr30 214 dcpl sp,gr30,#0
215
216 sti.p gr28,@(sp,#REG_GR(28)) 217 ori sp,0,gr28 218
219 # finish building the exception frame 220 stdi gr2,@(gr28,#REG_GR(2)) 221 stdi gr4,@(gr28,#REG_GR(4)) 222 stdi gr6,@(gr28,#REG_GR(6)) 223 stdi gr8,@(gr28,#REG_GR(8)) 224 stdi gr10,@(gr28,#REG_GR(10)) 225 stdi gr12,@(gr28,#REG_GR(12)) 226 stdi gr14,@(gr28,#REG_GR(14)) 227 stdi gr16,@(gr28,#REG_GR(16)) 228 stdi gr18,@(gr28,#REG_GR(18)) 229 stdi gr20,@(gr28,#REG_GR(20)) 230 stdi gr22,@(gr28,#REG_GR(22)) 231 stdi gr24,@(gr28,#REG_GR(24)) 232 stdi gr26,@(gr28,#REG_GR(26)) 233 sti gr29,@(gr28,#REG_GR(29)) 234 stdi.p gr30,@(gr28,#REG_GR(30)) 235
236 # note virtual interrupts will be fully enabled upon return
237 subicc gr0,#1,gr0,icc2 /* clear Z, set C */
238
239 movsg tbr ,gr20 240 movsg psr ,gr22 241 movsg pcsr,gr21 242 movsg isr ,gr23 243 movsg ccr ,gr24 244 movsg cccr,gr25 245 movsg lr ,gr26 246 movsg lcr ,gr27 247
248 setlos.p #-1,gr4 249 andi gr22,#PSR_PS,gr5 /* try to rebuild original PSR value */
250 andi.p gr22,#~(PSR_PS|PSR_S),gr6 251 slli gr5,#1,gr5 252 or gr6,gr5,gr5 253 andi.p gr5,#~PSR_ET,gr5 254
255 # set CCCR.CC3 to Undefined to abort atomic-modify completion inside the kernel 256 # - for an explanation of how it works, see: Documentation/frv/atomic-ops.txt 257 andi gr25,#~0xc0,gr25 258
259 sti gr20,@(gr28,#REG_TBR) 260 sti gr21,@(gr28,#REG_PC) 261 sti gr5 ,@(gr28,#REG_PSR) 262 sti gr23,@(gr28,#REG_ISR) 263 stdi gr24,@(gr28,#REG_CCR) 264 stdi gr26,@(gr28,#REG_LR) 265 sti gr4 ,@(gr28,#REG_SYSCALLNO) 266
267 movsg iacc0h,gr4 268 movsg iacc0l,gr5 269 stdi gr4,@(gr28,#REG_IACC0) 270
271 movsg gner0,gr4 272 movsg gner1,gr5 273 stdi.p gr4,@(gr28,#REG_GNER0) 274
275 # interrupts start off fully disabled in the interrupt handler 276 subcc gr0,gr0,gr0,icc2 /* set Z and clear C */
277
278 # set the return address 279 sethi.p %hi(__entry_return_from_kernel_interrupt),gr4 280 setlo %lo(__entry_return_from_kernel_interrupt),gr4 281 movgs gr4,lr 282
283 # clear power-saving mode flags 284 movsg hsr0,gr4 285 andi gr4,#~HSR0_PDM,gr4 286 movgs gr4,hsr0 287
288 # raise the minimum interrupt priority to 15 (NMI only) and enable exceptions 289 movsg psr,gr4 290 ori gr4,#PSR_PIL_14,gr4 291 movgs gr4,psr 292 ori gr4,#PSR_ET,gr4 293 movgs gr4,psr 294
295 LEDS 0x6212
296 bra do_IRQ 297
298 .size __entry_kernel_external_interrupt,.-__entry_kernel_external_interrupt 299
300 ############################################################################### 301 # 302 # deal with interrupts that were actually virtually disabled 303 # - we need to really disable them, flag the fact and return immediately 304 # - if you change this, you must alter break.S also 305 # 306 ############################################################################### 307 .balign L1_CACHE_BYTES 308 .globl __entry_kernel_external_interrupt_virtually_disabled 309 .type __entry_kernel_external_interrupt_virtually_disabled,@function 310 __entry_kernel_external_interrupt_virtually_disabled: 311 movsg psr,gr30 312 andi gr30,#~PSR_PIL,gr30 313 ori gr30,#PSR_PIL_14,gr30 ; debugging interrupts only 314 movgs gr30,psr 315 subcc gr0,gr0,gr0,icc2 ; leave Z set, clear C 316 rett #0
317
318 .size __entry_kernel_external_interrupt_virtually_disabled,.-__entry_kernel_external_interrupt_virtually_disabled 319
320 ############################################################################### 321 # 322 # deal with re-enablement of interrupts that were pending when virtually re-enabled 323 # - set ICC2.C, re-enable the real interrupts and return
324 # - we can clear ICC2.Z because we shouldn't be here if it's not 0 [due to TIHI] 325 # - if you change this, you must alter break.S also 326 # 327 ############################################################################### 328 .balign L1_CACHE_BYTES 329 .globl __entry_kernel_external_interrupt_virtual_reenable 330 .type __entry_kernel_external_interrupt_virtual_reenable,@function 331 __entry_kernel_external_interrupt_virtual_reenable: 332 movsg psr,gr30 333 andi gr30,#~PSR_PIL,gr30 ; re-enable interrupts 334 movgs gr30,psr 335 subicc gr0,#1,gr0,icc2 ; clear Z, set C 336 rett #0
337
338 .size __entry_kernel_external_interrupt_virtual_reenable,.-__entry_kernel_external_interrupt_virtual_reenable 339
340 ############################################################################### 341 # 342 # entry point for Software and Progam interrupts generated whilst executing userspace code 343 # 344 ############################################################################### 345 .globl __entry_uspace_softprog_interrupt 346 .type __entry_uspace_softprog_interrupt,@function 347 .globl __entry_uspace_handle_mmu_fault 348 __entry_uspace_softprog_interrupt: 349 LEDS 0x6000
350 #ifdef CONFIG_MMU 351 movsg ear0,gr28 352 __entry_uspace_handle_mmu_fault: 353 movgs gr28,scr2 354 #endif
355 sethi.p %hi(__kernel_frame0_ptr),gr28 356 setlo %lo(__kernel_frame0_ptr),gr28 357 ldi @(gr28,#0),gr28 358
359 # handle h/w single-step through exceptions 360 sti gr0,@(gr28,#REG__STATUS) 361
362 .globl __entry_uspace_softprog_interrupt_reentry 363 __entry_uspace_softprog_interrupt_reentry: 364 LEDS 0x6001
365
366 setlos #REG__END,gr30 367 dcpl gr28,gr30,#0
368
369 # set up the kernel stack pointer 370 sti.p sp,@(gr28,#REG_SP) 371 ori gr28,0,sp 372 sti gr0,@(gr28,#REG_GR(28)) 373
374 stdi gr20,@(gr28,#REG_GR(20)) 375 stdi gr22,@(gr28,#REG_GR(22)) 376
377 movsg tbr,gr20 378 movsg pcsr,gr21 379 movsg psr,gr22 380
381 sethi.p %hi(__entry_return_from_user_exception),gr23 382 setlo %lo(__entry_return_from_user_exception),gr23 383
384 bra __entry_common 385
386 .size __entry_uspace_softprog_interrupt,.-__entry_uspace_softprog_interrupt 387
388 # single-stepping was disabled on entry to a TLB handler that then faulted 389 #ifdef CONFIG_MMU 390 .globl __entry_uspace_handle_mmu_fault_sstep 391 __entry_uspace_handle_mmu_fault_sstep: 392 movgs gr28,scr2 393 sethi.p %hi(__kernel_frame0_ptr),gr28 394 setlo %lo(__kernel_frame0_ptr),gr28 395 ldi @(gr28,#0),gr28 396
397 # flag single-step re-enablement 398 sti gr0,@(gr28,#REG__STATUS) 399 bra __entry_uspace_softprog_interrupt_reentry 400 #endif
401
402
403 ############################################################################### 404 # 405 # entry point for Software and Progam interrupts generated whilst executing kernel code 406 # 407 ############################################################################### 408 .globl __entry_kernel_softprog_interrupt 409 .type __entry_kernel_softprog_interrupt,@function 410 __entry_kernel_softprog_interrupt: 411 LEDS 0x6004
412
413 #ifdef CONFIG_MMU 414 movsg ear0,gr30 415 movgs gr30,scr2 416 #endif
417
418 .globl __entry_kernel_handle_mmu_fault 419 __entry_kernel_handle_mmu_fault: 420 # set up the stack pointer 421 subi sp,#REG__END,sp 422 sti sp,@(sp,#REG_SP) 423 sti sp,@(sp,#REG_SP-4) 424 andi sp,#~7,sp 425
426 # handle h/w single-step through exceptions 427 sti gr0,@(sp,#REG__STATUS) 428
429 .globl __entry_kernel_softprog_interrupt_reentry 430 __entry_kernel_softprog_interrupt_reentry: 431 LEDS 0x6005
432
433 setlos #REG__END,gr30 434 dcpl sp,gr30,#0
435
436 # set up the exception frame 437 sti.p gr28,@(sp,#REG_GR(28)) 438 ori sp,0,gr28 439
440 stdi gr20,@(gr28,#REG_GR(20)) 441 stdi gr22,@(gr28,#REG_GR(22)) 442
443 ldi @(sp,#REG_SP),gr22 /* reconstruct the old SP */
444 addi gr22,#REG__END,gr22 445 sti gr22,@(sp,#REG_SP) 446
447 # set CCCR.CC3 to Undefined to abort atomic-modify completion inside the kernel 448 # - for an explanation of how it works, see: Documentation/frv/atomic-ops.txt 449 movsg cccr,gr20 450 andi gr20,#~0xc0,gr20 451 movgs gr20,cccr 452
453 movsg tbr,gr20 454 movsg pcsr,gr21 455 movsg psr,gr22 456
457 sethi.p %hi(__entry_return_from_kernel_exception),gr23 458 setlo %lo(__entry_return_from_kernel_exception),gr23 459 bra __entry_common 460
461 .size __entry_kernel_softprog_interrupt,.-__entry_kernel_softprog_interrupt 462
463 # single-stepping was disabled on entry to a TLB handler that then faulted 464 #ifdef CONFIG_MMU 465 .globl __entry_kernel_handle_mmu_fault_sstep 466 __entry_kernel_handle_mmu_fault_sstep: 467 # set up the stack pointer 468 subi sp,#REG__END,sp 469 sti sp,@(sp,#REG_SP) 470 sti sp,@(sp,#REG_SP-4) 471 andi sp,#~7,sp 472
473 # flag single-step re-enablement 474 sethi #REG__STATUS_STEP,gr30 475 sti gr30,@(sp,#REG__STATUS) 476 bra __entry_kernel_softprog_interrupt_reentry 477 #endif
478
479
480 ############################################################################### 481 # 482 # the rest of the kernel entry point code 483 # - on arriving here, the following registers should be set up: 484 # GR1 - kernel stack pointer 485 # GR7 - syscall number (trap 0 only) 486 # GR8-13 - syscall args (trap 0 only) 487 # GR20 - saved TBR 488 # GR21 - saved PC 489 # GR22 - saved PSR 490 # GR23 - return handler address 491 # GR28 - exception frame on stack 492 # SCR2 - saved EAR0 where applicable (clobbered by ICI & ICEF insns on FR451) 493 # PSR - PSR.S 1, PSR.ET 0
494 # 495 ############################################################################### 496 .globl __entry_common 497 .type __entry_common,@function 498 __entry_common: 499 LEDS 0x6008
500
501 # finish building the exception frame 502 stdi gr2,@(gr28,#REG_GR(2)) 503 stdi gr4,@(gr28,#REG_GR(4)) 504 stdi gr6,@(gr28,#REG_GR(6)) 505 stdi gr8,@(gr28,#REG_GR(8)) 506 stdi gr10,@(gr28,#REG_GR(10)) 507 stdi gr12,@(gr28,#REG_GR(12)) 508 stdi gr14,@(gr28,#REG_GR(14)) 509 stdi gr16,@(gr28,#REG_GR(16)) 510 stdi gr18,@(gr28,#REG_GR(18)) 511 stdi gr24,@(gr28,#REG_GR(24)) 512 stdi gr26,@(gr28,#REG_GR(26)) 513 sti gr29,@(gr28,#REG_GR(29)) 514 stdi gr30,@(gr28,#REG_GR(30)) 515
516 movsg lcr ,gr27 517 movsg lr ,gr26 518 movgs gr23,lr 519 movsg cccr,gr25 520 movsg ccr ,gr24 521 movsg isr ,gr23 522
523 setlos.p #-1,gr4 524 andi gr22,#PSR_PS,gr5 /* try to rebuild original PSR value */
525 andi.p gr22,#~(PSR_PS|PSR_S),gr6 526 slli gr5,#1,gr5 527 or gr6,gr5,gr5 528 andi gr5,#~PSR_ET,gr5 529
530 sti gr20,@(gr28,#REG_TBR) 531 sti gr21,@(gr28,#REG_PC) 532 sti gr5 ,@(gr28,#REG_PSR) 533 sti gr23,@(gr28,#REG_ISR) 534 stdi gr24,@(gr28,#REG_CCR) 535 stdi gr26,@(gr28,#REG_LR) 536 sti gr4 ,@(gr28,#REG_SYSCALLNO) 537
538 movsg iacc0h,gr4 539 movsg iacc0l,gr5 540 stdi gr4,@(gr28,#REG_IACC0) 541
542 movsg gner0,gr4 543 movsg gner1,gr5 544 stdi.p gr4,@(gr28,#REG_GNER0) 545
546 # set up virtual interrupt disablement 547 subicc gr0,#1,gr0,icc2 /* clear Z flag, set C flag */
548
549 # set up kernel global registers 550 sethi.p %hi(__kernel_current_task),gr5 551 setlo %lo(__kernel_current_task),gr5 552 sethi.p %hi(_gp),gr16 553 setlo %lo(_gp),gr16 554 ldi @(gr5,#0),gr29 555 ldi @(gr29,#4),gr15 ; __current_thread_info = current->thread_info 556
557 # switch to the kernel trap table 558 sethi.p %hi(__entry_kerneltrap_table),gr6 559 setlo %lo(__entry_kerneltrap_table),gr6 560 movgs gr6,tbr 561
562 # make sure we (the kernel) get div-zero and misalignment exceptions 563 setlos #ISR_EDE|ISR_DTT_DIVBYZERO|ISR_EMAM_EXCEPTION,gr5 564 movgs gr5,isr 565
566 # clear power-saving mode flags 567 movsg hsr0,gr4 568 andi gr4,#~HSR0_PDM,gr4 569 movgs gr4,hsr0 570
571 # multiplex again using old TBR as a guide 572 setlos.p #TBR_TT,gr3 573 sethi %hi(__entry_vector_table),gr6 574 and.p gr20,gr3,gr5 575 setlo %lo(__entry_vector_table),gr6 576 srli gr5,#2,gr5 577 ld @(gr5,gr6),gr5 578
579 LEDS 0x6009
580 jmpl @(gr5,gr0) 581
582
583 .size __entry_common,.-__entry_common 584
585 ############################################################################### 586 # 587 # handle instruction MMU fault 588 # 589 ############################################################################### 590 #ifdef CONFIG_MMU 591 .globl __entry_insn_mmu_fault 592 __entry_insn_mmu_fault: 593 LEDS 0x6010
594 setlos #0,gr8 595 movsg esr0,gr9 596 movsg scr2,gr10 597
598 # now that we've accessed the exception regs, we can enable exceptions
599 movsg psr,gr4 600 ori gr4,#PSR_ET,gr4 601 movgs gr4,psr 602
603 sethi.p %hi(do_page_fault),gr5 604 setlo %lo(do_page_fault),gr5 605 jmpl @(gr5,gr0) ; call do_page_fault(0,esr0,ear0) 606 #endif
607
608
609 ############################################################################### 610 # 611 # handle instruction access error 612 # 613 ############################################################################### 614 .globl __entry_insn_access_error 615 __entry_insn_access_error: 616 LEDS 0x6011
617 sethi.p %hi(insn_access_error),gr5 618 setlo %lo(insn_access_error),gr5 619 movsg esfr1,gr8 620 movsg epcr0,gr9 621 movsg esr0,gr10 622
623 # now that we've accessed the exception regs, we can enable exceptions
624 movsg psr,gr4 625 ori gr4,#PSR_ET,gr4 626 movgs gr4,psr 627 jmpl @(gr5,gr0) ; call insn_access_error(esfr1,epcr0,esr0) 628
629 ############################################################################### 630 # 631 # handle various instructions of dubious legality 632 # 633 ############################################################################### 634 .globl __entry_unsupported_trap 635 .globl __entry_illegal_instruction 636 .globl __entry_privileged_instruction 637 .globl __entry_debug_exception 638 __entry_unsupported_trap: 639 subi gr21,#4,gr21 640 sti gr21,@(gr28,#REG_PC) 641 __entry_illegal_instruction: 642 __entry_privileged_instruction: 643 __entry_debug_exception: 644 LEDS 0x6012
645 sethi.p %hi(illegal_instruction),gr5 646 setlo %lo(illegal_instruction),gr5 647 movsg esfr1,gr8 648 movsg epcr0,gr9 649 movsg esr0,gr10 650
651 # now that we've accessed the exception regs, we can enable exceptions
652 movsg psr,gr4 653 ori gr4,#PSR_ET,gr4 654 movgs gr4,psr 655 jmpl @(gr5,gr0) ; call ill_insn(esfr1,epcr0,esr0) 656
657 ############################################################################### 658 # 659 # handle atomic operation emulation for userspace 660 # 661 ############################################################################### 662 .globl __entry_atomic_op 663 __entry_atomic_op: 664 LEDS 0x6012
665 sethi.p %hi(atomic_operation),gr5 666 setlo %lo(atomic_operation),gr5 667 movsg esfr1,gr8 668 movsg epcr0,gr9 669 movsg esr0,gr10 670
671 # now that we've accessed the exception regs, we can enable exceptions
672 movsg psr,gr4 673 ori gr4,#PSR_ET,gr4 674 movgs gr4,psr 675 jmpl @(gr5,gr0) ; call atomic_operation(esfr1,epcr0,esr0) 676
677 ############################################################################### 678 # 679 # handle media exception 680 # 681 ############################################################################### 682 .globl __entry_media_exception 683 __entry_media_exception: 684 LEDS 0x6013
685 sethi.p %hi(media_exception),gr5 686 setlo %lo(media_exception),gr5 687 movsg msr0,gr8 688 movsg msr1,gr9 689
690 # now that we've accessed the exception regs, we can enable exceptions
691 movsg psr,gr4 692 ori gr4,#PSR_ET,gr4 693 movgs gr4,psr 694 jmpl @(gr5,gr0) ; call media_excep(msr0,msr1) 695
696 ############################################################################### 697 # 698 # handle data MMU fault 699 # handle data DAT fault (write-protect exception) 700 # 701 ############################################################################### 702 #ifdef CONFIG_MMU 703 .globl __entry_data_mmu_fault 704 __entry_data_mmu_fault: 705 .globl __entry_data_dat_fault 706 __entry_data_dat_fault: 707 LEDS 0x6014
708 setlos #1,gr8 709 movsg esr0,gr9 710 movsg scr2,gr10 ; saved EAR0 711
712 # now that we've accessed the exception regs, we can enable exceptions
713 movsg psr,gr4 714 ori gr4,#PSR_ET,gr4 715 movgs gr4,psr 716
717 sethi.p %hi(do_page_fault),gr5 718 setlo %lo(do_page_fault),gr5 719 jmpl @(gr5,gr0) ; call do_page_fault(1,esr0,ear0) 720 #endif
721
722 ############################################################################### 723 # 724 # handle data and instruction access exceptions 725 # 726 ############################################################################### 727 .globl __entry_insn_access_exception 728 .globl __entry_data_access_exception 729 __entry_insn_access_exception: 730 __entry_data_access_exception: 731 LEDS 0x6016
732 sethi.p %hi(memory_access_exception),gr5 733 setlo %lo(memory_access_exception),gr5 734 movsg esr0,gr8 735 movsg scr2,gr9 ; saved EAR0 736 movsg epcr0,gr10 737
738 # now that we've accessed the exception regs, we can enable exceptions
739 movsg psr,gr4 740 ori gr4,#PSR_ET,gr4 741 movgs gr4,psr 742 jmpl @(gr5,gr0) ; call memory_access_error(esr0,ear0,epcr0) 743
744 ############################################################################### 745 # 746 # handle data access error 747 # 748 ############################################################################### 749 .globl __entry_data_access_error 750 __entry_data_access_error: 751 LEDS 0x6016
752 sethi.p %hi(data_access_error),gr5 753 setlo %lo(data_access_error),gr5 754 movsg esfr1,gr8 755 movsg esr15,gr9 756 movsg ear15,gr10 757
758 # now that we've accessed the exception regs, we can enable exceptions
759 movsg psr,gr4 760 ori gr4,#PSR_ET,gr4 761 movgs gr4,psr 762 jmpl @(gr5,gr0) ; call data_access_error(esfr1,esr15,ear15) 763
764 ############################################################################### 765 # 766 # handle data store error 767 # 768 ############################################################################### 769 .globl __entry_data_store_error 770 __entry_data_store_error: 771 LEDS 0x6017
772 sethi.p %hi(data_store_error),gr5 773 setlo %lo(data_store_error),gr5 774 movsg esfr1,gr8 775 movsg esr14,gr9 776
777 # now that we've accessed the exception regs, we can enable exceptions
778 movsg psr,gr4 779 ori gr4,#PSR_ET,gr4 780 movgs gr4,psr 781 jmpl @(gr5,gr0) ; call data_store_error(esfr1,esr14) 782
783 ############################################################################### 784 # 785 # handle division exception 786 # 787 ############################################################################### 788 .globl __entry_division_exception 789 __entry_division_exception: 790 LEDS 0x6018
791 sethi.p %hi(division_exception),gr5 792 setlo %lo(division_exception),gr5 793 movsg esfr1,gr8 794 movsg esr0,gr9 795 movsg isr,gr10 796
797 # now that we've accessed the exception regs, we can enable exceptions
798 movsg psr,gr4 799 ori gr4,#PSR_ET,gr4 800 movgs gr4,psr 801 jmpl @(gr5,gr0) ; call div_excep(esfr1,esr0,isr) 802
803 ############################################################################### 804 # 805 # handle compound exception 806 # 807 ############################################################################### 808 .globl __entry_compound_exception 809 __entry_compound_exception: 810 LEDS 0x6019
811 sethi.p %hi(compound_exception),gr5 812 setlo %lo(compound_exception),gr5 813 movsg esfr1,gr8 814 movsg esr0,gr9 815 movsg esr14,gr10 816 movsg esr15,gr11 817 movsg msr0,gr12 818 movsg msr1,gr13 819
820 # now that we've accessed the exception regs, we can enable exceptions
821 movsg psr,gr4 822 ori gr4,#PSR_ET,gr4 823 movgs gr4,psr 824 jmpl @(gr5,gr0) ; call comp_excep(esfr1,esr0,esr14,esr15,msr0,msr1) 825
826 ############################################################################### 827 # 828 # handle interrupts and NMIs 829 # 830 ############################################################################### 831 .globl __entry_do_IRQ 832 __entry_do_IRQ: 833 LEDS 0x6020
834
835 # we can enable exceptions 836 movsg psr,gr4 837 ori gr4,#PSR_ET,gr4 838 movgs gr4,psr 839 bra do_IRQ 840
841 .globl __entry_do_NMI 842 __entry_do_NMI: 843 LEDS 0x6021
844
845 # we can enable exceptions 846 movsg psr,gr4 847 ori gr4,#PSR_ET,gr4 848 movgs gr4,psr 849 bra do_NMI 850
851 ############################################################################### 852 # 853 # the return path for a newly forked child process 854 # - __switch_to() saved the old current pointer in GR8 for us 855 # 856 ############################################################################### 857 .globl ret_from_fork 858 ret_from_fork: 859 LEDS 0x6100
860 call schedule_tail 861
862 # fork & co. return 0 to child 863 setlos.p #0,gr8 864 bra __syscall_exit 865
866 .globl ret_from_kernel_thread 867 ret_from_kernel_thread: 868 lddi.p @(gr28,#REG_GR(8)),gr20 869 call schedule_tail 870 calll.p @(gr21,gr0) 871 or gr20,gr20,gr8 872 bra __syscall_exit 873
874 ################################################################################################### 875 # 876 # Return to user mode is not as complex as all this looks, 877 # but we want the default path for a system call return to 878 # go as quickly as possible which is why some of this is
879 # less clear than it otherwise should be. 880 # 881 ################################################################################################### 882 .balign L1_CACHE_BYTES 883 .globl system_call 884 system_call: 885 LEDS 0x6101
886 movsg psr,gr4 ; enable exceptions 887 ori gr4,#PSR_ET,gr4 888 movgs gr4,psr 889
890 sti gr7,@(gr28,#REG_SYSCALLNO) 891 sti.p gr8,@(gr28,#REG_ORIG_GR8) 892
893 subicc gr7,#nr_syscalls,gr0,icc0 894 bnc icc0,#0,__syscall_badsys 895
896 ldi @(gr15,#TI_FLAGS),gr4 897 andicc gr4,#_TIF_SYSCALL_TRACE,gr0,icc0 898 bne icc0,#0,__syscall_trace_entry 899
900 __syscall_call: 901 slli.p gr7,#2,gr7 902 sethi %hi(sys_call_table),gr5 903 setlo %lo(sys_call_table),gr5 904 ld @(gr5,gr7),gr4 905 calll @(gr4,gr0) 906
907
908 ############################################################################### 909 # 910 # return to interrupted process 911 # 912 ############################################################################### 913 __syscall_exit: 914 LEDS 0x6300
915
916 # keep current PSR in GR23 917 movsg psr,gr23 918
919 ldi @(gr28,#REG_PSR),gr22 920
921 sti.p gr8,@(gr28,#REG_GR(8)) ; save return value 922
923 # rebuild saved psr - execve will change it for init/main.c 924 srli gr22,#1,gr5 925 andi.p gr22,#~PSR_PS,gr22 926 andi gr5,#PSR_PS,gr5 927 or gr5,gr22,gr22 928 ori.p gr22,#PSR_S,gr22 929
930 # make sure we don't miss an interrupt setting need_resched or sigpending between
931 # sampling and the RETT 932 ori gr23,#PSR_PIL_14,gr23 933 movgs gr23,psr 934
935 ldi @(gr15,#TI_FLAGS),gr4 936 andicc gr4,#_TIF_ALLWORK_MASK,gr0,icc0 937 bne icc0,#0,__syscall_exit_work 938
939 # restore all registers and return
940 __entry_return_direct: 941 LEDS 0x6301
942
943 andi gr22,#~PSR_ET,gr22 944 movgs gr22,psr 945
946 ldi @(gr28,#REG_ISR),gr23 947 lddi @(gr28,#REG_CCR),gr24 948 lddi @(gr28,#REG_LR) ,gr26 949 ldi @(gr28,#REG_PC) ,gr21 950 ldi @(gr28,#REG_TBR),gr20 951
952 movgs gr20,tbr 953 movgs gr21,pcsr 954 movgs gr23,isr 955 movgs gr24,ccr 956 movgs gr25,cccr 957 movgs gr26,lr 958 movgs gr27,lcr 959
960 lddi @(gr28,#REG_GNER0),gr4 961 movgs gr4,gner0 962 movgs gr5,gner1 963
964 lddi @(gr28,#REG_IACC0),gr4 965 movgs gr4,iacc0h 966 movgs gr5,iacc0l 967
968 lddi @(gr28,#REG_GR(4)) ,gr4 969 lddi @(gr28,#REG_GR(6)) ,gr6 970 lddi @(gr28,#REG_GR(8)) ,gr8 971 lddi @(gr28,#REG_GR(10)),gr10 972 lddi @(gr28,#REG_GR(12)),gr12 973 lddi @(gr28,#REG_GR(14)),gr14 974 lddi @(gr28,#REG_GR(16)),gr16 975 lddi @(gr28,#REG_GR(18)),gr18 976 lddi @(gr28,#REG_GR(20)),gr20 977 lddi @(gr28,#REG_GR(22)),gr22 978 lddi @(gr28,#REG_GR(24)),gr24 979 lddi @(gr28,#REG_GR(26)),gr26 980 ldi @(gr28,#REG_GR(29)),gr29 981 lddi @(gr28,#REG_GR(30)),gr30 982
983 # check to see if a debugging return is required 984 LEDS 0x67f0
985 movsg ccr,gr2 986 ldi @(gr28,#REG__STATUS),gr3 987 andicc gr3,#REG__STATUS_STEP,gr0,icc0 988 bne icc0,#0,__entry_return_singlestep 989 movgs gr2,ccr 990
991 ldi @(gr28,#REG_SP) ,sp 992 lddi @(gr28,#REG_GR(2)) ,gr2 993 ldi @(gr28,#REG_GR(28)),gr28 994
995 LEDS 0x67fe
996 // movsg pcsr,gr31 997 // LEDS32
998
999 #if 0
1000 # store the current frame in the workram on the FR451 1001 movgs gr28,scr2 1002 sethi.p %hi(0xfe800000),gr28 1003 setlo %lo(0xfe800000),gr28 1004
1005 stdi gr2,@(gr28,#REG_GR(2)) 1006 stdi gr4,@(gr28,#REG_GR(4)) 1007 stdi gr6,@(gr28,#REG_GR(6)) 1008 stdi gr8,@(gr28,#REG_GR(8)) 1009 stdi gr10,@(gr28,#REG_GR(10)) 1010 stdi gr12,@(gr28,#REG_GR(12)) 1011 stdi gr14,@(gr28,#REG_GR(14)) 1012 stdi gr16,@(gr28,#REG_GR(16)) 1013 stdi gr18,@(gr28,#REG_GR(18)) 1014 stdi gr24,@(gr28,#REG_GR(24)) 1015 stdi gr26,@(gr28,#REG_GR(26)) 1016 sti gr29,@(gr28,#REG_GR(29)) 1017 stdi gr30,@(gr28,#REG_GR(30)) 1018
1019 movsg tbr ,gr30 1020 sti gr30,@(gr28,#REG_TBR) 1021 movsg pcsr,gr30 1022 sti gr30,@(gr28,#REG_PC) 1023 movsg psr ,gr30 1024 sti gr30,@(gr28,#REG_PSR) 1025 movsg isr ,gr30 1026 sti gr30,@(gr28,#REG_ISR) 1027 movsg ccr ,gr30 1028 movsg cccr,gr31 1029 stdi gr30,@(gr28,#REG_CCR) 1030 movsg lr ,gr30 1031 movsg lcr ,gr31 1032 stdi gr30,@(gr28,#REG_LR) 1033 sti gr0 ,@(gr28,#REG_SYSCALLNO) 1034 movsg scr2,gr28 1035 #endif
1036
1037 rett #0
1038
1039 # return via break.S 1040 __entry_return_singlestep: 1041 movgs gr2,ccr 1042 lddi @(gr28,#REG_GR(2)) ,gr2 1043 ldi @(gr28,#REG_SP) ,sp 1044 ldi @(gr28,#REG_GR(28)),gr28 1045 LEDS 0x67ff
1046 break
1047 .globl __entry_return_singlestep_breaks_here 1048 __entry_return_singlestep_breaks_here: 1049 nop 1050
1051
1052 ############################################################################### 1053 # 1054 # return to a process interrupted in kernel space 1055 # - we need to consider preemption if that is enabled 1056 # 1057 ############################################################################### 1058 .balign L1_CACHE_BYTES 1059 __entry_return_from_kernel_exception: 1060 LEDS 0x6302
1061 movsg psr,gr23 1062 ori gr23,#PSR_PIL_14,gr23 1063 movgs gr23,psr 1064 bra __entry_return_direct 1065
1066 .balign L1_CACHE_BYTES 1067 __entry_return_from_kernel_interrupt: 1068 LEDS 0x6303
1069 movsg psr,gr23 1070 ori gr23,#PSR_PIL_14,gr23 1071 movgs gr23,psr 1072
1073 #ifdef CONFIG_PREEMPT 1074 ldi @(gr15,#TI_PRE_COUNT),gr5 1075 subicc gr5,#0,gr0,icc0 1076 beq icc0,#0,__entry_return_direct 1077
1078 subcc gr0,gr0,gr0,icc2 /* set Z and clear C */
1079 call preempt_schedule_irq 1080 #endif
1081 bra __entry_return_direct 1082
1083
1084 ############################################################################### 1085 # 1086 # perform work that needs to be done immediately before resumption 1087 # 1088 ############################################################################### 1089 .globl __entry_return_from_user_exception 1090 .balign L1_CACHE_BYTES 1091 __entry_return_from_user_exception: 1092 LEDS 0x6501
1093
1094 __entry_resume_userspace: 1095 # make sure we don't miss an interrupt setting need_resched or sigpending between
1096 # sampling and the RETT 1097 movsg psr,gr23 1098 ori gr23,#PSR_PIL_14,gr23 1099 movgs gr23,psr 1100
1101 __entry_return_from_user_interrupt: 1102 LEDS 0x6402
1103 ldi @(gr15,#TI_FLAGS),gr4 1104 andicc gr4,#_TIF_WORK_MASK,gr0,icc0 1105 beq icc0,#1,__entry_return_direct 1106
1107 __entry_work_pending: 1108 LEDS 0x6404
1109 andicc gr4,#_TIF_NEED_RESCHED,gr0,icc0 1110 beq icc0,#1,__entry_work_notifysig 1111
1112 __entry_work_resched: 1113 LEDS 0x6408
1114 movsg psr,gr23 1115 andi gr23,#~PSR_PIL,gr23 1116 movgs gr23,psr 1117 call schedule 1118 movsg psr,gr23 1119 ori gr23,#PSR_PIL_14,gr23 1120 movgs gr23,psr 1121
1122 LEDS 0x6401
1123 ldi @(gr15,#TI_FLAGS),gr4 1124 andicc gr4,#_TIF_WORK_MASK,gr0,icc0 1125 beq icc0,#1,__entry_return_direct 1126 andicc gr4,#_TIF_NEED_RESCHED,gr0,icc0 1127 bne icc0,#1,__entry_work_resched 1128
1129 __entry_work_notifysig: 1130 LEDS 0x6410
1131 ori.p gr4,#0,gr8 1132 call do_notify_resume 1133 bra __entry_resume_userspace 1134
1135 # perform syscall entry tracing 1136 __syscall_trace_entry: 1137 LEDS 0x6320
1138 call syscall_trace_entry 1139
1140 lddi.p @(gr28,#REG_GR(8)) ,gr8 1141 ori gr8,#0,gr7 ; syscall_trace_entry() returned new syscallno 1142 lddi @(gr28,#REG_GR(10)),gr10 1143 lddi.p @(gr28,#REG_GR(12)),gr12 1144
1145 subicc gr7,#nr_syscalls,gr0,icc0 1146 bnc icc0,#0,__syscall_badsys 1147 bra __syscall_call 1148
1149 # perform syscall exit tracing 1150 __syscall_exit_work: 1151 LEDS 0x6340
1152 andicc gr22,#PSR_PS,gr0,icc1 ; don't handle on return to kernel mode
1153 andicc.p gr4,#_TIF_SYSCALL_TRACE,gr0,icc0 1154 bne icc1,#0,__entry_return_direct 1155 beq icc0,#1,__entry_work_pending 1156
1157 movsg psr,gr23 1158 andi gr23,#~PSR_PIL,gr23 ; could let syscall_trace_exit() call schedule() 1159 movgs gr23,psr 1160
1161 call syscall_trace_exit 1162 bra __entry_resume_userspace 1163
1164 __syscall_badsys: 1165 LEDS 0x6380
1166 setlos #-ENOSYS,gr8 1167 sti gr8,@(gr28,#REG_GR(8)) ; save return value 1168 bra __entry_resume_userspace 1169
1170
1171 ############################################################################### 1172 # 1173 # syscall vector table 1174 # 1175 ############################################################################### 1176 .section .rodata 1177 ALIGN 1178 .globl sys_call_table 1179 sys_call_table: 1180 .long sys_restart_syscall /* 0 - old "setup()" system call, used for restarting */
1181 .long sys_exit 1182 .long sys_fork 1183 .long sys_read 1184 .long sys_write 1185 .long sys_open /* 5 */
1186 .long sys_close 1187 .long sys_waitpid 1188 .long sys_creat 1189 .long sys_link 1190 .long sys_unlink /* 10 */
1191 .long sys_execve 1192 .long sys_chdir 1193 .long sys_time 1194 .long sys_mknod 1195 .long sys_chmod /* 15 */
1196 .long sys_lchown16 1197 .long sys_ni_syscall /* old break syscall holder */
1198 .long sys_stat 1199 .long sys_lseek 1200 .long sys_getpid /* 20 */
1201 .long sys_mount 1202 .long sys_oldumount 1203 .long sys_setuid16 1204 .long sys_getuid16 1205 .long sys_ni_syscall // sys_stime /* 25 */
1206 .long sys_ptrace 1207 .long sys_alarm 1208 .long sys_fstat 1209 .long sys_pause 1210 .long sys_utime /* 30 */
1211 .long sys_ni_syscall /* old stty syscall holder */
1212 .long sys_ni_syscall /* old gtty syscall holder */
1213 .long sys_access 1214 .long sys_nice 1215 .long sys_ni_syscall /* 35 */ /* old ftime syscall holder */
1216 .long sys_sync 1217 .long sys_kill 1218 .long sys_rename 1219 .long sys_mkdir 1220 .long sys_rmdir /* 40 */
1221 .long sys_dup 1222 .long sys_pipe 1223 .long sys_times 1224 .long sys_ni_syscall /* old prof syscall holder */
1225 .long sys_brk /* 45 */
1226 .long sys_setgid16 1227 .long sys_getgid16 1228 .long sys_ni_syscall // sys_signal
1229 .long sys_geteuid16 1230 .long sys_getegid16 /* 50 */
1231 .long sys_acct 1232 .long sys_umount /* recycled never used phys( */
1233 .long sys_ni_syscall /* old lock syscall holder */
1234 .long sys_ioctl 1235 .long sys_fcntl /* 55 */
1236 .long sys_ni_syscall /* old mpx syscall holder */
1237 .long sys_setpgid 1238 .long sys_ni_syscall /* old ulimit syscall holder */
1239 .long sys_ni_syscall /* old old uname syscall */
1240 .long sys_umask /* 60 */
1241 .long sys_chroot 1242 .long sys_ustat 1243 .long sys_dup2 1244 .long sys_getppid 1245 .long sys_getpgrp /* 65 */
1246 .long sys_setsid 1247 .long sys_sigaction 1248 .long sys_ni_syscall // sys_sgetmask
1249 .long sys_ni_syscall // sys_ssetmask
1250 .long sys_setreuid16 /* 70 */
1251 .long sys_setregid16 1252 .long sys_sigsuspend 1253 .long sys_ni_syscall // sys_sigpending
1254 .long sys_sethostname 1255 .long sys_setrlimit /* 75 */
1256 .long sys_ni_syscall // sys_old_getrlimit
1257 .long sys_getrusage 1258 .long sys_gettimeofday 1259 .long sys_settimeofday 1260 .long sys_getgroups16 /* 80 */
1261 .long sys_setgroups16 1262 .long sys_ni_syscall /* old_select slot */
1263 .long sys_symlink 1264 .long sys_lstat 1265 .long sys_readlink /* 85 */
1266 .long sys_uselib 1267 .long sys_swapon 1268 .long sys_reboot 1269 .long sys_ni_syscall // old_readdir
1270 .long sys_ni_syscall /* 90 */ /* old_mmap slot */
1271 .long sys_munmap 1272 .long sys_truncate 1273 .long sys_ftruncate 1274 .long sys_fchmod 1275 .long sys_fchown16 /* 95 */
1276 .long sys_getpriority 1277 .long sys_setpriority 1278 .long sys_ni_syscall /* old profil syscall holder */
1279 .long sys_statfs 1280 .long sys_fstatfs /* 100 */
1281 .long sys_ni_syscall /* ioperm for i386 */
1282 .long sys_socketcall 1283 .long sys_syslog 1284 .long sys_setitimer 1285 .long sys_getitimer /* 105 */
1286 .long sys_newstat 1287 .long sys_newlstat 1288 .long sys_newfstat 1289 .long sys_ni_syscall /* obsolete olduname( syscall */
1290 .long sys_ni_syscall /* iopl for i386 */ /* 110 */
1291 .long sys_vhangup 1292 .long sys_ni_syscall /* obsolete idle( syscall */
1293 .long sys_ni_syscall /* vm86old for i386 */
1294 .long sys_wait4 1295 .long sys_swapoff /* 115 */
1296 .long sys_sysinfo 1297 .long sys_ipc 1298 .long sys_fsync 1299 .long sys_sigreturn 1300 .long sys_clone /* 120 */
1301 .long sys_setdomainname 1302 .long sys_newuname 1303 .long sys_ni_syscall /* old "cacheflush" */
1304 .long sys_adjtimex 1305 .long sys_mprotect /* 125 */
1306 .long sys_sigprocmask 1307 .long sys_ni_syscall /* old "create_module" */
1308 .long sys_init_module 1309 .long sys_delete_module 1310 .long sys_ni_syscall /* old "get_kernel_syms" */
1311 .long sys_quotactl 1312 .long sys_getpgid 1313 .long sys_fchdir 1314 .long sys_bdflush 1315 .long sys_sysfs /* 135 */
1316 .long sys_personality 1317 .long sys_ni_syscall /* for afs_syscall */
1318 .long sys_setfsuid16 1319 .long sys_setfsgid16 1320 .long sys_llseek /* 140 */
1321 .long sys_getdents 1322 .long sys_select 1323 .long sys_flock 1324 .long sys_msync 1325 .long sys_readv /* 145 */
1326 .long sys_writev 1327 .long sys_getsid 1328 .long sys_fdatasync 1329 .long sys_sysctl 1330 .long sys_mlock /* 150 */
1331 .long sys_munlock 1332 .long sys_mlockall 1333 .long sys_munlockall 1334 .long sys_sched_setparam 1335 .long sys_sched_getparam /* 155 */
1336 .long sys_sched_setscheduler 1337 .long sys_sched_getscheduler 1338 .long sys_sched_yield 1339 .long sys_sched_get_priority_max 1340 .long sys_sched_get_priority_min /* 160 */
1341 .long sys_sched_rr_get_interval 1342 .long sys_nanosleep 1343 .long sys_mremap 1344 .long sys_setresuid16 1345 .long sys_getresuid16 /* 165 */
1346 .long sys_ni_syscall /* for vm86 */
1347 .long sys_ni_syscall /* Old sys_query_module */
1348 .long sys_poll 1349 .long sys_ni_syscall /* Old nfsservctl */
1350 .long sys_setresgid16 /* 170 */
1351 .long sys_getresgid16 1352 .long sys_prctl 1353 .long sys_rt_sigreturn 1354 .long sys_rt_sigaction 1355 .long sys_rt_sigprocmask /* 175 */
1356 .long sys_rt_sigpending 1357 .long sys_rt_sigtimedwait 1358 .long sys_rt_sigqueueinfo 1359 .long sys_rt_sigsuspend 1360 .long sys_pread64 /* 180 */
1361 .long sys_pwrite64 1362 .long sys_chown16 1363 .long sys_getcwd 1364 .long sys_capget 1365 .long sys_capset /* 185 */
1366 .long sys_sigaltstack 1367 .long sys_sendfile 1368 .long sys_ni_syscall /* streams1 */
1369 .long sys_ni_syscall /* streams2 */
1370 .long sys_vfork /* 190 */
1371 .long sys_getrlimit 1372 .long sys_mmap2 1373 .long sys_truncate64 1374 .long sys_ftruncate64 1375 .long sys_stat64 /* 195 */
1376 .long sys_lstat64 1377 .long sys_fstat64 1378 .long sys_lchown 1379 .long sys_getuid 1380 .long sys_getgid /* 200 */
1381 .long sys_geteuid 1382 .long sys_getegid 1383 .long sys_setreuid 1384 .long sys_setregid 1385 .long sys_getgroups /* 205 */
1386 .long sys_setgroups 1387 .long sys_fchown 1388 .long sys_setresuid 1389 .long sys_getresuid 1390 .long sys_setresgid /* 210 */
1391 .long sys_getresgid 1392 .long sys_chown 1393 .long sys_setuid 1394 .long sys_setgid 1395 .long sys_setfsuid /* 215 */
1396 .long sys_setfsgid 1397 .long sys_pivot_root 1398 .long sys_mincore 1399 .long sys_madvise 1400 .long sys_getdents64 /* 220 */
1401 .long sys_fcntl64 1402 .long sys_ni_syscall /* reserved for TUX */
1403 .long sys_ni_syscall /* Reserved for Security */
1404 .long sys_gettid 1405 .long sys_readahead /* 225 */
1406 .long sys_setxattr 1407 .long sys_lsetxattr 1408 .long sys_fsetxattr 1409 .long sys_getxattr 1410 .long sys_lgetxattr /* 230 */
1411 .long sys_fgetxattr 1412 .long sys_listxattr 1413 .long sys_llistxattr 1414 .long sys_flistxattr 1415 .long sys_removexattr /* 235 */
1416 .long sys_lremovexattr 1417 .long sys_fremovexattr 1418 .long sys_tkill 1419 .long sys_sendfile64 1420 .long sys_futex /* 240 */
1421 .long sys_sched_setaffinity 1422 .long sys_sched_getaffinity 1423 .long sys_ni_syscall //sys_set_thread_area
1424 .long sys_ni_syscall //sys_get_thread_area
1425 .long sys_io_setup /* 245 */
1426 .long sys_io_destroy 1427 .long sys_io_getevents 1428 .long sys_io_submit 1429 .long sys_io_cancel 1430 .long sys_fadvise64 /* 250 */
1431 .long sys_ni_syscall 1432 .long sys_exit_group 1433 .long sys_lookup_dcookie 1434 .long sys_epoll_create 1435 .long sys_epoll_ctl /* 255 */
1436 .long sys_epoll_wait 1437 .long sys_remap_file_pages 1438 .long sys_set_tid_address 1439 .long sys_timer_create 1440 .long sys_timer_settime /* 260 */
1441 .long sys_timer_gettime 1442 .long sys_timer_getoverrun 1443 .long sys_timer_delete 1444 .long sys_clock_settime 1445 .long sys_clock_gettime /* 265 */
1446 .long sys_clock_getres 1447 .long sys_clock_nanosleep 1448 .long sys_statfs64 1449 .long sys_fstatfs64 1450 .long sys_tgkill /* 270 */
1451 .long sys_utimes 1452 .long sys_fadvise64_64 1453 .long sys_ni_syscall /* sys_vserver */
1454 .long sys_mbind 1455 .long sys_get_mempolicy 1456 .long sys_set_mempolicy 1457 .long sys_mq_open 1458 .long sys_mq_unlink 1459 .long sys_mq_timedsend 1460 .long sys_mq_timedreceive /* 280 */
1461 .long sys_mq_notify 1462 .long sys_mq_getsetattr 1463 .long sys_ni_syscall /* reserved for kexec */
1464 .long sys_waitid 1465 .long sys_ni_syscall /* 285 */ /* available */
1466 .long sys_add_key 1467 .long sys_request_key 1468 .long sys_keyctl 1469 .long sys_ioprio_set 1470 .long sys_ioprio_get /* 290 */
1471 .long sys_inotify_init 1472 .long sys_inotify_add_watch 1473 .long sys_inotify_rm_watch 1474 .long sys_migrate_pages 1475 .long sys_openat /* 295 */
1476 .long sys_mkdirat 1477 .long sys_mknodat 1478 .long sys_fchownat 1479 .long sys_futimesat 1480 .long sys_fstatat64 /* 300 */
1481 .long sys_unlinkat 1482 .long sys_renameat 1483 .long sys_linkat 1484 .long sys_symlinkat 1485 .long sys_readlinkat /* 305 */
1486 .long sys_fchmodat 1487 .long sys_faccessat 1488 .long sys_pselect6 1489 .long sys_ppoll 1490 .long sys_unshare /* 310 */
1491 .long sys_set_robust_list 1492 .long sys_get_robust_list 1493 .long sys_splice 1494 .long sys_sync_file_range 1495 .long sys_tee /* 315 */
1496 .long sys_vmsplice 1497 .long sys_move_pages 1498 .long sys_getcpu 1499 .long sys_epoll_pwait 1500 .long sys_utimensat /* 320 */
1501 .long sys_signalfd 1502 .long sys_timerfd_create 1503 .long sys_eventfd 1504 .long sys_fallocate 1505 .long sys_timerfd_settime /* 325 */
1506 .long sys_timerfd_gettime 1507 .long sys_signalfd4 1508 .long sys_eventfd2 1509 .long sys_epoll_create1 1510 .long sys_dup3 /* 330 */
1511 .long sys_pipe2 1512 .long sys_inotify_init1 1513 .long sys_preadv 1514 .long sys_pwritev 1515 .long sys_rt_tgsigqueueinfo /* 335 */
1516 .long sys_perf_event_open 1517 .long sys_setns 1518
1519 syscall_table_size = (. - sys_call_table)
三、总结
从整体过程来看，系统通过 int 0x80 从用户态进入内核态。在这个过程中系统先保存了中断环境，然后执行系统调用函数。system_call() 函数通过系统调用号查找系统调用表 sys_cal_table 来查找到具体的系统调用服务进程。在执行完系统调用后在执行 iret 之前，内核做了一系列检查，用于检查是否有新的中断产生。如果没有新的中断，则通过已保存的系统中断环境返回用户态。这样就完成了一个系统调用过程。
需要注意的是，系统调用通过 INT 0x80 进入内核，跳转到 system_call() 函数，然后执行相应服务进程。因为代表了用户进程，所以这个过程并不属于中断上下文，而是属于进程上下文。
李若森
原创作品转载请注明出处
《Linux内核分析》MOOC课程http://mooc.study.163.com/course/USTC-1000029000