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1/*
2 * linux/arch/arm/kernel/entry-common.S
3 *
4 * Copyright (C) 2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <asm/assembler.h>
12#include <asm/unistd.h>
13#include <asm/ftrace.h>
14#include <asm/unwind.h>
15#include <asm/memory.h>
16#ifdef CONFIG_AEABI
17#include <asm/unistd-oabi.h>
18#endif
19
20 .equ NR_syscalls, __NR_syscalls
21
22#ifdef CONFIG_NEED_RET_TO_USER
23#include <mach/entry-macro.S>
24#else
25 .macro arch_ret_to_user, tmp1, tmp2
26 .endm
27#endif
28
29#include "entry-header.S"
30
31saved_psr .req r8
32#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING)
33saved_pc .req r9
34#define TRACE(x...) x
35#else
36saved_pc .req lr
37#define TRACE(x...)
38#endif
39
40 .section .entry.text,"ax",%progbits
41 .align 5
42#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
43/*
44 * This is the fast syscall return path. We do as little as possible here,
45 * such as avoiding writing r0 to the stack. We only use this path if we
46 * have tracing and context tracking disabled - the overheads from those
47 * features make this path too inefficient.
48 */
49ret_fast_syscall:
50 UNWIND(.fnstart )
51 UNWIND(.cantunwind )
52 disable_irq_notrace @ disable interrupts
53 ldr r2, [tsk, #TI_ADDR_LIMIT]
54 cmp r2, #TASK_SIZE
55 blne addr_limit_check_failed
56 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
57 tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
58 bne fast_work_pending
59
60
61 /* perform architecture specific actions before user return */
62 arch_ret_to_user r1, lr
63
64 restore_user_regs fast = 1, offset = S_OFF
65 UNWIND(.fnend )
66ENDPROC(ret_fast_syscall)
67
68 /* Ok, we need to do extra processing, enter the slow path. */
69fast_work_pending:
70 str r0, [sp, #S_R0+S_OFF]! @ returned r0
71 /* fall through to work_pending */
72#else
73/*
74 * The "replacement" ret_fast_syscall for when tracing or context tracking
75 * is enabled. As we will need to call out to some C functions, we save
76 * r0 first to avoid needing to save registers around each C function call.
77 */
78ret_fast_syscall:
79 UNWIND(.fnstart )
80 UNWIND(.cantunwind )
81 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
82 disable_irq_notrace @ disable interrupts
83 ldr r2, [tsk, #TI_ADDR_LIMIT]
84 cmp r2, #TASK_SIZE
85 blne addr_limit_check_failed
86 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
87 tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
88 beq no_work_pending
89 UNWIND(.fnend )
90ENDPROC(ret_fast_syscall)
91
92 /* Slower path - fall through to work_pending */
93#endif
94
95 tst r1, #_TIF_SYSCALL_WORK
96 bne __sys_trace_return_nosave
97slow_work_pending:
98 mov r0, sp @ 'regs'
99 mov r2, why @ 'syscall'
100 bl do_work_pending
101 cmp r0, #0
102 beq no_work_pending
103 movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
104 ldmia sp, {r0 - r6} @ have to reload r0 - r6
105 b local_restart @ ... and off we go
106ENDPROC(ret_fast_syscall)
107
108/*
109 * "slow" syscall return path. "why" tells us if this was a real syscall.
110 * IRQs may be enabled here, so always disable them. Note that we use the
111 * "notrace" version to avoid calling into the tracing code unnecessarily.
112 * do_work_pending() will update this state if necessary.
113 */
114ENTRY(ret_to_user)
115ret_slow_syscall:
116 disable_irq_notrace @ disable interrupts
117ENTRY(ret_to_user_from_irq)
118 ldr r2, [tsk, #TI_ADDR_LIMIT]
119 cmp r2, #TASK_SIZE
120 blne addr_limit_check_failed
121 ldr r1, [tsk, #TI_FLAGS]
122 tst r1, #_TIF_WORK_MASK
123 bne slow_work_pending
124no_work_pending:
125 asm_trace_hardirqs_on save = 0
126
127 /* perform architecture specific actions before user return */
128 arch_ret_to_user r1, lr
129 ct_user_enter save = 0
130
131 restore_user_regs fast = 0, offset = 0
132ENDPROC(ret_to_user_from_irq)
133ENDPROC(ret_to_user)
134
135/*
136 * This is how we return from a fork.
137 */
138ENTRY(ret_from_fork)
139 bl schedule_tail
140 cmp r5, #0
141 movne r0, r4
142 badrne lr, 1f
143 retne r5
1441: get_thread_info tsk
145 b ret_slow_syscall
146ENDPROC(ret_from_fork)
147
148/*=============================================================================
149 * SWI handler
150 *-----------------------------------------------------------------------------
151 */
152
153 .align 5
154ENTRY(vector_swi)
155#ifdef CONFIG_CPU_V7M
156 v7m_exception_entry
157#else
158 sub sp, sp, #PT_REGS_SIZE
159 stmia sp, {r0 - r12} @ Calling r0 - r12
160 ARM( add r8, sp, #S_PC )
161 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
162 THUMB( mov r8, sp )
163 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
164 mrs saved_psr, spsr @ called from non-FIQ mode, so ok.
165 TRACE( mov saved_pc, lr )
166 str saved_pc, [sp, #S_PC] @ Save calling PC
167 str saved_psr, [sp, #S_PSR] @ Save CPSR
168 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
169#endif
170 zero_fp
171 alignment_trap r10, ip, __cr_alignment
172 asm_trace_hardirqs_on save=0
173 enable_irq_notrace
174 ct_user_exit save=0
175
176 /*
177 * Get the system call number.
178 */
179
180#if defined(CONFIG_OABI_COMPAT)
181
182 /*
183 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
184 * value to determine if it is an EABI or an old ABI call.
185 */
186#ifdef CONFIG_ARM_THUMB
187 tst saved_psr, #PSR_T_BIT
188 movne r10, #0 @ no thumb OABI emulation
189 USER( ldreq r10, [saved_pc, #-4] ) @ get SWI instruction
190#else
191 USER( ldr r10, [saved_pc, #-4] ) @ get SWI instruction
192#endif
193 ARM_BE8(rev r10, r10) @ little endian instruction
194
195#elif defined(CONFIG_AEABI)
196
197 /*
198 * Pure EABI user space always put syscall number into scno (r7).
199 */
200#elif defined(CONFIG_ARM_THUMB)
201 /* Legacy ABI only, possibly thumb mode. */
202 tst saved_psr, #PSR_T_BIT @ this is SPSR from save_user_regs
203 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
204 USER( ldreq scno, [saved_pc, #-4] )
205
206#else
207 /* Legacy ABI only. */
208 USER( ldr scno, [saved_pc, #-4] ) @ get SWI instruction
209#endif
210
211 /* saved_psr and saved_pc are now dead */
212
213 uaccess_disable tbl
214
215 adr tbl, sys_call_table @ load syscall table pointer
216
217#if defined(CONFIG_OABI_COMPAT)
218 /*
219 * If the swi argument is zero, this is an EABI call and we do nothing.
220 *
221 * If this is an old ABI call, get the syscall number into scno and
222 * get the old ABI syscall table address.
223 */
224 bics r10, r10, #0xff000000
225 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
226 ldrne tbl, =sys_oabi_call_table
227#elif !defined(CONFIG_AEABI)
228 bic scno, scno, #0xff000000 @ mask off SWI op-code
229 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
230#endif
231 get_thread_info tsk
232 /*
233 * Reload the registers that may have been corrupted on entry to
234 * the syscall assembly (by tracing or context tracking.)
235 */
236 TRACE( ldmia sp, {r0 - r3} )
237
238local_restart:
239 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
240 stmdb sp!, {r4, r5} @ push fifth and sixth args
241
242 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
243 bne __sys_trace
244
245 cmp scno, #NR_syscalls @ check upper syscall limit
246 badr lr, ret_fast_syscall @ return address
247 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
248
249 add r1, sp, #S_OFF
2502: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
251 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
252 bcs arm_syscall
253 mov why, #0 @ no longer a real syscall
254 b sys_ni_syscall @ not private func
255
256#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
257 /*
258 * We failed to handle a fault trying to access the page
259 * containing the swi instruction, but we're not really in a
260 * position to return -EFAULT. Instead, return back to the
261 * instruction and re-enter the user fault handling path trying
262 * to page it in. This will likely result in sending SEGV to the
263 * current task.
264 */
2659001:
266 sub lr, saved_pc, #4
267 str lr, [sp, #S_PC]
268 get_thread_info tsk
269 b ret_fast_syscall
270#endif
271ENDPROC(vector_swi)
272
273 /*
274 * This is the really slow path. We're going to be doing
275 * context switches, and waiting for our parent to respond.
276 */
277__sys_trace:
278 mov r1, scno
279 add r0, sp, #S_OFF
280 bl syscall_trace_enter
281
282 badr lr, __sys_trace_return @ return address
283 mov scno, r0 @ syscall number (possibly new)
284 add r1, sp, #S_R0 + S_OFF @ pointer to regs
285 cmp scno, #NR_syscalls @ check upper syscall limit
286 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
287 stmccia sp, {r4, r5} @ and update the stack args
288 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
289 cmp scno, #-1 @ skip the syscall?
290 bne 2b
291 add sp, sp, #S_OFF @ restore stack
292 b ret_slow_syscall
293
294__sys_trace_return:
295 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
296 mov r0, sp
297 bl syscall_trace_exit
298 b ret_slow_syscall
299
300__sys_trace_return_nosave:
301 enable_irq_notrace
302 mov r0, sp
303 bl syscall_trace_exit
304 b ret_slow_syscall
305
306 .align 5
307#ifdef CONFIG_ALIGNMENT_TRAP
308 .type __cr_alignment, #object
309__cr_alignment:
310 .word cr_alignment
311#endif
312 .ltorg
313
314 .macro syscall_table_start, sym
315 .equ __sys_nr, 0
316 .type \sym, #object
317ENTRY(\sym)
318 .endm
319
320 .macro syscall, nr, func
321 .ifgt __sys_nr - \nr
322 .error "Duplicated/unorded system call entry"
323 .endif
324 .rept \nr - __sys_nr
325 .long sys_ni_syscall
326 .endr
327 .long \func
328 .equ __sys_nr, \nr + 1
329 .endm
330
331 .macro syscall_table_end, sym
332 .ifgt __sys_nr - __NR_syscalls
333 .error "System call table too big"
334 .endif
335 .rept __NR_syscalls - __sys_nr
336 .long sys_ni_syscall
337 .endr
338 .size \sym, . - \sym
339 .endm
340
341#define NATIVE(nr, func) syscall nr, func
342
343/*
344 * This is the syscall table declaration for native ABI syscalls.
345 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
346 */
347 syscall_table_start sys_call_table
348#define COMPAT(nr, native, compat) syscall nr, native
349#ifdef CONFIG_AEABI
350#include <calls-eabi.S>
351#else
352#include <calls-oabi.S>
353#endif
354#undef COMPAT
355 syscall_table_end sys_call_table
356
357/*============================================================================
358 * Special system call wrappers
359 */
360@ r0 = syscall number
361@ r8 = syscall table
362sys_syscall:
363 bic scno, r0, #__NR_OABI_SYSCALL_BASE
364 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
365 cmpne scno, #NR_syscalls @ check range
366 stmloia sp, {r5, r6} @ shuffle args
367 movlo r0, r1
368 movlo r1, r2
369 movlo r2, r3
370 movlo r3, r4
371 ldrlo pc, [tbl, scno, lsl #2]
372 b sys_ni_syscall
373ENDPROC(sys_syscall)
374
375sys_sigreturn_wrapper:
376 add r0, sp, #S_OFF
377 mov why, #0 @ prevent syscall restart handling
378 b sys_sigreturn
379ENDPROC(sys_sigreturn_wrapper)
380
381sys_rt_sigreturn_wrapper:
382 add r0, sp, #S_OFF
383 mov why, #0 @ prevent syscall restart handling
384 b sys_rt_sigreturn
385ENDPROC(sys_rt_sigreturn_wrapper)
386
387sys_statfs64_wrapper:
388 teq r1, #88
389 moveq r1, #84
390 b sys_statfs64
391ENDPROC(sys_statfs64_wrapper)
392
393sys_fstatfs64_wrapper:
394 teq r1, #88
395 moveq r1, #84
396 b sys_fstatfs64
397ENDPROC(sys_fstatfs64_wrapper)
398
399/*
400 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
401 * offset, we return EINVAL.
402 */
403sys_mmap2:
404 str r5, [sp, #4]
405 b sys_mmap_pgoff
406ENDPROC(sys_mmap2)
407
408#ifdef CONFIG_OABI_COMPAT
409
410/*
411 * These are syscalls with argument register differences
412 */
413
414sys_oabi_pread64:
415 stmia sp, {r3, r4}
416 b sys_pread64
417ENDPROC(sys_oabi_pread64)
418
419sys_oabi_pwrite64:
420 stmia sp, {r3, r4}
421 b sys_pwrite64
422ENDPROC(sys_oabi_pwrite64)
423
424sys_oabi_truncate64:
425 mov r3, r2
426 mov r2, r1
427 b sys_truncate64
428ENDPROC(sys_oabi_truncate64)
429
430sys_oabi_ftruncate64:
431 mov r3, r2
432 mov r2, r1
433 b sys_ftruncate64
434ENDPROC(sys_oabi_ftruncate64)
435
436sys_oabi_readahead:
437 str r3, [sp]
438 mov r3, r2
439 mov r2, r1
440 b sys_readahead
441ENDPROC(sys_oabi_readahead)
442
443/*
444 * Let's declare a second syscall table for old ABI binaries
445 * using the compatibility syscall entries.
446 */
447 syscall_table_start sys_oabi_call_table
448#define COMPAT(nr, native, compat) syscall nr, compat
449#include <calls-oabi.S>
450 syscall_table_end sys_oabi_call_table
451
452#endif
453
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/kernel/entry-common.S
4 *
5 * Copyright (C) 2000 Russell King
6 */
7
8#include <asm/assembler.h>
9#include <asm/unistd.h>
10#include <asm/ftrace.h>
11#include <asm/unwind.h>
12#include <asm/memory.h>
13#ifdef CONFIG_AEABI
14#include <asm/unistd-oabi.h>
15#endif
16
17 .equ NR_syscalls, __NR_syscalls
18
19 .macro arch_ret_to_user, tmp
20#ifdef CONFIG_ARCH_IOP32X
21 mrc p15, 0, \tmp, c15, c1, 0
22 tst \tmp, #(1 << 6)
23 bicne \tmp, \tmp, #(1 << 6)
24 mcrne p15, 0, \tmp, c15, c1, 0 @ Disable cp6 access
25#endif
26 .endm
27
28#include "entry-header.S"
29
30saved_psr .req r8
31#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING_USER)
32saved_pc .req r9
33#define TRACE(x...) x
34#else
35saved_pc .req lr
36#define TRACE(x...)
37#endif
38
39 .section .entry.text,"ax",%progbits
40 .align 5
41#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING_USER) || \
42 IS_ENABLED(CONFIG_DEBUG_RSEQ))
43/*
44 * This is the fast syscall return path. We do as little as possible here,
45 * such as avoiding writing r0 to the stack. We only use this path if we
46 * have tracing, context tracking and rseq debug disabled - the overheads
47 * from those features make this path too inefficient.
48 */
49ret_fast_syscall:
50__ret_fast_syscall:
51 UNWIND(.fnstart )
52 UNWIND(.cantunwind )
53 disable_irq_notrace @ disable interrupts
54 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
55 movs r1, r1, lsl #16
56 bne fast_work_pending
57
58
59 /* perform architecture specific actions before user return */
60 arch_ret_to_user r1
61
62 restore_user_regs fast = 1, offset = S_OFF
63 UNWIND(.fnend )
64ENDPROC(ret_fast_syscall)
65
66 /* Ok, we need to do extra processing, enter the slow path. */
67fast_work_pending:
68 str r0, [sp, #S_R0+S_OFF]! @ returned r0
69 /* fall through to work_pending */
70#else
71/*
72 * The "replacement" ret_fast_syscall for when tracing, context tracking,
73 * or rseq debug is enabled. As we will need to call out to some C functions,
74 * we save r0 first to avoid needing to save registers around each C function
75 * call.
76 */
77ret_fast_syscall:
78__ret_fast_syscall:
79 UNWIND(.fnstart )
80 UNWIND(.cantunwind )
81 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
82#if IS_ENABLED(CONFIG_DEBUG_RSEQ)
83 /* do_rseq_syscall needs interrupts enabled. */
84 mov r0, sp @ 'regs'
85 bl do_rseq_syscall
86#endif
87 disable_irq_notrace @ disable interrupts
88 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
89 movs r1, r1, lsl #16
90 beq no_work_pending
91 UNWIND(.fnend )
92ENDPROC(ret_fast_syscall)
93
94 /* Slower path - fall through to work_pending */
95#endif
96
97 tst r1, #_TIF_SYSCALL_WORK
98 bne __sys_trace_return_nosave
99slow_work_pending:
100 mov r0, sp @ 'regs'
101 mov r2, why @ 'syscall'
102 bl do_work_pending
103 cmp r0, #0
104 beq no_work_pending
105 movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
106 ldmia sp, {r0 - r6} @ have to reload r0 - r6
107 b local_restart @ ... and off we go
108ENDPROC(ret_fast_syscall)
109
110/*
111 * "slow" syscall return path. "why" tells us if this was a real syscall.
112 * IRQs may be enabled here, so always disable them. Note that we use the
113 * "notrace" version to avoid calling into the tracing code unnecessarily.
114 * do_work_pending() will update this state if necessary.
115 */
116ENTRY(ret_to_user)
117ret_slow_syscall:
118#if IS_ENABLED(CONFIG_DEBUG_RSEQ)
119 /* do_rseq_syscall needs interrupts enabled. */
120 enable_irq_notrace @ enable interrupts
121 mov r0, sp @ 'regs'
122 bl do_rseq_syscall
123#endif
124 disable_irq_notrace @ disable interrupts
125ENTRY(ret_to_user_from_irq)
126 ldr r1, [tsk, #TI_FLAGS]
127 movs r1, r1, lsl #16
128 bne slow_work_pending
129no_work_pending:
130 asm_trace_hardirqs_on save = 0
131
132 /* perform architecture specific actions before user return */
133 arch_ret_to_user r1
134 ct_user_enter save = 0
135
136 restore_user_regs fast = 0, offset = 0
137ENDPROC(ret_to_user_from_irq)
138ENDPROC(ret_to_user)
139
140/*
141 * This is how we return from a fork.
142 */
143ENTRY(ret_from_fork)
144 bl schedule_tail
145 cmp r5, #0
146 movne r0, r4
147 badrne lr, 1f
148 retne r5
1491: get_thread_info tsk
150 b ret_slow_syscall
151ENDPROC(ret_from_fork)
152
153/*=============================================================================
154 * SWI handler
155 *-----------------------------------------------------------------------------
156 */
157
158 .align 5
159#ifdef CONFIG_HARDEN_BRANCH_HISTORY
160ENTRY(vector_bhb_loop8_swi)
161 sub sp, sp, #PT_REGS_SIZE
162 stmia sp, {r0 - r12}
163 mov r8, #8
1641: b 2f
1652: subs r8, r8, #1
166 bne 1b
167 dsb nsh
168 isb
169 b 3f
170ENDPROC(vector_bhb_loop8_swi)
171
172 .align 5
173ENTRY(vector_bhb_bpiall_swi)
174 sub sp, sp, #PT_REGS_SIZE
175 stmia sp, {r0 - r12}
176 mcr p15, 0, r8, c7, c5, 6 @ BPIALL
177 isb
178 b 3f
179ENDPROC(vector_bhb_bpiall_swi)
180#endif
181 .align 5
182ENTRY(vector_swi)
183#ifdef CONFIG_CPU_V7M
184 v7m_exception_entry
185#else
186 sub sp, sp, #PT_REGS_SIZE
187 stmia sp, {r0 - r12} @ Calling r0 - r12
1883:
189 ARM( add r8, sp, #S_PC )
190 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
191 THUMB( mov r8, sp )
192 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
193 mrs saved_psr, spsr @ called from non-FIQ mode, so ok.
194 TRACE( mov saved_pc, lr )
195 str saved_pc, [sp, #S_PC] @ Save calling PC
196 str saved_psr, [sp, #S_PSR] @ Save CPSR
197 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
198#endif
199 reload_current r10, ip
200 zero_fp
201 alignment_trap r10, ip, cr_alignment
202 asm_trace_hardirqs_on save=0
203 enable_irq_notrace
204 ct_user_exit save=0
205
206 /*
207 * Get the system call number.
208 */
209
210#if defined(CONFIG_OABI_COMPAT)
211
212 /*
213 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
214 * value to determine if it is an EABI or an old ABI call.
215 */
216#ifdef CONFIG_ARM_THUMB
217 tst saved_psr, #PSR_T_BIT
218 movne r10, #0 @ no thumb OABI emulation
219 USER( ldreq r10, [saved_pc, #-4] ) @ get SWI instruction
220#else
221 USER( ldr r10, [saved_pc, #-4] ) @ get SWI instruction
222#endif
223 ARM_BE8(rev r10, r10) @ little endian instruction
224
225#elif defined(CONFIG_AEABI)
226
227 /*
228 * Pure EABI user space always put syscall number into scno (r7).
229 */
230#elif defined(CONFIG_ARM_THUMB)
231 /* Legacy ABI only, possibly thumb mode. */
232 tst saved_psr, #PSR_T_BIT @ this is SPSR from save_user_regs
233 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
234 USER( ldreq scno, [saved_pc, #-4] )
235
236#else
237 /* Legacy ABI only. */
238 USER( ldr scno, [saved_pc, #-4] ) @ get SWI instruction
239#endif
240
241 /* saved_psr and saved_pc are now dead */
242
243 uaccess_disable tbl
244 get_thread_info tsk
245
246 adr tbl, sys_call_table @ load syscall table pointer
247
248#if defined(CONFIG_OABI_COMPAT)
249 /*
250 * If the swi argument is zero, this is an EABI call and we do nothing.
251 *
252 * If this is an old ABI call, get the syscall number into scno and
253 * get the old ABI syscall table address.
254 */
255 bics r10, r10, #0xff000000
256 strne r10, [tsk, #TI_ABI_SYSCALL]
257 streq scno, [tsk, #TI_ABI_SYSCALL]
258 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
259 ldrne tbl, =sys_oabi_call_table
260#elif !defined(CONFIG_AEABI)
261 bic scno, scno, #0xff000000 @ mask off SWI op-code
262 str scno, [tsk, #TI_ABI_SYSCALL]
263 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
264#else
265 str scno, [tsk, #TI_ABI_SYSCALL]
266#endif
267 /*
268 * Reload the registers that may have been corrupted on entry to
269 * the syscall assembly (by tracing or context tracking.)
270 */
271 TRACE( ldmia sp, {r0 - r3} )
272
273local_restart:
274 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
275 stmdb sp!, {r4, r5} @ push fifth and sixth args
276
277 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
278 bne __sys_trace
279
280 invoke_syscall tbl, scno, r10, __ret_fast_syscall
281
282 add r1, sp, #S_OFF
2832: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
284 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
285 bcs arm_syscall
286 mov why, #0 @ no longer a real syscall
287 b sys_ni_syscall @ not private func
288
289#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
290 /*
291 * We failed to handle a fault trying to access the page
292 * containing the swi instruction, but we're not really in a
293 * position to return -EFAULT. Instead, return back to the
294 * instruction and re-enter the user fault handling path trying
295 * to page it in. This will likely result in sending SEGV to the
296 * current task.
297 */
2989001:
299 sub lr, saved_pc, #4
300 str lr, [sp, #S_PC]
301 get_thread_info tsk
302 b ret_fast_syscall
303#endif
304ENDPROC(vector_swi)
305 .ltorg
306
307 /*
308 * This is the really slow path. We're going to be doing
309 * context switches, and waiting for our parent to respond.
310 */
311__sys_trace:
312 add r0, sp, #S_OFF
313 bl syscall_trace_enter
314 mov scno, r0
315 invoke_syscall tbl, scno, r10, __sys_trace_return, reload=1
316 cmp scno, #-1 @ skip the syscall?
317 bne 2b
318 add sp, sp, #S_OFF @ restore stack
319
320__sys_trace_return_nosave:
321 enable_irq_notrace
322 mov r0, sp
323 bl syscall_trace_exit
324 b ret_slow_syscall
325
326__sys_trace_return:
327 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
328 mov r0, sp
329 bl syscall_trace_exit
330 b ret_slow_syscall
331
332 .macro syscall_table_start, sym
333 .equ __sys_nr, 0
334 .type \sym, #object
335ENTRY(\sym)
336 .endm
337
338 .macro syscall, nr, func
339 .ifgt __sys_nr - \nr
340 .error "Duplicated/unorded system call entry"
341 .endif
342 .rept \nr - __sys_nr
343 .long sys_ni_syscall
344 .endr
345 .long \func
346 .equ __sys_nr, \nr + 1
347 .endm
348
349 .macro syscall_table_end, sym
350 .ifgt __sys_nr - __NR_syscalls
351 .error "System call table too big"
352 .endif
353 .rept __NR_syscalls - __sys_nr
354 .long sys_ni_syscall
355 .endr
356 .size \sym, . - \sym
357 .endm
358
359#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
360#define __SYSCALL(nr, func) syscall nr, func
361
362/*
363 * This is the syscall table declaration for native ABI syscalls.
364 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
365 */
366 syscall_table_start sys_call_table
367#ifdef CONFIG_AEABI
368#include <calls-eabi.S>
369#else
370#include <calls-oabi.S>
371#endif
372 syscall_table_end sys_call_table
373
374/*============================================================================
375 * Special system call wrappers
376 */
377@ r0 = syscall number
378@ r8 = syscall table
379sys_syscall:
380 bic scno, r0, #__NR_OABI_SYSCALL_BASE
381 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
382 cmpne scno, #NR_syscalls @ check range
383#ifdef CONFIG_CPU_SPECTRE
384 movhs scno, #0
385 csdb
386#endif
387 stmialo sp, {r5, r6} @ shuffle args
388 movlo r0, r1
389 movlo r1, r2
390 movlo r2, r3
391 movlo r3, r4
392 ldrlo pc, [tbl, scno, lsl #2]
393 b sys_ni_syscall
394ENDPROC(sys_syscall)
395
396sys_sigreturn_wrapper:
397 add r0, sp, #S_OFF
398 mov why, #0 @ prevent syscall restart handling
399 b sys_sigreturn
400ENDPROC(sys_sigreturn_wrapper)
401
402sys_rt_sigreturn_wrapper:
403 add r0, sp, #S_OFF
404 mov why, #0 @ prevent syscall restart handling
405 b sys_rt_sigreturn
406ENDPROC(sys_rt_sigreturn_wrapper)
407
408sys_statfs64_wrapper:
409 teq r1, #88
410 moveq r1, #84
411 b sys_statfs64
412ENDPROC(sys_statfs64_wrapper)
413
414sys_fstatfs64_wrapper:
415 teq r1, #88
416 moveq r1, #84
417 b sys_fstatfs64
418ENDPROC(sys_fstatfs64_wrapper)
419
420/*
421 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
422 * offset, we return EINVAL.
423 */
424sys_mmap2:
425 str r5, [sp, #4]
426 b sys_mmap_pgoff
427ENDPROC(sys_mmap2)
428
429#ifdef CONFIG_OABI_COMPAT
430
431/*
432 * These are syscalls with argument register differences
433 */
434
435sys_oabi_pread64:
436 stmia sp, {r3, r4}
437 b sys_pread64
438ENDPROC(sys_oabi_pread64)
439
440sys_oabi_pwrite64:
441 stmia sp, {r3, r4}
442 b sys_pwrite64
443ENDPROC(sys_oabi_pwrite64)
444
445sys_oabi_truncate64:
446 mov r3, r2
447 mov r2, r1
448 b sys_truncate64
449ENDPROC(sys_oabi_truncate64)
450
451sys_oabi_ftruncate64:
452 mov r3, r2
453 mov r2, r1
454 b sys_ftruncate64
455ENDPROC(sys_oabi_ftruncate64)
456
457sys_oabi_readahead:
458 str r3, [sp]
459 mov r3, r2
460 mov r2, r1
461 b sys_readahead
462ENDPROC(sys_oabi_readahead)
463
464/*
465 * Let's declare a second syscall table for old ABI binaries
466 * using the compatibility syscall entries.
467 */
468 syscall_table_start sys_oabi_call_table
469#undef __SYSCALL_WITH_COMPAT
470#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat)
471#include <calls-oabi.S>
472 syscall_table_end sys_oabi_call_table
473
474#endif
475