2 * linux/arch/arm/kernel/entry-common.S
4 * Copyright (C) 2000 Russell King
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.
11 #include <asm/assembler.h>
12 #include <asm/unistd.h>
13 #include <asm/ftrace.h>
14 #include <asm/unwind.h>
16 #include <asm/unistd-oabi.h>
19 .equ NR_syscalls, __NR_syscalls
21 #ifdef CONFIG_NEED_RET_TO_USER
22 #include <mach/entry-macro.S>
24 .macro arch_ret_to_user, tmp1, tmp2
28 #include "entry-header.S"
32 #if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
34 * This is the fast syscall return path. We do as little as possible here,
35 * such as avoiding writing r0 to the stack. We only use this path if we
36 * have tracing and context tracking disabled - the overheads from those
37 * features make this path too inefficient.
42 disable_irq_notrace @ disable interrupts
43 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
44 tst r1, #_TIF_SYSCALL_WORK
46 tst r1, #_TIF_WORK_MASK
49 /* perform architecture specific actions before user return */
50 arch_ret_to_user r1, lr
52 restore_user_regs fast = 1, offset = S_OFF
54 ENDPROC(ret_fast_syscall)
56 /* Ok, we need to do extra processing, enter the slow path. */
58 str r0, [sp, #S_R0+S_OFF]! @ returned r0
59 /* fall through to work_pending */
62 * The "replacement" ret_fast_syscall for when tracing or context tracking
63 * is enabled. As we will need to call out to some C functions, we save
64 * r0 first to avoid needing to save registers around each C function call.
69 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
70 disable_irq_notrace @ disable interrupts
71 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
72 tst r1, #_TIF_SYSCALL_WORK
74 tst r1, #_TIF_WORK_MASK
77 ENDPROC(ret_fast_syscall)
79 /* Slower path - fall through to work_pending */
83 tst r1, #_TIF_SYSCALL_WORK
84 bne __sys_trace_return_nosave
87 mov r2, why @ 'syscall'
91 movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
92 ldmia sp, {r0 - r6} @ have to reload r0 - r6
93 b local_restart @ ... and off we go
94 ENDPROC(ret_fast_syscall)
97 * "slow" syscall return path. "why" tells us if this was a real syscall.
98 * IRQs may be enabled here, so always disable them. Note that we use the
99 * "notrace" version to avoid calling into the tracing code unnecessarily.
100 * do_work_pending() will update this state if necessary.
104 disable_irq_notrace @ disable interrupts
105 ENTRY(ret_to_user_from_irq)
106 ldr r1, [tsk, #TI_FLAGS]
107 tst r1, #_TIF_WORK_MASK
108 bne slow_work_pending
110 asm_trace_hardirqs_on save = 0
112 /* perform architecture specific actions before user return */
113 arch_ret_to_user r1, lr
114 ct_user_enter save = 0
116 restore_user_regs fast = 0, offset = 0
117 ENDPROC(ret_to_user_from_irq)
121 * This is how we return from a fork.
129 1: get_thread_info tsk
131 ENDPROC(ret_from_fork)
133 /*=============================================================================
135 *-----------------------------------------------------------------------------
140 #ifdef CONFIG_CPU_V7M
143 sub sp, sp, #PT_REGS_SIZE
144 stmia sp, {r0 - r12} @ Calling r0 - r12
145 ARM( add r8, sp, #S_PC )
146 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
148 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
149 mrs r8, spsr @ called from non-FIQ mode, so ok.
150 str lr, [sp, #S_PC] @ Save calling PC
151 str r8, [sp, #S_PSR] @ Save CPSR
152 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
155 alignment_trap r10, ip, __cr_alignment
161 * Get the system call number.
164 #if defined(CONFIG_OABI_COMPAT)
167 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
168 * value to determine if it is an EABI or an old ABI call.
170 #ifdef CONFIG_ARM_THUMB
172 movne r10, #0 @ no thumb OABI emulation
173 USER( ldreq r10, [lr, #-4] ) @ get SWI instruction
175 USER( ldr r10, [lr, #-4] ) @ get SWI instruction
177 ARM_BE8(rev r10, r10) @ little endian instruction
179 #elif defined(CONFIG_AEABI)
182 * Pure EABI user space always put syscall number into scno (r7).
184 #elif defined(CONFIG_ARM_THUMB)
185 /* Legacy ABI only, possibly thumb mode. */
186 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
187 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
188 USER( ldreq scno, [lr, #-4] )
191 /* Legacy ABI only. */
192 USER( ldr scno, [lr, #-4] ) @ get SWI instruction
197 adr tbl, sys_call_table @ load syscall table pointer
199 #if defined(CONFIG_OABI_COMPAT)
201 * If the swi argument is zero, this is an EABI call and we do nothing.
203 * If this is an old ABI call, get the syscall number into scno and
204 * get the old ABI syscall table address.
206 bics r10, r10, #0xff000000
207 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
208 ldrne tbl, =sys_oabi_call_table
209 #elif !defined(CONFIG_AEABI)
210 bic scno, scno, #0xff000000 @ mask off SWI op-code
211 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
215 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
216 stmdb sp!, {r4, r5} @ push fifth and sixth args
218 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
221 cmp scno, #NR_syscalls @ check upper syscall limit
222 badr lr, ret_fast_syscall @ return address
223 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
226 2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
227 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
229 mov why, #0 @ no longer a real syscall
230 b sys_ni_syscall @ not private func
232 #if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
234 * We failed to handle a fault trying to access the page
235 * containing the swi instruction, but we're not really in a
236 * position to return -EFAULT. Instead, return back to the
237 * instruction and re-enter the user fault handling path trying
238 * to page it in. This will likely result in sending SEGV to the
249 * This is the really slow path. We're going to be doing
250 * context switches, and waiting for our parent to respond.
255 bl syscall_trace_enter
257 badr lr, __sys_trace_return @ return address
258 mov scno, r0 @ syscall number (possibly new)
259 add r1, sp, #S_R0 + S_OFF @ pointer to regs
260 cmp scno, #NR_syscalls @ check upper syscall limit
261 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
262 stmccia sp, {r4, r5} @ and update the stack args
263 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
264 cmp scno, #-1 @ skip the syscall?
266 add sp, sp, #S_OFF @ restore stack
270 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
272 bl syscall_trace_exit
275 __sys_trace_return_nosave:
278 bl syscall_trace_exit
282 #ifdef CONFIG_ALIGNMENT_TRAP
283 .type __cr_alignment, #object
289 .macro syscall_table_start, sym
295 .macro syscall, nr, func
297 .error "Duplicated/unorded system call entry"
303 .equ __sys_nr, \nr + 1
306 .macro syscall_table_end, sym
307 .ifgt __sys_nr - __NR_syscalls
308 .error "System call table too big"
310 .rept __NR_syscalls - __sys_nr
316 #define NATIVE(nr, func) syscall nr, func
319 * This is the syscall table declaration for native ABI syscalls.
320 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
322 syscall_table_start sys_call_table
323 #define COMPAT(nr, native, compat) syscall nr, native
325 #include <calls-eabi.S>
327 #include <calls-oabi.S>
330 syscall_table_end sys_call_table
332 /*============================================================================
333 * Special system call wrappers
335 @ r0 = syscall number
338 bic scno, r0, #__NR_OABI_SYSCALL_BASE
339 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
340 cmpne scno, #NR_syscalls @ check range
341 stmloia sp, {r5, r6} @ shuffle args
346 ldrlo pc, [tbl, scno, lsl #2]
350 sys_sigreturn_wrapper:
352 mov why, #0 @ prevent syscall restart handling
354 ENDPROC(sys_sigreturn_wrapper)
356 sys_rt_sigreturn_wrapper:
358 mov why, #0 @ prevent syscall restart handling
360 ENDPROC(sys_rt_sigreturn_wrapper)
362 sys_statfs64_wrapper:
366 ENDPROC(sys_statfs64_wrapper)
368 sys_fstatfs64_wrapper:
372 ENDPROC(sys_fstatfs64_wrapper)
375 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
376 * offset, we return EINVAL.
381 moveq r5, r5, lsr #PAGE_SHIFT - 12
392 #ifdef CONFIG_OABI_COMPAT
395 * These are syscalls with argument register differences
401 ENDPROC(sys_oabi_pread64)
406 ENDPROC(sys_oabi_pwrite64)
412 ENDPROC(sys_oabi_truncate64)
414 sys_oabi_ftruncate64:
418 ENDPROC(sys_oabi_ftruncate64)
425 ENDPROC(sys_oabi_readahead)
428 * Let's declare a second syscall table for old ABI binaries
429 * using the compatibility syscall entries.
431 syscall_table_start sys_oabi_call_table
432 #define COMPAT(nr, native, compat) syscall nr, compat
433 #include <calls-oabi.S>
434 syscall_table_end sys_oabi_call_table