1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1995-99, 2000- 02, 06 Ralf Baechle <ralf@linux-mips.org>
7 * Copyright (C) 2001 MIPS Technologies, Inc.
8 * Copyright (C) 2004 Thiemo Seufer
9 * Copyright (C) 2014 Imagination Technologies Ltd.
10 */
11#include <linux/errno.h>
12#include <asm/asm.h>
13#include <asm/asmmacro.h>
14#include <asm/irqflags.h>
15#include <asm/mipsregs.h>
16#include <asm/regdef.h>
17#include <asm/stackframe.h>
18#include <asm/isadep.h>
19#include <asm/sysmips.h>
20#include <asm/thread_info.h>
21#include <asm/unistd.h>
22#include <asm/asm-offsets.h>
23
24	.align	5
25NESTED(handle_sys, PT_SIZE, sp)
26	.set	noat
27	SAVE_SOME
28	TRACE_IRQS_ON_RELOAD
29	STI
30	.set	at
31
32	lw	t1, PT_EPC(sp)		# skip syscall on return
33
34	addiu	t1, 4			# skip to next instruction
35	sw	t1, PT_EPC(sp)
36
37	sw	a3, PT_R26(sp)		# save a3 for syscall restarting
38
39	/*
40	 * More than four arguments.  Try to deal with it by copying the
41	 * stack arguments from the user stack to the kernel stack.
42	 * This Sucks (TM).
43	 */
44	lw	t0, PT_R29(sp)		# get old user stack pointer
45
46	/*
47	 * We intentionally keep the kernel stack a little below the top of
48	 * userspace so we don't have to do a slower byte accurate check here.
49	 */
50	addu	t4, t0, 32
51	bltz	t4, bad_stack		# -> sp is bad
52
53	/*
54	 * Ok, copy the args from the luser stack to the kernel stack.
55	 */
56
57	.set    push
58	.set    noreorder
59	.set	nomacro
60
61load_a4: user_lw(t5, 16(t0))		# argument #5 from usp
62load_a5: user_lw(t6, 20(t0))		# argument #6 from usp
63load_a6: user_lw(t7, 24(t0))		# argument #7 from usp
64load_a7: user_lw(t8, 28(t0))		# argument #8 from usp
65loads_done:
66
67	sw	t5, 16(sp)		# argument #5 to ksp
68	sw	t6, 20(sp)		# argument #6 to ksp
69	sw	t7, 24(sp)		# argument #7 to ksp
70	sw	t8, 28(sp)		# argument #8 to ksp
71	.set	pop
72
73	.section __ex_table,"a"
74	PTR_WD	load_a4, bad_stack_a4
75	PTR_WD	load_a5, bad_stack_a5
76	PTR_WD	load_a6, bad_stack_a6
77	PTR_WD	load_a7, bad_stack_a7
78	.previous
79
80	lw	t0, TI_FLAGS($28)	# syscall tracing enabled?
81	li	t1, _TIF_WORK_SYSCALL_ENTRY
82	and	t0, t1
83	bnez	t0, syscall_trace_entry # -> yes
84syscall_common:
85	subu	v0, v0, __NR_O32_Linux	# check syscall number
86	sltiu	t0, v0, __NR_O32_Linux_syscalls
87	beqz	t0, illegal_syscall
88
89	sll	t0, v0, 2
90	la	t1, sys_call_table
91	addu	t1, t0
92	lw	t2, (t1)		# syscall routine
93
94	beqz	t2, illegal_syscall
95
96	jalr	t2			# Do The Real Thing (TM)
97
98	li	t0, -EMAXERRNO - 1	# error?
99	sltu	t0, t0, v0
100	sw	t0, PT_R7(sp)		# set error flag
101	beqz	t0, 1f
102
103	lw	t1, PT_R2(sp)		# syscall number
104	negu	v0			# error
105	sw	t1, PT_R0(sp)		# save it for syscall restarting
1061:	sw	v0, PT_R2(sp)		# result
107
108o32_syscall_exit:
109	j	syscall_exit_partial
110
111/* ------------------------------------------------------------------------ */
112
113syscall_trace_entry:
114	SAVE_STATIC
115	move	a0, sp
116
117	/*
118	 * syscall number is in v0 unless we called syscall(__NR_###)
119	 * where the real syscall number is in a0
120	 */
121	move	a1, v0
122	subu	t2, v0,  __NR_O32_Linux
123	bnez	t2, 1f /* __NR_syscall at offset 0 */
124	lw	a1, PT_R4(sp)
125
1261:	jal	syscall_trace_enter
127
128	bltz	v0, 1f			# seccomp failed? Skip syscall
129
130	RESTORE_STATIC
131	lw	v0, PT_R2(sp)		# Restore syscall (maybe modified)
132	lw	a0, PT_R4(sp)		# Restore argument registers
133	lw	a1, PT_R5(sp)
134	lw	a2, PT_R6(sp)
135	lw	a3, PT_R7(sp)
136	j	syscall_common
137
1381:	j	syscall_exit
139
140/* ------------------------------------------------------------------------ */
141
142	/*
143	 * Our open-coded access area sanity test for the stack pointer
144	 * failed. We probably should handle this case a bit more drastic.
145	 */
146bad_stack:
147	li	v0, EFAULT
148	sw	v0, PT_R2(sp)
149	li	t0, 1				# set error flag
150	sw	t0, PT_R7(sp)
151	j	o32_syscall_exit
152
153bad_stack_a4:
154	li	t5, 0
155	b	load_a5
156
157bad_stack_a5:
158	li	t6, 0
159	b	load_a6
160
161bad_stack_a6:
162	li	t7, 0
163	b	load_a7
164
165bad_stack_a7:
166	li	t8, 0
167	b	loads_done
168
169	/*
170	 * The system call does not exist in this kernel
171	 */
172illegal_syscall:
173	li	v0, ENOSYS			# error
174	sw	v0, PT_R2(sp)
175	li	t0, 1				# set error flag
176	sw	t0, PT_R7(sp)
177	j	o32_syscall_exit
178	END(handle_sys)
179
180	LEAF(sys_syscall)
181	subu	t0, a0, __NR_O32_Linux	# check syscall number
182	sltiu	v0, t0, __NR_O32_Linux_syscalls
183	beqz	t0, einval		# do not recurse
184	sll	t1, t0, 2
185	beqz	v0, einval
186	lw	t2, sys_call_table(t1)		# syscall routine
187
188	move	a0, a1				# shift argument registers
189	move	a1, a2
190	move	a2, a3
191	lw	a3, 16(sp)
192	lw	t4, 20(sp)
193	lw	t5, 24(sp)
194	lw	t6, 28(sp)
195	sw	t4, 16(sp)
196	sw	t5, 20(sp)
197	sw	t6, 24(sp)
198	jr	t2
199	/* Unreached */
200
201einval: li	v0, -ENOSYS
202	jr	ra
203	END(sys_syscall)
204
205#ifdef CONFIG_MIPS_MT_FPAFF
206	/*
207	 * For FPU affinity scheduling on MIPS MT processors, we need to
208	 * intercept sys_sched_xxxaffinity() calls until we get a proper hook
209	 * in kernel/sched/core.c.  Considered only temporary we only support
210	 * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
211	 * atm.
212	 */
213#define sys_sched_setaffinity	mipsmt_sys_sched_setaffinity
214#define sys_sched_getaffinity	mipsmt_sys_sched_getaffinity
215#endif /* CONFIG_MIPS_MT_FPAFF */
216
217#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, native)
218#define __SYSCALL(nr, entry) 	PTR_WD entry
219	.align	2
220	.type	sys_call_table, @object
221EXPORT(sys_call_table)
222#include <asm/syscall_table_o32.h>
223