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 - 2000, 2001 by Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2001 MIPS Technologies, Inc.
9 * Copyright (C) 2004 Thiemo Seufer
10 *
11 * Hairy, the userspace application uses a different argument passing
12 * convention than the kernel, so we have to translate things from o32
13 * to ABI64 calling convention.	 64-bit syscalls are also processed
14 * here for now.
15 */
16#include <linux/errno.h>
17#include <asm/asm.h>
18#include <asm/asmmacro.h>
19#include <asm/irqflags.h>
20#include <asm/mipsregs.h>
21#include <asm/regdef.h>
22#include <asm/stackframe.h>
23#include <asm/thread_info.h>
24#include <asm/unistd.h>
25#include <asm/sysmips.h>
26
27	.align	5
28NESTED(handle_sys, PT_SIZE, sp)
29	.set	noat
30	SAVE_SOME
31	TRACE_IRQS_ON_RELOAD
32	STI
33	.set	at
34	ld	t1, PT_EPC(sp)		# skip syscall on return
35
36	dsubu	t0, v0, __NR_O32_Linux	# check syscall number
37	sltiu	t0, t0, __NR_O32_Linux_syscalls
38	daddiu	t1, 4			# skip to next instruction
39	sd	t1, PT_EPC(sp)
40	beqz	t0, not_o32_scall
41#if 0
42 SAVE_ALL
43 move a1, v0
44 ASM_PRINT("Scall %ld\n")
45 RESTORE_ALL
46#endif
47
48	/* We don't want to stumble over broken sign extensions from
49	   userland. O32 does never use the upper half. */
50	sll	a0, a0, 0
51	sll	a1, a1, 0
52	sll	a2, a2, 0
53	sll	a3, a3, 0
54
55	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
56
57	/*
58	 * More than four arguments.  Try to deal with it by copying the
59	 * stack arguments from the user stack to the kernel stack.
60	 * This Sucks (TM).
61	 *
62	 * We intentionally keep the kernel stack a little below the top of
63	 * userspace so we don't have to do a slower byte accurate check here.
64	 */
65	ld	t0, PT_R29(sp)		# get old user stack pointer
66	daddu	t1, t0, 32
67	bltz	t1, bad_stack
68
69load_a4: lw	a4, 16(t0)		# argument #5 from usp
70load_a5: lw	a5, 20(t0)		# argument #6 from usp
71load_a6: lw	a6, 24(t0)		# argument #7 from usp
72load_a7: lw	a7, 28(t0)		# argument #8 from usp
73loads_done:
74
75	.section __ex_table,"a"
76	PTR_WD	load_a4, bad_stack_a4
77	PTR_WD	load_a5, bad_stack_a5
78	PTR_WD	load_a6, bad_stack_a6
79	PTR_WD	load_a7, bad_stack_a7
80	.previous
81
82	/*
83	 * absolute syscall number is in v0 unless we called syscall(__NR_###)
84	 * where the real syscall number is in a0
85	 * note: NR_syscall is the first O32 syscall but the macro is
86	 * only defined when compiling with -mabi=32 (CONFIG_32BIT)
87	 * therefore __NR_O32_Linux is used (4000)
88	 */
89
90	subu	t2, v0,  __NR_O32_Linux
91	bnez	t2, 1f /* __NR_syscall at offset 0 */
92	LONG_S	a0, TI_SYSCALL($28)	# Save a0 as syscall number
93	b	2f
941:
95	LONG_S	v0, TI_SYSCALL($28)	# Save v0 as syscall number
962:
97
98	li	t1, _TIF_WORK_SYSCALL_ENTRY
99	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
100	and	t0, t1, t0
101	bnez	t0, trace_a_syscall
102
103syscall_common:
104	dsll	t0, v0, 3		# offset into table
105	ld	t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0)
106
107	jalr	t2			# Do The Real Thing (TM)
108
109	li	t0, -EMAXERRNO - 1	# error?
110	sltu	t0, t0, v0
111	sd	t0, PT_R7(sp)		# set error flag
112	beqz	t0, 1f
113
114	ld	t1, PT_R2(sp)		# syscall number
115	dnegu	v0			# error
116	sd	t1, PT_R0(sp)		# save it for syscall restarting
1171:	sd	v0, PT_R2(sp)		# result
118
119o32_syscall_exit:
120	j	syscall_exit_partial
121
122/* ------------------------------------------------------------------------ */
123
124trace_a_syscall:
125	SAVE_STATIC
126	sd	a4, PT_R8(sp)		# Save argument registers
127	sd	a5, PT_R9(sp)
128	sd	a6, PT_R10(sp)
129	sd	a7, PT_R11(sp)		# For indirect syscalls
130
131	move	a0, sp
132	jal	syscall_trace_enter
133
134	bltz	v0, 1f			# seccomp failed? Skip syscall
135
136	RESTORE_STATIC
137	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
138	ld	a0, PT_R4(sp)		# Restore argument registers
139	ld	a1, PT_R5(sp)
140	ld	a2, PT_R6(sp)
141	ld	a3, PT_R7(sp)
142	ld	a4, PT_R8(sp)
143	ld	a5, PT_R9(sp)
144	ld	a6, PT_R10(sp)
145	ld	a7, PT_R11(sp)		# For indirect syscalls
146
147	dsubu	t0, v0, __NR_O32_Linux	# check (new) syscall number
148	sltiu	t0, t0, __NR_O32_Linux_syscalls
149	beqz	t0, not_o32_scall
150
151	j	syscall_common
152
1531:	j	syscall_exit
154
155/* ------------------------------------------------------------------------ */
156
157	/*
158	 * The stackpointer for a call with more than 4 arguments is bad.
159	 */
160bad_stack:
161	li	v0, EFAULT
162	sd	v0, PT_R2(sp)
163	li	t0, 1			# set error flag
164	sd	t0, PT_R7(sp)
165	j	o32_syscall_exit
166
167bad_stack_a4:
168	li	a4, 0
169	b	load_a5
170
171bad_stack_a5:
172	li	a5, 0
173	b	load_a6
174
175bad_stack_a6:
176	li	a6, 0
177	b	load_a7
178
179bad_stack_a7:
180	li	a7, 0
181	b	loads_done
182
183not_o32_scall:
184	/*
185	 * This is not an o32 compatibility syscall, pass it on
186	 * to the 64-bit syscall handlers.
187	 */
188#ifdef CONFIG_MIPS32_N32
189	j	handle_sysn32
190#else
191	j	handle_sys64
192#endif
193	END(handle_sys)
194
195LEAF(sys32_syscall)
196	subu	t0, a0, __NR_O32_Linux	# check syscall number
197	sltiu	v0, t0, __NR_O32_Linux_syscalls
198	beqz	t0, einval		# do not recurse
199	dsll	t1, t0, 3
200	beqz	v0, einval
201	ld	t2, sys32_call_table(t1)		# syscall routine
202
203	move	a0, a1			# shift argument registers
204	move	a1, a2
205	move	a2, a3
206	move	a3, a4
207	move	a4, a5
208	move	a5, a6
209	move	a6, a7
210	jr	t2
211	/* Unreached */
212
213einval: li	v0, -ENOSYS
214	jr	ra
215	END(sys32_syscall)
216
217#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, compat)
218#define __SYSCALL(nr, entry)	PTR_WD entry
219	.align	3
220	.type	sys32_call_table,@object
221EXPORT(sys32_call_table)
222#include <asm/syscall_table_o32.h>
223