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	li	t1, _TIF_WORK_SYSCALL_ENTRY
83	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
84	and	t0, t1, t0
85	bnez	t0, trace_a_syscall
86
87syscall_common:
88	dsll	t0, v0, 3		# offset into table
89	ld	t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0)
90
91	jalr	t2			# Do The Real Thing (TM)
92
93	li	t0, -EMAXERRNO - 1	# error?
94	sltu	t0, t0, v0
95	sd	t0, PT_R7(sp)		# set error flag
96	beqz	t0, 1f
97
98	ld	t1, PT_R2(sp)		# syscall number
99	dnegu	v0			# error
100	sd	t1, PT_R0(sp)		# save it for syscall restarting
1011:	sd	v0, PT_R2(sp)		# result
102
103o32_syscall_exit:
104	j	syscall_exit_partial
105
106/* ------------------------------------------------------------------------ */
107
108trace_a_syscall:
109	SAVE_STATIC
110	sd	a4, PT_R8(sp)		# Save argument registers
111	sd	a5, PT_R9(sp)
112	sd	a6, PT_R10(sp)
113	sd	a7, PT_R11(sp)		# For indirect syscalls
114
115	move	a0, sp
116	/*
117	 * absolute syscall number is in v0 unless we called syscall(__NR_###)
118	 * where the real syscall number is in a0
119	 * note: NR_syscall is the first O32 syscall but the macro is
120	 * only defined when compiling with -mabi=32 (CONFIG_32BIT)
121	 * therefore __NR_O32_Linux is used (4000)
122	 */
123	.set	push
124	.set	reorder
125	subu	t1, v0,  __NR_O32_Linux
126	move	a1, v0
127	bnez	t1, 1f /* __NR_syscall at offset 0 */
128	ld	a1, PT_R4(sp) /* Arg1 for __NR_syscall case */
129	.set	pop
130
1311:	jal	syscall_trace_enter
132
133	bltz	v0, 1f			# seccomp failed? Skip syscall
134
135	RESTORE_STATIC
136	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
137	ld	a0, PT_R4(sp)		# Restore argument registers
138	ld	a1, PT_R5(sp)
139	ld	a2, PT_R6(sp)
140	ld	a3, PT_R7(sp)
141	ld	a4, PT_R8(sp)
142	ld	a5, PT_R9(sp)
143	ld	a6, PT_R10(sp)
144	ld	a7, PT_R11(sp)		# For indirect syscalls
145
146	dsubu	t0, v0, __NR_O32_Linux	# check (new) syscall number
147	sltiu	t0, t0, __NR_O32_Linux_syscalls
148	beqz	t0, not_o32_scall
149
150	j	syscall_common
151
1521:	j	syscall_exit
153
154/* ------------------------------------------------------------------------ */
155
156	/*
157	 * The stackpointer for a call with more than 4 arguments is bad.
158	 */
159bad_stack:
160	li	v0, EFAULT
161	sd	v0, PT_R2(sp)
162	li	t0, 1			# set error flag
163	sd	t0, PT_R7(sp)
164	j	o32_syscall_exit
165
166bad_stack_a4:
167	li	a4, 0
168	b	load_a5
169
170bad_stack_a5:
171	li	a5, 0
172	b	load_a6
173
174bad_stack_a6:
175	li	a6, 0
176	b	load_a7
177
178bad_stack_a7:
179	li	a7, 0
180	b	loads_done
181
182not_o32_scall:
183	/*
184	 * This is not an o32 compatibility syscall, pass it on
185	 * to the 64-bit syscall handlers.
186	 */
187#ifdef CONFIG_MIPS32_N32
188	j	handle_sysn32
189#else
190	j	handle_sys64
191#endif
192	END(handle_sys)
193
194LEAF(sys32_syscall)
195	subu	t0, a0, __NR_O32_Linux	# check syscall number
196	sltiu	v0, t0, __NR_O32_Linux_syscalls
197	beqz	t0, einval		# do not recurse
198	dsll	t1, t0, 3
199	beqz	v0, einval
200	ld	t2, sys32_call_table(t1)		# syscall routine
201
202	move	a0, a1			# shift argument registers
203	move	a1, a2
204	move	a2, a3
205	move	a3, a4
206	move	a4, a5
207	move	a5, a6
208	move	a6, a7
209	jr	t2
210	/* Unreached */
211
212einval: li	v0, -ENOSYS
213	jr	ra
214	END(sys32_syscall)
215
216#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, compat)
217#define __SYSCALL(nr, entry)	PTR_WD entry
218	.align	3
219	.type	sys32_call_table,@object
220EXPORT(sys32_call_table)
221#include <asm/syscall_table_o32.h>
222