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
28 NESTED(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
69 load_a4: lw a4, 16(t0) # argument #5 from usp
70 load_a5: lw a5, 20(t0) # argument #6 from usp
71 load_a6: lw a6, 24(t0) # argument #7 from usp
72 load_a7: lw a7, 28(t0) # argument #8 from usp
73 loads_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
94 1:
95 LONG_S v0, TI_SYSCALL($28) # Save v0 as syscall number
96 2:
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
103 syscall_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
117 1: sd v0, PT_R2(sp) # result
118
119 o32_syscall_exit:
120 j syscall_exit_partial
121
122 /* ------------------------------------------------------------------------ */
123
124 trace_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
153 1: j syscall_exit
154
155 /* ------------------------------------------------------------------------ */
156
157 /*
158 * The stackpointer for a call with more than 4 arguments is bad.
159 */
160 bad_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
167 bad_stack_a4:
168 li a4, 0
169 b load_a5
170
171 bad_stack_a5:
172 li a5, 0
173 b load_a6
174
175 bad_stack_a6:
176 li a6, 0
177 b load_a7
178
179 bad_stack_a7:
180 li a7, 0
181 b loads_done
182
183 not_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
195 LEAF(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
213 einval: 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
221 EXPORT(sys32_call_table)
222 #include <asm/syscall_table_o32.h>
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