xref: /aosp_15_r20/trusty/kernel/lib/syscall/arch/arm/syscall.S (revision 344aa361028b423587d4ef3fa52a23d194628137)
1*344aa361SAndroid Build Coastguard Worker/*
2*344aa361SAndroid Build Coastguard Worker * Copyright (c) 2013, Google, Inc. All rights reserved
3*344aa361SAndroid Build Coastguard Worker *
4*344aa361SAndroid Build Coastguard Worker * Permission is hereby granted, free of charge, to any person obtaining
5*344aa361SAndroid Build Coastguard Worker * a copy of this software and associated documentation files
6*344aa361SAndroid Build Coastguard Worker * (the "Software"), to deal in the Software without restriction,
7*344aa361SAndroid Build Coastguard Worker * including without limitation the rights to use, copy, modify, merge,
8*344aa361SAndroid Build Coastguard Worker * publish, distribute, sublicense, and/or sell copies of the Software,
9*344aa361SAndroid Build Coastguard Worker * and to permit persons to whom the Software is furnished to do so,
10*344aa361SAndroid Build Coastguard Worker * subject to the following conditions:
11*344aa361SAndroid Build Coastguard Worker *
12*344aa361SAndroid Build Coastguard Worker * The above copyright notice and this permission notice shall be
13*344aa361SAndroid Build Coastguard Worker * included in all copies or substantial portions of the Software.
14*344aa361SAndroid Build Coastguard Worker *
15*344aa361SAndroid Build Coastguard Worker * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*344aa361SAndroid Build Coastguard Worker * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*344aa361SAndroid Build Coastguard Worker * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18*344aa361SAndroid Build Coastguard Worker * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19*344aa361SAndroid Build Coastguard Worker * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20*344aa361SAndroid Build Coastguard Worker * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21*344aa361SAndroid Build Coastguard Worker * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22*344aa361SAndroid Build Coastguard Worker */
23*344aa361SAndroid Build Coastguard Worker
24*344aa361SAndroid Build Coastguard Worker#include <asm.h>
25*344aa361SAndroid Build Coastguard Worker
26*344aa361SAndroid Build Coastguard Worker#define MODE_SVC	0x13
27*344aa361SAndroid Build Coastguard Worker
28*344aa361SAndroid Build Coastguard Worker.syntax unified
29*344aa361SAndroid Build Coastguard Worker
30*344aa361SAndroid Build Coastguard Worker/* ARM syscall ABI
31*344aa361SAndroid Build Coastguard Worker * ===============
32*344aa361SAndroid Build Coastguard Worker * Only syscalls with 4 args (max) are currently supported
33*344aa361SAndroid Build Coastguard Worker * r0-r3 = args
34*344aa361SAndroid Build Coastguard Worker * r0-r1 = return value (r0 only if 32-bit retval)
35*344aa361SAndroid Build Coastguard Worker * r12   = syscall number, expected to be trashed.
36*344aa361SAndroid Build Coastguard Worker * syscalls run with interrupts enabled
37*344aa361SAndroid Build Coastguard Worker */
38*344aa361SAndroid Build Coastguard WorkerFUNCTION (arm_syscall)
39*344aa361SAndroid Build Coastguard Worker	srsdb	sp!, #MODE_SVC
40*344aa361SAndroid Build Coastguard Worker	sub	sp, sp, #8
41*344aa361SAndroid Build Coastguard Worker	stmia	sp, { r13-r14 }^
42*344aa361SAndroid Build Coastguard Worker
43*344aa361SAndroid Build Coastguard Worker	cpsie	iaf
44*344aa361SAndroid Build Coastguard Worker
45*344aa361SAndroid Build Coastguard Worker	ldr	r14, =nr_syscalls
46*344aa361SAndroid Build Coastguard Worker	ldr	r14, [r14]
47*344aa361SAndroid Build Coastguard Worker	cmp	r12, r14
48*344aa361SAndroid Build Coastguard Worker
49*344aa361SAndroid Build Coastguard Worker	ldrlo	r14, =syscall_table
50*344aa361SAndroid Build Coastguard Worker	ldrlo	r14, [r14, r12, lsl#2]
51*344aa361SAndroid Build Coastguard Worker	rsbslo	r12, r14, #1	/* This will set the same flags as the cmp above */
52*344aa361SAndroid Build Coastguard Worker	ldrhs	r14,=sys_undefined
53*344aa361SAndroid Build Coastguard Worker	blx	r14
54*344aa361SAndroid Build Coastguard Worker
55*344aa361SAndroid Build Coastguard Worker	cpsid	iaf
56*344aa361SAndroid Build Coastguard Worker
57*344aa361SAndroid Build Coastguard Worker	ldmia	sp, { r13-r14 }^
58*344aa361SAndroid Build Coastguard Worker	add	sp, sp, #8
59*344aa361SAndroid Build Coastguard Worker	rfeia	sp!
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