1//
2//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
3//  Copyright (c) 2014, Linaro Limited. All rights reserved.
4//
5//  This program and the accompanying materials
6//  are licensed and made available under the terms and conditions of the BSD License
7//  which accompanies this distribution.  The full text of the license may be found at
8//  http://opensource.org/licenses/bsd-license.php
9//
10//  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11//  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12//
13//
14
15.text
16.align 3
17.arch_extension virt
18
19GCC_ASM_EXPORT(ArmCallHvc)
20
21ASM_PFX(ArmCallHvc):
22    push    {r4-r8}
23    // r0 will be popped just after the HVC call
24    push    {r0}
25
26    // Load the HVC arguments values into the appropriate registers
27    ldr     r7, [r0, #28]
28    ldr     r6, [r0, #24]
29    ldr     r5, [r0, #20]
30    ldr     r4, [r0, #16]
31    ldr     r3, [r0, #12]
32    ldr     r2, [r0, #8]
33    ldr     r1, [r0, #4]
34    ldr     r0, [r0, #0]
35
36    hvc     #0
37
38    // Pop the ARM_HVC_ARGS structure address from the stack into r8
39    pop     {r8}
40
41    // Load the HVC returned values into the appropriate registers
42    // A HVC call can return up to 4 values - we do not need to store back r4-r7.
43    str     r3, [r8, #12]
44    str     r2, [r8, #8]
45    str     r1, [r8, #4]
46    str     r0, [r8, #0]
47
48    mov     r0, r8
49
50    // Restore the registers r4-r8
51    pop     {r4-r8}
52
53    bx      lr
54