1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * efi_selftest_unaligned
4 *
5 * Copyright (c) 2018 Heinrich Schuchardt <xypron.glpk@gmx.de>
6 *
7 * Test unaligned memory access on ARMv7.
8 */
9
10 #include <efi_selftest.h>
11
12 struct aligned_buffer {
13 char a[8] __aligned(8);
14 };
15
16 /*
17 * Return an u32 at a given address.
18 * If the address is not four byte aligned, an unaligned memory access
19 * occurs.
20 *
21 * @addr: address to read
22 * Return: value at the address
23 */
deref(void * addr)24 static inline u32 deref(void *addr)
25 {
26 int ret;
27
28 asm(
29 "ldr %[out], [%[in]]\n\t"
30 : [out] "=r" (ret)
31 : [in] "r" (addr)
32 );
33 return ret;
34 }
35
36 /*
37 * Execute unit test.
38 * An unaligned memory access is executed. The result is checked.
39 *
40 * Return: EFI_ST_SUCCESS for success
41 */
execute(void)42 static int execute(void)
43 {
44 struct aligned_buffer buf = {
45 {0, 1, 2, 3, 4, 5, 6, 7},
46 };
47 u32 r = 0;
48
49 /* Read an unaligned address */
50 r = deref(&buf.a[1]);
51
52 /* UEFI only supports low endian systems */
53 if (r != 0x04030201) {
54 efi_st_error("Unaligned access failed");
55 return EFI_ST_FAILURE;
56 }
57
58 return EFI_ST_SUCCESS;
59 }
60
61 EFI_UNIT_TEST(unaligned) = {
62 .name = "unaligned memory access",
63 .phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
64 .execute = execute,
65 };
66