efi_selftest_unaligned.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* efi_selftest_unaligned
*
* Copyright (c) 2018 Heinrich Schuchardt <xypron.glpk@gmx.de>
*
* Test unaligned memory access on ARMv7.
*/
#include <efi_selftest.h>
struct aligned_buffer {
char a[8] __aligned(8);
};
/*
* Return an u32 at a give address.
* If the address is not four byte aligned, an unaligned memory access
* occurs.
*
* @addr: address to read
* @return: value at the address
*/
static inline u32 deref(u32 *addr)
{
int ret;
asm(
"ldr %[out], [%[in]]\n\t"
: [out] "=r" (ret)
: [in] "r" (addr)
);
return ret;
}
/*
* Execute unit test.
* An unaligned memory access is executed. The result is checked.
*
* @return: EFI_ST_SUCCESS for success
*/
static int execute(void)
{
struct aligned_buffer buf = {
{0, 1, 2, 3, 4, 5, 6, 7},
};
void *v = &buf;
u32 r = 0;
/* Read an unaligned address */
r = deref(v + 1);
/* UEFI only supports low endian systems */
if (r != 0x04030201) {
efi_st_error("Unaligned access failed");
return EFI_ST_FAILURE;
}
return EFI_ST_SUCCESS;
}
EFI_UNIT_TEST(unaligned) = {
.name = "unaligned memory access",
.phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
.execute = execute,
};