| /* SPDX-License-Identifier: GPL-2.0+ */ |
| /* |
| * Routines to access the system control register |
| * |
| * Copyright (c) 2019 Heinrich Schuchardt |
| */ |
| |
| #include <linux/linkage.h> |
| |
| /* |
| * void allow_unaligned(void) - allow unaligned access |
| * |
| * This routine sets the enable unaligned data support flag and clears the |
| * aligned flag in the system control register. |
| * After calling this routine unaligned access does no longer leads to a |
| * data abort or undefined behavior but is handled by the CPU. |
| * For details see the "ARM Architecture Reference Manual" for ARMv6. |
| */ |
| ENTRY(allow_unaligned) |
| mrc p15, 0, r0, c1, c0, 0 @ load system control register |
| orr r0, r0, #1 << 22 @ set unaligned data support flag |
| bic r0, r0, #2 @ clear aligned flag |
| mcr p15, 0, r0, c1, c0, 0 @ write system control register |
| bx lr @ return |
| ENDPROC(allow_unaligned) |