| Heinrich Schuchardt | d47a774 | 2019-11-19 04:02:10 +0100 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
| 2 | /* |
| 3 | * Routines to access the system control register |
| 4 | * |
| 5 | * Copyright (c) 2019 Heinrich Schuchardt |
| 6 | */ |
| 7 | |
| 8 | #include <linux/linkage.h> |
| 9 | |
| 10 | /* |
| 11 | * void allow_unaligned(void) - allow unaligned access |
| 12 | * |
| 13 | * This routine sets the enable unaligned data support flag and clears the |
| 14 | * aligned flag in the system control register. |
| 15 | * After calling this routine unaligned access does no longer leads to a |
| 16 | * data abort or undefined behavior but is handled by the CPU. |
| 17 | * For details see the "ARM Architecture Reference Manual" for ARMv6. |
| 18 | */ |
| 19 | ENTRY(allow_unaligned) |
| 20 | mrc p15, 0, r0, c1, c0, 0 @ load system control register |
| 21 | orr r0, r0, #1 << 22 @ set unaligned data support flag |
| 22 | bic r0, r0, #2 @ clear aligned flag |
| 23 | mcr p15, 0, r0, c1, c0, 0 @ write system control register |
| 24 | bx lr @ return |
| 25 | ENDPROC(allow_unaligned) |