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Diffstat (limited to 'arch/arm/cpu/arm11/sctlr.S')
| -rw-r--r-- | arch/arm/cpu/arm11/sctlr.S | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm11/sctlr.S b/arch/arm/cpu/arm11/sctlr.S new file mode 100644 index 0000000000..74a7fc4a25 --- /dev/null +++ b/arch/arm/cpu/arm11/sctlr.S @@ -0,0 +1,25 @@ +/* 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) |