sctlr.S 844 B

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  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. #include <linux/linkage.h>
  8. /*
  9. * void allow_unaligned(void) - allow unaligned access
  10. *
  11. * This routine sets the enable unaligned data support flag and clears the
  12. * aligned flag in the system control register.
  13. * After calling this routine unaligned access does no longer leads to a
  14. * data abort or undefined behavior but is handled by the CPU.
  15. * For details see the "ARM Architecture Reference Manual" for ARMv6.
  16. */
  17. ENTRY(allow_unaligned)
  18. mrc p15, 0, r0, c1, c0, 0 @ load system control register
  19. orr r0, r0, #1 << 22 @ set unaligned data support flag
  20. bic r0, r0, #2 @ clear aligned flag
  21. mcr p15, 0, r0, c1, c0, 0 @ write system control register
  22. bx lr @ return
  23. ENDPROC(allow_unaligned)