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56 lines
1.8 KiB
C
56 lines
1.8 KiB
C
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/* Helper functions for manipulating memory protection keys, for powerpc64.
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Copyright (C) 2017-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _ARCH_PKEY_H
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#define _ARCH_PKEY_H
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/* Read and write access bits in the AMR register. Needs to be
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translated from and to PKEY_DISABLE_* flags. */
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#define PKEY_AMR_READ 1UL
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#define PKEY_AMR_WRITE 2UL
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/* Return the value of the AMR register. */
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static inline unsigned long int
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pkey_read (void)
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{
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unsigned long int result;
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__asm__ volatile ("mfspr %0, 13" : "=r" (result));
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return result;
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}
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/* Overwrite the AMR register with VALUE. */
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static inline void
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pkey_write (unsigned long int value)
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{
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__asm__ volatile ("mtspr 13, %0" : : "r" (value));
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}
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/* Number of the largest supported key. This depends on the width of
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the AMR register. */
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#define PKEY_MAX (sizeof (unsigned long int) * 8 / 2 - 1)
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_Static_assert (PKEY_MAX == 15 || PKEY_MAX == 31, "PKEY_MAX value");
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/* Translate key number into AMR index position. */
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static inline int
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pkey_index (int key)
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{
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return 2 * (PKEY_MAX - key);
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}
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#endif /* _ARCH_PKEY_H */
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