177 lines
6.1 KiB
Diff
177 lines
6.1 KiB
Diff
commit a803367bab167f5ec4fde1f0d0ec447707c29520
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Fri Feb 14 20:55:39 2020 +0100
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powerpc64: Add memory protection key support [BZ #23202]
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The 32-bit protection key behavior is somewhat unclear on 32-bit powerpc,
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so this change is restricted to the 64-bit variants.
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Flag translation is needed because of hardware differences between the
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POWER implementation (read and write flags) and the Intel implementation
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(write and read+write flags).
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diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h b/sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h
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new file mode 100644
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index 0000000000000000..623b073d5a585d51
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--- /dev/null
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+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h
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@@ -0,0 +1,55 @@
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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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+
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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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+
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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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+
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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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+
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+#ifndef _ARCH_PKEY_H
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+#define _ARCH_PKEY_H
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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+#endif /* _ARCH_PKEY_H */
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diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_get.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_get.c
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new file mode 100644
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index 0000000000000000..856ba061b90eabd2
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--- /dev/null
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+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_get.c
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@@ -0,0 +1,42 @@
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+/* Reading the per-thread memory protection key, powerpc64 version.
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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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+
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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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+
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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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+
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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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+
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+#include <arch-pkey.h>
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+#include <errno.h>
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+#include <sys/mman.h>
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+
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+int
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+pkey_get (int key)
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+{
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+ if (key < 0 || key > PKEY_MAX)
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+ {
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+ __set_errno (EINVAL);
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+ return -1;
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+ }
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+ unsigned int index = pkey_index (key);
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+ unsigned long int amr = pkey_read ();
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+ unsigned int bits = (amr >> index) & 3;
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+
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+ /* Translate from AMR values. PKEY_AMR_READ standing alone is not
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+ currently representable. */
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+ if (bits & PKEY_AMR_READ)
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+ return PKEY_DISABLE_ACCESS;
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+ else if (bits == PKEY_AMR_WRITE)
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+ return PKEY_DISABLE_WRITE;
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+ return 0;
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+}
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diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_set.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_set.c
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new file mode 100644
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index 0000000000000000..20b372ee2983abd5
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--- /dev/null
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+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_set.c
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@@ -0,0 +1,48 @@
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+/* Changing the per-thread memory protection key, powerpc64 version.
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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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+
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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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+
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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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+
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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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+
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+#include <arch-pkey.h>
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+#include <errno.h>
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+#include <sys/mman.h>
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+
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+int
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+pkey_set (int key, unsigned int rights)
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+{
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+ if (key < 0 || key > PKEY_MAX || rights > 3)
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+ {
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+ __set_errno (EINVAL);
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+ return -1;
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+ }
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+
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+ /* Translate to AMR bit values. */
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+ unsigned long int bits;
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+ if (rights & PKEY_DISABLE_ACCESS)
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+ /* The PKEY_DISABLE_WRITE bit does not matter. */
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+ bits = PKEY_AMR_READ | PKEY_AMR_WRITE;
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+ else if (rights == PKEY_DISABLE_WRITE)
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+ bits = PKEY_AMR_WRITE;
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+ else
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+ bits = 0;
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+
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+ unsigned int index = pkey_index (key);
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+ unsigned long int mask = 3UL << index;
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+ unsigned long int amr = pkey_read ();
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+ amr = (amr & ~mask) | (bits << index);
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+ pkey_write (amr);
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+ return 0;
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+}
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