glibc/SOURCES/glibc-rh1642150-1.patch
2021-09-16 08:48:07 +00:00

177 lines
6.1 KiB
Diff

commit a803367bab167f5ec4fde1f0d0ec447707c29520
Author: Florian Weimer <fweimer@redhat.com>
Date: Fri Feb 14 20:55:39 2020 +0100
powerpc64: Add memory protection key support [BZ #23202]
The 32-bit protection key behavior is somewhat unclear on 32-bit powerpc,
so this change is restricted to the 64-bit variants.
Flag translation is needed because of hardware differences between the
POWER implementation (read and write flags) and the Intel implementation
(write and read+write flags).
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h b/sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h
new file mode 100644
index 0000000000000000..623b073d5a585d51
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h
@@ -0,0 +1,55 @@
+/* Helper functions for manipulating memory protection keys, for powerpc64.
+ Copyright (C) 2017-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _ARCH_PKEY_H
+#define _ARCH_PKEY_H
+
+/* Read and write access bits in the AMR register. Needs to be
+ translated from and to PKEY_DISABLE_* flags. */
+#define PKEY_AMR_READ 1UL
+#define PKEY_AMR_WRITE 2UL
+
+/* Return the value of the AMR register. */
+static inline unsigned long int
+pkey_read (void)
+{
+ unsigned long int result;
+ __asm__ volatile ("mfspr %0, 13" : "=r" (result));
+ return result;
+}
+
+/* Overwrite the AMR register with VALUE. */
+static inline void
+pkey_write (unsigned long int value)
+{
+ __asm__ volatile ("mtspr 13, %0" : : "r" (value));
+}
+
+/* Number of the largest supported key. This depends on the width of
+ the AMR register. */
+#define PKEY_MAX (sizeof (unsigned long int) * 8 / 2 - 1)
+_Static_assert (PKEY_MAX == 15 || PKEY_MAX == 31, "PKEY_MAX value");
+
+/* Translate key number into AMR index position. */
+static inline int
+pkey_index (int key)
+{
+ return 2 * (PKEY_MAX - key);
+}
+
+#endif /* _ARCH_PKEY_H */
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_get.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_get.c
new file mode 100644
index 0000000000000000..856ba061b90eabd2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_get.c
@@ -0,0 +1,42 @@
+/* Reading the per-thread memory protection key, powerpc64 version.
+ Copyright (C) 2017-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <arch-pkey.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+int
+pkey_get (int key)
+{
+ if (key < 0 || key > PKEY_MAX)
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+ unsigned int index = pkey_index (key);
+ unsigned long int amr = pkey_read ();
+ unsigned int bits = (amr >> index) & 3;
+
+ /* Translate from AMR values. PKEY_AMR_READ standing alone is not
+ currently representable. */
+ if (bits & PKEY_AMR_READ)
+ return PKEY_DISABLE_ACCESS;
+ else if (bits == PKEY_AMR_WRITE)
+ return PKEY_DISABLE_WRITE;
+ return 0;
+}
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_set.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_set.c
new file mode 100644
index 0000000000000000..20b372ee2983abd5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/pkey_set.c
@@ -0,0 +1,48 @@
+/* Changing the per-thread memory protection key, powerpc64 version.
+ Copyright (C) 2017-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <arch-pkey.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+int
+pkey_set (int key, unsigned int rights)
+{
+ if (key < 0 || key > PKEY_MAX || rights > 3)
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+
+ /* Translate to AMR bit values. */
+ unsigned long int bits;
+ if (rights & PKEY_DISABLE_ACCESS)
+ /* The PKEY_DISABLE_WRITE bit does not matter. */
+ bits = PKEY_AMR_READ | PKEY_AMR_WRITE;
+ else if (rights == PKEY_DISABLE_WRITE)
+ bits = PKEY_AMR_WRITE;
+ else
+ bits = 0;
+
+ unsigned int index = pkey_index (key);
+ unsigned long int mask = 3UL << index;
+ unsigned long int amr = pkey_read ();
+ amr = (amr & ~mask) | (bits << index);
+ pkey_write (amr);
+ return 0;
+}