Adds the definitions and generic handler for prctl control of the
PowerPC Dynamic Execution Control Register (DEXCR).
Signed-off-by: Benjamin Gray <bg...@linux.ibm.com>
---
include/uapi/linux/prctl.h | 13 +++++++++++++
kernel/sys.c | 16 ++++++++++++++++
2 files changed, 29 insertions(+)
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 3c36aeade991..85d66ad134b1 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -305,4 +305,17 @@ struct prctl_mm_map {
# define PR_RISCV_V_VSTATE_CTRL_NEXT_MASK 0xc
# define PR_RISCV_V_VSTATE_CTRL_MASK 0x1f
+/* PowerPC Dynamic Execution Control Register (DEXCR) controls */
+#define PR_PPC_GET_DEXCR 71
+#define PR_PPC_SET_DEXCR 72
+/* DEXCR aspect to act on */
+# define PR_PPC_DEXCR_SBHE 0 /* Speculative branch hint enable */
+# define PR_PPC_DEXCR_IBRTPD 1 /* Indirect branch recurrent target
prediction disable */
+# define PR_PPC_DEXCR_SRAPD 2 /* Subroutine return address
prediction disable */
+# define PR_PPC_DEXCR_NPHIE 3 /* Non-privileged hash instruction
enable */
+/* Action to apply / return */
+# define PR_PPC_DEXCR_CTRL_OFF (1UL << 0)
+# define PR_PPC_DEXCR_CTRL_ON (1UL << 1)
+# define PR_PPC_DEXCR_CTRL_INHERIT (1UL << 2)
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index 2410e3999ebe..0c1b8e9c3d16 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -146,6 +146,12 @@
#ifndef RISCV_V_GET_CONTROL
# define RISCV_V_GET_CONTROL() (-EINVAL)
#endif
+#ifndef PPC_GET_DEXCR_ASPECT
+# define PPC_GET_DEXCR_ASPECT(a, b) (-EINVAL)
+#endif
+#ifndef PPC_SET_DEXCR_ASPECT
+# define PPC_SET_DEXCR_ASPECT(a, b, c) (-EINVAL)
+#endif
/*
* this is where the system-wide overflow UID and GID are defined, for
@@ -2686,6 +2692,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2,
unsigned long, arg3,
case PR_GET_MDWE:
error = prctl_get_mdwe(arg2, arg3, arg4, arg5);
break;
+ case PR_PPC_GET_DEXCR:
+ if (arg3 || arg4 || arg5)
+ return -EINVAL;
+ error = PPC_GET_DEXCR_ASPECT(me, arg2);
+ break;
+ case PR_PPC_SET_DEXCR:
+ if (arg4 || arg5)
+ return -EINVAL;
+ error = PPC_SET_DEXCR_ASPECT(me, arg2, arg3);
+ break;
case PR_SET_VMA:
error = prctl_set_vma(arg2, arg3, arg4, arg5);
break;
--
2.41.0
