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 | 14 ++++++++++++++
kernel/sys.c | 16 ++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index a5e06dcbba13..b4720e8de6f3 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -281,6 +281,20 @@ struct prctl_mm_map {
# define PR_SME_VL_LEN_MASK 0xffff
# define PR_SME_VL_INHERIT (1 << 17) /* inherit across exec */
+/* PowerPC Dynamic Execution Control Register (DEXCR) controls */
+#define PR_PPC_GET_DEXCR 65
+#define PR_PPC_SET_DEXCR 66
+/* 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_PRCTL (1 << 0)
+# define PR_PPC_DEXCR_SET_ASPECT (1 << 1)
+# define PR_PPC_DEXCR_FORCE_SET_ASPECT (1 << 2)
+# define PR_PPC_DEXCR_CLEAR_ASPECT (1 << 3)
+
#define PR_SET_VMA 0x53564d41
# define PR_SET_VMA_ANON_NAME 0
diff --git a/kernel/sys.c b/kernel/sys.c
index 5fd54bf0e886..55b8f7369059 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -139,6 +139,12 @@
#ifndef GET_TAGGED_ADDR_CTRL
# define GET_TAGGED_ADDR_CTRL() (-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
@@ -2623,6 +2629,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2,
unsigned long, arg3,
error = sched_core_share_pid(arg2, arg3, arg4, arg5);
break;
#endif
+ 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;
--
2.38.1
