[RFC PATCH v3 21/22] arm64: Define TIF_PATCH_PENDING for livepatch

[madvenka at linux.microsoft.com]

From: "Madhavan T. Venkataraman" <madvenka at linux.microsoft.com>

	- Define TIF_PATCH_PENDING in arch/arm64/include/asm/thread_info.h
	  for livepatch.

	- Check TIF_PATCH_PENDING in do_notify_resume() to patch the
	  current task for livepatch.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh at gmail.com>
Signed-off-by: Madhavan T. Venkataraman <madvenka at linux.microsoft.com>
---
 arch/arm64/include/asm/thread_info.h | 4 +++-
 arch/arm64/kernel/signal.c           | 4 ++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 848739c15de8..42ba9d37e8d8 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -68,6 +68,7 @@ int arch_dup_task_struct(struct task_struct *dst,
 #define TIF_UPROBE		4	/* uprobe breakpoint or singlestep */
 #define TIF_MTE_ASYNC_FAULT	5	/* MTE Asynchronous Tag Check Fault */
 #define TIF_NOTIFY_SIGNAL	6	/* signal notifications exist */
+#define TIF_PATCH_PENDING	7	/* pending live patching update */
 #define TIF_SYSCALL_TRACE	8	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	9	/* syscall auditing */
 #define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
@@ -100,11 +101,12 @@ int arch_dup_task_struct(struct task_struct *dst,
 #define _TIF_SVE		(1 << TIF_SVE)
 #define _TIF_MTE_ASYNC_FAULT	(1 << TIF_MTE_ASYNC_FAULT)
 #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
+#define _TIF_PATCH_PENDING	(1 << TIF_PATCH_PENDING)
 
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
 				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
 				 _TIF_UPROBE | _TIF_MTE_ASYNC_FAULT | \
-				 _TIF_NOTIFY_SIGNAL)
+				 _TIF_NOTIFY_SIGNAL | _TIF_PATCH_PENDING)
 
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 9ad911f1647c..dea21ba60ff1 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -17,6 +17,7 @@
 #include <linux/sizes.h>
 #include <linux/string.h>
 #include <linux/resume_user_mode.h>
+#include <linux/livepatch.h>
 #include <linux/ratelimit.h>
 #include <linux/syscalls.h>
 
@@ -1120,6 +1121,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
 					       (void __user *)NULL, current);
 			}
 
+			if (thread_flags & _TIF_PATCH_PENDING)
+				klp_update_patch_state(current);
+
 			if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
 				do_signal(regs);
 
-- 
2.25.1