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

madvenka
2023-02-02T07:44:03Z

From: "Madhavan T. Venkataraman" <madvenka@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@gmail.com>
Signed-off-by: Madhavan T. Venkataraman <madvenka@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