Re: [PATCH 7/8] arm64: Define TIF_PATCH_PENDING for livepatch

[Prasanna Kumar T S M <ptsm@linux.microsoft.com>]

On 28-01-2025 03:03, Weinan Liu wrote:
> 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>
> Signed-off-by: Weinan Liu <wnliu@google.com>
> ---
>   arch/arm64/include/asm/thread_info.h | 4 +++-
>   arch/arm64/kernel/entry-common.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 1114c1c3300a..3810c2f3914e 100644
> --- a/arch/arm64/include/asm/thread_info.h
> +++ b/arch/arm64/include/asm/thread_info.h
> @@ -64,6 +64,7 @@ void arch_setup_new_exec(void);
>   #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 */
> @@ -99,11 +100,12 @@ void arch_setup_new_exec(void);
>   #define _TIF_MTE_ASYNC_FAULT	(1 << TIF_MTE_ASYNC_FAULT)
>   #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
>   #define _TIF_TSC_SIGSEGV	(1 << TIF_TSC_SIGSEGV)
> +#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/entry-common.c b/arch/arm64/kernel/entry-common.c
> index b260ddc4d3e9..b537af333b42 100644
> --- a/arch/arm64/kernel/entry-common.c
> +++ b/arch/arm64/kernel/entry-common.c
> @@ -8,6 +8,7 @@
>   #include <linux/context_tracking.h>
>   #include <linux/kasan.h>
>   #include <linux/linkage.h>
> +#include <linux/livepatch.h>
>   #include <linux/lockdep.h>
>   #include <linux/ptrace.h>
>   #include <linux/resume_user_mode.h>
> @@ -144,6 +145,9 @@ static 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);
>   

Looks good to me.
Reviewed-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>.