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

Prasanna Kumar T S M
2025-01-30T09:54:55Z

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>.