Hi Nikos,
On 3/19/21 12:24 PM, Nikos Nikoleris wrote:
> Introduce a new flag in the thread_info to track whether a thread_info
> struct is initialized yet or not.
There's no explanation why this is needed. The flag checked only by is_user(), and
before thread_info is initialized, flags is zero, so is_user() would return false,
right? Or am I missing something?
Thanks,
Alex
>
> Signed-off-by: Nikos Nikoleris <nikos.nikoleris@xxxxxxx>
> ---
> lib/arm/asm/thread_info.h | 1 +
> lib/arm/processor.c | 5 +++--
> lib/arm64/processor.c | 5 +++--
> 3 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/lib/arm/asm/thread_info.h b/lib/arm/asm/thread_info.h
> index eaa7258..926c2a3 100644
> --- a/lib/arm/asm/thread_info.h
> +++ b/lib/arm/asm/thread_info.h
> @@ -45,6 +45,7 @@ static inline void *thread_stack_alloc(void)
> }
>
> #define TIF_USER_MODE (1U << 0)
> +#define TIF_VALID (1U << 1)
>
> struct thread_info {
> int cpu;
> diff --git a/lib/arm/processor.c b/lib/arm/processor.c
> index a2d39a4..702fbc3 100644
> --- a/lib/arm/processor.c
> +++ b/lib/arm/processor.c
> @@ -119,7 +119,7 @@ void thread_info_init(struct thread_info *ti, unsigned int flags)
> {
> memset(ti, 0, sizeof(struct thread_info));
> ti->cpu = mpidr_to_cpu(get_mpidr());
> - ti->flags = flags;
> + ti->flags = flags | TIF_VALID;
> }
>
> void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr)
> @@ -143,7 +143,8 @@ void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr)
>
> bool is_user(void)
> {
> - return current_thread_info()->flags & TIF_USER_MODE;
> + struct thread_info *ti = current_thread_info();
> + return (ti->flags & TIF_VALID) && (ti->flags & TIF_USER_MODE);
> }
>
> bool __mmu_enabled(void)
> diff --git a/lib/arm64/processor.c b/lib/arm64/processor.c
> index ef55862..231d71e 100644
> --- a/lib/arm64/processor.c
> +++ b/lib/arm64/processor.c
> @@ -227,7 +227,7 @@ static void __thread_info_init(struct thread_info *ti, unsigned int flags)
> {
> memset(ti, 0, sizeof(struct thread_info));
> ti->cpu = mpidr_to_cpu(get_mpidr());
> - ti->flags = flags;
> + ti->flags = flags | TIF_VALID;
> }
>
> void thread_info_init(struct thread_info *ti, unsigned int flags)
> @@ -255,7 +255,8 @@ void start_usr(void (*func)(void *arg), void *arg, unsigned long sp_usr)
>
> bool is_user(void)
> {
> - return current_thread_info()->flags & TIF_USER_MODE;
> + struct thread_info *ti = current_thread_info();
> + return (ti->flags & TIF_VALID) && (ti->flags & TIF_USER_MODE);
> }
>
> bool __mmu_enabled(void)
