From: Alexandru Elisei <alexandru.elisei@arm.com>
To: Nikos Nikoleris <nikos.nikoleris@arm.com>, kvm@vger.kernel.org
Cc: drjones@redhat.com
Subject: Re: [kvm-unit-tests PATCH 3/4] arm/arm64: Track whether thread_info has been initialized
Date: Mon, 22 Mar 2021 10:34:14 +0000 [thread overview]
Message-ID: <9325d09d-aa0b-0715-f013-8926de3673cb@arm.com> (raw)
In-Reply-To: <20210319122414.129364-4-nikos.nikoleris@arm.com>
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@arm.com>
> ---
> 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)
next prev parent reply other threads:[~2021-03-22 10:34 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 12:24 [kvm-unit-tests PATCH 0/4] RFC: Minor arm/arm64 MMU fixes and checks Nikos Nikoleris
2021-03-19 12:24 ` [kvm-unit-tests PATCH 1/4] arm/arm64: Avoid calling cpumask_test_cpu for CPUs above nr_cpu Nikos Nikoleris
2021-03-22 9:31 ` Andrew Jones
2021-03-22 9:45 ` Nikos Nikoleris
2021-03-22 10:12 ` Andrew Jones
2021-03-22 10:40 ` Nikos Nikoleris
2021-03-22 10:53 ` Andrew Jones
2021-03-19 12:24 ` [kvm-unit-tests PATCH 2/4] arm/arm64: Read system registers to get the state of the MMU Nikos Nikoleris
2021-03-22 10:30 ` Alexandru Elisei
2021-03-22 11:14 ` Nikos Nikoleris
2021-03-22 15:25 ` Alexandru Elisei
2021-03-19 12:24 ` [kvm-unit-tests PATCH 3/4] arm/arm64: Track whether thread_info has been initialized Nikos Nikoleris
2021-03-22 10:34 ` Alexandru Elisei [this message]
2021-03-22 10:59 ` Nikos Nikoleris
2021-03-22 12:11 ` Andrew Jones
2021-03-19 12:24 ` [kvm-unit-tests PATCH 4/4] arm/arm64: Add sanity checks to the cpumask API Nikos Nikoleris
2021-03-23 11:24 ` [kvm-unit-tests PATCH 0/4] RFC: Minor arm/arm64 MMU fixes and checks Andrew Jones
2021-03-23 11:40 ` Alexandru Elisei
2021-03-23 11:51 ` Andrew Jones
2021-03-23 12:15 ` Nikos Nikoleris
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