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From: Florian Weimer <fweimer@redhat.com>
To: Gavin Shan <gshan@redhat.com>
Cc: shan.gavin@gmail.com, kvm@vger.kernel.org, maz@kernel.org,
	linux-kernel@vger.kernel.org, andrew.jones@linux.dev,
	mathieu.desnoyers@efficios.com, yihyu@redhat.com,
	linux-kselftest@vger.kernel.org, pbonzini@redhat.com,
	kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 1/2] KVM: selftests: Make rseq compatible with glibc-2.35
Date: Tue, 09 Aug 2022 08:33:31 +0200	[thread overview]
Message-ID: <8735e6ncxw.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20220809060627.115847-2-gshan@redhat.com> (Gavin Shan's message of "Tue, 9 Aug 2022 14:06:26 +0800")

* Gavin Shan:

> diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
> index a54d4d05a058..acb1bf1f06b3 100644
> --- a/tools/testing/selftests/kvm/rseq_test.c
> +++ b/tools/testing/selftests/kvm/rseq_test.c
> @@ -9,6 +9,7 @@
>  #include <string.h>
>  #include <signal.h>
>  #include <syscall.h>
> +#include <dlfcn.h>
>  #include <sys/ioctl.h>
>  #include <sys/sysinfo.h>
>  #include <asm/barrier.h>

I'm surprised that there isn't a Makefile update to link with -ldl
(still required for glibc 2.33 and earlier).

> @@ -36,6 +37,8 @@ static __thread volatile struct rseq __rseq = {
>   */
>  #define NR_TASK_MIGRATIONS 100000
>  
> +static bool __rseq_ownership;
> +static volatile struct rseq *__rseq_info;
>  static pthread_t migration_thread;
>  static cpu_set_t possible_mask;
>  static int min_cpu, max_cpu;
> @@ -49,11 +52,33 @@ static void guest_code(void)
>  		GUEST_SYNC(0);
>  }
>  
> +static void sys_rseq_ownership(void)
> +{
> +	long *offset;
> +	unsigned int *size, *flags;
> +
> +	offset = dlsym(RTLD_NEXT, "__rseq_offset");
> +	size = dlsym(RTLD_NEXT, "__rseq_size");
> +	flags = dlsym(RTLD_NEXT, "__rseq_flags");
> +
> +	if (offset && size && *size && flags) {
> +		__rseq_ownership = false;
> +		__rseq_info = (struct rseq *)((uintptr_t)__builtin_thread_pointer() +
> +					      *offset);

__builtin_thread_pointer doesn't work on all architectures/GCC versions.
Is this a problem for selftests?

Thanks,
Florian

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kvmarm@lists.cs.columbia.edu
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WARNING: multiple messages have this Message-ID (diff)
From: Florian Weimer <fweimer@redhat.com>
To: Gavin Shan <gshan@redhat.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	pbonzini@redhat.com, maz@kernel.org, oliver.upton@linux.dev,
	andrew.jones@linux.dev, seanjc@google.com,
	mathieu.desnoyers@efficios.com, yihyu@redhat.com,
	shan.gavin@gmail.com
Subject: Re: [PATCH 1/2] KVM: selftests: Make rseq compatible with glibc-2.35
Date: Tue, 09 Aug 2022 08:33:31 +0200	[thread overview]
Message-ID: <8735e6ncxw.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20220809060627.115847-2-gshan@redhat.com> (Gavin Shan's message of "Tue, 9 Aug 2022 14:06:26 +0800")

* Gavin Shan:

> diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
> index a54d4d05a058..acb1bf1f06b3 100644
> --- a/tools/testing/selftests/kvm/rseq_test.c
> +++ b/tools/testing/selftests/kvm/rseq_test.c
> @@ -9,6 +9,7 @@
>  #include <string.h>
>  #include <signal.h>
>  #include <syscall.h>
> +#include <dlfcn.h>
>  #include <sys/ioctl.h>
>  #include <sys/sysinfo.h>
>  #include <asm/barrier.h>

I'm surprised that there isn't a Makefile update to link with -ldl
(still required for glibc 2.33 and earlier).

> @@ -36,6 +37,8 @@ static __thread volatile struct rseq __rseq = {
>   */
>  #define NR_TASK_MIGRATIONS 100000
>  
> +static bool __rseq_ownership;
> +static volatile struct rseq *__rseq_info;
>  static pthread_t migration_thread;
>  static cpu_set_t possible_mask;
>  static int min_cpu, max_cpu;
> @@ -49,11 +52,33 @@ static void guest_code(void)
>  		GUEST_SYNC(0);
>  }
>  
> +static void sys_rseq_ownership(void)
> +{
> +	long *offset;
> +	unsigned int *size, *flags;
> +
> +	offset = dlsym(RTLD_NEXT, "__rseq_offset");
> +	size = dlsym(RTLD_NEXT, "__rseq_size");
> +	flags = dlsym(RTLD_NEXT, "__rseq_flags");
> +
> +	if (offset && size && *size && flags) {
> +		__rseq_ownership = false;
> +		__rseq_info = (struct rseq *)((uintptr_t)__builtin_thread_pointer() +
> +					      *offset);

__builtin_thread_pointer doesn't work on all architectures/GCC versions.
Is this a problem for selftests?

Thanks,
Florian


  reply	other threads:[~2022-08-09 10:28 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-09  6:06 [PATCH 0/2] kvm/selftests: Two rseq_test fixes Gavin Shan
2022-08-09  6:06 ` Gavin Shan
2022-08-09  6:06 ` [PATCH 1/2] KVM: selftests: Make rseq compatible with glibc-2.35 Gavin Shan
2022-08-09  6:06   ` Gavin Shan
2022-08-09  6:33   ` Florian Weimer [this message]
2022-08-09  6:33     ` Florian Weimer
2022-08-09  8:45     ` Gavin Shan
2022-08-09  8:45       ` Gavin Shan
2022-08-09  7:16       ` Florian Weimer
2022-08-09  7:16         ` Florian Weimer
2022-08-09  9:27         ` Gavin Shan
2022-08-09  9:27           ` Gavin Shan
2022-08-09 12:21           ` Mathieu Desnoyers
2022-08-09 12:21             ` Mathieu Desnoyers
2022-08-09 13:44             ` Mathieu Desnoyers
2022-08-09 13:44               ` Mathieu Desnoyers
2022-08-09 21:38               ` Sean Christopherson
2022-08-09 21:38                 ` Sean Christopherson
2022-08-10  0:37                 ` Gavin Shan
2022-08-10  0:37                   ` Gavin Shan
2022-08-10 12:29                   ` Mathieu Desnoyers
2022-08-10 12:29                     ` Mathieu Desnoyers
2022-08-10 12:35                     ` Paolo Bonzini
2022-08-10 12:35                       ` Paolo Bonzini
2022-08-10 12:13                 ` Mathieu Desnoyers
2022-08-10 12:13                   ` Mathieu Desnoyers
2022-08-10 23:52                   ` Gavin Shan
2022-08-10 23:52                     ` Gavin Shan
2022-08-10  9:14             ` Paolo Bonzini
2022-08-10  9:14               ` Paolo Bonzini
2022-08-10  9:59               ` Gavin Shan
2022-08-10  9:59                 ` Gavin Shan
2022-08-10 12:17               ` Mathieu Desnoyers
2022-08-10 12:17                 ` Mathieu Desnoyers
2022-08-10 12:19                 ` Paolo Bonzini
2022-08-10 12:19                   ` Paolo Bonzini
2022-08-10 23:34                   ` Gavin Shan
2022-08-10 23:34                     ` Gavin Shan
2022-08-09  6:06 ` [PATCH 2/2] KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test Gavin Shan
2022-08-09  6:06   ` Gavin Shan
2022-08-09  6:35   ` Florian Weimer
2022-08-09  6:35     ` Florian Weimer
2022-08-09  7:17     ` Florian Weimer
2022-08-09  7:17       ` Florian Weimer
2022-08-09  8:46       ` Gavin Shan
2022-08-09  8:46         ` Gavin Shan
2022-08-09 20:53         ` Sean Christopherson
2022-08-09 20:53           ` Sean Christopherson
2022-08-10  0:45           ` Gavin Shan
2022-08-10  0:45             ` Gavin Shan

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