From: Andrei Vagin <avagin@gmail.com> To: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Andrei Vagin <avagin@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Dmitry Safonov <dima@arista.com> Subject: [PATCH 2/5] arm64/vdso: Zap vvar pages when switching to a time namespace Date: Tue, 4 Feb 2020 09:59:10 -0800 [thread overview] Message-ID: <20200204175913.74901-3-avagin@gmail.com> (raw) In-Reply-To: <20200204175913.74901-1-avagin@gmail.com> The VVAR page layout depends on whether a task belongs to the root or non-root time namespace. Whenever a task changes its namespace, the VVAR page tables are cleared and then they will be re-faulted with a corresponding layout. Signed-off-by: Andrei Vagin <avagin@gmail.com> --- arch/arm64/kernel/vdso.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index c4b4758eaf0b..5ef808ddf08c 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -131,6 +131,38 @@ static int __vdso_init(enum arch_vdso_type arch_index) return 0; } +#ifdef CONFIG_TIME_NS +/* + * The vvar page layout depends on whether a task belongs to the root or + * non-root time namespace. Whenever a task changes its namespace, the VVAR + * page tables are cleared and then they will re-faulted with a + * corresponding layout. + * See also the comment near timens_setup_vdso_data() for details. + */ +int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) +{ + struct mm_struct *mm = task->mm; + struct vm_area_struct *vma; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + unsigned long size = vma->vm_end - vma->vm_start; + + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO].dm)) + zap_page_range(vma, vma->vm_start, size); +#ifdef CONFIG_COMPAT_VDSO + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO32].dm)) + zap_page_range(vma, vma->vm_start, size); +#endif + } + + up_write(&mm->mmap_sem); + return 0; +} +#endif + static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { -- 2.24.1
WARNING: multiple messages have this Message-ID (diff)
From: Andrei Vagin <avagin@gmail.com> To: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de>, Andrei Vagin <avagin@gmail.com>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Dmitry Safonov <dima@arista.com> Subject: [PATCH 2/5] arm64/vdso: Zap vvar pages when switching to a time namespace Date: Tue, 4 Feb 2020 09:59:10 -0800 [thread overview] Message-ID: <20200204175913.74901-3-avagin@gmail.com> (raw) In-Reply-To: <20200204175913.74901-1-avagin@gmail.com> The VVAR page layout depends on whether a task belongs to the root or non-root time namespace. Whenever a task changes its namespace, the VVAR page tables are cleared and then they will be re-faulted with a corresponding layout. Signed-off-by: Andrei Vagin <avagin@gmail.com> --- arch/arm64/kernel/vdso.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index c4b4758eaf0b..5ef808ddf08c 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -131,6 +131,38 @@ static int __vdso_init(enum arch_vdso_type arch_index) return 0; } +#ifdef CONFIG_TIME_NS +/* + * The vvar page layout depends on whether a task belongs to the root or + * non-root time namespace. Whenever a task changes its namespace, the VVAR + * page tables are cleared and then they will re-faulted with a + * corresponding layout. + * See also the comment near timens_setup_vdso_data() for details. + */ +int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) +{ + struct mm_struct *mm = task->mm; + struct vm_area_struct *vma; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + unsigned long size = vma->vm_end - vma->vm_start; + + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO].dm)) + zap_page_range(vma, vma->vm_start, size); +#ifdef CONFIG_COMPAT_VDSO + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO32].dm)) + zap_page_range(vma, vma->vm_start, size); +#endif + } + + up_write(&mm->mmap_sem); + return 0; +} +#endif + static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { -- 2.24.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-02-04 17:59 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-04 17:59 [PATCH 0/5] arm64: add the time namespace support Andrei Vagin 2020-02-04 17:59 ` Andrei Vagin 2020-02-04 17:59 ` [PATCH 1/5] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin 2020-02-04 17:59 ` Andrei Vagin 2020-02-20 12:36 ` Vincenzo Frascino 2020-02-20 12:36 ` Vincenzo Frascino 2020-02-04 17:59 ` Andrei Vagin [this message] 2020-02-04 17:59 ` [PATCH 2/5] arm64/vdso: Zap vvar pages when switching to a time namespace Andrei Vagin 2020-02-04 17:59 ` [PATCH 3/5] arm64/vdso: Add time napespace page Andrei Vagin 2020-02-04 17:59 ` Andrei Vagin 2020-02-20 12:03 ` Vincenzo Frascino 2020-02-20 12:03 ` Vincenzo Frascino 2020-02-04 17:59 ` [PATCH 4/5] arm64/vdso: Handle faults on timens page Andrei Vagin 2020-02-04 17:59 ` Andrei Vagin 2020-02-20 12:07 ` Vincenzo Frascino 2020-02-20 12:07 ` Vincenzo Frascino 2020-02-04 17:59 ` [PATCH 5/5] arm64/vdso: Restrict splitting VVAR VMA Andrei Vagin 2020-02-04 17:59 ` Andrei Vagin 2020-02-20 12:22 ` Vincenzo Frascino 2020-02-20 12:22 ` Vincenzo Frascino 2020-02-23 23:30 ` Andrei Vagin 2020-02-23 23:30 ` Andrei Vagin 2020-02-24 10:08 ` Vincenzo Frascino 2020-02-24 10:08 ` Vincenzo Frascino 2020-02-17 15:34 ` [PATCH 0/5] arm64: add the time namespace support Andrei Vagin 2020-02-17 15:34 ` Andrei Vagin 2020-02-17 18:25 ` Vincenzo Frascino 2020-02-17 18:25 ` Vincenzo Frascino 2020-02-20 12:40 ` Vincenzo Frascino 2020-02-20 12:40 ` Vincenzo Frascino 2020-02-23 8:08 ` Andrei Vagin 2020-02-23 8:08 ` Andrei Vagin
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