From: Andrei Vagin <avagin@gmail.com>
To: linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Dmitry Safonov <dima@arista.com>, Andrei Vagin <avagin@gmail.com>
Subject: [PATCH 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace
Date: Tue, 2 Jun 2020 11:02:55 -0700 [thread overview]
Message-ID: <20200602180259.76361-3-avagin@gmail.com> (raw)
In-Reply-To: <20200602180259.76361-1-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.
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
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 031ee1a8d4a8..33df3cdf7982 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
next prev parent reply other threads:[~2020-06-02 18:03 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 18:02 [PATCH RESEND v3 0/6] arm64: add the time namespace support Andrei Vagin
2020-06-02 18:02 ` [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin
2020-06-02 18:02 ` Andrei Vagin [this message]
2020-06-02 18:02 ` [PATCH 3/6] arm64/vdso: Add time namespace page Andrei Vagin
2020-06-02 19:29 ` Dmitry Safonov
2020-06-02 22:04 ` kbuild test robot
2020-06-03 6:42 ` kbuild test robot
2020-06-05 7:45 ` [PATCH 3/6 v4] " Andrei Vagin
2020-06-02 18:02 ` [PATCH 4/6] arm64/vdso: Handle faults on timens page Andrei Vagin
2020-06-02 18:02 ` [PATCH 5/6] arm64/vdso: Restrict splitting VVAR VMA Andrei Vagin
2020-06-02 18:02 ` [PATCH 6/6] arm64: enable time namespace support Andrei Vagin
2020-06-02 19:31 ` [PATCH RESEND v3 0/6] arm64: add the " Dmitry Safonov
2020-06-05 10:49 ` Mark Rutland
2020-06-06 8:58 ` Andrei Vagin
-- strict thread matches above, loose matches on Subject: below --
2020-06-24 8:33 [PATCH v5 " Andrei Vagin
2020-06-24 8:33 ` [PATCH 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Andrei Vagin
2020-06-24 15:18 ` Christian Brauner
2020-06-25 8:25 ` Andrei Vagin
2020-06-16 7:55 [PATCH v4 0/6] arm64: add the time namespace support Andrei Vagin
2020-06-16 7:55 ` [PATCH 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Andrei Vagin
2020-06-16 11:24 ` Mark Rutland
2020-06-16 13:47 ` Dmitry Safonov
2020-06-19 15:38 ` Christian Brauner
2020-06-23 7:33 ` Andrei Vagin
2020-06-23 8:40 ` Christian Brauner
2020-04-16 5:26 [PATCH v3 0/6] arm64: add the time namespace support Andrei Vagin
2020-04-16 5:26 ` [PATCH 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Andrei Vagin
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