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 v2 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace
Date: Mon, 24 Feb 2020 23:37:27 -0800 [thread overview]
Message-ID: <20200225073731.465270-3-avagin@gmail.com> (raw)
In-Reply-To: <20200225073731.465270-1-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 290c36d74e03..6ac9cdeac5be 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:[~2020-02-25 7:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 7:37 [PATCH v2 0/6] arm64: add the time namespace support Andrei Vagin
2020-02-25 7:37 ` [PATCH v2 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin
2020-04-09 12:01 ` Vincenzo Frascino
2020-02-25 7:37 ` Andrei Vagin [this message]
2020-04-09 12:01 ` [PATCH v2 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Vincenzo Frascino
2020-02-25 7:37 ` [PATCH v2 3/6] arm64/vdso: Add time napespace page Andrei Vagin
2020-04-09 12:03 ` Vincenzo Frascino
2020-04-14 17:20 ` Mark Rutland
2020-04-15 2:34 ` Andrei Vagin
2020-04-15 10:05 ` Mark Rutland
2020-04-15 10:16 ` Vincenzo Frascino
2020-04-15 12:27 ` Mark Rutland
2020-02-25 7:37 ` [PATCH v2 4/6] arm64/vdso: Handle faults on timens page Andrei Vagin
2020-04-09 12:04 ` Vincenzo Frascino
2020-02-25 7:37 ` [PATCH v2 5/6] arm64/vdso: Restrict splitting VVAR VMA Andrei Vagin
2020-04-09 12:05 ` Vincenzo Frascino
2020-02-25 7:37 ` [PATCH v2 6/6] arm64: enable time namespace support Andrei Vagin
2020-04-09 12:06 ` Vincenzo Frascino
2020-04-01 6:50 ` [PATCH v2 0/6] arm64: add the " Andrei Vagin
2020-04-01 9:02 ` Vincenzo Frascino
2020-04-09 13:24 ` Vincenzo Frascino
2020-04-11 7:33 ` Andrei Vagin
2020-04-14 9:02 ` Vincenzo Frascino
2020-04-15 16:14 ` Andrei Vagin
2020-04-15 16:35 ` Vincenzo Frascino
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