From: Xunlei Pang <xlpang@redhat.com>
To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org
Cc: akpm@linux-foundation.org, ebiederm@xmission.com,
Minfei Huang <mhuang@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
Dave Young <dyoung@redhat.com>, Xunlei Pang <xlpang@redhat.com>
Subject: [PATCH v2 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres()
Date: Wed, 6 Jan 2016 17:50:45 +0800 [thread overview]
Message-ID: <1452073845-1474-2-git-send-email-xlpang@redhat.com> (raw)
In-Reply-To: <1452073845-1474-1-git-send-email-xlpang@redhat.com>
Implement the protection method for the crash kernel memory
reservation for the 64-bit x86 kdump.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
---
arch/x86/kernel/machine_kexec_64.c | 41 ++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 819ab3f..cda867d 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -536,3 +536,44 @@ overflow:
return -ENOEXEC;
}
#endif /* CONFIG_KEXEC_FILE */
+
+static int
+kexec_mark_range(unsigned long start, unsigned long end, bool protect)
+{
+ struct page *page;
+ unsigned int nr_pages;
+
+ /* For physical range: [start, end] */
+ if (!start || !end || start > end)
+ return 0;
+
+ page = pfn_to_page(start >> PAGE_SHIFT);
+ nr_pages = (end + PAGE_SIZE - start) >> PAGE_SHIFT;
+ if (protect)
+ return set_pages_ro(page, nr_pages);
+ else
+ return set_pages_rw(page, nr_pages);
+}
+
+static void kexec_mark_crashkres(bool protect)
+{
+ unsigned long control;
+
+ kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
+
+ /* Don't touch the control code page used in crash_kexec().*/
+ control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
+ /* Control code page is located in the 2nd page. */
+ kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
+ kexec_mark_range(control + 2 * PAGE_SIZE, crashk_res.end, protect);
+}
+
+void arch_kexec_protect_crashkres(void)
+{
+ kexec_mark_crashkres(true);
+}
+
+void arch_kexec_unprotect_crashkres(void)
+{
+ kexec_mark_crashkres(false);
+}
--
2.5.0
next prev parent reply other threads:[~2016-01-06 9:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 9:50 [PATCH v2 1/2] kexec: Introduce a protection mechanism for the crashkernel reserved memory Xunlei Pang
2016-01-06 9:50 ` Xunlei Pang [this message]
2016-01-06 17:08 ` [PATCH v2 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres() Minfei Huang
2016-01-07 2:14 ` Xunlei Pang
2016-01-07 2:20 ` Xunlei Pang
2016-01-07 2:36 ` Minfei Huang
2016-01-07 5:08 ` Xunlei Pang
2016-01-07 9:20 ` Petr Tesarik
2016-01-07 11:14 ` Xunlei Pang
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