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authorXunlei Pang <xlpang@redhat.com>2016-05-23 16:24:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-23 17:04:14 -0700
commit1e5768ae7500e7ce6eb73e1b263574d5c19606cf (patch)
treef1ee8f6df689552e38c926fb2d028a8a5d358b93 /arch
parent9b492cf58077a0254eb4b9574029ac6e79add9f9 (diff)
downloadlinux-1e5768ae7500e7ce6eb73e1b263574d5c19606cf.tar.bz2
kexec: provide arch_kexec_protect(unprotect)_crashkres()
Implement the protection method for the crash kernel memory reservation for the 64-bit x86 kdump. Signed-off-by: Xunlei Pang <xlpang@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Dave Young <dyoung@redhat.com> Cc: Minfei Huang <mhuang@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/machine_kexec_64.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index ba7fbba9831b..5a294e48b185 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -538,3 +538,48 @@ 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]. We must skip the unassigned
+ * crashk resource with zero-valued "end" member.
+ */
+ if (!end || start > end)
+ return 0;
+
+ page = pfn_to_page(start >> PAGE_SHIFT);
+ nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
+ 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);
+ control += KEXEC_CONTROL_PAGE_SIZE;
+ kexec_mark_range(control, crashk_res.end, protect);
+}
+
+void arch_kexec_protect_crashkres(void)
+{
+ kexec_mark_crashkres(true);
+}
+
+void arch_kexec_unprotect_crashkres(void)
+{
+ kexec_mark_crashkres(false);
+}