Implement the protection method for the crash kernel memory
reservation for the 64-bit x86 kdump.
Signed-off-by: Xunlei Pang <xlpang at redhat.com>
---
Only provided x86_64 implementation, as I've only tested on x86_64 so far.
arch/x86/kernel/machine_kexec_64.c | 43 ++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 819ab3f..a3d289c 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -536,3 +536,46 @@ overflow:
return -ENOEXEC;
}
#endif /* CONFIG_KEXEC_FILE */
+
+#ifdef CONFIG_KEXEC_CORE
+static int
+kexec_mark_range(unsigned long start, unsigned long end, bool protect)
+{
+ struct page *page;
+ unsigned int nr_pages;
+
+ if (!start || !end || start >= end)
+ return 0;
+
+ page = pfn_to_page(start >> PAGE_SHIFT);
+ nr_pages = (end + 1 - 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. */
+ control = control + PAGE_SIZE;
+ kexec_mark_range(crashk_res.start, control - 1, protect);
+ kexec_mark_range(control + 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);
+}
+#endif
--
2.5.0
