[PATCH] i386: Avoid overwriting the current pgd (V4, i386)
kexec: Avoid overwriting the current pgd (V4, i386)
This patch upgrades the i386-specific kexec code to avoid overwriting the
current pgd. Overwriting the current pgd is bad when CONFIG_CRASH_DUMP is used
to start a secondary kernel that dumps the memory of the previous kernel.
The code introduces a new set of page tables. These tables are used to provide
an executable identity mapping without overwriting the current pgd.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/include/asm-i386/kexec.h b/include/asm-i386/kexec.h
index 53f0e06..4dfc9f5 100644
--- a/include/asm-i386/kexec.h
+++ b/include/asm-i386/kexec.h
@@ -1,6 +1,26 @@
#ifndef _I386_KEXEC_H
#define _I386_KEXEC_H
+#define PA_CONTROL_PAGE 0
+#define VA_CONTROL_PAGE 1
+#define PA_PGD 2
+#define VA_PGD 3
+#define PA_PTE_0 4
+#define VA_PTE_0 5
+#define PA_PTE_1 6
+#define VA_PTE_1 7
+#ifdef CONFIG_X86_PAE
+#define PA_PMD_0 8
+#define VA_PMD_0 9
+#define PA_PMD_1 10
+#define VA_PMD_1 11
+#define PAGES_NR 12
+#else
+#define PAGES_NR 8
+#endif
+
+#ifndef __ASSEMBLY__
+
#include <asm/fixmap.h>
#include <asm/ptrace.h>
#include <asm/string.h>
@@ -72,5 +92,12 @@
newregs->eip = (unsigned long)current_text_addr();
}
}
+asmlinkage NORET_TYPE void
+relocate_kernel(unsigned long indirection_page,
+ unsigned long control_page,
+ unsigned long start_address,
+ unsigned int has_pae) ATTRIB_NORET;
+
+#endif /* __ASSEMBLY__ */
#endif /* _I386_KEXEC_H */