kexec fails to boot kernels where CONFIG_RANDOMIZE_BASE=y is set
Thomas D.
whissi at whissi.de
Fri Aug 22 06:23:32 PDT 2014
Hi,
the patch works!
I am able to reboot my system using kexec when the kernel has this patch.
I had to slightly modify the patch, so it will apply against linux-3.15.10:
--- arch/x86/boot/compressed/misc.c.old 2014-08-22 14:52:20.792158801 +0200
+++ arch/x86/boot/compressed/misc.c 2014-08-22 14:58:21.250506919 +0200
@@ -230,8 +230,9 @@
asm("hlt");
}
-#if CONFIG_X86_NEED_RELOCS
-static void handle_relocations(void *output, unsigned long output_len)
+#ifdef CONFIG_X86_NEED_RELOCS
+static void handle_relocations(void *output_orig, void *output,
+ unsigned long output_len)
{
int *reloc;
unsigned long delta, map, ptr;
@@ -242,7 +243,7 @@
* Calculate the delta between where vmlinux was linked to load
* and where it was actually loaded.
*/
- delta = min_addr - LOAD_PHYSICAL_ADDR;
+ delta = min_addr - (unsigned long)output_orig;
if (!delta) {
debug_putstr("No relocation needed... ");
return;
@@ -299,7 +300,8 @@
#endif
}
#else
-static inline void handle_relocations(void *output, unsigned long
output_len)
+static inline void handle_relocations(void *output_orig, void *output,
+ unsigned long output_len)
{ }
#endif
@@ -360,6 +362,8 @@
unsigned char *output,
unsigned long output_len)
{
+ unsigned char *output_orig = output;
+
real_mode = rmode;
sanitize_boot_params(real_mode);
@@ -402,7 +406,7 @@
debug_putstr("\nDecompressing Linux... ");
decompress(input_data, input_len, NULL, NULL, output, NULL, error);
parse_elf(output);
- handle_relocations(output, output_len);
+ handle_relocations(output_orig, output, output_len);
debug_putstr("done.\nBooting the kernel.\n");
return output;
}
So now we have two "solutions":
1) Using kexec with "--entry-32bit" parameter
2) Use a patched kernel
-Thomas
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