x86-64: Handle PC-relative relocations on per-CPU data

This is in preparation of using RIP-relative addressing in many of the
per-CPU accesses.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/5458A15A0200007800044A9A@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 57ab74df7eea..644abd767c12 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -260,7 +260,7 @@ static void handle_relocations(void *output, unsigned long output_len)
 
         /*
          * Process relocations: 32 bit relocations first then 64 bit after.
-         * Two sets of binary relocations are added to the end of the kernel
+         * Three sets of binary relocations are added to the end of the kernel
          * before compression. Each relocation table entry is the kernel
          * address of the location which needs to be updated stored as a
          * 32-bit value which is sign extended to 64 bits.
@@ -270,6 +270,8 @@ static void handle_relocations(void *output, unsigned long output_len)
          * kernel bits...
          * 0 - zero terminator for 64 bit relocations
          * 64 bit relocation repeated
+         * 0 - zero terminator for inverse 32 bit relocations
+         * 32 bit inverse relocation repeated
          * 0 - zero terminator for 32 bit relocations
          * 32 bit relocation repeated
          *
@@ -286,6 +288,16 @@ static void handle_relocations(void *output, unsigned long output_len)
                 *(uint32_t *)ptr += delta;
         }
 #ifdef CONFIG_X86_64
+        while (*--reloc) {
+                long extended = *reloc;
+                extended += map;
+
+                ptr = (unsigned long)extended;
+                if (ptr < min_addr || ptr > max_addr)
+                        error("inverse 32-bit relocation outside of kernel!\n");
+
+                *(int32_t *)ptr -= delta;
+        }
         for (reloc--; *reloc; reloc--) {
                 long extended = *reloc;
                 extended += map;