Change the assembly code to use only relative references of symbols for the
kernel to be PIE compatible.

Position Independent Executable (PIE) support will allow to extended the
KASLR randomization range below the -2G memory limit.

Signed-off-by: Thomas Garnier <thgar...@google.com>
---
 arch/x86/kernel/relocate_kernel_64.S | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/relocate_kernel_64.S 
b/arch/x86/kernel/relocate_kernel_64.S
index 11eda21eb697..a7227dfe1a2b 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -208,9 +208,11 @@ identity_mapped:
        movq    %rax, %cr3
        lea     PAGE_SIZE(%r8), %rsp
        call    swap_pages
-       movq    $virtual_mapped, %rax
-       pushq   %rax
-       ret
+       jmp     *virtual_mapped_addr(%rip)
+
+       /* Absolute value for PIE support */
+virtual_mapped_addr:
+       .quad virtual_mapped
 
 virtual_mapped:
        movq    RSP(%r8), %rsp
-- 
2.16.2.660.g709887971b-goog

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