x86, setup: Allow global variables and functions in the decompressor

In order for global variables and functions to work in the
decompressor, we need to fix up the GOT in assembly code.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <4C57382E.8050501@zytor.com>

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index f543b70ffae25b24e89c15bc03b17576124efc7b..67a655a39ce43d3da454b7fd8f230b70d8a9c6bc 100644 (file)
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -123,6 +123,19 @@ relocated:
        shrl    $2, %ecx
        rep     stosl
 
+/*
+ * Adjust our own GOT
+ */
+       leal    _got(%ebx), %edx
+       leal    _egot(%ebx), %ecx
+1:
+       cmpl    %ecx, %edx
+       jae     2f
+       addl    %ebx, (%edx)
+       addl    $4, %edx
+       jmp     1b
+2:
+
 /*
  * Do the decompression, and jump to the new kernel..
  */

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index faff0dc9c06a2389a405cdcb3e089baf8c7ad285..52f85a196fa033df961d20349ce6b7437409e843 100644 (file)
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -279,6 +279,19 @@ relocated:
        shrq    $3, %rcx
        rep     stosq
 
+/*
+ * Adjust our own GOT
+ */
+       leaq    _got(%rip), %rdx
+       leaq    _egot(%rip), %rcx
+1:
+       cmpq    %rcx, %rdx
+       jae     2f
+       addq    %rbx, (%rdx)
+       addq    $8, %rdx
+       jmp     1b
+2:
+       
 /*
  * Do the decompression, and jump to the new kernel..
  */

diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
index 5ddabceee12408d55f22b6412bbd4617dc684c55..34d047c982848439e7ed907cbea7b4398bf860cd 100644 (file)
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -41,6 +41,12 @@ SECTIONS
                *(.rodata.*)
                _erodata = . ;
        }
+       .got : {
+               _got = .;
+               KEEP(*(.got.plt))
+               KEEP(*(.got))
+               _egot = .;
+       }
        .data : {
                _data = . ;
                *(.data)