Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon, 25 Jun 2018 15:38:53 -0700
From: Thomas Garnier <>
Cc: Thomas Garnier <>, Thomas Gleixner <>, 
	Ingo Molnar <>, "H. Peter Anvin" <>,, 
	"Kirill A. Shutemov" <>, Tom Lendacky <>,
Subject: [PATCH v5 05/27] x86: relocate_kernel - Adapt assembly for PIE support

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 extend the
KASLR randomization range 0xffffffff80000000.

Signed-off-by: Thomas Garnier <>
 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 */
+	.quad virtual_mapped
 	movq	RSP(%r8), %rsp

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.