[v10,06/11] x86/CPU: Adapt assembly for PIE support
diff mbox series

Message ID 20191205000957.112719-7-thgarnie@chromium.org
State New
Headers show
Series
  • x86: PIE support to extend KASLR randomization
Related show

Commit Message

Thomas Garnier Dec. 5, 2019, 12:09 a.m. UTC
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 below 0xffffffff80000000.

Signed-off-by: Thomas Garnier <thgarnie@chromium.org>
---
 arch/x86/include/asm/processor.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch
diff mbox series

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 0340aad3f2fc..77fa291a60bb 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -742,11 +742,13 @@  static inline void sync_core(void)
 		"pushfq\n\t"
 		"mov %%cs, %0\n\t"
 		"pushq %q0\n\t"
-		"pushq $1f\n\t"
+		"leaq 1f(%%rip), %q0\n\t"
+		"pushq %q0\n\t"
 		"iretq\n\t"
 		UNWIND_HINT_RESTORE
 		"1:"
-		: "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+		: "=&r" (tmp), ASM_CALL_CONSTRAINT
+		: : "cc", "memory");
 #endif
 }