[v8,06/11] x86/CPU: Adapt assembly for PIE support
diff mbox series

Message ID 20190708174913.123308-7-thgarnie@chromium.org
State New
Headers show
  • x86: PIE support to extend KASLR randomization
Related show

Commit Message

Thomas Garnier July 8, 2019, 5:48 p.m. UTC
Change the assembly code to use only relative references of symbols for the
kernel to be PIE compatible. Use the new _ASM_MOVABS macro instead of
the 'mov $symbol, %dst' construct.

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(-)

diff mbox series

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 3eab6ece52b4..3e2154b0e09f 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -713,11 +713,13 @@  static inline void sync_core(void)
 		"mov %%cs, %0\n\t"
 		"pushq %q0\n\t"
-		"pushq $1f\n\t"
+		"movabsq $1f, %q0\n\t"
+		"pushq %q0\n\t"
-		: "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+		: "=&r" (tmp), ASM_CALL_CONSTRAINT
+		: : "cc", "memory");