From: Thomas Garnier <thgar...@google.com>
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 <thgar...@google.com>
---
arch/x86/include/asm/processor.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c34a35c78618..5490a6ead17c 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -710,11 +710,13 @@ static inline void sync_core(void)
"pushfq\n\t"
"mov %%cs, %0\n\t"
"pushq %q0\n\t"
- "pushq $1f\n\t"
+ "movabsq $1f, %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
}
--
2.21.0.1020.gf2820cf01a-goog
