| Message ID | 20190708174913.123308-7-thgarnie@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: PIE support to extend KASLR randomization | expand |
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) "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 }
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(-)