Use 'cmpq' to force an 8-byte CMP when checking for a user provided exit handler. The handler is a pointer, which is guaranteed to be an 8-byte value since SGX is 64-bit mode only, and gcc defaults to 'cmpl' given a bare 'cmp', i.e. is only checking the lower 32 bits. This could cause a false negative when detecting a user exit handler. Acked-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> Acked-by: Jethro Beekman <jethro@xxxxxxxxxxxx> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> --- arch/x86/entry/vdso/vsgx_enter_enclave.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/entry/vdso/vsgx_enter_enclave.S b/arch/x86/entry/vdso/vsgx_enter_enclave.S index be7e467e1efb3..2d88acd408d4e 100644 --- a/arch/x86/entry/vdso/vsgx_enter_enclave.S +++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S @@ -48,7 +48,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave) /* Invoke userspace's exit handler if one was provided. */ .Lhandle_exit: - cmp $0, 0x20(%rbp) + cmpq $0, 0x20(%rbp) jne .Linvoke_userspace_handler .Lout: -- 2.28.0
