Re: [PATCH v3 5/9] selftests/sgx: Include memory clobber for inline asm in test enclave

[Jarkko Sakkinen]

On Sat Aug 19, 2023 at 12:43 PM EEST, Jo Van Bulck wrote:
> Add the "memory" clobber to the EMODPE and EACCEPT asm blocks to tell the
> compiler the assembly code accesses to the secinfo struct. This ensures
> the compiler treats the asm block as a memory barrier and the write to
> secinfo will be visible to ENCLU.
>
> Signed-off-by: Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx>
> Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
> ---
>  tools/testing/selftests/sgx/test_encl.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/sgx/test_encl.c b/tools/testing/selftests/sgx/test_encl.c
> index 7633fb7cb..b09550cb3 100644
> --- a/tools/testing/selftests/sgx/test_encl.c
> +++ b/tools/testing/selftests/sgx/test_encl.c
> @@ -24,10 +24,11 @@ static void do_encl_emodpe(void *_op)
>  	secinfo.flags = op->flags;
>  
>  	asm volatile(".byte 0x0f, 0x01, 0xd7"
> -				:
> +				: /* no outputs */
>  				: "a" (EMODPE),
>  				  "b" (&secinfo),
> -				  "c" (op->epc_addr));
> +				  "c" (op->epc_addr)
> +				: "memory" /* read from secinfo pointer */);
>  }
>  
>  static void do_encl_eaccept(void *_op)
> @@ -42,7 +43,8 @@ static void do_encl_eaccept(void *_op)
>  				: "=a" (rax)
>  				: "a" (EACCEPT),
>  				  "b" (&secinfo),
> -				  "c" (op->epc_addr));
> +				  "c" (op->epc_addr)
> +				: "memory" /* read from secinfo pointer */);
>  
>  	op->ret = rax;
>  }
> -- 
> 2.25.1

Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>

BR, Jarkko