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

Message ID 20230819094332.8535-6-jo.vanbulck@cs.kuleuven.be (mailing list archive)
State New, archived
Headers show
Series selftests/sgx: Fix compilation errors | expand

Commit Message

Jo Van Bulck Aug. 19, 2023, 9:43 a.m. UTC
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@cs.kuleuven.be>
Reviewed-by: Kai Huang <kai.huang@intel.com>
---
 tools/testing/selftests/sgx/test_encl.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

Jarkko Sakkinen Aug. 22, 2023, 10:10 a.m. UTC | #1
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@cs.kuleuven.be>
> Reviewed-by: Kai Huang <kai.huang@intel.com>
> ---
>  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@kernel.org>

BR, Jarkko
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Patch

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;
 }