[tip: x86/sgx] selftests/sgx: Include memory clobber for inline asm in test enclave

[tip-bot2 for Jo Van Bulck]

The following commit has been merged into the x86/sgx branch of tip:

Commit-ID:     853a57a43ebdb8c024160c1a0990bae85f4bcc2f
Gitweb:        https://git.kernel.org/tip/853a57a43ebdb8c024160c1a0990bae85f4bcc2f
Author:        Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx>
AuthorDate:    Thu, 05 Oct 2023 17:38:44 +02:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Fri, 08 Dec 2023 10:05:26 -08:00

selftests/sgx: Include memory clobber for inline asm in test enclave

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.

Fixes: 20404a808593 ("selftests/sgx: Add test for EPCM permission changes")
Signed-off-by: Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Link: https://lore.kernel.org/all/20231005153854.25566-4-jo.vanbulck%40cs.kuleuven.be
---
 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 c0d6397..ae791df 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;
 }